The density, ρ, and the speed of sound, u, of γ-aminobutyric acid (GABA) in water and in (0.005, 0.01, 0.02, 0.04, and 0.06) mol·kg–1 aqueous caffeine (CAF) solutions were measured at temperatures, T = (293.15–318.15) K and P = 0.1 MPa. The measured data have been used to calculate apparent molar volumes at infinitesimal concentration (V 2,ϕ o), apparent molar isentropic compressibility (K 2,ϕ o), the corresponding transfer parameters, and other derived properties. The negative transfer values suggest the dominance of hydrophobic interactions and the structure-breaking tendency of CAF molecules. UV–visible spectroscopic studies have been carried out, and the shifts in the absorption spectra signify the role of hydrogen-bonding interactions. The structures of GABA and CAF have also been optimized in gas phase and solution phase by employing density functional theory at B3LYP/6-31+G* theoretical level, and the H-bond interactions between the two molecules have been studied. It is observed that there are strong H-bond interactions between GABA and CAF.

The polarographic technique gives a convenient method for studying redox reactions. The complexes studied give well defined, diffusion controlled one electron transfer reduction waves. The waves are irreversible in behavior. In case of P+(II) complexes, a regular cathodic shift in half wave potential of changing over from the trans structural macro cycle to the is observed. The redox properties of polyaza macrocyclic ligands have been of continued interest. As a result of these studies several macro cyclic complexes have been used as oxidant, reductants and electro catalysts. Earlier work on the redox behavior of macrocyclic complexes had mainly dealt with unsaturated systems. Later studies have dealt with many types of saturated systems also. It is important to study the effect of ligand structure, chelate ring size, donar unsaturation, substituent pattern and relative position of five and six membered chelate rings. It has been shown that a decrease in the ligand field strength of the macrocyclic ligands conclude in an anodic shift in the oxidant and reduction potentials. A change in the nature of the ring substituents changes the redox potential. The changes in the redox potential in these complexes are influence the substituents on the metal nitrogen interaction. In this we discuss the polarographic behavior of the complexes of (L1) Me2 (ET4) ( 14) diene (C20H40N4), Me2 (ET4) (14) ane (C20H44N4), (L3) Me6 (ET4) (14) diene (C16H35N4) and, (L4) Me2 (14) ane (C16H36N4). The polarograms of the complexes in aqueous solution were marked on a Metrohm Polarecord 50 usig a dropping mercury electrode (d.m.e.) as the working device. To choose a correct supporting electrolyte, polarographic wave of a few complexes were recorded in different electrolytes. It was observed that the best waves were prepared in 0.1 M sodium perchlorate. The one electron transfer irreversible waves related to the reduction of Pt (II) to Pt (I) and Pd (II) to Pd (I). It is reasonable to assume that the Pt -N distance is the significant factor. It has been seen that a change in the symmetry of the ligand result in change in the ligand field strength.

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Introduction Poor academic performance has been linked to factors such as sleep, health, illicit drug use, physical fighting, social media use, cyber bullying, physical activity, homelessness, times spent in video games and television. It is difficult to get a sense of the interplay between and relative importance of different behaviours/factors on academic performance as only limited research has been aimed at quantifying these factors. Objectives To evaluate association of school performance and variables in five categories of the YRBSS: physical fighting, diet/lifestyle, electronic device usage, concurrent substance use, and violence/self-harm. Methods The CDC Youth Risk Behavior Surveillance System (YRBSS) data from 1991-2019 was used in study. Respondents were grouped by good and poor school performance and variables related to nutrition/lifestyle, electronic device use, concurrent substance use, mood/violence/self-harm were analyzed using chi-square test. Results A total of 41,235 student respondents.Nutrition/Lifestyle, electronic device use, concurrent substance use, mood/violence/self-harm are found to be significantly correlated with school performance. Poor Performance n(%) Good Performance n(%) Total n(%) p-Value Nutrition/Lifestyle Daily breakfast 2,715(26) 11,429(38.22) 14,144(35.06) <0.0001 Sodas ≥2/day 1,998(19.12) 2,710(9.03) 4,708(11.63) <0.0001 Concurrent Substance Use Alcohol use 3,544(37.55) 8,067(28.49) 11,611(30.75) <0.0001 Cigarette smoking 1,616(15.74) 1,845(6.17) 3,461(8.61) <0.0001 Mood/Violence/Self-Harm Difficulty concentrating 4,188(46.34) 7,327(28.27) 11,516(32.94) <0.0001 Felt sad or hopeless 4,373(41.06) 9,038(29.67) 13,410(32.62) <0.0001 Considered suicide 2,567(24.14) 4,810(15.8) 7,377(17.96) <0.0001 Conclusions In national data, we found school performance is affected by nutrition, lifestyle, substance use, mood and exposure to surrounding violence, and self-harm. Further studies should be planned to evaluate benefits from the risk stratification to reduce this burden amongst US adolescents. Disclosure No significant relationships.

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