Специализированные платформы анализа математических моделей в экономике

Evaluation of the effectiveness of the mathematical model in the economic field is one of the pressing problems at the present time. A number of parameters can often be neglected when simplifying the model; however, it is difficult to assess how adequate the model will remain. In order to get this estimate, it became necessary to determine how the behavior of the model has changed, how the data and their nature have changed. Comparative and statistical analyzes help to find answers to the questions posed. A platform that can evaluate the impact of changes made to the model by some criteria and compare the changed model with its original version using statistical analysis methods was implemented to study this problem.La evaluación de la efectividad del modelo matemático en el campo económico es uno de los problemas apremiantes en la actualidad. Una serie de parámetros a menudo se pueden descuidar al simplificar el modelo; sin embargo, es difícil evaluar qué tan adecuado seguirá siendo el modelo. Para obtener esta estimación, se hizo necesario determinar cómo ha cambiado el comportamiento del modelo, cómo han cambiado los datos y su naturaleza. Los análisis comparativos y estadísticos ayudan a encontrar respuestas a las preguntas planteadas. Para implementar este problema, se implementó una plataforma que puede evaluar el impacto de los cambios realizados en el modelo mediante algunos criterios y comparar el modelo modificado con su versión original utilizando métodos de análisis estadístico.Оценка эффективности работы математической модели в экономической области является одной из актуальных проблем в настоящее время. Часто при упрощении модели рядом параметров можно пренебречь, однако достаточно трудно оценить, насколько адекватной она останется. Для того, чтобы получить данную оценку, возникла необходимость определить, насколько изменилось поведение модели, как поменялись данные и их характер. Найти ответы на поставленные вопросы позволяют сравнительный и статистический анализы. Для исследования этой проблемы была реализована платформа, которая может по некоторым признакам оценить влияние внесенных изменений в модель и сравнить с помощью методов статистического анализа измененную модель с ее исходной версией

Silicon-[18F]Fluorine Radiochemistry: Basics, Applications and Challenges

Silicon-[18F]Fluorine (Si-18F) radiochemistry has recently emerged alongside other unconventional approaches such as aluminum-F-18 and boron-F-18 based labeling strategies, reshaping the landscape of modern F-18-radiochemistry. All these novel methodologies are driven by the demand for more convenient F-18-labeling procedures to further disseminate one of the most sophisticated imaging technologies, Positron Emission Tomography (PET). The PET methodology requires special radionuclides such as F-18 (one of the most prominent examples) to be introduced into bioactive molecules. Si-F-18 radiochemistry contributed greatly towards the development of new radiopharmaceuticals for PET imaging. Herein, we describe the radiochemical basics of Si-F-18 bond formation, the application of Si-F-18 tracers for PET imaging, and additionally, the inherent chemical intricacies of this methodology

τBu₂SiF-Derivatized D₂-Receptor Ligands: The First SiFA-Containing Small Molecule Radiotracers for Target-Specific PET-Imaging

The synthesis, radiolabeling and in vitro evaluation of new silicon-fluoride acceptor (SiFA) derivatized D-2-receptor ligands is reported. The SiFA-technology simplifies the introduction of fluorine-18 into target specific biomolecules for Positron-Emission-Tomography (PET). However, one of the remaining challenges, especially for small molecules such as receptor-ligands, is the bulkiness of the SiFA-moiety. We therefore synthesized four Fallypride SiFA-conjugates derivatized either directly at the benzoic acid ring system (SiFA-DMFP, SiFA-FP, SiFA-DDMFP) or at the butyl-side chain (SiFA-M-FP) and tested their receptor affinities. We found D2-receptor affinities for all compounds in the nanomolar range (Ki(SiFA-DMFP) = 13.6 nM, Ki(SiFA-FP) = 33.0 nM, Ki(SiFA-DDMFP) = 62.7 nM and Ki(SiFA-M-FP) = 4.21 nM). The radiofluorination showed highest yields when 10 nmol of the precursors were reacted with F-18]fluoride/TBAHCO(3) in acetonitrile. After a reversed phased cartridge purification the desired products could be isolated as an injectable solution after only 10 min synthesis time with radiochemical yields (RCY) of more than 40% in the case of SiFA-DMFP resulting in specific activities >41 GBq/mu mol (>1,100 Ci/mmol). Furthermore, the radiolabeled products were shown to be stable in the injectable solutions, as well as in human plasma, for at least 90 min

Silicon-[18F]Fluorine Radiochemistry: Basics, Applications and Challenges

Silicon-[18F]Fluorine (Si-18F) radiochemistry has recently emerged alongside other unconventional approaches such as aluminum-F-18 and boron-F-18 based labeling strategies, reshaping the landscape of modern F-18-radiochemistry. All these novel methodologies are driven by the demand for more convenient F-18-labeling procedures to further disseminate one of the most sophisticated imaging technologies, Positron Emission Tomography (PET). The PET methodology requires special radionuclides such as F-18 (one of the most prominent examples) to be introduced into bioactive molecules. Si-F-18 radiochemistry contributed greatly towards the development of new radiopharmaceuticals for PET imaging. Herein, we describe the radiochemical basics of Si-F-18 bond formation, the application of Si-F-18 tracers for PET imaging, and additionally, the inherent chemical intricacies of this methodology

Axial Vibration Control Technique for Crystal Growth from the Melt: Analysis of Vibrational Flows’ Behavior

A problem of efficacy of crystal growth methods for crystallization from solutions or melt has been investigated. The axial vibrational control (AVC) technique was considered as a perspective method to manage both heat-mass transfer and chemical component composition of the melts in the case of crystallization of complex chemical compounds. Numerical modeling and the search for generalized dependencies made it possible to predict the AVC parameters that provide optimal heat and mass transfer modes for creating flat liquid-solid interfaces, as well as the component composition of dissociated melts of various chemical compounds—Ge, NaNO3, CdTe

18F-Labeled Silicon-Based Fluoride Acceptors: Potential Opportunities for Novel Positron Emitting Radiopharmaceuticals

Background. Over the recent years, radiopharmaceutical chemistry has experienced a wide variety of innovative pushes towards finding both novel and unconventional radiochemical methods to introduce fluorine-18 into radiotracers for positron emission tomography (PET). These “nonclassical” labeling methodologies based on silicon-, boron-, and aluminium-18F chemistry deviate from commonplace bonding of an [18F]fluorine atom (18F) to either an aliphatic or aromatic carbon atom. One method in particular, the silicon-fluoride-acceptor isotopic exchange (SiFA-IE) approach, invalidates a dogma in radiochemistry that has been widely accepted for many years: the inability to obtain radiopharmaceuticals of high specific activity (SA) via simple IE. Methodology. The most advantageous feature of IE labeling in general is that labeling precursor and labeled radiotracer are chemically identical, eliminating the need to separate the radiotracer from its precursor. SiFA-IE chemistry proceeds in dipolar aprotic solvents at room temperature and below, entirely avoiding the formation of radioactive side products during the IE. Scope of Review. A great plethora of different SiFA species have been reported in the literature ranging from small prosthetic groups and other compounds of low molecular weight to labeled peptides and most recently affibody molecules. Conclusions. The literature over the last years (from 2006 to 2014) shows unambiguously that SiFA-IE and other silicon-based fluoride acceptor strategies relying on 18F− leaving group substitutions have the potential to become a valuable addition to radiochemistry

Cholinergic Depletion in Alzheimer’s Disease Shown by [18F]FEOBV Autoradiography

Rationale. Alzheimer’s Disease (AD) is a neurodegenerative condition characterized in part by deficits in cholinergic basalocortical and septohippocampal pathways. [18F]Fluoroethoxybenzovesamicol ([18F]FEOBV), a Positron Emission Tomography ligand for the vesicular acetylcholine transporter (VAChT), is a potential molecular agent to investigate brain diseases associated with presynaptic cholinergic losses. Purpose. To demonstrate this potential, we carried out an [18F]FEOBV autoradiography study to compare postmortem brain tissues from AD patients to those of age-matched controls. Methods. [18F]FEOBV autoradiography binding, defined as the ratio between regional grey and white matter, was estimated in the hippocampus (13 controls, 8 AD) and prefrontal cortex (13 controls, 11 AD). Results. [18F]FEOBV binding was decreased by 33% in prefrontal cortex, 25% in CA3, and 20% in CA1. No changes were detected in the dentate gyrus of the hippocampus, possibly because of sprouting or upregulation toward the resilient glutamatergic neurons of the dentate gyrus. Conclusion. This is the first demonstration of [18F]FEOBV focal binding changes in cholinergic projections to the cortex and hippocampus in AD. Such cholinergic synaptic (and more specifically VAChT) alterations, in line with the selective basalocortical and septohippocampal cholinergic losses documented in AD, indicate that [18F]FEOBV is indeed a promising ligand to explore cholinergic abnormalities in vivo