On Wiener Polarity Index and Wiener Index of Certain Triangular Networks

A topological index of graph G is a numerical quantity which describes its topology. If it is applied to the molecular structure of chemical compounds, it reflects the theoretical properties of the chemical compounds. A number of topological indices have been introduced so far by different researchers. The Wiener index is one of the oldest molecular topological indices defined by Wiener. The Wiener index number reflects the index boiling points of alkane molecules. Quantitative structure activity relationships (QSAR) showed that they also describe other quantities including the parameters of its critical point, density, surface tension, viscosity of its liquid phase, and the van der Waals surface area of the molecule. The Wiener polarity index has been introduced by Wiener and known to be related to the cluster coefficient of networks. In this paper, the Wiener polarity index W p G and Wiener index W G of certain triangular networks are computed by using graph-theoretic analysis, combinatorial computing, and vertex-dividing technology.

Applications of Flory’s Statistical Theory to Ionic Liquids in the Extended Pressure Range and at Different Temperatures

Introduction: Flory’s statistical theory (FST) for the first time, has been applied successfully to two pure ionic liquids, [C3mim][NTf2] and [C5mim][NTf2] over an extended range of pressure (0.10 – 59.9) MPa and at different temperatures (298.15 – 333.15) K . Methods: : Density and sound speed data have been employed to compute a number of useful and important properties of these ionic liquids in the light of FST. Using Flory parameters (P*, T*, V*, P̃, T̃, Ṽ) the expression for the surface tension (σ) has been deduced in the form σ = σ* σ᷉ (Ṽ), σ* and σ᷉ (Ṽ) being the characteristic and reduced values of surface tension. Since the experimental σ of liquids is not known, the validity of FST has been tested by calculating u using four different u-ρ- σ correlations, namely Auerbach (1948), Altenberg (1950) Singh et al (1997) and Modified Auerbach (2016). Results: A number of useful and important properties of ionic liquids, under the varying physical conditions, have been deduced and compared with the observed ones with quite satisfactory agreement. Such properties include Pint, van der Waals constants (a & b), parachor [P], Eötvas constant (kB), energy (∆EV) and heat of vaporization (∆HV), cohesive energy density (ced), polarity index (n) and solubility parameter (δ). Conclusion: Thus the validity of FST to two ionic liquids under the present study, has been confirmed.

Gel-permeation chromatography as a method for monitoring transformations of heavy petroleum fractions during secondary oil refining

A rapid and easy to use method for monitoring transformations of heavy oil fractions during secondary processes of oil refining is proposed. The method is based on the study of changes in the molecular weight characteristics by gel-permeation chromatography (GPC) using a refractometric detector. Optimal conditions for registration of the chromatograms (temperature, eluent consumption and its composition) were specified. Heptane, toluene, and toluene added with 1% and 5% of methanol were studied as eluents, the polarity indices being arranged in a series 0.2; 2.4; 2.43; 2.54. The effect of the nature of the solvent on the type of the product chromatogram is determined. It is shown that addition of a polar solvent to a nonpolar one increases the polarity index, reduces both the degree of association of petroleum molecules and adsorption on the gel. The most available toluene which meets the GPC requirements is chosen as an eluent. Addition of 1% CH3OH to the eluent promotes suppression of polyelectrolyte effects and adsorption. The revealed absence of the dependence of the retained volume and the type of chromatograms on the eluent flow rate and temperature indicates that separation is carried out under conditions of exclusion and completely obeys the theory of exclusive liquid chromatography. The transformation of raw materials during a technological process of oil production at the JSC «ANKhK» was studied using the GPC method under above-mentioned chromatographic conditions. We have studied vacuum distillate of the primary oil refining unit ELOU+AVT-6 (VD) and the product of hydrocracking of the vacuum distillate of the 123PM unit (HVD). It is shown that determination of the molecular weight characteristics provides an important information about the behavior of technological processes. The HVD meets the requirements for hydrocracking products. A decrease in the content of aromatic hydrocarbons in comparison with the raw feedstock is proved by the data of thin layer chromatography (TLC).

Antimicrobial Activity of Extracts from the Humiria balsamifera (Aubl)

Humiria balsamifera (Aubl), commonly known as “mirim”, is a plant of the Humiriaceae family, which consists of 39 species divided between eight genera: Duckesia, Endopleura, Humiria, Humiriastrum, Hylocara, Sacoglottis, Schistostemon, and Vantenea. This study aimed to characterize H. balsamifera extracts by LC-MS/MS and evaluate their antimicrobial potential through in vitro and in vivo assays. The leaves and stem bark of H. balsamifera were collected and dried at room temperature and then ground in a knife mill. The extracts were prepared with organic solvents in order to increase the polarity index (hexane, ethyl acetate, and methanol). The antimicrobial effects of these extracts were evaluated against the following bacterial strains: Escherichia coli ATCC 25922, Listeria monocytogenes ATCC 15313, Salmonella enterica Typhimurium ATCC 14028, and Staphylococcus aureus ATCC 6538. The best activity was observed in the ethyl acetate (EALE = 780 µg/mL), methanol (MLE = 780 µg/mL), and hexane (HLE = 1560 µg/mL) leaf extracts against S. aureus. Considering the results for both antimicrobial and antibiofilm activities, the EALE extract was chosen to proceed to the infection assays, which used Tenebrio molitor larvae. The EALE treatment was able to extend the average lifespan of the larvae (6.5 days) in comparison to S. aureus-infected larvae (1 day). Next, the samples were characterized by High-Performance Liquid Chromatography coupled to a mass spectrometer, allowing the identification of 11 substances, including seven flavonoids, substances whose antimicrobial activity is already well-reported in the literature. The number of bioactive compounds found in the chemical composition of H. balsamifera emphasizes its significance in both traditional medicine and scientific research that studies new treatments based on substances from the Brazilian flora.

Predominant Polarity and Polarity Index of Maintenance Treatments for Bipolar Disorder: A Validation Study in a Large Naturalistic Sample in Italy

Background and Objectives: Predominant polarity (PP) may be a useful course specifier in at least a significant proportion of patients with Bipolar Disorder (BD), being associated with several clinically relevant correlates. Emerging evidence suggests that the concept of PP might influence the selection of maintenance treatments, based on a drug polarity index (PI) which measures the greater antidepressive vs. antimanic preventive efficacy of mood stabilizers over long-term maintenance treatment. In this study, we aimed to validate the PI in a large sample of Italian BD patients with accurate longitudinal characterization of the clinical course, which ensured a robust definition of the PP. Materials and Methods: Our sample is comprised of 653 patients with BD, divided into groups based on the predominant polarity (manic/hypomanic predominant polarity—MPP, depressive predominant polarity—DPP and no predominant polarity). Subsequently we calculated the mean total polarity index for each group, and we compared the groups. Results: When we examined the mean PI of treatments prescribed to individuals with DPP, MPP and no predominant polarity, calculated using two different methods, we failed to find significant differences, with the exception of the PI calculated with the Popovic method and using the less stringent criterion for predominant polarity (PP50%). Conclusions: Future prospective studies are needed in order to determine whether the predominant polarity is indeed one clinical factor that might guide the clinician in choosing the right mood stabilizer for BD maintenance treatment.

Algorithms for Computing Wiener Indices of Acyclic and Unicyclic Graphs

Let G = V G , E G be a molecular graph, where V G and E G are the sets of vertices (atoms) and edges (bonds). A topological index of a molecular graph is a numerical quantity which helps to predict the chemical/physical properties of the molecules. The Wiener, Wiener polarity, and the terminal Wiener indices are the distance-based topological indices. In this paper, we described a linear time algorithm (LTA) that computes the Wiener index for acyclic graphs and extended this algorithm for unicyclic graphs. The same algorithms are modified to compute the terminal Wiener index and the Wiener polarity index. All these algorithms compute the indices in time O n .

Involving clinicians in management: assessing views of doctors and nurses on hybrid professionalism in clinical directorates

Background Hybrid professionalism is one of the most effective ways to involve clinicians in management practices and responsibilities. With this study we investigated the perceptions of doctors and nurses on hybridization in clinical directorates (CDs) in hospitals. Methods We investigated the attitudes of healthcare professionals (doctors and nurses) towards eight hospital CDs in the Local Health Authority (LHA) of Bologna (Emilia Romagna, Italy) 6 years after their implementation. We used a validated questionnaire by Braithwaite and Westbrook (2004). Drawing on Palmer et al. (2007), we added a section about the characteristics of department heads. In all, 123 healthcare professionals in managerial roles completed and returned the questionnaire. The return rate was 47.4% for doctors and 31.6% for nurses. Results Doctors reported an increase in clinical governance, interdisciplinarity collaboration, and standardization of clinical work. Hybridization of practices was noted to have taken place. While doctors did not see these changes as a threat to professional values, they felt that hospital managers had taken greater control. There was a large overlap of attitudes between doctors and nurses: inter-professional integration in CDs fostered alignment of values and aims. The polarity index was higher for responses from the doctors than from the nurses. Conclusion The study findings have implications for policy makers and managers: mission and strategic mandate of CDs; governance of CDs, leadership issues; opportunities for engaging healthcare professionals; changes in managerial involvement during the COVID-19 pandemic. We also discuss the limitations of the present study and future areas for research into hybrid structures.