scholarly journals Dimeric and Trimeric Catenation of Giant Chiral [8+12] Imine Cubes Driven by Weak Supramolecular Interactions

2021 ◽  
Author(s):  
Bahiru Punja Benke ◽  
Tobias Kirschbaum ◽  
Jürgen Graf ◽  
Michael Mastalerz
Keyword(s):  
Driving Forces ◽  
Three Dimensional ◽  
Molecular Switches ◽  
Supramolecular Interactions ◽  
Reaction Conditions ◽  
Π Stacking ◽  
Methoxy Groups ◽  
Dimensional Shape ◽  
First Time ◽  
Three Dimensional Shape

Mechanically interlocked structures, such as catenanes or rotaxanes are fascinating synthetic targets and are the basis of molecular switches and machines. Today, the vast majority of catenated structures are built upon macrocycles and only a very few examples of three?dimensional shape-persistent organic cages forming such structures are reported. However, the catenation in all these cases was based on a thermodynamically favoured π-π stacking under certain reaction conditions. Here, we present our findings that catenane formation can be driven by even less directional dispersion (Keesom) interactions of methoxy-groups during the synthesis of chiral [8+12] imine cubes, giving dimeric and also for the first time trimeric catenated organic cages. To further elucidate the underlying driving forces, twelve differently 1,4-substituted benzene dialdehydes have been reacted with a chiral triamino tribenzotriquinacene under various conditions to study whether monomeric cages or catenated cage dimers are the preferred products.

scholarly journals Dimeric and Trimeric Catenation of Giant Chiral [8+12] Imine Cubes Driven by Weak Supramolecular Interactions

2021 ◽  
Author(s):  
Bahiru Punja Benke ◽  
Tobias Kirschbaum ◽  
Jürgen Graf ◽  
Michael Mastalerz
Keyword(s):  
Driving Forces ◽  
Three Dimensional ◽  
Molecular Switches ◽  
Supramolecular Interactions ◽  
Reaction Conditions ◽  
Π Stacking ◽  
Methoxy Groups ◽  
Dimensional Shape ◽  
First Time ◽  
Three Dimensional Shape

Mechanically interlocked structures, such as catenanes or rotaxanes are fascinating synthetic targets and are the basis of molecular switches and machines. Today, the vast majority of catenated structures are built upon macrocycles and only a very few examples of three?dimensional shape-persistent organic cages forming such structures are reported. However, the catenation in all these cases was based on a thermodynamically favoured π-π stacking under certain reaction conditions. Here, we present our findings that catenane formation can be driven by even less directional dispersion (Keesom) interactions of methoxy-groups during the synthesis of chiral [8+12] imine cubes, giving dimeric and also for the first time trimeric catenated organic cages. To further elucidate the underlying driving forces, twelve differently 1,4-substituted benzene dialdehydes have been reacted with a chiral triamino tribenzotriquinacene under various conditions to study whether monomeric cages or catenated cage dimers are the preferred products.

scholarly journals The perception of shape from shading in a new light

2013 ◽  
Author(s):  
Michael J Proulx
Keyword(s):  
Bayesian Models ◽  
Three Dimensional ◽  
Internal Representation ◽  
Shape From Shading ◽  
Two Dimensional ◽  
Persuasive Power ◽  
Dimensional Shape ◽  
External Light Source ◽  
First Time ◽  
Three Dimensional Shape

How do humans see three-dimensional shape based on two-dimensional shading? Much research has assumed that a ‘light from above’ bias solves the ambiguity of shape from shading. Counter to the ‘light from above’ bias, studies of Bayesian priors have found that such a bias can be swayed by other light cues. Despite the persuasive power of the Bayesian models, many new studies and books cite the original ‘light from above’ findings. Here I present a version of the Bayesian result that can be experienced. The perception of shape-from-shading based was found here to be influenced by an external light source, even when the light was obstructed and did not directly illuminate a two-dimensional stimulus. The results imply that this effect is robust and not low-level in nature. The perception of shape from shading is not necessarily based on a hard-wired internal representation of lighting direction, but rather assesses the direction of lighting in the scene adaptively. Here, for the first time, is an experiential opportunity to see what the Bayesian models have supported all along.

scholarly journals Postcopulatory sexual selection and the evolution of shape complexity in the carnivoran baculum

2020 ◽  
Vol 287 (1936) ◽  
pp. 20201883
Author(s):  
Charlotte A. Brassey ◽  
Julia Behnsen ◽  
James D. Gardiner
Keyword(s):  
Sexual Selection ◽  
Driving Forces ◽  
Three Dimensional ◽  
Group Living ◽  
Postcopulatory Sexual Selection ◽  
Monogamous Species ◽  
Socially Monogamous ◽  
Dimensional Shape ◽  
Shape Complexity ◽  
Three Dimensional Shape

The baculum is an enigmatic bone within the mammalian glans penis, and the driving forces behind its often bizarre shape have captivated evolutionary biologists for over a century. Hypotheses for the function of the baculum include aiding in intromission, stimulating females and assisting with prolonged mating. Previous attempts to test these hypotheses have focused on the gross size of the baculum and have failed to reach a consensus. We conducted three-dimensional imaging and apply a new method to quantify three-dimensional shape complexity in the carnivoran baculum. We show that socially monogamous species are evolving towards complex-shaped bacula, whereas group-living species are evolving towards simple bacula. Overall three-dimensional baculum shape complexity is not related to relative testes mass, but tip complexity is higher in induced ovulators and species engaging in prolonged copulation. Our study provides evidence of postcopulatory sexual selection pressures driving three-dimensional shape complexity in the carnivore baculum.

scholarly journals The perception of shape from shading in a new light

2013 ◽  
Author(s):  
Michael J Proulx
Keyword(s):  
Bayesian Models ◽  
Three Dimensional ◽  
Internal Representation ◽  
Shape From Shading ◽  
Two Dimensional ◽  
Persuasive Power ◽  
Dimensional Shape ◽  
External Light Source ◽  
First Time ◽  
Three Dimensional Shape

How do humans see three-dimensional shape based on two-dimensional shading? Much research has assumed that a ‘light from above’ bias solves the ambiguity of shape from shading. Counter to the ‘light from above’ bias, studies of Bayesian priors have found that such a bias can be swayed by other light cues. Despite the persuasive power of the Bayesian models, many new studies and books cite the original ‘light from above’ findings. Here I present a version of the Bayesian result that can be experienced. The perception of shape-from-shading based was found here to be influenced by an external light source, even when the light was obstructed and did not directly illuminate a two-dimensional stimulus. The results imply that this effect is robust and not low-level in nature. The perception of shape from shading is not necessarily based on a hard-wired internal representation of lighting direction, but rather assesses the direction of lighting in the scene adaptively. Here, for the first time, is an experiential opportunity to see what the Bayesian models have supported all along.

Four Dimensions of Diamond T: Combination Trade Marks of Colours And Shapes

2006 ◽  
Vol 37 (4) ◽  
pp. 583
Author(s):  
Michael McGowan
Keyword(s):  
Three Dimensional ◽  
Trade Mark ◽  
Fourth Dimension ◽  
Trade Marks ◽  
Four Dimensions ◽  
Trade Mark Law ◽  
Dimensional Shape ◽  
Three Dimensional Shape

This article examines the relatively new fields of colour and shape trade marks. It was initially feared by some academics that the new marks would encroach on the realms of patent and copyright.  However, the traditional requirements of trade mark law, such as functionality and descriptiveness, have meant that trade marks in colour and shape are extremely hard to acquire if they do not have factual distinctiveness. As colour and shape trade marks have no special restrictions, it is proposed that the combination trade mark theory and analysis from the Diamond T case should be used as a way to make them more accessible. The combination analysis can be easily applied because every product has a three dimensional shape and a fourth dimension of colour.

Acoustic Analysis of Detailed Three-Dimensional Shape of the Human Nasal Cavity and Paranasal Sinuses

2017 ◽  
Author(s):  
Tatsuya Kitamura ◽  
Hironori Takemoto ◽  
Hisanori Makinae ◽  
Tetsutaro Yamaguchi ◽  
Kotaro Maki
Keyword(s):  
Nasal Cavity ◽  
Paranasal Sinuses ◽  
Acoustic Analysis ◽  
Three Dimensional ◽  
Dimensional Shape ◽  
Three Dimensional Shape
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