Biomimicry designs for passive optical solutions for nanoscale radiative cooling applications

Inspired by the mechanism of the wings of Morpho butterfly, here we propose biomimicry designs which have the potential to be used for radiative cooling purposes. We numerically analyzed the spontaneous emission at near-field and determined radiative heat flux at nano-scale in order to investigate the impact of geometric variations and material selection in these systems. Our findings suggest that these metasurfaces which support phononic surface waves, can be used to tailor radiative heat transfer at nano-scale in the atmospheric transparency window (8-13 mu m) within the infrared regime

Atrial fibrillation genetic risk differentiates cardioembolic stroke from other stroke subtypes

AbstractObjectiveWe sought to assess whether genetic risk factors for atrial fibrillation can explain cardioembolic stroke risk.MethodsWe evaluated genetic correlations between a prior genetic study of AF and AF in the presence of cardioembolic stroke using genome-wide genotypes from the Stroke Genetics Network (N = 3,190 AF cases, 3,000 cardioembolic stroke cases, and 28,026 referents). We tested whether a previously-validated AF polygenic risk score (PRS) associated with cardioembolic and other stroke subtypes after accounting for AF clinical risk factors.ResultsWe observed strong correlation between previously reported genetic risk for AF, AF in the presence of stroke, and cardioembolic stroke (Pearson’s r=0.77 and 0.76, respectively, across SNPs with p &lt; 4.4 × 10−4 in the prior AF meta-analysis). An AF PRS, adjusted for clinical AF risk factors, was associated with cardioembolic stroke (odds ratio (OR) per standard deviation (sd) = 1.40, p = 1.45×10−48), explaining ∼20% of the heritable component of cardioembolic stroke risk. The AF PRS was also associated with stroke of undetermined cause (OR per sd = 1.07, p = 0.004), but no other primary stroke subtypes (all p &gt; 0.1).ConclusionsGenetic risk for AF is associated with cardioembolic stroke, independent of clinical risk factors. Studies are warranted to determine whether AF genetic risk can serve as a biomarker for strokes caused by AF.</jats:sec

Stroke genetics informs drug discovery and risk prediction across ancestries

Previous genome-wide association studies (GWASs) of stroke — the second leading cause of death worldwide — were conducted predominantly in populations of European ancestry1,2. Here, in cross-ancestry GWAS meta-analyses of 110,182 patients who have had a stroke (five ancestries, 33% non-European) and 1,503,898 control individuals, we identify association signals for stroke and its subtypes at 89 (61 new) independent loci: 60 in primary inverse-variance-weighted analyses and 29 in secondary meta-regression and multitrait analyses. On the basis of internal cross-ancestry validation and an independent follow-up in 89,084 additional cases of stroke (30% non-European) and 1,013,843 control individuals, 87% of the primary stroke risk loci and 60% of the secondary stroke risk loci were replicated (P < 0.05). Effect sizes were highly correlated across ancestries. Cross-ancestry fine-mapping, in silico mutagenesis analysis3, and transcriptome-wide and proteome-wide association analyses revealed putative causal genes (such as SH3PXD2A and FURIN) and variants (such as at GRK5 and NOS3). Using a three-pronged approach4, we provide genetic evidence for putative drug effects, highlighting F11, KLKB1, PROC, GP1BA, LAMC2 and VCAM1 as possible targets, with drugs already under investigation for stroke for F11 and PROC. A polygenic score integrating cross-ancestry and ancestry-specific stroke GWASs with vascular-risk factor GWASs (integrative polygenic scores) strongly predicted ischaemic stroke in populations of European, East Asian and African ancestry5. Stroke genetic risk scores were predictive of ischaemic stroke independent of clinical risk factors in 52,600 clinical-trial participants with cardiometabolic disease. Our results provide insights to inform biology, reveal potential drug targets and derive genetic risk prediction tools across ancestries

Relevanz und Nutzung von Anionen-pi Wechselwirkungen

In this thesis the relevance and the use of a new intermolecular force between anions and electrondeficient arenes was investigated. In the last ten years the anion-pi interaction has gain a growing interest in the supramolecular community. It should be useful for the design of novel anion receptors. For this purpose the nature of the anion-pi interactions has to be examined. The present studies show the relevance of this interaction in solution and in the solid state. The solid state studies showed a high flexibility in the relative orientation of the anion to the pi-system and that it can easily be influenced by other non-covalent interactions and packing effects. By the use of rigide and highly symmetric receptors the position of the anion is fixed above the center of the pentafluorophenyl group. Whereas in more flexible and less symmetric receptors the anion is pushed into the direction of one rim of the pi-system. Further studies investigated the influence of the anion geometry. While the geometry of the anion seems to play a minor role, the size of the anion controls the molecular packing. Moreover, the stabilization of sensitive anions like the tetraiodide dianion with the help of anion-pi interactions was observed in the solid state. The present studies also confirm a strong dependence of the interactions between the anion and the fluorination degree of the arene. Highly electron deficient phenyl groups interact attractively with the anion, while more electron rich systems lead to an increasing distance between the arene and the anion. An attractive interaction between metallfree, non-charged receptors in the solid state could be shown in the crystal structure of the tetraethylammonium bromide and pentafluorobenzamide cocrystal. The large number of obtained crystal structures proves that an attractive interaction of anions and electron deficient arenes can be observed in the solid state. In many cases the anion is fixed above the pi-center, which indicates that the anion-pi interaction is not only an effect of crystallization. During the solution experiments it was found that the differential binding constants of pentafluorobenzyl ammonium and phosphonium salts give no hint for an attractive interaction between anions and Pentafluorophenyl groups. The weak anion-pi interaction is covered by other competing interactions like CH-anion and coulomb attraction. Further studies revealed a difference in the association constants between benzamide receptors with electron rich and poor phenyl groups. But it could not be clearified if this is an effect of the attractive interaction of anions with pi-systems or just due to the higher acidity of the amide protons. The performed solution experiments could not clear up the role of anion-pi interaction in solution. But it can be suggested, that due to the weakness of this interaction, it can easily be covered by competing interactions or solution effects. But nevertheless, the design of novel anion receptors by using anion-pi interactions can lead to new applications in supramolecular chemistry. For this purpose further investigations of the nature of the intermoleculare force between anion and electron deficient arenes are necesserary

Relevanz und Nutzung von Anionen-pi Wechselwirkungen

In this thesis the relevance and the use of a new intermolecular force between anions and electrondeficient arenes was investigated. In the last ten years the anion-pi interaction has gain a growing interest in the supramolecular community. It should be useful for the design of novel anion receptors. For this purpose the nature of the anion-pi interactions has to be examined. The present studies show the relevance of this interaction in solution and in the solid state. The solid state studies showed a high flexibility in the relative orientation of the anion to the pi-system and that it can easily be influenced by other non-covalent interactions and packing effects. By the use of rigide and highly symmetric receptors the position of the anion is fixed above the center of the pentafluorophenyl group. Whereas in more flexible and less symmetric receptors the anion is pushed into the direction of one rim of the pi-system. Further studies investigated the influence of the anion geometry. While the geometry of the anion seems to play a minor role, the size of the anion controls the molecular packing. Moreover, the stabilization of sensitive anions like the tetraiodide dianion with the help of anion-pi interactions was observed in the solid state. The present studies also confirm a strong dependence of the interactions between the anion and the fluorination degree of the arene. Highly electron deficient phenyl groups interact attractively with the anion, while more electron rich systems lead to an increasing distance between the arene and the anion. An attractive interaction between metallfree, non-charged receptors in the solid state could be shown in the crystal structure of the tetraethylammonium bromide and pentafluorobenzamide cocrystal. The large number of obtained crystal structures proves that an attractive interaction of anions and electron deficient arenes can be observed in the solid state. In many cases the anion is fixed above the pi-center, which indicates that the anion-pi interaction is not only an effect of crystallization. During the solution experiments it was found that the differential binding constants of pentafluorobenzyl ammonium and phosphonium salts give no hint for an attractive interaction between anions and Pentafluorophenyl groups. The weak anion-pi interaction is covered by other competing interactions like CH-anion and coulomb attraction. Further studies revealed a difference in the association constants between benzamide receptors with electron rich and poor phenyl groups. But it could not be clearified if this is an effect of the attractive interaction of anions with pi-systems or just due to the higher acidity of the amide protons. The performed solution experiments could not clear up the role of anion-pi interaction in solution. But it can be suggested, that due to the weakness of this interaction, it can easily be covered by competing interactions or solution effects. But nevertheless, the design of novel anion receptors by using anion-pi interactions can lead to new applications in supramolecular chemistry. For this purpose further investigations of the nature of the intermoleculare force between anion and electron deficient arenes are necesserary