Histopathological Image Analysis with Style-Augmented Feature Domain Mixing for Improved Generalization

Histopathological images are essential for medical diagnosis and treatment planning, but interpreting them accurately using machine learning can be challenging due to variations in tissue preparation, staining and imaging protocols. Domain generalization aims to address such limitations by enabling the learning models to generalize to new datasets or populations. Style transfer-based data augmentation is an emerging technique that can be used to improve the generalizability of machine learning models for histopathological images. However, existing style transfer-based methods can be computationally expensive, and they rely on artistic styles, which can negatively impact model accuracy. In this study, we propose a feature domain style mixing technique that uses adaptive instance normalization to generate style-augmented versions of images. We compare our proposed method with existing style transfer-based data augmentation methods and found that it performs similarly or better, despite requiring less computation and time. Our results demonstrate the potential of feature domain statistics mixing in the generalization of learning models for histopathological image analysis.Comment: Paper is published in MedAGI 2023 (MICCAI 2023 1st International Workshop on Foundation Models for General Medical AI) Code link: https://github.com/Vaibhav-Khamankar/FuseStyle Paper link: https://nbviewer.org/github/MedAGI/medagi.github.io/blob/main/src/assets/papers/P17.pd

Ultrafast structural changes direct the first molecular events of vision

視覚に関わるタンパク質の超高速分子動画 --薄暗いところで光を感じる仕組み--. 京都大学プレスリリース. 2023-03-23.Vision is initiated by the rhodopsin family of light-sensitive G protein-coupled receptors (GPCRs). A photon is absorbed by the 11-cis retinal chromophore of rhodopsin, which isomerizes within 200 femtoseconds to the all-trans conformation, thereby initiating the cellular signal transduction processes that ultimately lead to vision. However, the intramolecular mechanism by which the photoactivated retinal induces the activation events inside rhodopsin remains experimentally unclear. Here we use ultrafast time-resolved crystallography at room temperature to determine how an isomerized twisted all-trans retinal stores the photon energy that is required to initiate the protein conformational changes associated with the formation of the G protein-binding signalling state. The distorted retinal at a 1-ps time delay after photoactivation has pulled away from half of its numerous interactions with its binding pocket, and the excess of the photon energy is released through an anisotropic protein breathing motion in the direction of the extracellular space. Notably, the very early structural motions in the protein side chains of rhodopsin appear in regions that are involved in later stages of the conserved class A GPCR activation mechanism. Our study sheds light on the earliest stages of vision in vertebrates and points to fundamental aspects of the molecular mechanisms of agonist-mediated GPCR activation

Construction productivity and global inequality

Two well established stylized facts of economic development are a strong correlation between investment and income, and large differences in investment rates across countries. Construction is the largest component of investment. This paper examines the implications of heterogeneity in construction productivity on cross-country income disparity. We estimate the 10:1 spread in construction productivity among 145 countries in 2005 as a factor of 61.7-fold. Based on a general equilibrium model with input-output linkages, we find that the 10:1 spread in income per capita declines by 45 per cent when the construction productivity gap is eliminated. Sectoral characterization of the aggregate effect of a change in construction productivity shows heterogeneous sectoral contributions to income convergence. Electrical equipment, metals, and transport equipment play stronger roles in transforming the effect of a change in construction productivity to the aggregate level in China compared with other countries

A comprehensive benchmark of the XMS-CASPT2 method for the photochemistry of a retinal chromophore model

The performance of the extended multi-state (XMS)-complete active space second-order perturbation theory (CASPT2) method has been assessed for the benchmark of a truncated retinal model, the penta-2,4-dieniminium cation (PSB3). This benchmark presents a challenge for multireference electronic structure methods because the wave function character is changing considerably. The assessment comprises ground and excited state pathways of the isomerisation, including transition states and conical intersection (CI) points. It also includes circular paths centred around different CIs, and 2D potential energy scans located in the branching planes. In this work, we compare the performance of the previous formulations of CASPT2, the single-state and the multi-state, with the recently developed XMS-CASPT2. Besides, we have also tested two variants of internal contraction in XMS-CASPT2, namely, the single-state single reference (SS-SR) and multi-state multireference (MS-MR) schemes. In our study, we find that XMS-CASPT2 corrects the artefacts and discontinuities present in other CASPT2 variants. The investigation of a circular loop and 2D potential energy surfaces around the surface crossing point shows that XMS-CASPT2 exhibits a smooth topology at the CI with the correct degeneracy. It also agrees better with the reference method MRCISD+Q in regions of the potential energy surfaces further away from CIs. Another observation is the close agreement between the results from the SS-SR contraction scheme and the more demanding MS-MR scheme

π‑Stacked Dimers of Fluorophenylacetylenes: Role of Dipole Moment

The homodimers of singly fluorine-substituted phenylacetylenes were investigated using electronic and vibrational spectroscopic methods in combination with density functional theory calculations. The IR spectra in the acetylenic C–H stretching region show a marginal red shift for the dimers relative to the monomers. Further, the marginal red shifts indicate that the acetylenic group in all the dimers is minimally perturbed relative to the corresponding monomer. The observed spectra were assigned to a set of π-stacked structures within an energy range of 1.5 kJ mol^–1, which differ in the relative orientation of the two monomers on the basis of M06-2X/aug-cc-pVTZ level calculation. The observed red shift in the acetylenic C–H stretching vibration of the dimers suggests that the antiparallel structures contribute predominantly based on a simple coupled dipole model. Energy decomposition analysis using symmetry-adapted perturbation theory indicates that dispersion plays a pivotal role in π–π stacking with appreciable contribution of electrostatics. The stabilization energies of fluorophenylacetylene dimers follow the same ordering as their dipole moments, which suggests that dipole moment enhances the ability to form π-stacked structures

Octanuclear Zinc Phosphates with Hitherto Unknown Cluster Architectures: Ancillary Ligand and Solvent Assisted Structural Transformations Thereof

Structural variations in zinc phosphate cluster chemistry have been achieved through a careful selection of phosphate ligand, ancillary ligand, and solvent medium. The use of 4-haloaryl phosphates (X-dippH₂) as phosphate source in conjunction with 2-hydroxypyridine (hpy) ancillary ligand in acetonitrile solvent resulted in the isolation of the first examples of octameric zinc phosphates [Zn₈(X-dipp)₈(hpy)₄­(CH₃CN)₂(H₂O)₂]·4H₂O (X = Cl <b>2</b>, Br <b>3</b>) and not the expected tetranuclear D4R cubane clusters. Use of 2,3-dihydroxypyridine (dhpy) as ancillary ligand, under otherwise similar reaction conditions with the same set of phosphate ligands and solvent, resulted in isolation of another type of octanuclear zinc phosphate clusters {[(Zn₈(X-dipp)₄(X-dippH)₄­(dhpyH)₄­(dhpyH₂)₂(H₂O)₂]·2solvent} (X = Cl, solvent = MeCN <b>4</b>; Br, solvent = H₂O <b>5</b>), as the only isolated products. X-ray crystal diffraction studies reveal that <b>2</b> and <b>3</b> are octanuclear clusters that are essentially formed by edge fusion of two D4R zinc phosphates. Although <b>4</b> and <b>5</b> are also octanuclear clusters, they exhibit a completely different cluster architecture and have been presumably formed by the ability of 2,3-dihydroxypyridine to bridge zinc centers in addition to the X-dipp ligands. Dissolution of both types of octanuclear clusters in DMSO followed by crystallization yields D4R cubanes [Zn­(X-dipp)­(DMSO)]₄ (X = Cl <b>6</b>, Br <b>7</b>), in which the ancillary ligands such as hpy, H₂O, and CH₃CN originally present on the zinc centers of <b>2</b>–<b>5</b> have been replaced by DMSO. DFT calculations carried out to understand the preference of Zn₈ versus Zn₄ clusters in different solvent media reveal that use of CH₃CN as solvent favors the formation of fused cubanes of the type <b>2</b> and <b>3</b>, whereas use of DMSO as the solvent medium promotes the formation of D4R structures of the type <b>6</b> and <b>7</b>. The calculations also reveal that the vacant exocluster coordination sites on the zinc centers at the bridgehead positions prefer coordination by water to hpy or CH₃CN. Interestingly, the initially inaccessible D4R cubanes [Zn­(X-dipp)­(hpy)]₄·2MeCN (X = Cl <b>8</b>, Br <b>9</b>) could be isolated as the sole products from the corresponding DMSO-decorated cubanes <b>6</b> and <b>7</b> by combining them with hpy in CH₃CN