The mathematical model of the functioning of the thyroid gland

Štítná žláza je endokrinní orgán s funkcí produkovat hormony, které přispívají k rozvoji celého organismu. Hlavní složkou výměny je jod. Žláza sama o sobě sestává z folikulů - strukturních prvků orgánu, ve kterém se syntetizovaný tyreoidální hormon hromadí ve stavu navázaném na bílkoviny. Uvažuje se bodový jednokomorový matematický model folikulu štítné žlázy. Model folikulu představuje jediná kamera - kombinace koloidu a tyreocytů. V navrhovaném modelu rychlost výměny jódu závisí na objemu folikulu. Objem koloidu ve folikulu zase závisí na koncentraci treoglobulinu a dalších molekul. V tomto modelu je tedy rychlost výměny jodu závislá na koncentraci látek v koloidu. Štítná žláza se skládá z asi třiceti milionů folikulů různých velikostí. Velikost jednoho folikulu se mění v poměrně širokém rozsahu. Kromě toho je velikost folikulu štítné žlázy přibližně distribuována podle normální distribuce. Práce celé štítné žlázy byla považována za megasystem skládající se z jednotlivých folikulů majících jiný objem. Matematický model je problémem mezních hodnot pro soustavu nelineárních diferenciálních rovnic s ohledem na koncentrace látek ve folikule. Výpočty byly provedeny na grafických procesorech. Uvažuje se dynamika změn velikosti jednotlivých folikulů a systému jako celku za různých počátečních a vnějších podmínek. Byl odhadnut stupeň vlivu objemu folikulu na rychlost jodu ve folikulu a na produkci hormonu štítné žlázy T4.The thyroid gland is an endocrine organ with the function of producing hormones that contribute to the development of the whole organism. The main exchange component is iodine. The gland itself consists of follicles - structural elements of the organ, in which the synthesized thyroid hormone accumulates in a state bound to protein. The point-like single-chamber mathematical model of the follicle of the thyroid gland is considered. The follicle model is represented by a single camera - the combination of colloid and thyrocytes. In the proposed model, the rate of iodine exchange depends on the volume of the follicle. In turn, the volume of a colloid in the follicle depends on the concentration of treoglobulin and other molecules. Thus, in this model, the rate of exchange of iodine is made dependent on the concentration of substances in the colloid. The thyroid gland consists of about thirty million follicles of various sizes. The size of a single follicle varies in a fairly wide range. Moreover, the size of the follicle of the thyroid gland is approximately distributed according to the normal distribution. The work of the entire thyroid gland was considered as a megasystem consisting of individual follicles having a different volume. The mathematical model is a boundary value problem for a system of non-linear differential equations with respect to the concentrations of substances in the follicle. Calculations were carried out on graphic processors. The dynamics of changes in the size of both the individual follicle and the system as a whole under different initial and external conditions are considered. The degree of influence of the follicle volume on the rate of iodine in the follicle and on the output of the thyroid hormone T4 was estimated

LM-Polygraph: Uncertainty Estimation for Language Models

Recent advancements in the capabilities of large language models (LLMs) have paved the way for a myriad of groundbreaking applications in various fields. However, a significant challenge arises as these models often "hallucinate", i.e., fabricate facts without providing users an apparent means to discern the veracity of their statements. Uncertainty estimation (UE) methods are one path to safer, more responsible, and more effective use of LLMs. However, to date, research on UE methods for LLMs has been focused primarily on theoretical rather than engineering contributions. In this work, we tackle this issue by introducing LM-Polygraph, a framework with implementations of a battery of state-of-the-art UE methods for LLMs in text generation tasks, with unified program interfaces in Python. Additionally, it introduces an extendable benchmark for consistent evaluation of UE techniques by researchers, and a demo web application that enriches the standard chat dialog with confidence scores, empowering end-users to discern unreliable responses. LM-Polygraph is compatible with the most recent LLMs, including BLOOMz, LLaMA-2, ChatGPT, and GPT-4, and is designed to support future releases of similarly-styled LMs.Comment: Accepted at EMNLP-202

Возможности МР-динамического контрастирования в дифференциальной диагностике первичных и вторичных опухолей головного мозга

Aim: the article is devoted to determine the capabilities of T1-dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) in differentiation diagnosis primary and secondary brain tumors. Materials and methods. The analysis was based on data generated from MRI examinations using a T1-DCE protocol of 74 patients with intracerebral tumors: gliomas - 24 (32.4%) cases (glioblastoma - 17, astrocytoma - 5 and oligodendroglioma - 2), meningioma - 23 (31.1%) and metastases - 27 (36.5%) cases (melanoma - 8, breast cancer - 7 and lung cancer - 12). MRI was performed on 3,0-T scanner (Skyra, Siemens AG, Erlangen Germany) and included following sequences: a) routine sequences in axial direction before contrast agent injection (T1-SE, T2-SE, T2-FLAIR, DWI), b) T1-Vibe with two different flip angles and DCE-protocol, c) T1-VIBE in axial direction after contrast injection with 3D-reconstruction. Results. The highest average Ktrans and Ve were observed in meningiomas (0.097 ± 0.019 min-1 and 0.151 ± 0.017), the lowest in gliomas Grade I-II (0.022 ± 0.001 min-1 and 0.029 ± 0.003). The highest average were in melanoma mts (1.14 ± 0.331 min-1) and lowest - in breast cancer mts (0.063 ± 0.193 min-1). Conclusion. DCE MRI - potentially perspective and demanding further studying method allowing to assume possibility of carrying out effective differential diagnostics of various brain tumors by a cumulative assessment of the pharmacokinetic parameters providing valuable information on hemodynamic and proliferative properties of tumor tissue.Цель исследования: оценка возможностей методики МР-динамического контрастирования (МР-ДК) в дифференциальной диагностике первичных и вторичных новообразований головного мозга. Материал и методы. В исследование включены результаты МР-исследований с использованием МР-ДК, которые были проведены у 74 пациентов с впервые выявленным поражением вещества головного мозга, не получавших предшествующего противоопухолевого лечения. Гистологическое исследование: глиальные опухоли - у 24 (32,4%) пациентов (из них глиобластомы - 17, астроцитомы - 5, олигодендроглиомы - 2), менингиомы - у 23 (31,1%), метастазы в веществе головного мозга - у 27 (36,5%) (метастазы меланомы - у 8, рака молочной железы - у 7, рака легкого - у 12). МР-исследования выполняли на томографе с напряженностью поля 3,0 Тл при использовании 20-канальной головной катушки (Skyra, Siemens AG, Erlangen Germany). Каждое исследование включало в себя: а) стандартные последовательности в аксиальной проекции до внутривенного (в/в) введения контрастного вещества - T1-SE, T2-SE, T2-FLAIR, DWI, б) две последовательности T1-VIBE с разными углами отклонения и МР-ДК последовательности c отсроченным болюсным в/в введением контрастного вещества, в) в завершение T1-VIBE после внутривенного контрастирования с последующей 3D-реконструкцией. Результаты. Наиболее высокие средние показатели Ktrans и Ve были выявлены в менингиомах (0,097 ± 0,019 мин-1 и 0,151 ± 0,017 соответственно), самые низкие - в глиальных опухолях низкой степени злокачественности (0,022 ± 0,001 мин-1 и 0,029 ± 0,003 соответственно). Наиболее высокие средние показатели Kep выявлены в метастазах меланомы (1,14 ± 0,331 мин-1), наиболее низкие - в метастазах рака молочной железы (0,063 ± 0,193 мин-1). Заключение. МР-ДК - потенциально перспективный и требующий дальнейшего изучения метод, позволяющий предполагать возможность проведения эффективной дифференциальной диагностики различных новообразований головного мозга путем совокупной оценки фармакокинетических параметров, предоставляющих ценную информацию о гемодинамических и пролиферативных свойствах опухолевой ткани

Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

Correction to: Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

The original version of this article unfortunately contained a mistake

Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

General theoretical approaches to the choice of company strategy

Abstract. Amid a swiftly changing economic situation and a fierce competitive struggle, risk and uncertainty companies ought to not only focus on the current state of affairs but strive to work out a long-term strategy for their conduct, which will help keep abreast with changes taking place around them. The lack of strategy within the company leads to defeat in the market struggle. This article examines the essence of and classifies company strategies. The authors also delineate strategies that best fit smaller companies. [Fadeeva E.A., Margaryan A.A. General theoretical approaches to the choice of company strategy Life Sci J 2014;11(12s):253-256] (ISSN:1097-8135). http://www.lifesciencesite.com. 5

Mathematical model of thyroid gland functioning as a follicles system

The thyroid gland represents one of the endocrine glands. Despite the relatively small size of the gland, it plays an essential role in controlling the regulation of metabolism and individual cells' growth using hormones. The main component of the hormones is iodine. The gland consists of follicles that are the organ's structural elements, in which the synthesized thyroid hormone accumulates in a state associated with protein. To construct a model in which the rate of iodine metabolism is set in dependence on the concentration of substances in the colloid. To investigate the change in the size of the follicle and the entire thyroid gland from the concentration of iodine using a mathematical model. The entire thyroid glands work is considered a mega-system, consisting of individual follicles having different volumes. The mathematical model represents a boundary value problem for a system of nonlinear differential equations for concentrations of substances in the follicle. The dynamics of changes in the size of both an individual follicle and the system as a whole is considered under various initial and external conditions. The degree of influence of follicle volume on the level of iodine in the follicle as well as on the production of the thyroid hormone is assessed. The thyroid gland's work is studied, and a mathematical model of the thyroid gland is constructed, which considers the thyroid gland as a mega-system consisting of a certain number of follicles. According to the results of studies, this approach allows more accurate tracking of changes occurring with a single follicle and, consequently, the work of the entire organ. If the thyroid gland is healthy, the follicle size distribution is lognormal