Applying direct heteroarylation synthesis to evaluate organic dyes as the core component in PDI-based molecular materials for fullerene-free organic solar cells

Direct heteroarylation has emerged as a versatile and powerful tool to access π-conjugated materials through atom-economical Pd-catalyzed carbon–carbon bond forming reactions. Employing this synthetic protocol has enabled the facile evaluation of a series of organic dyes in a PDI-dye-PDI framework. Material properties are largely dictated by the PDI components, but the incorporation of either thienoisoindigo, diketopyrrolopyrrole or isoindigo has been shown to influence the ionization potential and absorption profiles of the final materials. Solution-processable organic solar cell devices were fabricated to investigate the influence of the different dye cores on photovoltaic performance when paired with the donor polymer PTB7-Th. It was found that the diketopyrrolopyrrole-based material out-performed the other organic dyes, demonstrating energy losses of less than 0.6 eV, promising efficiencies when cast from non-halogenated solvents and the ability to dictate self-assembly induced by small volume fractions of the high-boiling solvent additive 1,8-diiodooctane to reach best device efficiencies of 4.1%

Direct (Hetero)Arylation Polymerization of a Spirobifluorene and a Dithienyl-Diketopyrrolopyrrole Derivative: New Donor Polymers for Organic Solar Cells

The synthesis and preliminary evaluation as donor material for organic photovoltaics of the poly(diketopyrrolopyrrole-spirobifluorene) (PDPPSBF) is reported herein. Prepared via homogeneous and heterogeneous direct (hetero)arylation polymerization (DHAP), through the use of different catalytic systems, conjugated polymers with comparable molecular weights were obtained. The polymers exhibited strong optical absorption out to 700 nm as thin-films and had appropriate electronic energy levels for use as a donor with PC70BM. Bulk heterojunction solar cells were fabricated giving power conversion efficiencies above 4%. These results reveal the potential of such polymers prepared in only three steps from affordable and commercially available starting material

Simply Complex: The Efficient Synthesis of an Intricate Molecular Acceptor for High-Performance Air-Processed and Air-Tested Fullerene-Free Organic Solar Cells

A perylene diimide (PDI) flanked diketopyrrolopyrrole (DPP) π-conjugated small molecule has been synthesized through an efficient and sustainable direct heteroarylation protocol. When paired with the donor polymer PTB7-Th, air-processed and tested bulk-heterojunction (BHJ) organic solar cells (OSCs) achieved a high power conversion efficiency (PCE) of 5.6%. The new acceptor showed favorable morphological changes upon solvent vapor annealing leading to a near 3-fold increase in PCE. This result is among the best reported utilizing DPP-based acceptors in air-processed and tested OSCs. All solar cells exhibited good air and light stability over a 35-day evaluation period

Biodiversity surveys of grassland and coastal habitats in 2021 as a documentation of pre-war status in southern Ukraine

Background This paper presents two sampling-event datasets with occurrences of vascular plants, bryophytes and lichens collected in May-June 2021 in southern Ukraine. We aimed to collect high-quality biodiversity data in an understudied region and contribute it to international databases and networks. The study was carried out during the 15th Eurasian Dry Grassland Group (EDGG) Field Workshop in southern Ukraine and the Dark Diversity Network (DarkDivNet) sampling in the Kamianska Sich National Nature Park. By chance, these datasets were collected shortly before the major escalation of the Russian invasion in Ukraine. Surveyed areas in Kherson and Mykolaiv Regions, including established monitoring plots, were severely affected by military actions in 2022. Therefore, collected data are of significant value in the context of biodiversity documentation. The knowledge about the biodiversity of this area will help to assess the environmental impact of the war and plan restoration of the damaged or destroyed habitats. The first preliminary analysis of collected data demonstrates the biodiversity richness and conservation value of studied grassland habitats. New information We provide sampling-event datasets with 7467 occurrences, which represent 708 taxa (vascular plants, bryophytes and lichens) collected in 275 vegetation relevés. Amongst them, vascular plants are represented by 6665 occurrences (610 taxa), lichens - 420 (46) and bryophytes - 381 (51). Several new species were reported for the first time at the national or regional level. In particular, one vascular plant species (Torilis pseudonodosa) and two lichen species (Cladonia conista, Endocarpon loscosii) were new to Ukraine. One vascular plant (Stipa tirsa), two species of bryophytes (Rhynchostegium megapolitanum, Ptychostomum torquescens) and three species of lichens (Cladonia cervicornis, C. symphycarpa, Involucropyrenium breussi) were recorded for the first time for the Kherson Region. Additionally, these datasets contain occurrences of taxa with narrow distribution, specialists of rare habitat types and, therefore, represented by a low number of occurrences in relevant biodiversity databases and particularly in GBIF. This publication highlights the diversity of natural vegetation and its flora in southern Ukraine and raises conservation concerns

EVOLUTION OF SCIENTIFIC VIEWS ON STEPPE LANDSCAPES IN THE BOTANIST GEOGRAPHICAL RESEARCHES

Дайнеко, П. М. Еволюція наукових уявлень про степові ландшафти в ботаніко-географічних дослідженнях / П. М. Дайнеко // Природничий альманах. Біологічній науки : зб. наук. праць / редкол. : В. П. Зав’ялов (голова), М. Ф. Бойко, А. М. Волох та ін. – Херсон : Вид-во ФОП Вишемирський В. С., 2018. – № 25. – С. 17-24.В процесі написання статті розкриті особливості трансформації наукових поглядів на степові ландшафті в контексті розвитку та становлення ботанічних та географічних досліджень, обґрунтована доцільність конкретизації даної термінології для вирішення регіональних питань раціонального природокористування. In the process of writing the article we reveald the features of transformation the scientific views on steppe landscapes in the context of development and formation botanical and geographical researches, the relevance of a refinement of this terminology for the solution of regional issues of rational use is reasoned. The presence of a large number of different opinions about the nature of the steppes, its characteristic features indicate a long process of forming geoecological representations about steppe landscapes in domestic and foreign science. During the progress of geographical and botanical knowledge (mid-XIXearly XX century), the change in the level of development and settlement of the steppes of the northern Black Sea coast, as well as the transformation of social and scientific thinking, an expansion of ideas about steppe landscapes was leading to formulation two approaches to the study of the concept of «steppe»: geographical and geobotanical. As Viacheslav Mordkovich observes, the objective reason for the ambiguous impression about the steppes is the extraordinary variety of steppe biomes, which predetermined primarily by their large expanse. The scientist rightly confirm that to accurate determination of steppe ecosystem is necessary to apply all its constituent elements: climate, flora and fauna, microflora and soil. Geographic and geobotanical sides of steppes definition complement each other in interwined lines.Therefore, a truly complete and unbiased determination of the steppes is only possible by combination of the botanical and geographic approach, when the steppe zone is allocated not only by geographical indices (flatness of relief, the dryness of the climate, black earth ), and also with phytocenological characteristics

Prospective Assessment of mrTRG System Used for Determining the Efficiency of Neoadjuvant Chemoradiotherapy in Patients with Rectal Cancer

Background. Evaluation of the therapeutic effect of neoadjuvant chemoradiotherapy (nCRT) for rectal cancer (RC) is of prognostic value and allows to individually plan the type and extent of further surgical intervention. One of the most promising methods of MRI evaluation is magnetic resonance tumour regression grade (mrTRG) system. However, the reliability and safety of this method must be confirmed by the results of clinical trials and practical application.Objective: to analyze our experience in the prospective use of mrTRG system and evaluate the additional contribution of diffusion-weighted images (DWI) to its diagnostic efficiency.Material and methods. The mrTRG values were determined in 125 (including 30 with DWI) patients with locally advanced RC who received combined treatment with nCRT in Tsyb Medical Radiological Research Centre from 2015 to 2019. The obtained data were compared with the modified pathologic response based on Lushnikov’s definition, and the diagnostic parameters of differentiation of patients responding and nonresponding to nCRT were calculated.Results. When the mrTRG system was used without DWI, the following sensitivity and specificity values as well as positive and negative predictive values were obtained: 75%, 60%, 70% and 67%, respectively, with DWI – 87%, 87%, 87% and 87%, respectively.Conclusion. A prospective evaluation of the result of nCRT using the mrTRG system has moderate accuracy for stratification of patients responding and non-responding to nCRT, which requires the use of additional criteria for MRI scores to select patients who may receive less aggressive surgical treatment. Despite the small number of patients with DWI, we obtained higher values of the diagnostic parameters. In this regard, we consider it appropriate to use DWI when assessing the treatment response

MRI-PATHOLOGICAL PARALLELS WITH THE COMPLETE TUMOR RESPONSE TO NEOADJUVANT CHEMORADIATION TREATMENT OF RECTAL CANCER

Purpose of the study. To study the patterns of forming an MRI picture of a complete pathological morphological response (pCR) of colorectal cancer a er neoadjuvant chemoradia on therapy (NHLT) based on comparisons with the pathomorphological picture. Patients and methods. Among 130 patients with locally advanced colorectal cancer who received a combined treatment with NHL at A. Tsyb MRRC clinic — a Branch of HMRRC of the Ministry of Health of the Russian Federation within the period 2012–2017 thirteen patients were selected for the study, in whom pCR was achieved, according to the pathological analysis of surgical specimen. MRI was performed on all patients before the NHLT and atier the end (atier 6–10 weeks) of treatment. We analyzed the MRI fi ndings from case histories (prospective assessment) on degree of tumor regression (mrTRG) using a fi ve-point grading scale. Ten of these patients had MRI examinations available for re-review (retrospective assessment), which allowed for a qualitate ve assessment of the signal intensity in T2 mode on a nominal scale, according to which low, medium, moderately elevated and high MR signals were discerned; signal localization was determined relative to the intestinal lumen with conditional selection of the inner and outer layer of the wall, and the outer contour was charactezied (smooth or uneven due to hypointense spicules). The obtained data on the localization of the MR signal of varying intensity were compared with the data of the pathological description of the operating drugs.Results. A prospective MRI assessment of pCR in 77% of cases corresponded to TRG2 and in 92% — y N0. Macroscopically, the pCR in all patients had an appearance of an ulcerative defect of the intestinal wall, to which on T2-WI in 80% of cases corresponded to a moderately elevated MR signal from the inside of the wall, due to necroti c changes and granulations, and in 100% of cases — a low MR signal from the outer layer of the intestinal wall, caused by a more mature connective tissue, the outer contour in 50% of cases was tight due to the desmoplastic reaction; hypo-intensive inclusions corresponded to lime deposits, and “mucous lakes” — inclusions with high signal intensity and clear contours.Conclusion The features of forming MRI picture of the pCR are due to a range of radiation pathomorphosis manifestations, including destructive, regenera ve and infl ammatory processes in the tumor stroma

Тerminology of rectal cancer: consensus agreement of the expert working group

Unified terminology is a necessary condition for successful interdisciplinary communication within the field of oncology. The variety of anatomical, pathomorphological, and clinical terms used in rectal cancer is often accompanied by their ambiguous interpretation both in domestic and foreign scientific literature. This not only complicates the interaction between specialists, but also complicates the comparison of the results of rectal cancer treatment obtained in different medical institutions. Based on the analysis of recent domestic and international scientific and methodological literature on rectal cancer, the key terms used in the diagnosis and treatment planning of rectal cancer were selected, followed by a two-time online discussion of their interpretations by experts from the Russian Society of Radiologists and Therapeutic Radiation Oncologists, the Association of Oncologists of Russia, and the Russian Association of Therapeutic Radiation Oncologists until reaching consensus (≥80%) of experts on all items. Terms that fail to attain consensus were excluded in the final list. A list of anatomical, pathomorphological, and clinical terms used in the diagnosis, staging, and treatment planning of rectal cancer has been compiled and, based on expert consensus, their interpretation has been determined. A lexicon recommended in the description and formulation of the conclusion of diagnostic studies in patients with rectal cancer is proposed