Reconsideration of mass-distribution models

The mass-distribution model proposed by Kuzmin and Veltmann (1973) is revisited. It is subdivided into two models which have a common case. Only one of them is subject of the present study. The study is focused on the relation between the density ratio (the central one to that corresponding to the core radius) and the total-mass fraction within the core radius. The latter one is an increasing function of the former one, but it cannot exceed one quarter, which takes place when the density ratio tends to infinity. Therefore, the model is extended by representing the density as a sum of two components. The extension results into possibility of having a correspondence between the infinite density ratio and 100% total-mass fraction. The number of parameters in the extended model exceeds that of the original model. Due to this, in the extended model, the correspondence between the density ratio and total-mass fraction is no longer one-to-one; several values of the total-mass fraction can correspond to the same value for the density ratio. In this way, the extended model could explain the contingency of having two, or more, groups of real stellar systems (subsystems) in the diagram total-mass fraction versus density ratio. [Projekat Ministarstva nauke Republike Srbije, br. 176011: Dynamics and Kinematics of Celestial Bodies and Systems

On Orbits for a Particular Case of Axial Symmetry

A particular case of steady state and axial symmetry - the potentialformula proposed by Miyamoto and Nagai - is studied. A number of orbits of abound test particle is determined numerically, with both, the potentialparameters and initial conditions, varied. Unlike special cases, such asnearly circular and nearly planar orbits, in the case of "truly spatial orbits" the time dependence of the coordinates becomes very complicated and amathematical treatment including any known periodic functions is hardlypossible. Bearing in mind that orbits studied in the present paper aredetermined by three elements, the authors propose the mean values over time ofthe squares of velocity components to characterize them

Synthesis and Characterization of 3-(1-((3,4-Dihydroxyphenethyl)amino)ethylidene)-chroman-2,4-dione as a Potential Antitumor Agent

The newly synthesized coumarin derivative with dopamine, 3-(1-((3,4-dihydroxyphenethyDamino)ethylidene)-chroman-2,4-dione, was completely structurally characterized by X-ray crystallography. It was shown that several types of hydrogen bonds are present, which additionally stabilize the structure. The compound was tested in vitro against different cell lines, healthy human keratinocyte HaCaT, cervical squamous cell carcinoma SiHa, breast carcinoma MCF7, and hepatocellular carcinoma HepG2. Compared to control, the new derivate showed a stronger effect on both healthy and carcinoma cell lines, with the most prominent effect on the breast carcinoma MCF7 cell line. The molecular docking study, obtained for ten different conformations of the new compound, showed its inhibitory nature against CDKS protein. Lower inhibition constant, relative to one of 4-OH-coumarine, proved stronger and more numerous interactions with CDKS protein. These interactions were carefully examined for both parent molecule and derivative and explained from a structural point of view

Role of non-covalent interactions in modification of properties of high energetic materials

У овом раду смо испитивали утицај нековалентних интеракција на електростатичке потенцијале и осетљивост ка детонацији одабраних високоенергетских молекула. Резултати прорачуна рађених на M06/cc-PVDZ нивоу су показали да водоничне везе значајно утичу на вредности електростатичког потенцијала и осетљивост ка детонацији високоенергетских молекула. У случајевима када високоенергетски молекул игра улогу акцептора водоника, вредности електростатичког потенцијала изнад центара високоенергетских молекула се смањују за 20-25%. Ово даје могућност за коришћење водоничног везивања за модификовање осетљивости високоенергетских молекула.In this work we studied influence of non-covalent interactions on the electrostatic potentials and impact sensitivity of selected high energetic molecules (HEM). Study was performed using quantum chemical calculations on model systems and crystal structures of selected HEMs. Results of M06/cc-PVDZ calculations showed that hydrogen bonding significantly affects electrostatic potential values and impact sensitivities of HEMs. In cases in which HEM molecules act as hydrogen atom acceptors, electrostatic potential values in the centers of HEM molecules decreases by 20-25%. This gives opportunity for modification of impact sensitivities of HEM molecules.57th MEETING OF THE SERBIAN CHEMICAL SOCIETY, Kragujevac, Serbia, June 18-19, 202

Supplementary data for the article: Ninković, D. B.; Moncho, S.; Petrović, P. V.; Zarić, S. D.; Hall, M. B.; Brothers, E. N. Methane Activations by Titanium Neopentylidene Complexes: Electronic Resilience and Steric Control. Inorganic Chemistry 2017, 56 (15), 9264–9272. https://doi.org/10.1021/acs.inorgchem.7b01340

Supporting information for: [https://doi.org/10.1021/acs.inorgchem.7b01340 ]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/317

Supplementary data for the article: Ninković, D. B.; Moncho, S.; Petrović, P. V.; Zarić, S. D.; Hall, M. B.; Brothers, E. N. Methane Activations by Titanium Neopentylidene Complexes: Electronic Resilience and Steric Control. Inorganic Chemistry 2017, 56 (15), 9264–9272. https://doi.org/10.1021/acs.inorgchem.7b01340

Supporting information for: [https://doi.org/10.1021/acs.inorgchem.7b01340 ]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/317

Role of non-covalent interactions in modification of properties of high energetic materials

У овом раду смо испитивали утицај нековалентних интеракција на електростатичке потенцијале и осетљивост ка детонацији одабраних високоенергетских молекула. Резултати прорачуна рађених на M06/cc-PVDZ нивоу су показали да водоничне везе значајно утичу на вредности електростатичког потенцијала и осетљивост ка детонацији високоенергетских молекула. У случајевима када високоенергетски молекул игра улогу акцептора водоника, вредности електростатичког потенцијала изнад центара високоенергетских молекула се смањују за 20-25%. Ово даје могућност за коришћење водоничног везивања за модификовање осетљивости високоенергетских молекула

Role of hydrogen bonding in modifications of impact sensitivities of high energetic materials: evidence from crystal structures and quantum chemical calculations

The development of new classes of high energetic materials (HEM) with high efficiency and low impact sensitivity is in the focus of numerous experimental and theoretical studies [1]. However, the high efficiency of HEM molecules is usually related to the high sensitivity towards detonation [2]. It is known that the sensitivity of HEM molecules towards detonation depends on many factors, including oxygen balance, energy content, and positive values of electrostatic potential above the central regions of the molecular surface. Analysis of positive values of molecular electrostatic potentials (MEP) showed to be an excellent tool in the assessment of impact sensitivities of high energetic molecules since positive values of MEP above the central regions of molecules are associated with high sensitivity towards detonation of HEM molecules [2]. Here we analysed the influence of hydrogen bonding on the values of the electrostatic potentials of fragments of HEM molecules extracted from crystal structures [3]. Crystal structures of three selected high energetic molecules were extracted from Cambridge Structural Database (CSD) and analysed in terms of non-covalent interactions. Three well-known HEM molecules were selected for the analysis: 1,3,5-Trinitrobenzene (TNB), 2,4,6-Trinitrophenol (TNP), and 2,4,6-Trinitrotoluene (TNT). Geometries of these molecules were used for electrostatic potentials calculations and for the design of model systems for interaction energies calculations. Electrostatic potential maps were calculated for TNB, TNP, and TNT geometries extracted from crystal structures for free molecules and molecules involved in hydrogen bonding. Values of electrostatic potentials above the central regions of molecules were analysed and compared for non-bonded HEM molecules and HEM molecules involved in hydrogen bonding. Analysis of crystal structures showed that selected HEM molecules are involved in three types of hydrogen bonds: O-H…O-N interactions, C-H…O-H interactions, and in the case of TNP molecule O-H…O-H interactions. Analysis of positive values of the electrostatic potentials showed that hydrogen bonds have a significant influence on the values of the electrostatic potential in the central regions of HEM molecules. Calculations performed at M06/cc-PVDZ level showed that in the case when HEM molecules are involved in hydrogen bonding as hydrogen atom donors, positive values of electrostatic potentials in the centres of molecules decreased by 20 – 25%. In the case when HEM molecules were involved in hydrogen bonding as hydrogen atom acceptors, positive values of electrostatic potentials in the centres of HEM molecules increased by 10%. Results presented in this study show that hydrogen bonds could be used as a tool for the modification of positive values of MEP above the central regions of HEM molecules and for the modification of their sensitivities towards detonation. Moderate change of positive electrostatic potential values above the central regions of HEM molecules upon formation of hydrogen bonds provide an opportunity for fine-tuning of sensitivities of HEM molecules towards detonation

The Effects of alpha-Lipoic Acid on Liver Oxidative Stress and Free Fatty Acid Composition in Methionine-Choline Deficient Diet-Induced NAFLD

Development of nonalcoholic fatty liver disease (NAFLD) occurs through initial steatosis and subsequent oxidative stress. The aim of this study was to examine the effects of -lipoic acid (LA) on methionine-choline deficient (MCD) diet-induced NAFLD in mice. Male C57BL/6 mice (n=21) were divided into three groups (n=7 per group): (1) control fed with standard chow, (2) MCD2 groupfed with MCD diet for 2 weeks, and (3) MCD2+LA group2 weeks on MCD receiving LA i.p. 100mg/kg/day. After the treatment, liver samples were taken for pathohistology, oxidative stress parameters, antioxidative enzymes, and liver free fatty acid (FFA) composition. Mild microvesicular hepatic steatosis was found in MCD2 group, while it was reduced to single fat droplets evident in MCD2+LA group. Lipid peroxidation and nitrosative stress were increased by MCD diet, while LA administration induced a decrease in liver malondialdehyde and nitrates+nitrites level. Similary, LA improved liver antioxidative capacity by increasing total superoxide dismutase (tSOD), manganese SOD (MnSOD), and copper/zinc-SOD (Cu/ZnSOD) activity as well as glutathione (GSH) content. Liver FFA profile has shown a significant decrease in saturated acids, arachidonic, and docosahexaenoic acid (DHA), while LA treatment increased their proportions. It can be concluded that LA ameliorates lipid peroxidation and nitrosative stress in MCD diet-induced hepatic steatosis through an increase in SOD activity and GSH level. In addition, LA increases the proportion of palmitic, stearic, arachidonic, and DHA in the fatty liver. An increase in DHA may be a potential mechanism of anti-inflammatory and antioxidant effects of LA in MCD diet-induced NAFLD

Application of the Schroth Method in the Treatment of Idiopathic Scoliosis: A Systematic Review and Meta-Analysis

Background: Idiopathic scoliosis can be defined as a complex three-dimensional deformity of the spine and trunk, which occurs in basically healthy children. Schroth scoliosis-specific exercises have shown good results in reducing idiopathic scoliosis progression. This study aimed to critically evaluate the effect size of Schroth’s method through a systematic review and meta-analysis. Methods: Four databases were included in the search: PubMed, Cochrane Library, Web of Science, and Google Scholar. The following keywords were used: “Schroth exercise”, “idiopathic scoliosis”, “Cobb angle”, “angle of trunk rotation”, and “quality of life”. Only articles written in English that met the following criteria were included in our study: subjects who had idiopathic scoliosis, the Schroth method was applied, and Cobb angle or angle of trunk rotation or quality of life as outcomes. Results: Ten randomized controlled trials were included in this study. The effect size of the Schroth exercise ranged from almost moderate to large, for the outcomes used: Cobb angle (ES = −0.492, p ˂ 0.005); ATR (ES = −0.471, p = 0.013); QoL (ES = 1.087, p ˂ 0.001). Conclusions: The current meta-analysis indicates that the Schroth method has a positive effect on subjects with idiopathic scoliosis