Mechanical Rupture-Based Antibacterial and Cell-Compatible ZnO/SiO2 Nanowire Structures Formed by Bottom-Up Approaches

There are growing interests in mechanical rupture-based antibacterial surfaces with nanostructures that have little toxicity to cells around the surfaces; however, current surfaces are fabricated via top-down nanotechnologies, which presents difficulties to apply for bio-surfaces with hierarchal three-dimensional structures. Herein, we developed ZnO/SiO2 nanowire structures by using bottom-up approaches and demonstrated to show mechanical rupture-based antibacterial activity and compatibility with human cells. When Escherichia coli were cultured on the surface for 24 h, over 99% of the bacteria were inactivated, while more than 80% of HeLa cells that were cultured on the surface for 24 h were still alive. This is the first demonstration of mechanical rupture-based bacterial rupture via the hydrothermally synthesized nanowire structures with antibacterial activity and cell compatibility.

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Manufacturing of two and three-dimensional micro/nanostructures by integrating optical tweezers with chemical assembly

Robotica ◽

10.1017/s0263574704000864 ◽

2005 ◽

Vol 23 (4) ◽

pp. 435-439 ◽

Cited By ~ 23

Author(s):

Kenneth Castelino ◽

Srinath Satyanarayana ◽

Metin Sitti

Keyword(s):

Optical Tweezers ◽

Manufacturing System ◽

Three Dimensional ◽

Inorganic Materials ◽

Top Down ◽

Bottom Up ◽

Complementary Dna ◽

Nanoscale Manufacturing ◽

2D And 3D

Optical tweezers have been used as versatile tools for non-contact manipulation of micrometer-sized entities. This paper proposes a hybrid micro/nanoscale manufacturing system using optical tweezers and chemical linkages for fabricating 2D and 3D micro/nanostructures. A holographic multiple trap optical tweezers system is first used to trap particles in a desired pattern. The particles are then connected to form rigid units using suitable chemistry. Connection schemes based on gold seeding, complementary-DNA linkage and streptavidin-biotin chemistry are presented and possible applications of this technique are explored. This method combines the advantages of top-down and bottom-up approaches and is compatible with organic and inorganic materials.

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Bioactivity of Isostructural Hydrogen Bonding Frameworks Built from Pipemidic Acid Metal Complexes

Molecules ◽

10.3390/molecules25102374 ◽

2020 ◽

Vol 25 (10) ◽

pp. 2374

Author(s):

Paula C. Alves ◽

Patrícia Rijo ◽

Catarina Bravo ◽

Alexandra M. M. Antunes ◽

Vânia André

Keyword(s):

Escherichia Coli ◽

Antimicrobial Activity ◽

Drug Resistance ◽

Antibacterial Activity ◽

Hydrogen Bonding ◽

Three Dimensional ◽

Artemia Salina ◽

Gram Negative Bacteria ◽

Pipemidic Acid ◽

Gram Negative

We report herein three novel complexes whose design was based on the approach that consists of combining commercially available antibiotics with metals to attain different physicochemical properties and promote antimicrobial activity. Thus, new isostructural three-dimensional (3D) hydrogen bonding frameworks of pipemidic acid with manganese (II), zinc (II) and calcium (II) have been synthesised by mechanochemistry and are stable under shelf conditions. Notably, the antimicrobial activity of the compounds is maintained or even increased; in particular, the activity of the complexes is augmented against Escherichia coli, a representative of Gram-negative bacteria that have emerged as a major concern in drug resistance. Moreover, the synthesised compounds display similar general toxicity (Artemia salina model) levels to the original antibiotic, pipemidic acid. The increased antibacterial activity of the synthesised compounds, together with their appropriate toxicity levels, are promising outcomes.

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Visional Attentional Allocation of Top-down and Bottom-up Cues in Three-Dimensional Space

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.179-180.1322 ◽

2011 ◽

Vol 179-180 ◽

pp. 1322-1326

Author(s):

Ru Ting Xia

Keyword(s):

Visual Attention ◽

Dimensional Space ◽

Three Dimensional ◽

Depth Information ◽

Top Down ◽

Bottom Up ◽

Attentional Allocation ◽

3D Space ◽

Target Locations ◽

Three Dimensional Space

The aim of the present experiment was to investigate visual attentional allocation of top-down and bottom-up cues in three-dimensional (3D) space. Near and far stimuli were used by a 3D attention measurement apparatus. Two experiments were conducted in order to examine top-down and bottom-up controls of visual attention. In the experiment 1, the cue about the location of a target by means of location information. In the experiment 2, color cue by brief change of color at target locations was presented. Observers were required to judge whether the target presented nearer than fixation point or further than it. The results in experiment 1 and experiment 2 show that both location and color cue have the effect on reaction time, and that shift of attention were faster from far to near than the reverse. These findings suggest that (1) attention in 3D space might be operated with both location and color controls included the depth information, (2) the shift of visual attention in 3D space has an asymmetric characteristic in depth.

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Prediction of Potential Cracking Failure Modes in Three-Dimensional Airfield Rigid Pavements with Existing Cracks and Flaws

Transportation Research Record Journal of the Transportation Research Board ◽

10.3141/2266-02 ◽

2012 ◽

Vol 2266 (1) ◽

pp. 11-19 ◽

Cited By ~ 2

Author(s):

Francisco Evangelista ◽

Jeffery R. Roesler ◽

C. Armando Duarte

Keyword(s):

Failure Modes ◽

Concrete Slab ◽

Three Dimensional ◽

Fatigue Cracking ◽

Crack Size ◽

Concrete Slabs ◽

Shear Mode ◽

Generalized Finite Element Method ◽

Top Down ◽

Bottom Up

This paper predicts the potential for crack propagation in concrete pavements under aircraft loading given a starter fatigue crack at the bottom of the concrete slab or a surface-initiated shrinkage crack on top of the slab. The generalized finite element method was used to evaluate the stress intensity factors for quarter elliptical cracks placed at the critical top and bottom tensile stress locations. The pavement was loaded with a single triple-dualtandem (TDT) gear and two TDTs accounting for the entire belly gears. When the pavement was loaded with the two TDT gear configuration, the analyses showed significantly higher KI (shear mode) values for surface-initiated cracks than for bottom-initiated cracks for the same crack size. Therefore, concrete slabs with preexisting surface cracks are more likely to exhibit top-down crack growth despite being designed for bottom-up fatigue cracking under certain loading conditions. The theoretical framework allows for improved assessment of the fracture susceptibility of concrete slabs under aircraft loading, specifically the potential for top-down over bottom-up cracking.

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A New Process to Fabricate Three Dimensional Ordered Nano Dot Array Structures by Nano Plastic Forming and Dewetting

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.523-524.627 ◽

2012 ◽

Vol 523-524 ◽

pp. 627-632

Author(s):

Zhen Xing Li ◽

Akinori Yamanaka ◽

Masahiko Yoshino

Keyword(s):

Metal Layer ◽

Low Cost ◽

Three Dimensional ◽

Process Conditions ◽

Top Down ◽

Bottom Up ◽

Spacer Layer ◽

New Process ◽

Plastic Forming ◽

Array Structures

Three dimensional (3D) nano/quantum dot array structures have attracted more and more attention due to their broad applications. A new fabrication method of multilayer ordered nano dot array with low cost and high throughput is developed in this paper. This process is combination of Top-down and Bottom-up approaches: Nano Plastic Forming (NPF) patterning of metal layer coated on the substrate as Top-down approach and self-organization by dewetting as Bottom-up approach. Effects of process conditions on 3D nano-dot array formation are studied experimentally. Regularity and uniformity of first layer nano-dot array is transferred to the second layer nano-dots by optimizing thickness of the spacer layer and Au coating layer. Multilayer ordered nano dot array structures with good alignment are obtained by repeating coating and annealing processes.

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Three-Dimensional Trait System: Binding Together the Main Sources of Diversity in Personality Traits

10.31234/osf.io/jg6zr ◽

2019 ◽

Author(s):

Sergei Shchebetenko

Keyword(s):

Personality Traits ◽

Big Five ◽

Personality Trait ◽

Three Dimensional ◽

Lifespan Development ◽

Top Down ◽

Bottom Up ◽

The Third ◽

History Of

Why are there various personality traits and why are those traits revealed in widely-acclaimed models such as the Big Five? The Three-Dimensional Trait System (3D-TRASY) states that any personality trait can be defined in terms of three basic sources. The first source represents traits’ variability with regard to the brain’s functioning in terms of bottom-up and top-down processes. The second source connects to positive (rewards) and negative (punishments) social reinforcements of the trait. The third source reflects a multitude of situations in which a trait may unfold. Thus, Extraversion can be defined as a proximate bottom-up positive while Conscientiousness is a distal top-down positive. 3D-TRASY provides a framework for formal, non-tautological definitions of traits; it provides explanations for various phenomena in trait research including the super-traits of Stability and Plasticity and the maturity principle of lifespan development. 3D-TRASY presumes that some traits can occasionally closely correlate and thus establish an amalgam, which exemplifies itself in Eysenckian Psychoticism and the Big-Five’s Agreeableness. In the history of trait research, this amalgamation may explain controversies that would have facilitated emergence of novel models such as the Big Five or HEXACO. The paper contains empirical demonstrations on how 3D-TRASY can explain apparently empirical artifacts.

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The Research on Automatic Recognition of Assembly Feature and Converse Parametric Design Method Based on UG

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.580.87 ◽

2012 ◽

Vol 580 ◽

pp. 87-90

Author(s):

Bin Fang ◽

Liang Tian

Keyword(s):

Parametric Design ◽

Design Method ◽

Three Dimensional ◽

Automatic Recognition ◽

One Dimension ◽

Top Down ◽

Bottom Up ◽

Assembly Features ◽

Assembly Feature ◽

One To One

No matter the bottom-up design mode is adopted or the top-down design is chosen, one-to-one dimension relation can be realized alone among assembly-components in three-dimensional CAD systems.In the paper, a method of automatic recognition is put forward based on assembly features in UG and various definitions as well as expressional methods of assembly features are analyzed. The interrelated dimension relation is established on account of the fit dimension chain. The converse parametric design is realized besides an independent module in UG is developed to achieve the function.

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