ABSTRACT
The solubilities of glycine, l-leucine, l-phenylalanine, and l-aspartic acid were measured in aqueous MgCl2, Mg(NO3)2, CaCl2,, and Ca(NO3)2 solutions with concentrations ranging from 0 to 2 mol/kg at 298.2 K. The isothermal analytical method was used combined with the refractive index measurements for composition analysis guaranteeing good accuracy. All salts induced a salting-in effect with a higher magnitude for those containing the Ca2+ cation. The nitrate anions also showed stronger binding with the amino acids, thus increasing their relative solubility more than the chloride anions. In particular, calcium nitrate induces an increase in the amino acid solubility from 2.4 (glycine) to 4.6 fold (l-aspartic acid) compared to the corresponding value in water. Amino acid solubility data in aqueous MgCl2 and CaCl2 solutions collected from the open literature were combined with that from this work, allowing us to analyze the relations between the amino acid structure and the salting-in magnitude.
ABSTRACT
AIMS: Birth weight (BW) estimation with ultrasound is of great importance in delivery decision and management of complications of delivery. The aim was to evaluate the effect of femur, humerus, and clavicular soft tissue thickness on BW and developed a formula for proper estimation of fetal weight. METHODS: This prospective cohort study, included 231singleton pregnancies, with 34 and 42 weeks of gestation, delivered within 48 h after ultrasound examination. In addition to four biometric ultrasound measures, shoulder soft tissue thickness, thigh and arm soft tissue thickness were measured from outer margin of skin to outer margin of bone shaft by same investigator. Spearman correlation test was used to assess correlations between soft tissue thickness measurements and BW. Linear regression model was used and R2 to test accuracy of the new formula. RESULTS: The mean humerus soft tissue thickness (HSTT) was 12 ± 3.5 mm (6-23.9 mm), mean femur soft tissue thickness (FSTT) was 15.9 ± 3.8 mm (7.3-32 mm), mean clavicular soft tissue thickness (CSTT) was 12.9 ± 3.2 mm (7.3-24 mm). There was a low correlation between BW and FSTT (r = 0.21, p = 0.001) and CSTT (r = 0.18, p = 0.005). Best fit formula was Log (BW) = -5697 + 7.2 (HC) + 15.3 (AC) + 22.6 (FL) + 17 (CSTT), was significantly correlated with BW (R2 = 0.60). CONCLUSION: BW increased as the ultrasound shoulder soft tissue thickness increased. Adding soft tissue thickness measurements to fetal biometry is similar in terms of estimating fetal weight from the existing estimated fetal weight formula.
