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Статті в журналах з теми "Natural Self-assembly Process"
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Pidaparti, Ramana M., David Primeaux, and Brandon Saunders. "Modeling and Simulation of Biological Self-Assembly Structures from Nanoscale Entities." Journal of Nanoscience and Nanotechnology 7, no. 12 (December 1, 2007): 4248–53. http://dx.doi.org/10.1166/jnn.2007.863.
Повний текст джерелаАнотація:
Many natural and biological systems are formed by the process of molecular self-assembly. Molecular self-assembly is defined as the spontaneous organization of molecules under thermodynamic equilibrium conditions into structurally well defined and rather stable arrangements. In this paper, we developed a novel computational methodology to investigate the self-assembly process of simple 1-D structures representing protein monomers into long filaments, rings, pyramids, bundles, etc. Based on the preliminary results obtained, the methodology was extended to mimic the microtubule self-assembly, which occurs in all eukaryotic cells.
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LIANG, YUJIA, YONG XIE, ZHENING ZHU, YINGLU JI, XIAOCHUN WU, and QIAN LIU. "SELF-ASSEMBLY OF GOLD NANORODS ON WRINKLED TEMPLATE." Nano 09, no. 07 (October 2014): 1450076. http://dx.doi.org/10.1142/s1793292014500763.
Повний текст джерелаАнотація:
Self-assembly of nanoparticles has attracted more attention in the last decade due to their potential applications in many fields, such as sensors, surface-enhanced Raman scattering (SERS) substrate and optical/plasmonic components. Wrinkles, as one kind of common natural surface, are used to be a template/substrate in microfluidic sieves and solar cells. In this work, a wrinkled template with depth of about 200 nm and period of 1.64 μm is used for modulating the self-assembly process of gold nanorods (GNRs) to obtain patterned self-assemblies for potential application. In order to fully reflect the role of the wrinkled template in the self-assembly, the templates are placed uprightly in the GNRs solution to intensify the interplay between the wrinkled surface and nanorods. The self-assembly process is carried out in a climate chamber, where the temperature and humidity can be controlled programmingly to modulate the self-assembly conditions. The experimental results show that for the fixed wrinkled template, an obvious effect on the self-assembly is at the temperature range from 30°C to 50°C. Nematic, curved (mostly are end-to-end) and transition mode can be obtained. According to humidity, GNRs tend to form the nematic fashion in humidity lower than 60%, and the curved fashion in a higher humidity.
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Gabora, Liane, and Mike Steel. "An evolutionary process without variation and selection." Journal of The Royal Society Interface 18, no. 180 (July 2021): 20210334. http://dx.doi.org/10.1098/rsif.2021.0334.
Повний текст джерелаАнотація:
Natural selection successfully explains how organisms accumulate adaptive change despite that traits acquired over a lifetime are eliminated at the end of each generation. However, in some domains that exhibit cumulative, adaptive change—e.g. cultural evolution, and earliest life—acquired traits are retained; these domains do not face the problem that Darwin’s theory was designed to solve. Lack of transmission of acquired traits occurs when germ cells are protected from environmental change, due to a self-assembly code used in two distinct ways: (i) actively interpreted during development to generate a soma, and (ii) passively copied without interpretation during reproduction to generate germ cells. Early life and cultural evolution appear not to involve a self-assembly code used in these two ways. We suggest that cumulative, adaptive change in these domains is due to a lower-fidelity evolutionary process, and model it using reflexively autocatalytic and foodset-generated networks. We refer to this more primitive evolutionary process as self–other reorganization (SOR) because it involves internal self-organizing and self-maintaining processes within entities, as well as interaction between entities. SOR encompasses learning but in general operates across groups. We discuss the relationship between SOR and Lamarckism, and illustrate a special case of SOR without variation.
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Astanov, Salikh Khusenovich, and Siddiq Kakhkharovich Kakhkharov. "SPECTROSCOPIC STUDY OF THE PROCESS OF HYPOCHROMIC EFFECT IN SOL T IN SOLUTIONS OF N UTIONS OF NATURAL D TURAL DYES AND VI YES AND VITAMIN B2 AMIN B2." Scientific Reports of Bukhara State University 4, no. 3 (June 26, 2020): 21–27. http://dx.doi.org/10.52297/2181-1466/2020/4/3/11.
Повний текст джерелаАнотація:
The process of self-assembly of riboflavin molecules in aqueous and binary mixtures of solvents was investigated by the spectroscopic method. It was shown that during the assembly of vitamin B2 molecules, dipole-dipole interaction occurs, as a result of which resonant splitting of excited electronic levels of riboflavin molecules occurs. And the observable hypo chromic effect is due to a decrease in the intense absorption capacity of the aggregated riboflavin molecules themselves.
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Han, Pingping, Jiafu Shi, Teng Nie, Shaohua Zhang, Xueyan Wang, Pengfei Yang, Hong Wu, and Zhongyi Jiang. "Conferring Natural-Derived Porous Microspheres with Surface Multifunctionality through Facile Coordination-Enabled Self-Assembly Process." ACS Applied Materials & Interfaces 8, no. 12 (March 17, 2016): 8076–85. http://dx.doi.org/10.1021/acsami.6b00335.
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Morii, Nahoko, Giyuu Kido, Hiroyuki Suzuki, and Hisayuki Morii. "Annular self-assembly of DNA molecular chains occurring in natural dry process of diluted solutions." Biopolymers 77, no. 3 (2005): 163–72. http://dx.doi.org/10.1002/bip.20203.
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Xu, P., T. Erdem, and E. Eiser. "A simple approach to prepare self-assembled, nacre-inspired clay/polymer nanocomposites." Soft Matter 16, no. 23 (2020): 5497–505. http://dx.doi.org/10.1039/c9sm01585j.
Повний текст джерелаАнотація:
Inspired by the relationship between the ordered architecture of aragonite crystals and biopolymers found in natural nacre, we present a facile strategy to construct organic/inorganic nanocomposites with hierarchical structure via a water-evaporation driven self-assembly process.
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González, Andrea, Sandeep Kumar Singh, Macarena Churruca, and Ricardo B. Maccioni. "Alzheimer’s Disease and Tau Self-Assembly: In the Search of the Missing Link." International Journal of Molecular Sciences 23, no. 8 (April 10, 2022): 4192. http://dx.doi.org/10.3390/ijms23084192.
Повний текст джерелаАнотація:
Alzheimer’s disease (AD) is a multifactorial neurodegenerative disease characterized by progressive cognitive impairment, apathy, and neuropsychiatric disorders. Two main pathological hallmarks have been described: neurofibrillary tangles, consisting of tau oligomers (hyperphosphorylated tau) and Aβ plaques. The influence of protein kinases and phosphatases on the hyperphosphorylation of tau is already known. Hyperphosphorylated tau undergoes conformational changes that promote its self-assembly. However, the process involving these mechanisms is yet to be elucidated. In vitro recombinant tau can be aggregated by the action of polyanions, such as heparin, arachidonic acid, and more recently, the action of polyphosphates. However, how that process occurs in vivo is yet to be understood. In this review, searching the most accurate and updated literature on the matter, we focus on the precise molecular events linking tau modifications, its misfolding and the initiation of its pathological self-assembly. Among these, we can identify challenges regarding tau phosphorylation, the link between tau heteroarylations and the onset of its self-assembly, as well as the possible metabolic pathways involving natural polyphosphates, that may play a role in tau self-assembly.
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Chen, Hui, Xiao Hui Wang, Dong Li, Yan Zhu Guo, and Run Cang Sun. "Preparation and Characterization of Quaternary Chitosan/sodium Alginate Self-Assembled Microcapsules." Advanced Materials Research 554-556 (July 2012): 263–67. http://dx.doi.org/10.4028/www.scientific.net/amr.554-556.263.
Повний текст джерелаАнотація:
Biocompatible quaternary chitosan/sodium alginate multilayer microcapsules were prepared by layer-by-layer (LBL) self-assembly on the template of monodispersed melamine formaldehyde resin microspheres (MF). The process of self-assembly was monitored by measuring the surface zeta-potential of colloidal particles. The particle size was determined by digital light scattering (DLS) after each deposition, and the average thickness of monolayer film was revealed to be 3.9 nm. Using rhodamine B-labeled quaternary chitosan as the positive polyelectrolyte and sodium alginate as the negative polyelectrolyte, self-assembled multilayer microcapsules with strong red-light emitting were obtained and observed with fluorescence microscope. The fluorescent microcapsules self-assembled from the biocompatible natural polysaccharides may be potentially applied in drug delivery and fluorescence diagnosis.
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Han, Pingping, Jiafu Shi, Teng Nie, Shaohua Zhang, Xueyan Wang, Pengfei Yang, Hong Wu, and Zhongyi Jiang. "Correction to Conferring Natural-Derived Porous Microspheres with Surface Multifunctionality through Facile Coordination-Enabled Self-Assembly Process." ACS Applied Materials & Interfaces 8, no. 23 (June 6, 2016): 14893. http://dx.doi.org/10.1021/acsami.6b04734.
Повний текст джерелаДисертації з теми "Natural Self-assembly Process"
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Kinuthia, Wanyee. "“Accumulation by Dispossession” by the Global Extractive Industry: The Case of Canada." Thèse, Université d'Ottawa / University of Ottawa, 2013. http://hdl.handle.net/10393/30170.
Повний текст джерелаАнотація:
This thesis draws on David Harvey’s concept of “accumulation by dispossession” and an international political economy (IPE) approach centred on the institutional arrangements and power structures that privilege certain actors and values, in order to critique current capitalist practices of primitive accumulation by the global corporate extractive industry. The thesis examines how accumulation by dispossession by the global extractive industry is facilitated by the “free entry” or “free mining” principle. It does so by focusing on Canada as a leader in the global extractive industry and the spread of this country’s mining laws to other countries – in other words, the transnationalisation of norms in the global extractive industry – so as to maintain a consistent and familiar operating environment for Canadian extractive companies. The transnationalisation of norms is further promoted by key international institutions such as the World Bank, which is also the world’s largest development lender and also plays a key role in shaping the regulations that govern natural resource extraction. The thesis briefly investigates some Canadian examples of resource extraction projects, in order to demonstrate the weaknesses of Canadian mining laws, particularly the lack of protection of landowners’ rights under the free entry system and the subsequent need for “free, prior and informed consent” (FPIC). The thesis also considers some of the challenges to the adoption and implementation of the right to FPIC. These challenges include embedded institutional structures like the free entry mining system, international political economy (IPE) as shaped by international institutions and powerful corporations, as well as concerns regarding ‘local’ power structures or the legitimacy of representatives of communities affected by extractive projects. The thesis concludes that in order for Canada to be truly recognized as a leader in the global extractive industry, it must establish legal norms domestically to ensure that Canadian mining companies and residents can be held accountable when there is evidence of environmental and/or human rights violations associated with the activities of Canadian mining companies abroad. The thesis also concludes that Canada needs to address underlying structural issues such as the free entry mining system and implement FPIC, in order to curb “accumulation by dispossession” by the extractive industry, both domestically and abroad.
Частини книг з теми "Natural Self-assembly Process"
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Ellis-Monaghan, Joanna, and Nataša Jonoska. "From Molecules to Mathematics." In Natural Computing Series, 189–206. Singapore: Springer Nature Singapore, 2023. http://dx.doi.org/10.1007/978-981-19-9891-1_11.
Повний текст джерелаАнотація:
AbstractTo celebrate the 40th anniversary of bottom-up DNA nanotechnology we highlight the interaction of the field with mathematics. DNA self-assembly as a method to construct nanostructures gave impetus to an emerging branch of mathematics, called here ‘DNA mathematics’. DNA mathematics models and analyzes structures obtained as bottom-up assembly, as well as the process of self-assembly. Here we survey some of the new tools from DNA mathematics that can help advance the science of DNA self-assembly. The theory needed to develop these tools is now driving the field of mathematics in new and exciting directions. We describe some of these rich questions, focusing particularly on those related to knot theory, graph theory, and algebra.
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Vecchioni, Simon, Ruojie Sha, and Yoel P. Ohayon. "Beyond Watson-Crick: The Next 40 Years of Semantomorphic Science." In Natural Computing Series, 3–15. Singapore: Springer Nature Singapore, 2023. http://dx.doi.org/10.1007/978-981-19-9891-1_1.
Повний текст джерелаАнотація:
AbstractIt should come as no surprise that the world of DNA nanotechnology is still learning how to fully master the different steps of the self-assembly process. Semantomorphic science, as the late Ned Seeman would describe DNA nanotechnology, relies on the programmability of nucleic acids (semanto-) to encourage short oligomers to put themselves together (-morphic) into designed architectures (science?). In the same way that Gibson assembly frustrates the molecular biologist, semantomorphic self-assembly has for decades, and continues to, defy the scientist in question. In a brief analogy, Gibson assembly can be thought of as enzymatically directed self-assembly [1] that follows the same general rules as Seeman assembly: (1) guess conditions; (2) set up reaction; (3) pray to entity of choice; (4) check result; and (5) repeat as needed. In other words, when it works, it works well; when it doesn’t, troubleshooting the sticky-ended cohesion between too-large or too-small building blocks with imperfect assays can take months. Returning to semantomorphic science, it is still mesmerizing that any of this works at all, and for that, we owe our deepest gratitude to Ned and his generations-spanning vision.
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Ahsan, Haseeb, Salman Ul Islam, Muhammad Bilal Ahmed, Adeeb Shehzad, Mazhar Ul Islam, Young Sup Lee, and Jong Kyung Sonn. "Principles of Supra Molecular Self Assembly and Use of Fiber mesh Scaffolds in the Fabrication of Biomaterials." In Biomaterial Fabrication Techniques, 218–42. BENTHAM SCIENCE PUBLISHERS, 2022. http://dx.doi.org/10.2174/9789815050479122010012.
Повний текст джерелаАнотація:
Tissue engineering techniques aim to create a natural tissue architecture using biomaterials that have all the histological and physiological properties of human cells to replace or regenerate damaged tissue or organs. Nanotechnology is on the rise and expanding to all fields of science, including engineering, medicine, diagnostics and therapeutics. Nanostructures (biomaterials) specifically designed to mimic the physiological signals of the cellular/extracellular environment may prove to be indispensable tools in regenerative medicine and tissue engineering. In this chapter, we have discussed biomaterial design from two different perspectives. Supramolecular self-assembly is the bottom-up approach to biomaterials design that takes advantage of all the forces and interactions present in biomolecules and are responsible for their functional organization. This approach has the potential for one of the greatest breakthroughs in tissue engineering technology because it mimics the natural, complex process of coiling and folding biomolecules. In contrast, a fiber mesh scaffold is a top.down approach in which cells are seeded. The scaffolds form the cellular scaffold while the cells produce and release the desired chemical messengers to support the regeneration process. Therefore, both techniques, if efficiently explored, may lead to the development of ideal biomaterials produced by self-assembly or by the fabrication of optimal scaffolds with long shelf life and minimal adverse reactions.
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Beruashvili, Natalia. "The International Importance of Civil and Political Rights." In Advances in Human Services and Public Health, 279–300. IGI Global, 2022. http://dx.doi.org/10.4018/978-1-6684-4543-3.ch014.
Повний текст джерелаАнотація:
Civil and political rights are a class of rights that protect individuals' freedoms from infringement by governments, social organizations, and private individuals. They ensure one's entitlement to participate in the civil and political life of society and the state without discrimination or repression. Civil rights include the ensuring of peoples' physical and mental integrity, life, and safety; protection from discrimination on grounds such as race, gender, national origin, color, sexual orientation, ethnicity, religion, or disability; and individual rights such as privacy, the freedoms of thought and conscience, speech and expression, religion, the press, assembly, and movement. Political rights include natural justice (procedural fairness) in law, such as the rights of the accused, including the right to a fair trial, due process, the right to seek redress or a legal remedy, and rights of participation in civil society and politics such as freedom of association, the right to assemble, the right to petition, the right of self-defense, and the right to vote.
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"Self-Assembly and Biomimetics." In Nanoscopic Materials: Size-Dependent Phenomena and Growth Principles, 296–326. 2nd ed. The Royal Society of Chemistry, 2014. http://dx.doi.org/10.1039/bk9781849739078-00296.
Повний текст джерелаАнотація:
Self-assembly is a process in which structural motives provide specific interaction for directed aggregation of the modular building blocks under equilibrium conditions. Interactions among the building blocks but also between building blocks and solvent play a role. This allows the formation of oriented unimolecular layers and bilayers, such as soap films or biological cell membranes. Depending on the shape of the units, oriented packing may lead to curvature. The interface of the layer to the solvent is associated with a small interfacial energy, and curved surfaces separate regimes of different pressure. In isotropic systems this leads to structures of constant curvature. Nature makes extensive use of these construction principles, and chemists can take advantage of them in biomimetic synthesis in the laboratory. The building motives are often elongated or polar organic molecules such as surfactants, but in liquid crystals the mesogenes can also be disc-shaped. The resulting soft matter structures can be used as moulds for the synthesis of quite artistic architectures from hard ceramics at or near room temperature via the sol–gel process. Alternatively, three-dimensional structures can be designed and synthesised from modules with specific coupling elements. Metal–organic frameworks are examples of such structures which after removal of the solvent are porous and may be stable, suitable for gas adsorption or separation, or catalysis.
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"Self Assembly and Building Nano Structures." In Polymer Structure Characterization: From Nano to Macro Organization in Small Molecules and Polymers, 393–424. 2nd ed. The Royal Society of Chemistry, 2013. http://dx.doi.org/10.1039/bk9781849734332-00393.
Повний текст джерелаАнотація:
Self assembly has been a developing theme through this monograph. Some structures, by the nature of the processes used in their synthesis form molecules which naturally self assemble. Carbon-based spheres and nano tubes have interesting and important characteristics. Sheets of carbon, graphene, exhibits electrical conductivity and physical property characteristics which make these materials potentially very important technologically. So-called intrinsic conducting polymers have been developed form polyacetylene and are utilized in display applications. Reinforcement of polymer systems can also be achieved by the use of exfoliated clay systems, in which the nano scale of the clay platelets allows order to be created within the polymer matrix. Combining inorganic and organic elements it is possible to create structures with large voids for permeation applications and to influence the growth or inorganic crystals by habit control.
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Patel, Preeti, Ashish K. Parashar, Monika Kaurav, Krishna Yadav, Dilpreet Singh, G. D. Gupta, and Balak Das Kurmi. "Niosome: A Vesicular Drug Delivery Tool." In Nanoparticles and Nanocarriers-Based Pharmaceutical Formulations, 333–64. BENTHAM SCIENCE PUBLISHERS, 2022. http://dx.doi.org/10.2174/9789815049787122010014.
Повний текст джерелаАнотація:
Niosomes, which are well recognized for their non-ionic surfactant characteristics, are considered to be innovative drug delivery methods since they improve the solubility and stability of medicinal compounds when administered orally. It has been shown that niosome vesicles are closed bilayer structures that may exist in aqueous fluids and are produced by the self-assembly of different types of hydrated non-ionic surfactants and amphiphile monomers in aqueous media. Because the monomers maintain a wide range of kinetic activity inside the assembly, they are referred to as liquid crystal structures in terms of thermodynamics. It is just the total of different processes for the dispersion of monomers and solvents that results in the formation of the final systems. Niosomes are made up mostly of lipid molecules and nonionic surfactants, which are the two most important components in the process of making them. Nonetheless, as the name suggests, component surfactants play a key role in the creation of niosomes, owing to the fact that non-ionic surfactants were often employed to organize niosomes during their formation. They are especially well-suited for drug delivery because they have the ability to encapsulate medicines that are both lipophilic and hydrophilic in nature. These materials are appealing for a number of drug delivery goals, including drug targeting, controlled release, and permeability enhancement, because of their chemical stability, cheap production costs, and composed of biodegradable and non-immunogenic components. Niosomal vesicular carriers can also help to minimize problems such as physical and chemical instability. This book chapter contains a brief knowledge about structural components and integrity concerning the advanced method of noisome preparation. The characterization techniques essential for noisome have also been discussed in detail. The recent examples for different applications are also included for therapy /diagnostic purposes based on the route of administration and disease state.
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Dutta, Binita. "An Emerging Avenue of Nanomaterials Manufacturing and Prospectives." In Bio-Inspired Nanotechnology, 73–105. BENTHAM SCIENCE PUBLISHERS, 2023. http://dx.doi.org/10.2174/9789815080179123010007.
Повний текст джерелаАнотація:
Nanotechnology is a perfect blend of science, engineering, and technology conducted on a nano-scale. Few nanomaterials can occur naturally, however, in recent times, we are interested in engineered nanomaterials which can be manufactured according to their applicability in a lot of commercial products and processes. For the synthesis of new nanomaterials, scientists mostly opt the bottom-up methods which are capable of offering various kinds of self-assembly of nanoscale species. Parallelly, top.down methods are also being investigated to yield desired nanomaterials and nanopatterns through state-of-art modern techniques like lithographic ablation and chemical etching. In this chapter, after providing an introduction to nanotechnology and nanomaterials, the various methods of nanomaterial synthesis were discussed. Nanotechnology is now being explored vastly to reach the next generation phase of many technologies and industrial sectors. Contributions of nanomaterials to some of such emerging technologies, like the food industry, agricultural science, medicinal science, and the power sector have been briefly overviewed. The rapidly developing sectors involving ultrafine nanoparticles introduced mankind to their hazardous side too. To avoid nanotoxicity, the awareness and related risk management approach are also a matter of utmost importance.
Тези доповідей конференцій з теми "Natural Self-assembly Process"
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Sinha, Ashok, Ranjan Ganguly, and Ishwar K. Puri. "Magnetically Assembled 3-D Mesoscopic Patterns Using Suspension of Superparamagnetic Nanoparticles." In ASME 2004 3rd Integrated Nanosystems Conference. ASMEDC, 2004. http://dx.doi.org/10.1115/nano2004-46091.
Повний текст джерелаАнотація:
A self assembly process is characterized by the spontaneous and ordered aggregation of similar components. At the nanoscale, these constituents can be colloids, or other nanoparticles that combine to form structures of meso- and macroscopic dimensions. Self assembly is most evident during the growth of biological structures. Due to its natural elegance, there is considerable interest in investigating similar methods in other fields of sciences. In principle, the process of dynamic self assembly is characterized by a competition between at least two forces — one attractive and the other repulsive — in thermodynimacally nonequilibrium systems. Several researchers have described self assembly in configurations where biological [1] or chemical [2] mediation, electrostatic [3], capillary [4] or fluid dynamic [5] forces have provided a motive potential.
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Adnan, Ashfaq, and Wing Kam Liu. "Electrostatic Self-Assembly of Functionalized Nanodiamonds and Their Binding Capacity With Doxorubicin Drugs." In ASME 2010 First Global Congress on NanoEngineering for Medicine and Biology. ASMEDC, 2010. http://dx.doi.org/10.1115/nemb2010-13164.
Повний текст джерелаАнотація:
While cancers have no known cure, some of them can be successfully treated with the combination of surgery and systematic therapy. In general, systemic/widespread chemotherapy is usually injected into the bloodstream to attempt to target cancer cells. Such procedure often imparts devastating side effects because cancer drugs are nonspecific in activity, and transporting them throughout the bloodstream further reduces their ability to target the right region. This means that they kill both healthy and unhealthy cells. It has been observed that the physiological conditions of the fluids around living cells can be characterized by pH, and the magnitude of pH around a living cell is different from cancerous cells. Moreover, a multiscale anatomy of carcinoma will reveal that the microstructure of cancer cells contains some characteristic elements such as specific biomarker receptors and DNA molecules that exclusively differentiate them from healthy cells. If these cancer specific ligands can be intercalated by some functional molecules supplied from an implantable patch, then the patch can be envisioned to serve as a complementary technology with current systemic therapy to enhance localized treatment efficiency, minimize excess injections/surgeries, and prevent tumor recurrence. The broader objective of our current research is to capture some fundamental insights of such drug delivery patch system. It is envisioned that the essential components of the device is nanodiamonds (ND), parylene buffer layer and doxorubicin (DOX) drugs. In its simplest form, self-assembled nanodiamonds - functionalized or pristine, and DOX molecules are contained inside parylene capsule. The efficient functioning of the device is characterized by its ability to precisely detect targets (cancer cells) and then to release drugs at a controlled manner. The fundamental science issues concerning the development of the ND-based device include: 1. A precise identification of the equilibrium structure and self assembled morphology of nanodiamonds, 2. Fundamental understanding of the drug adsorption and desorption process to and from NDs, and 3. The rate of drug release through the parylene buffers. The structure of the nanodiamond (ND) is crucial to the adsorption and desorption of drug molecules because it not only changes the self-assembly configuration but also alters the surface electrostatics. To date, the structure and electrostatics of NDs are not yet well understood. A density functional tight binding theory (DFTB) study on smaller [2] NDs suggests a facet dependent charge distributions on ND surfaces. These charges are estimated by Mulliken Analysis [1]. Using the charges for smaller NDs (∼valid for 1–3.3 nm dia ND) we first projected surface charges for larger (4–10 nm) truncated octahedral nanodiamonds (TOND), and it has been found that the [100] face and the [111] face contain positively and negatively charged atoms, respectively. These projected charges are then utilized to obtain the self assembled structure of pristine TONDs from Molecular Dynamics (MD) simulations [4] as shown in Fig. 1. The opposite charges on the [100] and [111] face invoked electrostatic attractions among the initially isolated NDs and a network of nanodiamond agglutinates are formed as evidenced in Fig. 1(b). This study confirms why as manufactured NDs are found in agglomerated form. The study also suggests that a large fraction of ND surfaces become unavailable for drug absorption as many of the [100] faces are coherently connected to [111] faces. As a result, it can be perceived that effective area for drug adsorption on ND surfaces will be less compared to theoretical prediction which suggests that a 4nm TOND may contain as high 360 drug molecules on its surface [5]. It has been observed that as manufactured NDs may contain a variety of functional groups, and currently, we are studying the mechanism of self-assembly for functionalized nanodiamonds so that we understand the role of functional groups. The next phase of calculation involves binding of the DOX to the NDs. Essentially, the understanding of drug absorption and desorption profile at a controlled rate to and from NDs is the most critical part of the device design. Some recent quantum calculation suggests that part of NDs and drug molecules contain opposite charges at their surfaces; it has been a natural interpretation that interactions between ND and drug molecules should be straight-forward — NDs should attract to drugs as soon as they come closure. Recent experiments [6], however, suggest that NDs usually do not interact with drug molecules in the presence of neutral solutions. Addition of NaCl in the solution improves the interaction dramatically. In the first part of the study, we [3–5] have studied the interaction of single DOX molecules with TOND surfaces via MD simulation. As shown in Fig. 2, this study suggests that DOX molecules first arrange them around the preferential sites on nanodiamonds (e.g. around the [111] face) and then spontaneously attach on the surface. It is also observed that only DOX molecule is attached per facets of TONDs. It can be noted that each TOND has 6 [100] face and 8 [111] faces. Figure 3 shows the energy minimization process during the DOX-ND interaction. It can be noted that these simulations have been performed in vacuum environment. In order to see how DOX interacts in solution media, another set of simulations have been conducted where “vacuum” environment have been replaced with solution media of different pH. Moreover, functionalization on the ND surfaces will create a different environment for the DOX molecules. Research is underway to capture the fundamental physics on the DOX loading and release to and from functionalized nanodiamonds. Once we understand the essential physics of drug loading and unloading, in the future we plan to model diffusion controlled drug release through ND coated film device by incorporating the multiscale science learned from the current study. Results from this study will provide fundamental insight on the definitive targeting of infected cells and high resolution controlling of drug molecules.
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Accornero, Mariana Esther, Marcela Catalina Mambrini, and Carola Rossetti. "Contributions of textile design to the regional identity of the Sierras de Córdoba, Argentina." In LINK 2021. Tuwhera Open Access, 2021. http://dx.doi.org/10.24135/link2021.v2i1.122.
Повний текст джерелаАнотація:
Based on a survey of the textile production of textile makers from the Sierras de Córdoba and attempting to reconstruct a regional aesthetic from the records of clothing in archaeological pieces of the indigenous Comechingonas cultures and ethnographic production, this research work is proposed as a contribution to the contemporary textile design and identity. The project was developed from the concept of “Disruptive Design”, that is to say: produce-create and consume-create in a different way than usual (Gardetti, 2017) and Strategic Design focused on more environmentally friendly production processes, reversing current methods, generating innovation strategies approach that provide added value to the product from the following guidelines: a) Raw materials based on natural fibers. b) Reuse of dyeing properties, artisanal processes of native natural dyes. c) Innovative pattern based on textile typologies focused on the reuse of fibers, zero waste. d) Consumer awareness in relation to the use and maintenance of clothing, environmental problems in the life cycle of the product. e) Optimization of sequences and processes of creation-production of clothing in which cleaner production is involved under controlled processes (Salcedo, 2014). Another important aspect that was taken into account is the ethics of the designer in the search for innovative and transformative processes, and in promoting the impulse of regional economies through employment, use of natural fibers and collaborationism in the production of designs co-producing jointly with the artisan textile. The methodology used was participant observation, data collection and primary sources; for this, archaeological statuettes and ethnographic textile typologies were taken that are conceptualized in the creative process of each clothing-accessory-complement. In the clothing design process, typologies were created in which the user can interact and transform the clothing from disassembly and / or assembly in alternation of "pattern-texture-color designs" according to tastes and preferences, producing co- design between the designer and the user, including different body types, ages. The collections developed by two designer researchers: “Chasca Arqueológica”, a project by Carola Rossetti and “Chasca Etnográfica”, a project by Marcela Catalina Mambrini, highlight the archaeological-ethnographic textile, producing the recovery and revaluation of the textile heritage of our province with the enhancement and safeguarding textile techniques in danger of extinction due to lack of transmission. The term Chasca refers to the dawn star, the one that enables the new day. This concept was taken as a metaphor for design a new starting point for the artisan textile production of Córdoba. The results of this research work have been made available to the cooperatives of mountain textile makers, in order to begin to manage the mechanisms of self-sustaining production for vulnerable regions in the interior of the province, with the aim of generating micro textile enterprises that consolidate and spread the cultural identity of our province through clothing, complements and accessories.
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Zeng, Siyuan, Yicong Gao, Jianrong Tan, and Zhe Wei. "Self-Assembly by 4D Printing: Design and Fabrication of Sequential Self-Folding." In ASME 2022 Conference on Smart Materials, Adaptive Structures and Intelligent Systems. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/smasis2022-89459.
Повний текст джерелаАнотація:
Abstract Folding-based self-assembly is ubiquitous in nature with examples ranging from the formation of cellular components to winged insects. It has highly potential applications in packaging of solar cells and space structures. In this study, we present a sequential self-assembly design and fabrication approach that is realized by thermal activation of bilayer actuators and transforms two-dimensional nets into three-dimensional structures. The time-dependent behaviors and shape memory performances of each bilayer actuator via experimental methods are investigated. The relationship between structure design parameters of bilayer actuators and their correspondingly self-assembly speed has been studied. Our main findings the process parameters of 4D printing is a simple and effective design principle for controlling the speed of self-assembly. By properly designing the bilayer actuators, 3D printed structures with programmed bilayer actuators respond rapidly to a thermal stimulus, and self-fold to specified shapes in controlled shape changing sequences. A folding box structure is used as an example to illustrate the methodology, which normally requires a folding sequence in order to form a stable and fully packed structure. Measurements of the spatial and temporal nature of self-assembly structures are in good agreement with the desired configurations.
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Banerjee, Soumik. "Molecular Simulation of the Self-Agglomeration of Carbon Nanostructures in Various Chemical Environments." In ASME 2012 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/imece2012-89697.
Повний текст джерелаАнотація:
Self-assembly of carbon nanostructures in solutions provides a cost-effective means to synthesize uniform vertically-aligned nanostructures with specific morphologies including shapes such as wires, sheets and spherical particles. In addition to facilitating the synthesis of bulk carbon nanomaterial, a complete understanding of the agglomeration mechanics also provides a means to deposit uniform layers of carbon nanostructures on top of substrates to produce molecularly-tailored composites with specific mechanical properties. Self-assembly is a complex dynamical process that involves the interaction between the nanoparticle precursors, the transport properties of the individual precursor molecules as well as the precursor-solvent interactions. Depending on the chemical nature of the solvent used during the process various nanostructures of varying shapes and morphologies can be synthesized starting from individual buckyballs and nanotubes. However, despite its wide range of applications, there is a lack of understanding of the self-assembly of carbon nanoparticles. Some of the key factors that govern the agglomeration process are the π-π interaction of the aromatic carbon nanostructures and their interaction with the solvent molecules. A predictive model for self-assembly, that relates the above parameters to the morphology, therefore needs to account for the specific molecular interactions. We present molecular simulation results that incorporate the above effects and shows that the nature of association of the nanoparticle precursors determines the shape and size of the agglomerate. Furthermore, our results show the dependency of the agglomerate size on the concentration of precursors as well as the ambient temperature.
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Moraru, George F. "Nonlinear Dynamics in Drilling and Boring Operations Assisted by Low Frequency Vibration." In ASME 2007 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. ASMEDC, 2007. http://dx.doi.org/10.1115/detc2007-35043.
Повний текст джерелаАнотація:
The nonlinear dynamics of the drilling process assisted by self-excited axial vibrations is analyzed. Models are developed and discussed, including regenerative effect and various phenomena contributing to the process damping in drilling and boring operations. Stability and bifurcation analysis, using several assumptions on the damping in the cutting process, are carried out using linear analysis tools or simulations. A simple predictive model based on a harmonic balance method is presented. Behavior charts are constructed using simulations. Hypothesis on the nature of the process damping and nonlinear behavior of the machining system are proved by experiments. A possible application to the gundrilling boring process in aircraft drilling and assembly process is presented.
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Jung, Yung J., Laila Jaber-Ansari, Xugang Xiong, Sinan Mu¨ftu¨, Ahmed Busnaina, Swastik Kar, Caterina Soldano, and Pulickel M. Ajayan. "Highly Organized Carbon Nanotube-PDMS Hybrid System for Multifunctional Flexible Devices." In ASME 2007 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. ASMEDC, 2007. http://dx.doi.org/10.1115/detc2007-35442.
Повний текст джерелаАнотація:
We will present a method to fabricate a new class of hybrid composite structures based on highly organized multiwalled carbon nanotube (MWNT) and singlewalled carbon nanotube (SWNT) network architectures and a polydimethylsiloxane (PDMS) matrix for the prototype high performance flexible systems which could be used for many daily-use applications. To build 1–3 dimensional highly organized network architectures with carbon nanotubes (both MWNT and SWNT) in macro/micro/nanoscale we used various nanotube assembly processes such as selective growth of carbon nanotubes using chemical vapor deposition (CVD) and self-assembly of nanotubes on the patterned trenches through solution evaporation with dip coating. Then these vertically or horizontally aligned and assembled nanotube architectures and networks are transferred in PDMS matrix using casting process thereby creating highly organized carbon nanotube based flexible composite structures. The PDMS matrix undergoes excellent conformal filling within the dense nanotube network, giving rise to extremely flexible conducting structures with unique electromechanical properties. We will demonstrate its robustness under large stress conditions, under which the composite is found to retain its conducting nature. We will also demonstrate that these structures can be directly utilized as flexible field-emission devices. Our devices show some of the best field enhancement factors and turn-on electric fields reported so far.
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Trask, Richard S. "Ultrasonic Assembly of Biologically Inspired Anisotropic Short Fibre Reinforced Composites." In ASME 2014 Conference on Smart Materials, Adaptive Structures and Intelligent Systems. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/smasis2014-7558.
Повний текст джерелаАнотація:
In nature, both material and structure are formed according to the principles of biologically controlled self-assembly, a process defined as the spontaneous and reversible ordering of small molecular building blocks under the influence of non-covalent, static interactions. The orientation and distribution of reinforcing entities in engineering composites is key to enabling structural efficiency, yet the architecture remains simplistic when compared to the distinctive and unique hierarchies found in Nature. These biological ‘composite’ materials achieve such configurations by accurately controlling the orientation of anisotropic nano- and micro-sized ‘building blocks’, thereby reinforcing the material in specific directions to carry the multidirectional external loads at different length scales. Capturing the design principles underlying the exquisite architecture of such biological materials will overcome many of the mechanical limitations of current engineering composites. The scientific vision for this study is the development of a novel and highly ordered complex architecture fibrous material for additive layer manufacturing. Using novel chemistry and controlled field-effect assembly, functionally graded, stiffness modulated architectures, analogous to those found in nature, are synthesised to realise enhanced mechanical performance, multi-dimensional composite structures. To achieve this, both hierarchical discontinuous fibres (glass fibres with ZnO nanrods) and a new type of ultrasonic device has been developed. The two studies reported here have been successfully employed to manufacture and mechanically characterise the fibres and aligned discontinuous fibres. A 43 % improvement in strength was observed for samples tested parallel to the direction of the fibre reinforcement over those strained normal to the fibre direction, despite the relatively low volume percentage of the reinforcement phase. This technique shows great potential for the low cost instantaneous alignment of structural reinforcement to generate the light-weight high performance structures required for the future.
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Yu, Shuangcheng, Yichi Zhang, Chen Wang, Won-kyu Lee, Biqin Dong, Teri W. Odom, Cheng Sun, and Wei Chen. "Characterization and Design of Functional Quasi-Random Nanostructured Materials Using Spectral Density Function." In ASME 2016 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/detc2016-60118.
Повний текст джерелаАнотація:
Quasi-random nanostructured material systems (NMSs) are emerging engineered material systems via cost-effective, scalable bottom-up processes, such as the phase separation of polymer mixtures or the mechanical self-assembly based on thin-film wrinkling. Current development of functional quasi-random NMSs mainly follows a sequential strategy without considering the fabrication conditions in nanostructure optimization, which limits the feasibility of the optimized design for large-scale, parallel nanomanufacturing using bottom-up processes. We propose a novel design methodology for designing quasi-random NMSs that employs spectral density function (SDF) to concurrently optimize the nanostructure and design the corresponding nanomanufacturing conditions of a bottom-up process. Alternative to the well-known correlation functions for characterizing the structural correlation of NMSs, the SDF provides a convenient and informative design representation to bridge the gap between processing-structure and structure-performance relationships, to enable fast explorations of optimal fabricable nanostructures, and to exploit the stochastic nature of manufacturing processes. In this paper, we first introduce the SDF as a non-deterministic design representation for quasi-random NMSs, compared with the two-point correlation function. Efficient reconstruction methods for quasi-random NMSs are developed for handling different morphologies, such as the channel-type and particle-type, in simulation-based design. The SDF based computational design methodology is illustrated by the optimization of quasi-random light-trapping nanostructures in thin-film solar cells for both channel-type and particle-type NMSs. Finally, the concurrent design strategy is employed to optimize the quasi-random light-trapping structure manufactured via scalable wrinkle nanolithography process.
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Crivoi, Alexandru, and Fei Duan. "Fractal Patterns in the Nanofluidic Sessile Droplet Drying." In ASME 2012 10th International Conference on Nanochannels, Microchannels, and Minichannels collocated with the ASME 2012 Heat Transfer Summer Conference and the ASME 2012 Fluids Engineering Division Summer Meeting. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/icnmm2012-73112.
Повний текст джерелаАнотація:
The two-dimensional lattice-gas kinetic Monte Carlo model is used to simulate the process of a nanofluidic sessile droplet drying with a moving contact line in this study. A new modeling approach is implemented by introducing the two-dimensional circular simulation domain in order to operate with the top view of spherical cap of a drying droplet. The non-uniform effective chemical potential function is applied to the model, taking into account the thickness profile of a droplet. Although our simulation is two-dimensional, this modification mimics to some extent the three-dimensional nature of a mesoscopic sessile droplet. Hence we introduce a new, pseudo-3D modification of Monte Carlo simulation model, i.e., a 2D model with additional dependence of the chemical potential on the local droplet thickness. In result, the evaporation-induced nanoparticle self-assembly led to the formation of a fractal-like structure, which is observed in simulation runs. Interestingly, the fractal-shaped patterns obtained in numerous simulations are comparable to the experimentally recorded images of dried nanoparticle structures. The difference in average fractal dimensions of simulated and experimental images is estimated to be less than 5%. It is suggested that the lattice-gas model provides an easy way to reproduce the formation of branched structures from nanoparticles during the drying of spherical sessile droplets.