Relevant bibliographies by topics / Hydrophobic aggregation

Academic literature on the topic 'Hydrophobic aggregation'

Author: Grafiati
Published: 10 December 2022
Last updated: 29 January 2023

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Journal articles on the topic "Hydrophobic aggregation"

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Zhang, Xiao-ping, Yue-hua Hu, and Run-qing Liu. "Hydrophobic aggregation of ultrafine kaolinite." Journal of Central South University of Technology 15, no. 3 (June 2008): 368–72. http://dx.doi.org/10.1007/s11771-008-0069-9.

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Nogueira, Francielle Câmara, Otávia Martins Silva Rodrigues, Stephânia da Consolação Silva Nogueira, and Carlos Alberto Pereira. "HYDROPHOBIC AGGREGATION OF GALENA FINE PARTICLES." Brazilian Journal of Development 6, no. 7 (2020): 53581–90. http://dx.doi.org/10.34117/bjdv6n7-849.

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Bandyopadhyay, Sanjoy, John C. Shelley, Mounir Tarek, Preston B. Moore, and Michael L. Klein. "Surfactant Aggregation at a Hydrophobic Surface." Journal of Physical Chemistry B 102, no. 33 (August 1998): 6318–22. http://dx.doi.org/10.1021/jp982051c.

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Zhao, Jian-xi, Fen Liu, and Dan-hua Xie. "Vesicle aggregation based on hydrophobic interactions." Colloid and Polymer Science 293, no. 12 (August 27, 2015): 3633–39. http://dx.doi.org/10.1007/s00396-015-3747-9.

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López-León, Teresa, Juan Luis Ortega-Vinuesa, and Delfina Bastos-González. "Ion-Specific Aggregation of Hydrophobic Particles." ChemPhysChem 13, no. 9 (May 3, 2012): 2382–91. http://dx.doi.org/10.1002/cphc.201200120.

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Nomula, Srinivas, and Stuart L. Cooper. "Hydrophobic Aggregation in Polyurethane Ionomer Solutions." Journal of Colloid and Interface Science 205, no. 2 (September 1998): 331–39. http://dx.doi.org/10.1006/jcis.1998.5623.

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Chen, Jun, Fanfei Min, Lingyun Liu, Chenliang Peng, and Fangqin Lu. "Hydrophobic aggregation of fine particles in high muddied coal slurry water." Water Science and Technology 73, no. 3 (October 12, 2015): 501–10. http://dx.doi.org/10.2166/wst.2015.513.

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The hydrophobic aggregation of fine particles in high muddied coal slurry water in the presence of four quaternary ammonium salts of 1231(dodecyl trimethyl ammonium chloride), 1431(tetradecyl trimethyl ammonium chloride), 1631(cetyl trimethyl ammonium chloride) and 1831(octadecyl trimethyl ammonium chloride) was investigated through the measurement of contact angles, zeta potentials, aggregation observation, adsorption and sedimentation. The results show that quaternary ammonium salts can enhance the hydrophobicity and reduce the electronegativity of particle surface, and thus induce a strong hydrophobic aggregation of slurry fine particles which promotes the settlement of coal slurry water. The adsorption of quaternary ammonium salts on slurry particles increases with the increase of alkyl chain length and reagent dosage, and will reach equilibrium when the dosage reaches a certain value. Weak alkaline conditions also can promote quaternary ammonium salts to be adsorbed on the coal slurry fine particles. In addition, reasonable energy input and a chemical environment of weak alkaline solution are conducive to hydrophobic aggregation settlement of high muddied coal slurry water with quaternary ammonium salts. The main mechanism of hydrophobic aggregation of coal slurry particles with quaternary ammonium salts is ‘adsorption charge neutralization’ and hydrophobic interaction.
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Thiebault, F., and J. Coulon. "Influence of carbon source and surface hydrophobicity on the aggregation of the yeastKluyveromyces bulgaricus." Canadian Journal of Microbiology 51, no. 1 (January 1, 2005): 91–94. http://dx.doi.org/10.1139/w04-106.

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Aggregation of the yeast Kluyveromyces bulgaricus is mediated by the galactose-specific lectin KbCWL1. This lectin contains hydrophobic amino acids and its activity is calcium dependent. A specific fluorescent probe, 1-anilinonaphthalene-8-sulfonic acid in the free acid form (ANS; Sigma Chemical Co., St. Louis, Missouri), was used to study the hydrophobic areas on the cellular surface of K. bulgaricus. Changes in surface hydrophobicity during the growth and aggregation of yeast cells were studied. Surface hydrophobicity increased during growth and depended on the amount of yeast cells in the culture medium. During growth, the size of the hydrophobic areas on the cell surface was measured using ANS and was found to increase with the percentage of flocculating yeasts. Our results strongly suggest that the hydrophobic areas of the cell walls of yeast cells are involved in the aggregation of K. bulgaricus.Key words: aggregation, carbon source, fluorescence probe, hydrophobicity, yeast.
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March, David, Valentino Bianco, and Giancarlo Franzese. "Protein Unfolding and Aggregation near a Hydrophobic Interface." Polymers 13, no. 1 (January 3, 2021): 156. http://dx.doi.org/10.3390/polym13010156.

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The behavior of proteins near interfaces is relevant for biological and medical purposes. Previous results in bulk show that, when the protein concentration increases, the proteins unfold and, at higher concentrations, aggregate. Here, we study how the presence of a hydrophobic surface affects this course of events. To this goal, we use a coarse-grained model of proteins and study by simulations their folding and aggregation near an ideal hydrophobic surface in an aqueous environment by changing parameters such as temperature and hydrophobic strength, related, e.g., to ions concentration. We show that the hydrophobic surface, as well as the other parameters, affect both the protein unfolding and aggregation. We discuss the interpretation of these results and define future lines for further analysis, with their possible implications in neurodegenerative diseases.
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Soto, Patricia, Andrij Baumketner, and Joan-Emma Shea. "Aggregation of polyalanine in a hydrophobic environment." Journal of Chemical Physics 124, no. 13 (April 7, 2006): 134904. http://dx.doi.org/10.1063/1.2179803.

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Dissertations / Theses on the topic "Hydrophobic aggregation"

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Lazar, Laurentiu. "Controlled aggregation of polymer latices and encapsulation of hydrophobic substances in polymer clusters." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq35969.pdf.

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2

Boglaienko, Daria. "Capture and Densification of Floating Hydrophobic Liquids by Natural Granular Materials." FIU Digital Commons, 2017. http://digitalcommons.fiu.edu/etd/3261.

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Densification and submergence of floating crude oil is proposed as a novel oil spills treatment method. Surface application of dry granular materials (e.g., quartz sand, limestone) on top of a floating oil layer increases the density of the floating oil phase/granule mixture and leads to formation of relatively large and stable aggregates with significant amounts of captured oil. The aggregates separate from the floating hydrophobic phase and settle by gravity. Implementation of this method will reduce the impact radius of a spill and its mobility, preventing direct contamination of beaches, coastal flora and fauna. The major objective of this research was to examine interactions of particles with hydrophobic liquid-water interface from different perspectives. The important characteristics of the process, such as oil removal efficiencies, optimal particle-to-oil ratios and particle size ranges, were experimentally defined. A series of experiments was conducted to investigate aggregation and dissolution rate constants of the submerged hydrophobic liquids in salt water and deionized water, and to study the impact of the surface porosity of the granular particles on oil capture efficiencies. In addition to crude oil (South Louisiana crude, MC 252), aggregation volumes of quartz sand with other hydrophobic liquids (alkanes and aromatics) were analyzed in relation to wetting characteristics and physical properties of the liquids. A classification of the main types of oil-particle aggregates was developed based on the formation characteristics of the aggregates. Moreover, under specific conditions, depending on the application rates of the granular materials, unique interactions of the particles with the hydrophobic liquid-water interface were observed and defined (bowl formation and roping). These concepts can be utilized to control surface mobility of floating oils, especially during the initial stages of an oil spill, while the oil layer is intact, and when other treatment methods may not be suitable near coastal areas, where transport of floating oils can significantly impact coastal ecosystems.
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Benson, Sven P. [Verfasser], and Jürgen [Akademischer Betreuer] Pleiss. "Molecular modeling of hydrophobic effects in complex biomolecular systems : from simple mixtures to protein-interface aggregation / Sven P. Benson. Betreuer: Jürgen Pleiss." Stuttgart : Universitätsbibliothek der Universität Stuttgart, 2015. http://d-nb.info/1066646015/34.

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Banerjee, Amartya. "Beta-Peptide Helices As Transmembrane Domains: Aggregation, Recognition and Lipid-Peptide Interaction." Doctoral thesis, Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2018. http://hdl.handle.net/11858/00-1735-0000-002E-E56E-5.

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প্লাজমা ঝিল্লি একটি প্রাথমিক কার্যকরী ইউনিট হিসাবে একটি কোষ দক্ষ কার্যকরী জন্য অপরিহার্য হিসাবে গণ্য করা হয়। এই ঝিল্লিগুলি বহিরাগত কোষের কোষের ভিতরের অংশটিকে পৃথক করে এবং পাশাপাশি এটি জুড়ে চলমান নিয়ন্ত্রনের বাধা হিসাবে কাজ করে। প্লাজমা ঝিল্লিগুলি বিভিন্ন বিভিন্ন উপাদানের সাথে গঠিত, তবে সবার মধ্যে, ঝিল্লি প্রোটিনগুলিকে বৈজ্ঞানিক সম্প্রদায়ের দ্বারা প্লাজমা ঝিল্লির প্রধান কাঠামোগত এবং কার্যকরী স্তম্ভগুলির মধ্যে সর্বসম্মতিক্রমে গ্রহণ করা হয়। বৈজ্ঞানিক গবেষণায়, ঝিল্লী প্রোটিনগুলির কার্যকারিতা গুরুতর রোগের জন্য দায়ী বলে মনে করা হয়েছে। সুতরাং, এটি কৃত্রিম ট্রান্সমেম্রেন প্রোটিন ডোমেনগুলি ডিজাইন এবং বিকাশের জন্য একটি দুর্দান্ত বৈজ্ঞানিক আগ্রহ রয়েছে যা স্বাভাবিকের ত্রুটিগুলির সমাধান করতে সক্ষম। এই প্রোটিন ডোমেনগুলির ভাঁজ গঠন এবং ট্রান্সমেমব্রেন গতিবিদ্যা পিছনে আণবিক শক্তি এবং অন্যান্য পদার্থ-রাসায়নিক প্রক্রিয়াগুলি বোঝা হালনাগাদকৃত কৃত্রিম ট্রান্সমিম্ব্রেন প্রোটিন ডোমেনগুলি বিকাশের প্রক্রিয়ার অবিচ্ছেদ্য অংশ। গত দুই দশক ধরে, বিটা-পেপটাইডগুলি আরও প্রতিশ্রুতিশীল পেপটিডোমিম্যাটিক মোটিফগুলির মধ্যে একটি হিসাবে বিবর্তন হয়েছে। প্রোটিলাইটিক হ্রাসের বিরুদ্ধে অসাধারণ স্থিতিশীলতা এবং স্থিতিশীল হেলিকাল সেকেন্ডারি স্ট্রাকচার যেমন 14 -12- এবং বিকল্প 10 / 1২-হেলিসেসগুলি 4-6 এমিনো এসিডগুলি তৈরি করার ক্ষমতা, এর পিছনে দুটি প্রধান কারণ peptidomimetics মধ্যে β-peptides এর বিমোচন এন্ট্রি। অন্যান্য গুরুত্বপূর্ণ প্যারামিটারগুলির পাশাপাশি পেপটাইডের হেলিক্যাল ম্যাক্রো-ডিপোল মুহূর্তটি ট্রান্সমেম্রেন সন্নিবেশ এবং বিস্তারের ক্ষেত্রে গুরুত্বপূর্ণ ভূমিকা বলে মনে করা হয়। পেপটাইডগুলির হেলিক্যাল ম্যাক্রো-ডিপোল মুহূর্তের সরাসরি পরীক্ষামূলক সিদ্ধান্ত অত্যন্ত চ্যালেঞ্জিং হচ্ছে, হেলিক্যাল ম্যাক্রো-ডিপোল মুহূর্তের সম্ভাব্য প্রভাবগুলি কেবলমাত্র তাত্ত্বিকভাবে প্রস্তাবিত। অতএব, এই থিসিসের প্রধান উদ্দেশ্যগুলি ট্রান্সমেম্রেন সন্নিবেশ এবং বিস্তারের পাশাপাশি পরোক্ষ পরীক্ষার মাধ্যমে সেলুলার উপসর্গের মধ্যে হেলিক্যাল ম্যাক্রো-ডিপোল মুহূর্তের সম্ভাব্য ভূমিকা পালন করা। সাধারণভাবে, β-peptides নির্দিষ্ট হেলিক্যাল ম্যাক্রো-ডিপোল মুহূর্ত থাকে তবে প্রাকৃতিকভাবে ঘটমান α-peptide analogues এর তুলনায় বিপরীত দিকে থাকে। ধারণাটি হল বিটা-পেপটাইডের একটি ধরণের সনাক্তকরণ এবং সংশ্লেষ করা যার প্রায় মোট কোনও হেলিক্যাল ম্যাক্রো-ডিপোল মুহূর্ত নেই এবং β-peptides সহ এবং হেলিক্যাল ম্যাক্রো-ডিপোল ছাড়া ট্রান্সমেমব্রেন সন্নিবেশ স্টাডিজগুলি অন্যান্য সমস্ত পরামিতিগুলিকে ধ্রুবক রাখে। ক্ষেত্রে, তারা ঝিল্লি সন্নিবেশের জন্য কোন ডিফারেনশিয়াল ক্ষমতা প্রদর্শন করে, এটি পরীক্ষামূলকভাবে নিজ নিজ পদার্থ-রাসায়নিক ঘটনায় হেলিক্যাল ম্যাক্রো-ডিপোলের ভূমিকা নির্দেশ করবে। ব্যাপক গবেষণার পরে, বিকল্প β3 / β2-amino অ্যাসিডের সংযোজিত বিকল্প 10/12-হেলিকাল β-peptides তাদের অনন্য রূপান্তরিত অভিযোজন কারণে সামগ্রিক অলঙ্কৃত হেলিক্যাল ম্যাক্রো-ডিপোল পাওয়া যায় নি। অতএব, বিভিন্ন ধরণের β-peptides সহ 14-, 12- এবং বিকল্প 10/12-হেলিক্যাল পেপটাইড তুলনীয় ট্রান্সমেম্রেন দৈর্ঘ্য এবং ক্রম সহ বিভিন্ন সিন্থেটিক কৌশল মিশ্রিত করে সংশ্লেষিত করার পরিকল্পনা করা হয়েছে, যেমন মাইক্রোওয়েভ সহায়তায় ম্যানুয়াল SPPS, অ- মাইক্রোওয়েভ সহায়তায় ম্যানুয়াল SPPS, এবং ফ্লুরোস-ট্যাগ সংযুক্ত তরল ফেজ পেপটাইড সংশ্লেষণ। পরের ধাপে, পেপাইডাইডগুলির ট্রান্সমেমব্রেন সন্নিবেশ হাইড্রোফোবিক মাইক্রো-এনভায়রনমেন্ট সংবেদনশীল ট্রপ-ফ্লোরেসেন্স স্পেকট্রোস্কপি দ্বারা পরীক্ষা করা হবে। তিনটি ভিন্ন লিপিড, ডিএলপিসি / ডিএমপিসি / পিওপিসি এর একই গোষ্ঠীটি বিভিন্ন 14-, 12-এবং বিকল্প 10/12-হেলিক্যাল পেপাইডাইডের জন্য তুলনামূলক দৈর্ঘ্যের সাথে এইভাবে নির্বাচিত হয় যে নেতিবাচক হাইড্রোফোবিক মেলেম্যাচ ধীরে ধীরে একটি প্রায় পুরোপুরি hydrophobic ম্যাচিং পরিস্থিতি। এটি ভালভাবে জানা গেছে যে নেতিবাচক হাইড্রোফোবিক মেলেম্যাচের থ্রেশহোল্ড মানের উপরে ট্রান্সমেমব্রেন সন্নিবেশ সম্ভব নয়। অন্য দিকে, ইথানল মত শর্ট চেইন অ্যালকোহল, অ্যাসিড চেইন interdigitating দ্বারা লিপিড ঝিল্লি বেধ কমানোর একটি উচ্চারণ প্রভাব ভোগ করতে পরিচিত। অতএব, ETOH এর ক্রমবর্ধমান বৃদ্ধি ঘনত্বটি বিভিন্ন পেপটাইডের জন্য ব্যবহার করা হবে এবং একই লিপিডের জন্য একই পেপাইডাইডগুলির জন্য প্রতিটি পেপাইডাইডের জন্য প্রয়োজনীয় ন্যূনতম থ্রেশহোল্ড ঘনত্বের অনুরূপ নেতিবাচক হাইড্রোফোবিক মেলেম্যাচটি সাবধানে ন্যূনতম ক্ষতিপূরণ নেতিবাচক ক্ষতিপূরণ হিসাবে পর্যবেক্ষণ করা হবে। Trp-fluorescence বর্ণালী ক্রিয়ার সাহায্যে সফল ট্রান্সমেমব্রেন সন্নিবেশের জন্য অপরিসীম প্রয়োজন। এই পরীক্ষামূলক ফলাফল থেকে, এই সিদ্ধান্তে পৌঁছানো সম্ভব হবে যে পেপাইডাইডটি ETOH- এর আরো কম ঘনত্বের প্রয়োজন, যা নেতিবাচক মেলামেশের উচ্চতর ক্ষতিপূরণ, লিপিড ঝিল্লিতে পুনর্গঠন করতে সফলভাবে, ট্রান্সমেম্রেন সন্নিবেশ এবং বিস্তারের দিকে কম প্রবণ। ক্ষেত্রে, হেলিক্যাল ম্যাক্রো-ডিপোল মুহূর্তের সাথে এবং পেপাইডাইডগুলি এই আচরণের প্রতি কোনও ডিফারেনশিয়াল প্রবণতা প্রদর্শন করে, এটি পরোক্ষভাবে নির্দেশ করে এবং পরীক্ষামূলকভাবে ট্রান্সমেম্রেন সন্নিবেশ এবং স্প্যানিংয়ের মধ্যে হেলিক্যাল ম্যাক্রো-ডিপোল মুহূর্তের উল্লেখযোগ্য ভূমিকা যাচাই করবে (যেহেতু পেপাইডাইডগুলির মধ্যে প্রধান পার্থক্য হল হেলিক্যাল ম্যাক্রো-ডিপোল মুহূর্তের উপস্থিতি এবং অনুপস্থিতি)। তাছাড়া, লিপিড পরিবেশের অভ্যন্তরে যখন চারিত্রিক হেলিক্যাল প্যাটার্নটি রক্ষণাবেক্ষণ করা হয় কিনা তা ব্যাখ্যা করার জন্য, বিভিন্ন পেপাইডাইডগুলির দ্বিতীয় হেলিক্যাল কাঠামো সমাধান এবং পাশাপাশি অভ্যন্তরীণ লিপিড ভিসিক্যালগুলিতে নির্ধারণ করা হবে। তাপমাত্রা নির্ভর সিডি-স্পেকট্রসকপি দ্বারা সমাধান হিসাবে তুলনায় লিপিড vesicles ভিতরে যখন 14- এবং 10/12-হেলিক্যাল পেপটাইড স্থিতিশীলতা পরিবর্তন করা হয় কিনা তা পরীক্ষা করা হবে। হেলিক্যাল ম্যাক্রো-ডিপোল মুহূর্তটি সমাধান বা অভ্যন্তরীণ লিপিড vesicles মধ্যে সেকেন্ডারি হেলিকাল কাঠামো স্থিতিশীল করতে কোনো প্রভাব আছে কিনা তাও ইঙ্গিত করে। অবশেষে, 6-অ্যামিনো অ্যাসিড দীর্ঘ শৃঙ্খল চেইন 14-হেলিকাল এবং 10 / 1২-হেলিকাল 5 (6) -ফ্যাম সংযুক্ত পেপটাইডগুলি মানব ব্রোঞ্চিয়াল এডেনোকার্কিনোমা সেল লাইন A549 ব্যবহার করে সেলুলার আপটেক স্টাডিজের জন্য সংশ্লেষিত হয়। প্রথমটি ক্লোজোজেনিক অ্যাস এবং এমটিটি-অ্যাস দ্বারা একই কোষ লাইনে সাইটোটক্সিসটিটি পরীক্ষা করা হয়। যদি 1 μM ঘনত্ব না হওয়া পর্যন্ত অ-সাইটোটক্সিক পাওয়া যায়, তাহলে ফ্লোরোসেন্স অ্যাক্টিভেটেড সেল সোর্সিং (FACS) দ্বারা পরিমাণগত সেলুলার উত্তোলনের দক্ষতার দিকে আরও গবেষণা 14- এবং বিকল্প 10/12-হেলিক্যাল পেপাইডাইডগুলি হয়। একটি সুপরিচিত কোষ তীক্ষ্ণ পেপটাইড, এইচআইভি -1 ট্যাট, একটি রেফারেন্স মান হিসাবে ব্যবহৃত হয়। দুটি লক্ষ্য পেপটাইডগুলির মধ্যে সেলুলার আপটেক কার্যকারিতাগুলির মধ্যে কোন পার্থক্য পরীক্ষামূলকভাবে নির্দেশ করবে যে হেলিক্যাল ম্যাক্রো-ডিপোল মুহূর্তটি ট্রান্সমেমব্রেন সন্নিবেশ এবং বিস্তারকে প্রভাবিত করে না তবে সেলুলার অ্যাকটেককেও নিয়ন্ত্রণ করে। FACS ফলাফলগুলি নিশ্চিত এবং সমর্থন করার জন্য, পেপাইডাইডগুলি কন confocal লেজার স্ক্যানিং ফ্লুরোসেন্স মাইক্রোস্কপি অধীনে দৃশ্যমান হবে। মাইক্রোস্কোপি ইমেজিং প্রদর্শন করবে যে টার্গেট পেপাইডগুলি প্রকৃতপক্ষে সেল অনুপ্রবেশের মাধ্যমে অভ্যন্তরীণ হয় কিনা বা শুধুমাত্র ঝিল্লিতে আটকা পড়ে। উপরন্তু, যদি কোন লক্ষ্য β-peptides উল্লেখযোগ্য কোষ অনুপ্রবেশ ক্ষমতা পাওয়া যায়, এটি নতুনত্ব, হাইড্রোফোবিক, uncharged সেল ভেতরে পেপটাইড (সিপিপি) প্রার্থী যারা proteases উপস্থিতি স্থিতিশীল স্থিতিশীল দিকে একটি নতুন বর্ণমালা খুলতে হবে। অবশেষে, এই সমস্ত গবেষণাগুলি পরীক্ষামূলকভাবে ট্রান্সমেম্রেন সন্নিবেশ, বিস্তার এবং সেলুলার উপসাগরীয় অঞ্চলে ঝিল্লি প্রোটিন ডোমেনের হেলিক্যাল ম্যাক্রো-ডিপোল মুহূর্তের নিয়ন্ত্রক প্রভাবের উপর আলোকপাত করবে। এই তথ্যটি এই গুরুত্বপূর্ণ পদার্থ-রাসায়নিক ঘটনাগুলিতে পেপটাইড হেলিক্যাল ম্যাক্রো-ডিপোল মুহূর্তের প্রভাবকে মোকাবেলা করবে এবং β-পেপটাইড ভিত্তিক মডেল ট্রান্সমেম্রেন ডোমেন সিস্টেমগুলি পাশাপাশি β-পেপটাইড-ভিত্তিক নতুন প্রজন্মের কোষ তীব্র পেপটাইডগুলি ডিজাইনে সহায়তা করবে।
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5

Schneider, Alexander. "Modellierung und Visualisierung von Systemen zur Beschreibung der intra- und intermolekularen Wechselwirkungen in hydrophoben Peptiden." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-155164.

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Die vorliegende Arbeit beschäftigt sich mit der Untersuchung und Beschreibung der Eigenschaften der synthetischen Dekapeptide Cetrorelix und Ozarelix durch analytische Methoden und computergestützte Modellierung. Diese Moleküle sind hydrophobe, aggregierende Antagonisten des Gonadotropin-Releasing-Hormons (GnRH). Zusätzlich wurden amyloidbildende Peptidstrukturen als Modelle für die Assoziationsprozesse in hydrophoben Peptiden untersucht und visualisiert. Die intrinsische Fluoreszenz der GnRH-Antagonisten und zusätzlich der Peptide Teverelix und D-Phe6-GnRH sowie von verkürzten Fragmenten des Cetrorelix wurde untersucht. Ein Strukturmodell für die Beschreibung der Aggregation der Dekapeptide wurde erarbeitet. Der Aufbau eines Rechenclusters durch das Einbinden der Computer am Lehrstuhl in ein Linux-System zur Verteilung von Rechenprozessen über das Netzwerk ermöglichte die Bereitstellung der notwendigen Leistung zur Realisierung der Berechnungen. Es wurden Werkzeuge zur Modellierung der solvatisierten Aggregate von Peptiden ohne eindeutige Vorzugsstruktur programmiert und in ein Docking-System für beliebige Moleküle eingebunden. Verwendet wurde das Kraftfeld MMFF94 mit einer Erweiterung durch ein Verfahren zur dynamischen Berechnung von Partialladungen in Molekülstrukturen. Solvatisierte Aggregate der Dekapeptide und von bekannten amyloidbildenden Strukturen wurden modelliert (Docking). Berechnet wurden als aggregierend beschriebene Sequenzen und entsprechende Vergleichsstrukturen des Calcitonins, des Insel-Amyloid-Polypeptides, des beta2-Mikroglobulins, des Amyloid-beta-Proteins, des Lactoferrins und weitere Modellpeptide. Die wesentlichen Wechselwirkungen während der Aggregation konnten schließlich anhand von Dynamik-Simulationen der faltblattartigen Dimere des Cetrorelix und Ozarelix beschrieben werden. So wurden die Prozesse der hydrophoben Assoziation und Stabilisierung durch Wasserstoffbrücken von Peptiden veranschaulicht und auf molekularer Ebene erfolgreich analysiert. Die Visualisierung der erhaltenen Modellierungsergebnisse erfolgt durch die Darstellung der Strukturen und Dynamik-Simulationen als interaktive 3D-Modelle in einem für diese Arbeit aufgebauten Internetauftritt
This work discusses the analysis of the aggregation properties of the gonadotropin releasing hormone antagonists Cetrorelix, Teverelix, Ozarelix and of small amyloid forming model peptides by analytical fluorescence spectroscopy and molecular modelling. A high performance linux compute cluster was developed for calculation of molecular structures. Solvated aggregate clusters of peptides without defined secondary structure were modelled by molecular mechanics methods (forcefield mmff94) in combination with an advanced charge equilibration and docking technique. Molecular dynamics of solvated peptide dimers were implemented and the role of hydrophic association and hydrogen bond formation in hydrophobic peptide aggregates was explained. Finally, an aggregation model for the directed association of hydrophobic peptides is presented. The modelling results, 3d structures and dynamic simulations are visualized in an interactive web material
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6

Kjellin, Mikael. "Structure-Property Relationships of Surfactants at Interfaces and Polyelectrolyte-Surfactant Aggregates." Doctoral thesis, KTH, Chemistry, 2002. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3299.

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The first part of this thesis is concerned with thestructure-property relationships in nonionic surfactantsystems. The main aim was to investigate how the surfactantstructure influences the adsorption at interfaces andinteractions between surfactant coated interfaces.Particularly, the effect of the structure of the surfactantheadgroups was investigated. These were sugar-based headgroupwith varying size and flexibility and poly(ethylene oxide)based headgroups with or without an additional amide or estergroup. The hydrophobic part of the surfactant consisted mostlyof straight alkyl chains, except for one type of poly(ethyleneoxide) based surfactant with a dehydroabietic hydrophobe.

The main technique that was used is the surface forcetechnique, with which the forces acting between two adsorbedsurfactant layers on hydrophilic or hydrophobic surfaces can bemeasured. These forces are important for e.g. the stability ofdispersions. The hydrophilic surfaces employed were glass andmica, whereas the hydrophobic surfaces were silanized glass andhydrophobized mica. The adsorption behavior on hydrophilicsurfaces is highly dependent on the type of headgroup andsurface, whereas similar results were obtained on the two typesof hydrophobic surfaces. To better understand how the surfaceforces are affected by the surfactant structure, measurementsof adsorbed amount and theoretical mean-field latticecalculations were carried out. The results show that the sugarsurfactant layers and poly(ethylene oxide) surfactant layersgive rise to very different surface forces, but that the forcesare more similar within each group. The structure-propertyrelationships for many other physical properties have beenstudied as well. These include equilibrium and dynamicadsorption at the liquid-vapor interface, micelle size, micelledynamics, and wetting.

The second part in this thesis is about the aggregationbetween cationic polyelectrolytes and an anionic surfactant.The surface force technique was used to study the adsorption ofa low charged cationic polyelectrolyte on mica, and theaggregation between the adsorbed polyelectrolyte with theanionic surfactant. The aggregation in bulk was studied withturbidimetry, small angle neutron scattering (SANS), and smallangle x-ray scattering (SAXS). An internal hexagonal aggregatestructure was found for some of the bulk aggregates.

Keywords:nonionic surfactant, sugar surfactant,poly(ethylene oxide), amide, ester, polyelectrolyte, SDS,hydrophobic surface, glass surface, mica, adsorption,aggregation, micelle size, surface forces, wetting, dynamicsurface tension, NMR, TRFQ, SANS, SAXS, mean-field latticecalculations.

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Book chapters on the topic "Hydrophobic aggregation"

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Song, Shaoxian, and Shouci Lu. "The Hydrophobic Aggregation Flotation of Rutile Particles." In Advances in Fine Particles Processing, 279–83. Boston, MA: Springer US, 1990. http://dx.doi.org/10.1007/978-1-4684-7959-1_23.

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Frank, Curtis W., David J. Hemker, and Hideko T. Oyama. "Hydrophobic Effects on Complexation and Aggregation in Water-Soluble Polymers." In ACS Symposium Series, 303–19. Washington, DC: American Chemical Society, 1991. http://dx.doi.org/10.1021/bk-1991-0467.ch020.

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Paschek, Dietmar, Thomas Engels, Wolfgang v. Rybinski, and Alfons Geiger. "Hydrophobic Aggregation of Nonionic Surfactants in Aqueous Solution: An MD Simulation Study." In Scientific Computing in Chemical Engineering II, 126–33. Berlin, Heidelberg: Springer Berlin Heidelberg, 1999. http://dx.doi.org/10.1007/978-3-642-60185-9_13.

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"Chapter 8 Hydrophobic flocculation and hydrophobic aggregation separation (HAS)." In Studies in Interface Science, 415–96. Elsevier, 2005. http://dx.doi.org/10.1016/s1383-7303(05)80009-2.

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Shouci, Lu, and Dai Zongfu. "Separation of ultrafine mineral particles by hydrophobic aggregation methods." In Production and Processing of Fine Particles, 317–27. Elsevier, 1988. http://dx.doi.org/10.1016/b978-0-08-036448-3.50038-4.

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Aveyard, Bob. "What are surfactants?" In Surfactants, 3–16. Oxford University Press, 2019. http://dx.doi.org/10.1093/oso/9780198828600.003.0001.

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Surface active agents (surfactants) are molecules or ions with a dual nature. One or more moieties in a surfactant are ‘water-hating’ (hydrophobic) ‘tail’ groups and one or more are ‘water-liking’ (hydrophilic) ‘head’ groups. Surfactants adsorb from aqueous (or other) solution to various interfaces and in sufficiently concentrated solutions simultaneously aggregate into micelles or other structures. The tail(s) are frequently hydrocarbon or fluorocarbon groups and the head(s) can be polar or ionic. Adsorption and aggregation are often driven by removal of tails from water to an air/water or nonpolar oil/water interface, or to the interior of surfactant aggregates. The ability to adsorb and to aggregate in solution makes surfactants invaluable in industry, in nature, and in the home. Here a brief description is given of the classes of surfactant most commonly encountered, and their usefulness is mentioned. Forward reference is made to appropriate chapters where material is covered in more detail.
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Kumar Mitra, Rajib, and Dipak Kumar Palit. "Probing Biological Water Using Terahertz Absorption Spectroscopy." In Terahertz Technology [Working Title]. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.97603.

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Hydrogen bonding properties of water molecules, which are confined in microcavities of biological interfaces, are significantly different from those of bulk water and drive most of the complex biological processes. While NMR, X-ray and UV–vis-IR spectroscopic techniques have been found inadequate for describing the dynamics of the thick (20–40 Å) sheath of hydration layer around biomolecules, recently developed THz spectroscopy has emerged as a powerful technique to directly probe the collective dynamics of hydrogen bonds in the hydration layer, which control all important functions of the biomolecules in life. Both laser and accelerator-based THz sources are intense enough to penetrate up to about 100 μm thick water samples, which makes THz transmission and/or dielectric relaxation measurements possible in aqueous solutions. These measurements provide valuable information about the rattling and rotational motions of hydrated ions, making, breaking and rearrangement of hydrogen bonds in hydration layer as well as hydrophilic and hydrophobic interactions between biomolecule and water. THz spectroscopy has also been successfully applied to study the effect of modulation of the physical conditions, like temperature, pH, concentration of proteins and chemical additives, on the structure and dynamics of hydration layer. THz spectroscopy has also been applied to study the processes of denaturation, unfolding and aggregation of biomolecules.
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Shevchenko, Valery V., Alexandr V. Stryutsky, Mariana A. Gumenna, Nina S. Klimenko, and Valeri V. Klepko. "Synthesis, structure and properties of oligomeric ionic liquids of highly branched structure and special features of their self-arrangement." In NEW FUNCTIONAL SUBSTANCES AND MATERIALS FOR CHEMICAL ENGINEERING, 199–209. PH “Akademperiodyka”, 2021. http://dx.doi.org/10.15407/akademperiodyka.444.199.

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Synthesis, features of structural organization and behavior in aqueous solution of amphiphilic reactive aprotic cationic oligomeric ionic liquids obtained on the basis of a mixture of oligomeric amino- and hydroxyl-containing silsesquioxanes were considered. The dependence of the glass transition temperature, the value of ionic conductivity, self-organization in dilute aqueous solutions and the ζ-potential on the length of the alkyl substituent near the quaternary nitrogen atom in the composition of the synthesized compounds was shown. It was found that quaternization of the tertiary nitrogen atom of the starting oligomer causes a sharp decrease in the glass transition temperature. The value of the latter increases with an increase in the length of the hydrophobic alkyl fragments due to their association. In this case the ionic conductivity under anhydrous conditions decreases and at temperatures above 100°C drops by almost an order of magnitude. The maximum conductivity was reached for the oligomeric ionic liquid with the short alkyl chain and its value was 10-3 S/cm at 120oC. In dilute aqueous solutions the synthesized oligomeric ionic liquids with the short alkyl chain form aggregates with an average size of 100 nm while increasing the length of the alkyl chain prevents aggregation of silsesquioxane nuclei and leads to formation of unimolecular micelles with an average size of 3 nm
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Conference papers on the topic "Hydrophobic aggregation"

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Torres, J. R., G. D. Jay, M. L. Warman, and K. S. Kim. "Adhesive Force Reduction and Molecular Aggregation on Lubricin-Coated Contacts." In World Tribology Congress III. ASMEDC, 2005. http://dx.doi.org/10.1115/wtc2005-64016.

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The atomic force microscope (AFM) was employed in dry conditions in order to test the surface modifying ability of lubricin. The present work shows that lubricin forms independent aggregates, which coalesce once a threshold concentration is reached providing uniform coating of a hydrophobic surface.
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Lv, Xiaoxing, Kai Yue, Qingchun Lei, and Xinxin Zhang. "A Molecular Dynamics Simulation of Au Nanoparticles Aggregation in Ionic Solution." In ASME 2013 Heat Transfer Summer Conference collocated with the ASME 2013 7th International Conference on Energy Sustainability and the ASME 2013 11th International Conference on Fuel Cell Science, Engineering and Technology. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/ht2013-17373.

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Due to unique and tunable optical properties, gold nanoparticles (GNPs) are becoming more widely used in biological and biomedical applications. However, nanoparticles in fluid tend to lose the specific function because of aggregation in the transport process of use. Therefore, it is necessary to investigate the aggregation behavior for having a good understanding of aggregation mechanism and inhibiting GNPs aggregation. A MD simulation in this study was performed to investigate the physical aggregation behavior of GNPs in biological media. By analyzing the aggregation proportion of GNPs in different conditions and the changes in center-to-center distance between GNPs with the time, the effects of the hydrophilic/hydrophobic characteristics of GNPs, velocity of ionic solution, size of GNPs, initial distance between two GNPs, and surface charge were discussed. The simulation results indicate that the aggregation proportion of GNPs with hydrophilic modification is 62.5%, which is less than 87.5% in the model without surface modification, while the final aggregation proportion of GNPs with hydrophobic modification increased to 100%. When the velocity of the NaCl aqueous solution is 0.1 m/s, the final aggregation proportion of GNPs is 87.5%, which is similar with the model without flow velocity. But the final aggregation proportion increased to 100% when the velocity is 1m/s. Under the same conditions, the GNPs of 1 nm diameter aggregated at 0.16 ns, but the GNPs of 1.5 nm and 2 nm diameters aggregated at 0.6 ns and 0.8 ns, respectively. For the GNPs of 1 nm diameter, the GNPs can only get close to each other very slowly when the distance between the surfaces of GNPs is within the range of 0.8–1.2 nm, whereas the GNPs will aggregate quickly when the distance is close enough. GNPs can retain stable by modified with appropriate negative charge. But ions in the solution will weaken this effect.
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Jamaluddin, Moideen P. "PLATELET AGGREGATION DOES NOT CONFORM TO SIMPLE PARTICLE COLLISION THEORY." In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1644550.

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Platelet aggregation kinetics, according to the particle collision theory, generally assumed to apply, ought to conform to a second order type of rate law. But published data on the time-course of ADP-induced single platelet recruitment into aggregates were found not to do so and to lead to abnormal second order rate constants much larger than even their theoretical upper bounds. The data were, instead, found to fit a first order type of rate law rather well with rate constants in the range of 0.04 - 0.27 s-1. These results were confirmed in our laboratory employing gelfiltered calf platelets. Thus a mechanism much more complex than hithertofore recognized, is operative. The following kinetic scheme was formulated on the basis of information gleaned from the literature.where P is the nonaggregable, discoid platelet, A the agonist, P* an aggregable platelet form with membranous protrusions, and P** another aggregable platelet form with pseudopods. Taking into account the relative magnitudes of the k*s and assuming aggregation to be driven by hydrophobic interaction between complementary surfaces of P* and P** species, a rate equation was derived for aggregation. The kinetic scheme and the rate equation could account for the apparent first order rate law and other empirical observations in the literature.
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Homem-de-Mello, P., E. A. Takeuchi, E. M. C. de Lima, F. C. T. Antonio, G. S. Mol, J. R. de Souza, M. M. F. de Moraes, et al. "Evaluation of computational approaches to design new photosensitizers." In VIII Simpósio de Estrutura Eletrônica e Dinâmica Molecular. Universidade de Brasília, 2020. http://dx.doi.org/10.21826/viiiseedmol2020-29.

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From dye-sensitized solar cells to photodynamic therapy, the design of new photosensitizers involves different computational strategies. In this work, we present selected examples aiming at illustrating the limitations and advantages of each selected strategy, as well as listing useful descriptors. Hybrid functionals are reasonable approaches to determine properties related to the electronic absorption spectrum; however, for metallic complexes such as metalloporphyrins, one may be careful in selecting the DFT approach. Self-aggregation of dyes is a phenomenon the experimentalists try to avoid, and it is essential to include dispersion corrections and solvation effects to understand the energetics of this process. Aggregation may be driven by π-stacking or hydrophobic effects, depending on the dye composition. Besides all those characteristics, the design of a new photosensitizer may involve evaluating substitution and anchoring groups, push-pull effects, photostability, and reaction mechanisms in the excited states.
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Boachie, Ruth, Ogadimma Okagu, Raliat Abioye, Nico Huttmann, Teresa Oliviero, Edoardo Capuano, Vincenzo Fogliano, and Chibuike Udenigwe. "Formation of Lentil Protein-tannic Acid Complexes Limits in Vitro Peptic Hydrolysis and Alters Peptidomic Profiles of the Protein." In 2022 AOCS Annual Meeting & Expo. American Oil Chemists' Society (AOCS), 2022. http://dx.doi.org/10.21748/txix9391.

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Food protein interaction with other biopolymers, such as tannic acids, within a food matrix can alter their structure and functionality. In this study, the nature of lentil protein-tannic acid (LPTA) interaction and its effect on in vitro peptic hydrolysis were investigated. In LPTA mixtures containing 1% w/v LP and 0.001% - 0.5% TA, a twenty-fold increase in particle size was observed in LPTA 0.5% compared to LPI, indicating aggregation. Static quenching of tryptophan residues within the protein hydrophobic folds were observed. Increasing TA content caused an overall increase in α-helix fractions. A 56.79% reduction in free amino nitrogen of LPTA 0.5%, relative to LPI, was observed after digestion. High molecular weight hydrolysates from LPTA 0.5% recorded slightly different amino acid profile. This study showed that 0.5% w/v TA induced protein aggregation, reduced lentil protein digestibility by hindering accessibility of pepsin to protein network, and modified amino acid profile.
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Kim, Moo Hwan. "The Effect of Nanoscale Surface Modification on Boiling Heat Transfer and Critical Heat Flux." In ASME 2010 8th International Conference on Nanochannels, Microchannels, and Minichannels collocated with 3rd Joint US-European Fluids Engineering Summer Meeting. ASMEDC, 2010. http://dx.doi.org/10.1115/fedsm-icnmm2010-31276.

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Recently, there were lots of researches about enormous CHF enhancement with the nanofluid in pool boiling and flow boiling. It is supposed the deposition of nanoparticles on the heated surface is one of main reasons. In a real application, nanofluid has a lot of problems to be used as the working fluid because of sedimentation and aggregation. The artificial surfaces on silicon and metal were developed to have the similar effect with nanoparticles deposited on the surface. The modified surface showed the enormous ability to increase CHF in pool boiling. Furthermore, under flow boiling, it had also good results to increase CHF. In these studies, we concluded that wetting ability of surface; e.g. wettability and liquid spreading ability (hydrophilic property of surface) was a key parameter to increase CHF under both pool and flow boiling. In addition, using wettability difference of surface; e.g. hydrophilic and hydrophobic, we conducted some tests of BHT (boiling heat transfer) enhancement using the oxide silicon which have micro-sized hydrophobic islands on hydrophilic surface. By using both of these techniques, we propose an optimized surface to increase both CHF and BHT. Also, the fuel surface of nuclear power plants is modified to have same effect and the results shows a good enhancement of CHF, too.
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Steiner, B., and D. R. Phillips. "CA2+-INDUCED STRUCTURAL TRANSITIONS OF THE PLATELET GP IIb-IIIa COMPLEX." In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1643956.

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Previous studies have shown that the membrane glycoprotein (GP) IIb-IIIa complex can be reversibly dissociated by incubating platelets for 5 min at 37°C in an EDTA-containing buffer. Prolonged incubations (30 min) with EDTA, however, result in the formation of high molecular weight aggregates of GP IIb and GP IIIa. These aggregates of individual GP's neither bind fibrinogen nor support platelet aggregation, indicating that chelation of Ca2+ can affect the functional activity of GP IIb-IIIa. The present study was designed to identify conditions for the generation of functionally active GP IIb and GP IIIa. Functionally active subunits were defined as those which reformed GP IIb-IIIa complexes. The complexes were quantified by sucrose gradient sedimentation (complexed, dissociated and aggregated GP’s have different sedimentation coefficients) and thrombin hydrolysis (dissociated and aggregated GP lib are susceptible to hydrolysis by thrombin while GP lib in the GP IIb-IIIa complex is thrombin resistant). Purified GP IIb-IIIa could be dissociated by a 5 min incubation at 37°C with ≤ 10−5 M Ca2+. When the complexes were dissociated in the presence of Ca2+ concentrations below 10−6 m, the monomeric GP IIIa was converted to a slower sedimenting form; this change in structure caused it to become functionally inactive. In the presence of very low Ca2+ concentrations 10−6 M) both dissociated subunits subsequently formed high molecular weight aggregates. However, these changes in structure and loss in function could be prevented by dissociating the complexes in 10−6 M Ca2+ and immediately readding raM Ca2+ at 4°C. When this solution was warmed to 20°C, almost 70% of the dissociated subunits reformed heterodimeric complexes. Storage at 4°C for as long as 6 h did not alter the functional activity of these subunits. Octylglucoside, but not Triton X-100, completely inhibited reassociation. Experiments performed in the presence of various H+ and salt concentrations showed that the interactive forces between GP IIb and GP IIIa are both electrostatic and hydrophobic. Thus, conditions have been obtained for the preparation of functionally active GP IIb and GP IIIa which can reform the native heterodimeric complex. Various Ca2+ concentrations can have multiple effects on the structure of the dissociated subunits.
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Hawiger, J. "PLATELET RECEPTOR RECOGNITION DOMAINS AND THEIR SYNTHETIC PEPTIDE ANALOGS." In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1643726.

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Adhesive molecules and their receptorsplay an essential role in hemostasis and thrombosis. Platelet thrombi are formed through the interaction of cell adhesion molecules (CAMs) with intercellular adhesion molecules (IAMs)and substrate adhesion molecules (SAMs). Platelet CAMs encompass membrane glycoproteins lb, lib, Ilia,and possibly la and IV, which constitutemembrane receptors for IAMs(e.g., fibrinogen) and for SAMs encompassingvon Willebrand Factor (vWF), fibronectin, vitronectin, collagen, and thrcmbospondin. Receptorfunction of platelet CAMs can be specific,i.e., only one adhesive protein among IAMs and SAMs is selected forbinding as exemplified by GPIb and vWF. Alternatively,more than one adhesive protein can interact with platelet CAMs comprising the GPIIb/IIIa complex.This common adhesive receptor mechanism switched on by thrombin, ADP, phorbol ester or ionophore A23187 is turned off by a rise in intraplatelet cyclic AMP which provides a negative control.Fibrinogen, the most abundant adhesiveprotein in plasma, interacts with platelet CAMs via receptor recognition domains on gamma and alpha chains. Pinpointing platelet receptor recognition domain to a carboxy-terminal segment of the gamma chain encompassing residues 400-411gave rise to a series of synthetic peptide analogs which do not interfere with themetabolic pathways of platelets but blockbinding of I fibrinogen to its receptors on stimulated platelets, inhibit their aggregation in vitro, and formation of a platelet thrombus in vivo. The alpha chain of human fibrinogen contains the sequenceRGD (residues 95-97 and 572-574). Synthetpeptide analogs of the RGD sequence, which constitute the "cell adhesion site" of fibronectin, also inhibit binding of 125I-fibrinogen to stimulated platelets. However, these synthetic peptides are not "specific" for fibrinogen chains because thealpha chain of human fibrinogen which hasnosequence homology with gamma 400-411 is prevented by a peptide gamma 400-411 from interaction with platelet receptors. Viceversa, the human gamma chain is blocked by tetrapeptide RGDS not expressed in the human gamma chain. Interaction of human vWF with human platelets is blocked by synthetic peptide analogs of gamma 400-411 (not present in vWF)and of RGD sequence (present in vWF).These synthetic peptides inhibite "common" receptor pathwaystimulated with ADP, thrombin, or phorbolester, but they do not interfere with binding of 125I-vWF via a "specific" pathvoy induced with ristocetin and involving GPIb.The design of synthetic peptide analogs which inhibit platelet receptors for adhesive molecules includes the following considerations: ligand specificity (is thepeptide inhibitory toward binding of one or more adhesive molecules?),cell speciicity (is the peptide specific for platelets or does it perturb the adhesive properties of other cells, e.g.,endothelium?);the hydrophilic character; protection against degradation by peptidases; and a sufficiently long half-life to achieve platelet inhibitory potency in vivo without overloading the blood with excessive amounts of peptide.This is accomplished by constructing a peptide-albumin conjugate with ahalf-life extended at least 30 times.Whenpeptides are modeled with predominantly hydrophilic or hydrophobic residues, only the hydrophilic peptide remained active to block the platelet receptor. This agreed with the general observation that sequences on adhesive molecules that are knownto interact with cellular receptors have a hydrophilic rather than a hydrophobic character. Furthermore, changing the charge of synthetic peptides toward the negative reduced the reactivity, whereas introducing additional arginine residues enhanced the reactivity toward platelet receptors. Localization of the functionally important binding domain in the flexible segment of an adhesive protein increases the likelihood that the synthetic peptide will assume the conformation mimicking such a domain in the native adhesive protein. Structure-function studies of the receptor recognition domains on adhesive molecules led to development of a new class of platelet inhibitors acting at the membranereceptors responsible for anchoring of platelets to the vessel wall and linking them to each other.
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Gordon, Stuart, Bonnie Sloane, Phil Cavanugh, Barbara Cross, Kenneth Honn, and Mohanathasan Chelladurai. "PURIFICATION AND CHARACTERIZATION OF TWO PROCOAGULANTS FROM WALKER 256 CARCINOSARCOMA TUMORS,." In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1643666.

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Activation of the coagulation system bytumor cells may play an important role in tumor growth and metastases. Becauseprocoagulant activities have been identified in different tumor cells by different investigators, effective comparison of these activities has been difficult. Therefore, we purified and characterized two different procoagulant proteins from the same Walker 256 tumors. The first procoagulant activity/platelet aggregating activity (PCA/PAA) was purified from a 1% CHAPS detergent extract oftumor homogenate followed by (NH4)2SO4 fractionation, anion exchange and hydrophobic chromatography. The protein had a molecular weight of 58,000, required phospholipid and an intact coagulation pathway from factor X through fibrinogen for activity, but did not require factors VII or IX forits procoagulant activity. The procoagulant activity was not inhibited by 5mMphenyl-methyl sulfonyl fluoride, iodoacetamide or phenanthroline; there was noevidence of proteinase activity. The PAA was due to thrombin generation during coagulation. The second procoagulant,cancer procoagulant (CP), was extracted from tumors in barbital buffer (pH 7.4) without detergent, purified by immunoaffinity (using a polyclonal goat antibody to CP from V2 carcinoma) and mercurial-benzoate affinity chromatography. CP had a molecular weight of 68,000, an isoelectric point of 4.8 and initiated coagulation by directly activating factor X in the coagulation system. CP was inhibited by Hg++ and iodoacetamide, cysteine proteinase inhibitors. The purified CP formed an immunodiffusion precipitin band against the polyclonal anti-CP goat antibody. Thus, thepurified CP had the same physicochemical, enzymatic and immunologic propertiesas CP from rabbit V2 carcinoma. Neither procoagulant had the properties of tissue factor. These results suggest that there aretwo distinct procoagulant activities inWalker 256 and that both may contributeto the coagulation abnormalities that are associated with tumor growthand metastases.
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