Black-box optimization for integer-variable problems using Ising machines and factorization machines

Black-box optimization has potential in numerous applications such as hyperparameter optimization in machine learning and optimization in design of experiments. Ising machines are useful for binary optimization problems because variables can be represented by a single binary variable of Ising machines. However, conventional approaches using an Ising machine cannot handle black-box optimization problems with non-binary values. To overcome this limitation, we propose an approach for integer-variable black-box optimization problems by using Ising/annealing machines and factorization machines in cooperation with three different integer-encoding methods. The performance of our approach is numerically evaluated with different encoding methods using a simple problem of calculating the energy of the hydrogen molecule in the most stable state. The proposed approach can calculate the energy using any of the integer-encoding methods. However, one-hot encoding is useful for problems with a small size.Comment: 12 pages, 5 figure

Flattened 1D fragments of fullerene C₆₀ that exhibit robustness toward multi-electron reduction

フラーレンに迫る電子受容能をもつ平坦な一次元π共役炭化水素の開発. 京都大学プレスリリース. 2023-05-15.Flat fullerene fragments attractive to electrons. 京都大学プレスリリース. 2023-06-01.Fullerenes are compelling molecular materials owing to their exceptional robustness toward multi-electron reduction. Although scientists have attempted to address this feature by synthesizing various fragment molecules, the origin of this electron affinity remains unclear. Several structural factors have been suggested, including high symmetry, pyramidalized carbon atoms, and five-membered ring substructures. To elucidate the role of the five-membered ring substructures without the influence of high symmetry and pyramidalized carbon atoms, we herein report the synthesis and electron-accepting properties of oligo(biindenylidene)s, a flattened one-dimensional fragment of fullerene C₆₀. Electrochemical studies corroborated that oligo(biindenylidene)s can accept electrons up to equal to the number of five-membered rings in their main chains. Moreover, ultraviolet/visible/near-infrared absorption spectroscopy revealed that oligo(biindenylidene)s exhibit enhanced absorption covering the entire visible region relative to C₆₀. These results highlight the significance of the pentagonal substructure for attaining stability toward multi-electron reduction and provide a strategy for the molecular design of electron-accepting π-conjugated hydrocarbons even without electron-withdrawing groups

Facile synthesis of an ambient stable pyreno[4,5-b]pyrrole monoanion and pyreno[4,5-b:9,10-b ']dipyrrole dianion: from serendipity to design

The stability of singly or multiply negatively charged π-conjugated organic compounds is greatly influenced by their electronic delocalization. Herein, we report a strategic methodology for isolation of a mysterious compound. The isolated compounds, a pyreno[4, 5-b]pyrrole monoanion and pyreno[4, 5-b:9, 10-b′]dipyrrole dianion, were highly stable under ambient conditions due to high delocalization of the negative charge over multiple electron deficient C[triple bond, length as m-dash]N groups and pyrene π-scaffolds and allowed purification by column chromatography. To our knowledge, this is the first report on TCNE type reductive condensation of malononitrile involving pyrene di- and tetraone and formation of pyrenopyrrole. All compounds were characterized by spectroscopic methods and X-ray crystallography. A UV-vis spectroscopic study shows an intense low energy absorption band with a large absorption coefficient (ε)

Distribution of β2-adrenergic receptor mRNA expression along the hamster nephron segments

AbstractDistribution of β2-adrenergic receptor mRNA expression along the microdissected hamster nephron segments was examined by the reverse transcription-polymerase chain reaction (RT-PCR) technique. Conventional RT-PCR using a set of primers on separate exons could not be applied for the detection of β2-adrenergic receptor mRNA because of its intronless nature. We used the ‘rapid amplification of cDNA ends’ protocol [(1985) Proc. Natl. Acad. Sci. USA 85, 8998-9002] as a maneuver for RT-PCR of an intronless gene. Using this method, we successfully located hamster β2-adrenergic receptor mRNA only in glomeruli and early proximal convoluted tubule along the nephron segments tested

Cyclobuteno[60]fullerenes as efficient n-type organic semiconductors

Cyclobuteno[3,4:1,2][60]fullerenes have been prepared in a straightforward manner by a simple reaction between [60]fullerene and readily available allenoates or alkynoates as organic reagents under basic and mild conditions. The chemical structure of the new modified fullerenes has been determined by standard spectroscopic techniques and confirmed by X-Ray diffraction analysis. Some of these new fullerene derivatives exhibit a remarkable intrinsic electron mobility – determined by using flash-photolysis time-resolved microwave conductivity (FP-TRMC) measurements – which surpasses that of the well-known PCBM, thus behavi ng as promising n-type organic semiconductors

Repeat protein scaffolds: ordering photo- and electroactive molecules in solution and solid state

The precise control over the organization of photoactive components at the nanoscale is one of the main challenges for the generation of new and sophisticated macroscopically ordered materials with enhanced properties. In this work we present a novel bioinspired approach using protein-based building blocks for the arrangement of photo and electroactive porphyrin derivatives. We used a designed repeat protein scaffold with demonstrated unique features that allow for the control of their structure, functionality, and assembly. Our designed domains act as exact biomolecular templates to organize porphyrin molecules at the required distance. The hybrid conjugates retain the structure and assembly properties of the protein scaffold and display the spectroscopic features of orderly aggregated porphyrins along the protein structure. Finally,we achieved a solid ordered bio-organic hybrid thin film with anisotropic photoconductivity

Cyclophane self-assembly from carbazole-based diradicals

The investigation of π-conjugated diradical compounds, featuring radical centers in the ground state, is key to understanding the nature of chemical bonds.[1] Occasionally, these systems can form long σ C-C bonds between two unpaired electrons resulting in macrocyclic or staircase oligomers or polymers by self-assembly processes. Furthermore, these new C-C bonds are longer than an ordinary bond between two sp3 carbon resulting in reversible dissociation/formation behavior between isolated radical species and cyclophane structures. Therefore, these materials are potential building blocks for dynamic covalent chemistry (DCC).[2] Hereinto, we present an experimental and theoretical study of carbazole and indolocarbazole-based diradicals (Figure 1) with dicyanomethylene (DCM) groups in different positions (para-DCM or meta-DCM) to identify new building blocks to obtain multi-responsive materials.[3-5] To this end, we investigated the dynamic interconversion between the isolated diradical and the cyclophane structures under external stimuli such as temperature, pressure and so on. Specifically, our main aim is to study how the DCM substitution and the elongation of the conjugated core affect the diradical character and to understand the connection between this parameter and the cyclophanes stability. In addition, we want to investigate if this transformation is reversible or not.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Carbazole and indolcarbazole-based systems: impact of the structural changes on the system properties

π-Conjugated diradical compounds, featuring unique unsaturated valences and radical centres in the ground state, are fundamentally important for understanding the nature of chemical bonds and have potential applications in material science [1] . During the last decade, there has been an increasing interest in the rationalization of how the structural changes stabilize (or destabilize) the diradical system. The tunability of the diradical character has been studied for different structural motifs such as the substitution pattern of lateral groups[2], the elongation of the conjugated core[3] or the molecular isomerism[4], among others. In this sense, we have recently reported an experimental/theoretical study of a family of carbazole-based diradicaloids with dicyanomethylene (DCM) groups incorporated via para (p-Cz and p-ICz) or meta positions (mCz and m-ICz) aiming to investigate how external stimuli impact on the molecular structure and supramolecular organization, and thus on the resulting optical and electronic properties. In addition, we theoretically investigate at the DFT level a set of ten indolocarbazole-based isomers substituted with DCM groups to disclose how their chemical reactivity and physical properties are affected by isomerism and different substitution pattern.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. Plan Propio de Investigación de la UM