scholarly journals Programming function into mechanical forms by directed assembly of silk bulk materials

2016 ◽  
Vol 114 (3) ◽  
pp. 451-456 ◽  
Author(s):  
Benedetto Marelli ◽  
Nereus Patel ◽  
Thomas Duggan ◽  
Giovanni Perotto ◽  
Elijah Shirman ◽  
...  

We report simple, water-based fabrication methods based on protein self-assembly to generate 3D silk fibroin bulk materials that can be easily hybridized with water-soluble molecules to obtain multiple solid formats with predesigned functions. Controlling self-assembly leads to robust, machinable formats that exhibit thermoplastic behavior consenting material reshaping at the nanoscale, microscale, and macroscale. We illustrate the versatility of the approach by realizing demonstrator devices where large silk monoliths can be generated, polished, and reshaped into functional mechanical components that can be nanopatterned, embed optical function, heated on demand in response to infrared light, or can visualize mechanical failure through colorimetric chemistries embedded in the assembled (bulk) protein matrix. Finally, we show an enzyme-loaded solid mechanical part, illustrating the ability to incorporate biological function within the bulk material with possible utility for sustained release in robust, programmably shapeable mechanical formats.

Author(s):  
И.В. Бачериков ◽  
Б.М. Локштанов

При проектировании открытых и закрытых хранилищ измельченных сыпучих материалов древесных материалов, таких как щепа и опилки, большое значение имеет угол естественного откоса (статический и динамический) этих материалов. В технической литературе приводятся противоречивые сведения о величине этих углов, что приводит к ошибкам при проектировании складов. В справочных данных не учитываются условия, в которых эксплуатируются емкости для хранения сыпучих материалов, свойства и состояние этих сыпучих материалов. В свою очередь, ошибки при проектировании приводят к проблемам (зависание, сводообразование, «затопление» и т. д.) и авариям при эксплуатации бункеров и силосов на производстве. В статье представлены сведения, посвященные влиянию влажности и температуры на угол естественного откоса сыпучих материалов. На основании лабораторных и натурных экспериментов, проведенных с помощью специально разработанных методик и установок, была скорректирована формула для определения углов естественного откоса (статического и динамического) для измельченных древесных материалов в зависимости от их фракционного и породного состава, влажности (абсолютной и относительной) и температуры. При помощи скорректированной формулы можно определить угол естественного откоса древесных сыпучих материалов со среднегеометрическим размером частицы от 0,5 мм до 15 мм (от древесной пыли до технологической щепы) в различных производственных условиях. Статья может быть полезна проектировщикам при расчете угла наклона граней выпускающей воронки бункеров и силосов предприятий лесной отрасли и целлюлозо-бумажной промышленности. In the design of open and closed storage warehouses chopped wood materials for bulk materials such as wood chips and sawdust, great importance has an angle of repose (static and dynamic) of these materials. In the technical literature are conflicting reports about the magnitude of these angles, which leads to errors in the design of warehouses. In the referencesdoes not take into account the conditions under which operated capacities for storage of bulk materials, and properties and condition of the bulk material. The design errors lead to problems (hanging, arching, «flooding», etc.) and accidents in the operation of hoppers and silos at the mills. The article provides information on the impact of humidity and temperature on the angle of repose of granular materials. On the basis of laboratory and field experiments, conducted with the help of specially developed techniques and facilities has been adjusted formula for determining the angle of repose (static and dynamic) for the shredded wood materials depending on their fractional and species composition, humidity (absolute and relative) and temperature. It is possible, by using the corrected formula, to determine the angle of repose of loose wood materials with average particle size of from 0.5 mm to 15 mm (wood dust to pulpchips) in various operating conditions. The article can be helpful to designers in the calculation of the angle of inclination of the funnel faces produces bunkers and silos forest industries and pulp and paper industry.


Pharmaceutics ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1110
Author(s):  
Kunal Jhunjhunwala ◽  
Charles W. Dobard ◽  
Sunita Sharma ◽  
Natalia Makarova ◽  
Angela Holder ◽  
...  

Receptive anal intercourse (RAI) contributes significantly to HIV acquisition underscoring the need to develop HIV prevention options for populations engaging in RAI practices. We explored the feasibility of formulating rectal suppositories with potent antiviral drugs for on-demand use. A fixed-dose combination of tenofovir (TFV) and elvitegravir (EVG) (40 mg each) was co-formulated in six different suppository bases (three fat- and three water-soluble). Fat-soluble witepsol H15 and water-soluble polyethylene glycol (PEG) based suppositories demonstrated favorable in vitro release and were advanced to assess in vivo pharmacokinetics following rectal administration in macaques. In vivo drug release profiles were similar for both suppository bases. Median concentrations of TFV and EVG detected in rectal fluids at 2 h were 1- and 2-logs higher than the in vitro IC50, respectively; TFV-diphosphate levels in rectal tissues met or exceeded those associated with high efficacy against rectal simian HIV (SHIV) exposure in macaques. Leveraging on these findings, a PEG-based suppository with a lower dose combination of tenofovir alafenamide (TAF) and EVG (8 mg each) was developed and found to achieve similar rectal drug exposures in macaques. This study establishes the utility of rectal suppositories as a promising on-demand strategy for HIV PrEP and supports their clinical development.


2021 ◽  
Vol 45 (5) ◽  
pp. 2830-2830
Author(s):  
Duong Duc La ◽  
Jotiram N. Malegaonkar ◽  
Mohammad Al Kobaisi ◽  
Rajesh S. Bhosale ◽  
Sidhanath V. Bhosale ◽  
...  
Keyword(s):  

Correction for ‘Spermine-directed supramolecular self-assembly of water-soluble AIE-active tetraphenylethylene: nanobelt, nanosheet, globular and nanotubular structures’ by Duong Duc La et al., New J. Chem., 2018, 42, 15379–15386, DOI: 10.1039/C8NJ02636J.


2021 ◽  
Vol 9 (1) ◽  
pp. 38-50
Author(s):  
Hien Phan ◽  
Vincenzo Taresco ◽  
Jacques Penelle ◽  
Benoit Couturaud

Stimuli-responsive amphiphilic block copolymers obtained by PISA have emerged as promising nanocarriers for enhancing site-specific and on-demand drug release in response to a range of stimuli such as pH, redox agents, light or temperature.


Author(s):  
Joshua D. Carter ◽  
Chenxiang Lin ◽  
Yan Liu ◽  
Hao Yan ◽  
Thomas H. LaBean

This article examines the DNA-based self-assembly of nanostructures. It first reviews the development of DNA self-assembly and DNA-directed assembly, focusing on the main strategies and building blocks available in the modern molecular construction toolbox, including the design, construction, and analysis of nanostructures composed entirely of synthetic DNA, as well as origami nanostructures formed from a mixture of synthetic and biological DNA. In particular, it considers the stepwise covalent synthesis of DNA nanomaterials, unmediated assembly of DNA nanomaterials, hierarchical assembly, nucleated assembly, and algorithmic assembly. It then discusses DNA-directed assembly of heteromaterials such as proteins and peptides, gold nanoparticles, and multicomponent nanostructures. It also describes the use of complementary DNA cohesion as 'smart glue' for bringing together covalently linked functional groups, biomolecules, and nanomaterials. Finally, it evaluates the potential future of DNA-based self-assembly for nanoscale manufacturing for applications in medicine, electronics, photonics, and materials science.


RSC Advances ◽  
2013 ◽  
Vol 3 (46) ◽  
pp. 23953 ◽  
Author(s):  
Yingjie Ma ◽  
Jie Yang ◽  
Jinying Li ◽  
Xiaodong Chi ◽  
Min Xue
Keyword(s):  

2006 ◽  
Vol 20 (26) ◽  
pp. 1645-1651
Author(s):  
JIAFU CHEN ◽  
YU YE ◽  
QIANWANG CHEN

A novel hexagonal network structure formed by self-assembly of discrete nickel ferrite nanoparticles on a carbon-coated Cu grid is reported. Each hexagon consists of about 22 discrete nanoparticles with sizes from 120 to 250 nm. The side of the regular hexagon contains 4–6 discrete nanoparticles. The sample displays a large coercivity of 622.6 Oe, exhibiting a hard magnetic feature different from those of the corresponding bulk materials, and is closely related to the hexagonal network structure of nickel ferrite nanoparticles.


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