Publications by authors named "Augulis R"

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  • The management of kidney transplant patients heavily relies on biopsy diagnoses, which currently lack consistency and reproducibility in assessing rejection features and tissue changes.
  • This study introduces a computational method that uses deep learning to automate the assessment of kidney biopsy histopathology, specifically focusing on the tubulointerstitial area.
  • By analyzing a large dataset of biopsy images, the researchers were able to identify distinct patterns of acute and chronic injury, offering a more precise approach for classifying and understanding kidney allograft conditions.
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  • * This study applied digital image analysis (DIA) to analyze whole slide images from 254 ER-positive HER2-negative BC patients, focusing on the prognostic value of ITH indicators, particularly using Haralick's texture metrics for Ki67.
  • * The findings revealed that Ki67 entropy, which assesses the spatial arrangement of tumor cells, is a significant predictor of BC-specific survival, surpassing the traditional proliferation rate evaluations and highlighting the importance of ITH in prognosis.
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Despite advances in diagnostic and treatment technologies, predicting outcomes of patients with hepatocellular carcinoma (HCC) remains a challenge. Prognostic models are further obscured by the variable impact of the tumor properties and the remaining liver parenchyma, often affected by cirrhosis or non-alcoholic fatty liver disease that tend to precede HCC. This study investigated the prognostic value of reticulin and collagen microarchitecture in liver resection samples.

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  • Ki67 is a key biomarker in breast cancer but struggles with consistent measurement between labs, prompting research into automated digital image analysis (DIA).
  • The study assessed Ki67 levels using specially prepared slides from 30 breast cancer patients, with analysis conducted by 17 labs to evaluate consistency in scoring.
  • Results showed a strong correlation between consecutive sections, but core biopsy samples had notably higher Ki67 scores than whole sections, indicating that core biopsies may provide a more accurate biological status of the tumor.
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  • The extracellular matrix (ECM) collagen changes significantly during cancer development, but these changes are often overlooked in traditional cancer diagnostics, which typically use H&E staining.
  • A new technique called polarimetric second-harmonic generation (P-SHG) microscopy allows for detailed imaging and analysis of collagen structures without the need for staining, providing more information about tissue characteristics.
  • The study demonstrates that P-SHG microscopy can effectively differentiate between tumor and normal breast tissue, achieving high accuracy rates (94.2% accuracy) and suggesting it could be a valuable tool in cancer diagnostics and prognosis.
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Breast cancer (BC) categorized as human epidermal growth factor receptor 2 (HER2) borderline [2+ by immunohistochemistry (IHC 2+)] presents challenges for the testing, frequently obscured by intratumoral heterogeneity (ITH). This leads to difficulties in therapy decisions. We aimed to establish prognostic models of overall survival (OS) of these patients, which take into account spatial aspects of ITH and tumor microenvironment by using hexagonal tiling analytics of digital image analysis (DIA).

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Diatoms are a major group of algae, responsible for a quarter of the global primary production on our planet. Their adaptation to marine environments is ensured by their light-harvesting antenna - the fucoxanthin-chlorophyll protein (FCP) complex, which absorbs strongly in the blue-green spectral region. Although these essential proteins have been the subject of many studies, for a long time their comprehensive description was not possible in the absence of structural data.

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Immunohistochemistry (IHC) for ER, PR, HER2, and Ki67 is used to predict outcome and therapy response in breast cancer patients. The current IHC assessment, visual or digital, is based mostly on global biomarker expression levels in the tissue sample. In our study, we explored the prognostic value of digital image analysis of conventional breast cancer IHC biomarkers supplemented with their intratumoral heterogeneity and tissue immune response indicators.

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The distribution of tumor-infiltrating lymphocytes (TILs) within the tumor microenvironment provides strong prognostic value, which is increasingly important with the arrival of new immunotherapy modalities. Both visual and image analysis-based assays are developed to assess the immune contexture of the tumors. We propose an automated method based on grid subsampling of microscopy image analysis data to extract the tumor-stroma interface zone (IZ) of controlled width.

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Uncontrolled proliferation is a hallmark of cancer and can be assessed by labelling breast tissue using immunohistochemistry for Ki67, a protein associated with cell proliferation. Accurate measurement of Ki67-positive tumour nuclei is of critical importance, but requires annotation of the tumour regions by a pathologist. This manual annotation process is highly subjective, time-consuming and subject to inter- and intra-annotator experience.

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Detailed studies of the excitation dynamics in photosynthetic pigment-proteins require an application of a wide range of spectroscopic methods. From the later part of the previous century, pump-probe and time-resolved fluorescence spectroscopy provided an impressive amount of information. Being simple to grasp, these methods are well-understood and widely used by the photosynthesis research community.

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Clinical interpretation of patients' plasma adiponectin (APN) remains challenging; its value as biomarker in dilated cardiomyopathy (DCM) is equivocal. We evaluated whether circulating APN level is an independent predictor of composite outcome: death, left ventricle assist device (LVAD) implantation, and heart transplantation (HT) in patients with nonischemic DCM. 57 patients with nonischemic DCM (average LV diastolic diameter 6.

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  • HER2-targeted therapy for breast cancer is mainly based on detecting HER2 overexpression through immunohistochemistry (IHC), and cases with uncertain results are further analyzed using fluorescence in situ hybridization (FISH).
  • The study explored how automated image analysis (IA) of FISH data from borderline HER2 cases can improve the understanding of HER2 heterogeneity, despite IA sometimes underestimating certain HER2 metrics compared to manual methods.
  • By using factor analysis, researchers identified new indicators for tumor classification into categories like amplified and equivocal/polysomy, suggesting that automated IA can enhance HER2 testing and redefine existing definitions of genetic heterogeneity in breast cancer.
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The role of quantum coherence in photochemical functions of molecular systems such as photosynthetic complexes is a broadly debated topic. Coexistence and intermixing of electronic and vibrational coherences has been proposed to be responsible for the observed long-lived coherences and high energy transfer efficiency. However, clear experimental evidence of coherences with different origins operating at the same time has been elusive.

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  • Gene expression studies have highlighted the need for effective tissue sampling criteria based on immunohistochemistry (IHC) markers, specifically the Ki67 labeling index, for subclassifying breast cancer and advising chemotherapy.
  • The study utilized digital image analysis on 297 breast cancer samples to assess Ki67 expression and evaluated intratumoral heterogeneity, categorizing tumors accordingly.
  • Findings revealed that the number of tissue cores required for accurate biomarker assessment varies; homogeneous tumors needed 5-6 cores while heterogeneous ones needed 11-12 cores to maintain a 10% error margin.
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The photosynthetic apparatus of green plants is well known for its extremely high efficiency that allows them to operate under dim light conditions. On the other hand, intense sunlight may result in overexcitation of the light-harvesting antenna and the formation of reactive compounds capable of 'burning out' the whole photosynthetic unit. Non-photochemical quenching is a self-regulatory mechanism utilized by green plants on a molecular level that allows them to safely dissipate the detrimental excess excitation energy as heat.

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A comparative study of fluorescence relaxation kinetics of σ-conjugated poly(methylphenylsilane) (PMPS) polymer film and nanocomposites has been performed by ultrafast time-gated fluorescence measurements at various temperatures. Investigations have revealed a fine structure of excitonic σ-σ* band. We attribute this structure to emission from two spatially independent states with different ordering of the polymer chain segments, type gauche and trans conformations.

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Proliferative activity, assessed by Ki67 immunohistochemistry (IHC), is an established prognostic and predictive biomarker of breast cancer (BC). However, it remains under-utilized due to lack of standardized robust measurement methodologies and significant intratumor heterogeneity of expression. A recently proposed methodology for IHC biomarker assessment in whole slide images (WSI), based on systematic subsampling of tissue information extracted by digital image analysis (DIA) into hexagonal tiling arrays, enables computation of a comprehensive set of Ki67 indicators, including intratumor variability.

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Energy transfer processes and coherent phenomena in the fucoxanthin-chlorophyll protein complex, which is responsible for the light harvesting function in marine algae diatoms, were investigated at 77 K by using two-dimensional electronic spectroscopy. Experiments performed on femtosecond and picosecond timescales led to separation of spectral dynamics, witnessing evolutions of coherence and population states of the system in the spectral region of Qy transitions of chlorophylls a and c. Analysis of the coherence dynamics allowed us to identify chlorophyll (Chl) a and fucoxanthin intramolecular vibrations dominating over the first few picoseconds.

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Fucoxanthin-chlorophyll protein (FCP) is the key molecular complex performing the light-harvesting function in diatoms, which, being a major group of algae, are responsible for up to one quarter of the total primary production on Earth. These photosynthetic organisms contain an unusually large amount of the carotenoid fucoxanthin, which absorbs the light in the blue-green spectral region and transfers the captured excitation energy to the FCP-bound chlorophylls. Due to the large number of fucoxanthins, the excitation energy transfer cascades in these complexes are particularly tangled.

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The crucial step in the conversion of solar to chemical energy in Photosynthesis takes place in the reaction center where the absorbed excitation energy is converted into a stable charge separated state by ultrafast electron transfer events. However, the fundamental mechanism responsible for the near unity quantum efficiency of this process is unknown. Here we elucidate the role of coherence in determining the efficiency of charge separation in the plant photosystem II reaction centre (PSII RC) by comprehensively combining experiment (two-dimensional electronic spectroscopy) and theory (Redfield theory).

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Light-harvesting in photosynthesis is determined by the excitonic interactions in disordered antennae and the coupling of collective electronic excitations to fast nuclear motions, producing efficient energy transfer with a complicated interplay between exciton and vibrational coherences. Two-dimensional electronic spectroscopy (2DES) is a powerful tool to study the presence of these coherences in photosynthetic complexes. However, the unambiguous assignment of the nature of the observed coherences is still under debate.

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Chlorosomes are light-harvesting antennae that enable exceptionally efficient light energy capture and excitation transfer. They are found in certain photosynthetic bacteria, some of which live in extremely low-light environments. In this work, chlorosomes from the green sulfur bacterium Chlorobaculum tepidum were studied by coherent electronic two-dimensional (2D) spectroscopy.

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In many potential applications of two-dimensional (2D) electronic spectroscopy the excitation energies per pulse are strictly limited, while the samples are strongly scattering. We demonstrate a technique, based on double-modulation of incident laser beams with mechanical choppers, which can be implemented in almost any non-collinear four wave mixing scheme including 2D spectroscopy setup. The technique virtually eliminates artifacts or "ghost" signals in 2D spectra, which arise due to scattering and accumulation of long-lived species.

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The femto- and picosecond time resolved spectroscopy of (eta(6)-cis-stilbene)Cr(CO)(3) provides evidence for three optically accessible excited states one leading to cis-trans isomerisation of the coordinated stilbene ligand and another which results in a slow release of CO.

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