Ionic interactions in solutions of electrolytes as studied by ultra-violet spectroscopy

Spectrophotometric evidence for the formation of contact ion-pairs in solutions of tetra-alkylammonium iodides in certain solvents of poor ion-solvating power, such as carbon tetrachloride, is presented.

Since the band ascribed to contact ion-pairs is not detected for solutions in other solvents, such as chloroform, it is concluded that the ion-pairs detectable by other techniques in such solvents are separated by solvent molecules.     

ESR spectroscopy applied to the study of radiation mechanisms

ESR spectroscopy is a powerful tool for detecting radicals or radical-ions trapped in solids, and in many cases “primary” electron-gain and-loss centres can be identified and their structures elucidated. Sometimes these primary centres are trapped in pairs, separated byca. 5 to 15 Å giving triplet state ESR spectra. The significance of pair-trapping in relation to current theories for the action of ionizing radiation will be discussed with reference to several recent examples. Generally, the primary centres are well separated and ESR does not give useful information about spurs or local regions of high radical densities. Reasons for trapping will be summarized with specific reference to DNA and proteins. The question of electron-return will be discussed, and several examples of this will be reported.     

Electron spin resonance spectrum for a radical in γ-irradiated N-iodosuccinimide

A radical exhibiting a very large hyperfine coupling to ¹²⁷I, together with a small coupling to ¹⁴N, formed in γ-irradiated N-iodosuccinimide at 77 K is identified as a σ* radical anion in which the added electron is accommodated primarily in the N-I antibonding σ-orbital.     

Nuclear structure of proton-rich unstable nucleus 28P studied by g-factor measurement*

Nuclear structure of proton-rich unstable nucleus 28P has been studied by measuring its g-factor for the first time. The g-factor of 28P (Iπ =3+, T1/2=270.3 ms) was measured by means of β-NMR technique combined with the new polarization technique for charge exchange reaction product in the intermediate energy heavy ion collisions. The obtained g-factor of g=0.1028(27) is very much quenched from the Schmidt value,but is well reproduced by the shell model (+0.102). In connection with the magnetic moment of the mirror partner and the β-ray transition probability, the orbital angular momenta and intrinsic spins of protons and neutrons have been determined as 〈lp〉 = 0.43(29), 〈ln〉 = 1.85(29), 〈Sp〉 = 0.28(4), and 〈Sn〉 = 0.44(4).     

A dynamical systems model of intrauterine fetal growth

ABSTRACT

The underlying mechanisms for how maternal perinatal obesity and intrauterine environment influence foetal development are not well understood and thus require further understanding. In this paper, energy balance concepts are used to develop a comprehensive dynamical systems model for foetal growth that illustrates how maternal factors (energy intake and physical activity) influence foetal weight and related components (fat mass, fat-free mass, and placental volume) over time. The model is estimated from intensive measurements of foetal weight and placental volume obtained as part of Healthy Mom Zone (HMZ), a novel intervention for managing gestational weight gain in obese/overweight women. The overall result of the modelling procedure is a parsimonious system of equations that reliably predicts foetal weight gain and birth weight based on a sensible number of assessments. This model can inform clinical care recommendations as well as how adaptive interventions, such as HMZ, can influence foetal growth and birth outcomes.     

NMR on short-lived beta-emitter43Ti using new fragment separator at LBL

The lifetime and magnetic moment of⁴³Ti (I^π-7/2⁻, T_1/2=0.50 sec), one of the mirror beta-radioactive nuclei in the f_7/2-shell, have been measured with a fragment separator built at the Bevalac of the LBL. By means of the beta-NMR method on⁴³Ti, a preliminary value of the magnetic moment of⁴³Ti was determined to be μ=(0.70±0.07) μ_π.     

The use of infrared probes in solvation studies: Acetone in mixed protic-aprotic solvents

Infrared spectra ot acetone in the CO stretching region have been studied as a function of the composition of a range of mixed protic-aprotic solvents. For methanolic systems, equilibria between hydrogen-bonded and non hydrogen-bonded acetone dominate the spectral changes, but for aqueous systems at least four distinct components need to be considered.     

Zur ann?hernden Bestimmung von Harzim Ceresin

Ohne Zusammenfassung