Latvian Academy of Sciences

PURPOSE:Carbonic anhydrase IX (CAIX), overexpressed in multiple cancers but limited in normal tissue, is a promising target for radionuclide therapy. This study evaluates [212Pb]Pb-MKV-509, a novel DOTA-conjugated small-molecule ligand, for CAIX-targeted alpha therapy in preclinical renal carcinoma (SK-RC-52) and colorectal (HT-29) cancer models. MATERIALS AND METHODS:[212Pb]Pb-MKV-509 was assessed for radiochemical purity and stability. Binding assays determined receptor density and dissociation constants. Clonogenic survival, flow cytometry (viability, DNA damage, cell cycle), and spheroid assays (cross-sectional area, doubling time) evaluated biological responses. An in vivo biodistribution study was performed in SK-RC-52 xenograft-bearing mice, with and without carbonic anhydrase pre-blocking using acetazolamide. RESULTS:[212Pb]Pb-MKV-509 exhibited high radiochemical purity (>96%) and stability for up to 48 h. Specific binding was higher in SK-RC-52 than in HT-29 cells. Treatment induced activity-dependent clonogenic inhibition, G2/M arrest, and DNA damage, with greater sensitivity observed in SK-RC-52 cells. Clonogenic survival was reduced by 50% at 3.4 kBq/mL (SK-RC-52) and 7.1 kBq/mL (HT-29). In spheroid models, 2.5-5.0 kBq/mL delayed growth and prolonged doubling time, indicating cross-fire effects. The biodistribution study revealed significant tumor uptake (4.7%IA/g at 2 h), along with high gastrointestinal accumulation. Pretreatment with acetazolamide partially reduced uptake in the stomach and intestines as well as in the tumor. CONCLUSIONS:These findings highlight the potential of CAIX-targeted alpha therapy. CAIX expression and receptor density impact binding affinity and therapeutic response. The study demonstrates the importance of 3D tumor models in evaluating alpha-particle cross-fire effects. Further ligand optimization is warranted to enhance tumor specificity and minimize off-target uptake.

tüssama This article examines the origin of the Estonian verb tüssama ’to deceive, to cheat, to outwit’. It is proposed that tüssama and its dialectal variants of limited distribution – tüsama, tüskama, and tussama – are borrowings from the Middle Low German verb tuschen (tūschen) ’to deceive, to cheat, to mock, to tease; to mislead, to lead astray, to deal with someone, to make a fool of someone’. The occurrence of parallel forms with u and ü (tüsama, tüssama ~ tussama) in Estonian Low German loanwords reflects dialectal variation in the source language. The alternation s(s) ~ sk (tussama, tüsama, tüssama ~ tüskama) points to repeated borrowing: the pronunciation of the Middle Low German internal orthographic cluster sch in the Low German spoken in Estonia was likely [sχ]or [sk], which in Estonian was rendered either as s(s) (tussama, tüsama, tüssama) or sk (tüskama). Previous etymological treatments of tüssama have not sufficiently taken into account the phonetic variability within this word family and its underlying causes; as a result, a convincing etymology has not previously been established.

We report the development of an atomic layer deposition (ALD) process for depositing titanium dioxide (TiO2) nanofilms onto porous activated carbon (AC) electrodes to enhance the electrochemical performance of supercapacitors. This study investigates previously unexplored aspects of the ALD process, including the influence of precursor pulse duration and film thickness on the deposition behavior within complex porous AC structures. The deposited TiO2 nanofilms were amorphous and exhibited excellent uniformity and conformality across the AC surface. Electrochemical measurements revealed a combination of surface redox and intercalation-type pseudocapacitance, with surface redox reactions identified as the dominant energy storage mechanism. An optimal balance between accessible surface area and film thickness was achieved at 60 ALD cycles, corresponding to a TiO2 film thickness of approximately 2.3 nm. Under these conditions, the specific capacitance of TiO2-coated supercapacitors exceeded that of bare AC electrodes, owing to the additional pseudocapacitance contributed by the TiO2 layer. These findings demonstrate an effective strategy for utilizing ALD to engineer advanced electrode materials for high-performance supercapacitors.

In conditions of martial law, macroeconomic instability, high credit risks, and deterioration in counterparties’ solvency, the problem of reliably assessing receivables and forming reserves for expected credit losses becomes particularly urgent. However, traditional approaches to assessing reserves for doubtful debts do not fully meet the requirements of risk management and the predictive assessment of credit risks required by IFRS 9. This article aims to reveal the practical aspects of applying the expected credit loss measurement methodology under IFRS 9 “Financial Instruments” and to improve the primary, synthetic, and analytical accounting for loss allowances for impairment of financial assets, using the example of receivables of Ukrainian agricultural enterprises. The research methodology includes abstract-logical, monographic, comparative, and computational-constructive (including the ECL method provided for in IFRS 9 “Financial Instruments”) methods, as well as a systematic approach, analysis, and synthesis. The article presents a simplified methodological approach to assessing expected credit losses based on payment history, receivables due dates, and analysis of counterparties’ payment reliability. The authors proposed a system of color-coded debtors’ credit risk zones based on ECL levels and signs of default. Also, they improved the organization of analytical accounting for financial assets by separating sub-accounts for expected credit losses directly on receivables accounts. An important part of the research results is samples of primary documents and analytical accounting registers developed by the authors for calculating and summarizing information on reserves for expected credit losses. The results of this study can be used to increase the reliability of financial reporting, improve risk management systems, strengthen the economic security of agricultural enterprises in Ukraine, and adapt national accounting practices to international financial reporting standards.

The rehabilitation of tuhar This article examines the etymology of the South Estonian dialect word tuhar : tuhara ‘the paired posterior part of the body formed by muscles and fat pads extending from the iliac bone and attached to the femur; buttock, posterior’ and traces its path into written Estonian. In contemporary Estonian, tuhar is a neutral anatomical term that is widely known and used throughout the standard language. The origin of the word has been repeatedly discussed in the etymological literature, but no convincing explanation has emerged. Among the proposed hypotheses, the one that deserves particular attention is that of the Estonian etymologist Julius Mägiste, who suggested that tuhar is derived from tuha, itself possibly a verbal noun formed from the onomatopoetic verb tuhama = tuhisema ‘to produce a dull, monotonous sound (of fire or a strong current of air); to move, travel, or glide rapidly’. Alongside tuhar, both Standard Estonian and the dialects contain other body-part names formed with the suffix -r, or words otherwise closely related to the same semantic group, such as näbar : näbara, nägar : nägara, and sakar : sagara. I argue that Mägiste’s proposed etymology is supported by an analogous derivational pattern in Latvian. Latvian dialects and colloquial speech provide clear examples in which a verb denoting a sound serves as the base for a word meaning ‘buttocks’ (Lat. podex): Latvian dùkt, -cu, -cu ‘to hum, drone, roar, hiss, whoosh’ ⇒ dùcamais, dūkamais ‘buttocks’. Early Estonian health and medical literature employed vernacular vocabulary, including words and expressions that gradually came to be regarded as vulgar (among them terms for the buttocks) and were subsequently replaced in written usage by more neutral alternatives. Efforts to develop Estonian medical terminology began in the final quarter of the nineteenth century. One of the most significant contributors to this undertaking was the physician Peeter Hellat (1857–1912). In creating new technical terms, Hellat relied primarily on dialect words, often favouring those from South Estonian. The South Estonian word tuhar appears in his work Terwise õpetus (1894), both in the plural form tuharad and as a component of compounds such as tuharluu (‘pelvic bone’) and tuharlihased (‘gluteal muscles’). In 1918, the word tuhar entered general dictionaries of Standard Estonian with the publication of the Dictionary of Estonian Orthography (Eesti keele õigekirjutuse-sõnaraamat).