Determination of oil in aqueous emulsions by wide-line NMR

The radio frequency (r-f) saturation method was shown valid for determination of four edible oils in aqueous emulsions but not in commercial margarine. The interference in case of margarine was shown to be due to nonfat solids. The signal from water at low RF level was eliminated by converting to water of crystallization. Of three anhydrous salts studied for this purpose, only magnesium perchlorate was satisfactory. The method could be made quantitative for oil in margarine only by addition of carbon tetrachloride to the margarine before addition of magnesium perchlorate. One of 10 papers to be published from the Symposium “Wide Line Nuclear Magnetic Resonance,” presented at the AOCS Meeting, Minneapolis, October 1969.     

Effects of pH on the bioconcentration of pyrene in the larval midge, Chironomus riparius

Bioconcentration, depuration and biotransformation of the polycyclic aromatic hydrocarbon, pyrene, were studied at pH 4, 6 and 8 with larval stages of the chironomid midge, Chironomus riparius. ¹⁴C-labelled pyrene was applied. The results revealed pH-dependant bioconcentration and depuration-kinetics as well as biotransformation of pyrene. At higher pH the bioconcentration rate (k₁) was greater than at lower pH. Hereby the bioconcentration rate correlated with the accumulation potential of pyrene. That means at pH 8 the larvae accumulated pyrene strongest, at pH 4 the bioconcentration of the larvae was lowest. Due to biotransformation of pyrene the calculated bioconcentration factor (BCF) based on total ¹⁴C found in the larvae. Depuration revealed a biphasic kinetic. Data were fit with a two compartment model to calculate the volume of each of the two compartments. To calculate for the depuration rate (k₂), data were additionally fit with a one compartment model. The larvae displayed an intriguing pH-dependent behaviour: At pH 4 the Chironomus larvae started to increase mucus-production of the salivary glands and accelerated the built up of their tubes. The latter were of “cocoon”-like structure. At pH 8 the composition of the tubes was more loose. It is hypothezised that this response to an acidified environment caused the reduced bioconcentration rate as well as the reduced biconcentration.     

Evaluation of revised details of end zone of the prestressed concrete I-girders using finite element method

Prestressed concrete I-girders are becoming more widely used in bridges. However, the high prestressing force applied to these girders can lead to cracks in the end zone upon stress transfer. Recently, the standard drawing details for prestressed concrete I-girders were modified by the Ohio Department of Transportation (ODOT). The primary difference in the new drawings is the reinforcement details and usage of welded wire reinforcement at the end of the girders. In order to evaluate end cracking performance resulting from changes to the ODOT standard drawings, girders with various end reinforcement configurations were analysed using linear and non-linear finite element models. The strains and stresses at the end zone in the concrete and rebar were then evaluated. The non-linear finite element models were verified using available experimental data. After verification, the non-linear models were used to identify the location of the end zone cracks observed in the girders. The verified model was used to evaluate the revised details of end zone region. The results show that the modified details in the standard drawings meet the requirements of the AASHTO LRFD design specification. In addition, the end zone strains in the concrete and stresses in the reinforcement were reduced.     

Tetradecylthioacetic acid incorporated into very low density lipoprotein: changes in the fatty acid composition and reduced plasma lipids in cholesterol-fed hamsters

The mechanism behind the hypolipidemic effect of tetradecylthioacetic acid (CMTTD, a non-beta-oxidizable 3-thia fatty acid) was studied in hamsters fed a high cholesterol diet (2%), which resulted in hyperlipidemia. Treating hyperlipidemic hamsters with CMTTD resulted in a progressive hypocholesterolemic and hypotriacylglycerolemic effect. Decreased plasma cholesterol was followed by a 39% and 30% reduction in VLDL-cholesterol and LDL-cholesterol, respectively. In contrast, the HDL-cholesterol content was not affected, thus decreasing the VLDL-cholesterol/HDL-cholesterol and LDL-cholesterol/HDL-cholesterol ratios. 3-Hydroxy-3-methylglutaryl- (HMG) CoA reductase activity and its mRNA level were unchanged after CMTTD administration. Also, the LDL receptor and LDL receptor-related protein (LRP-4) mRNAs were unchanged. The decrease in plasma triacylglycerol was accompanied by a 45% and 56% reduction in VLDL-triacylglycerol and LDL-triacylglycerol, respectively. The hypolipidemic effect of CMTTD was followed by a 1.4-fold increase in mitochondrial fatty acid oxidation and a 2.3-fold increase in peroxisomal fatty acid oxidation. CMTTD treatment led to an accumulation of dihomo-gamma-linolenic acid (20:3n-6) in liver, plasma, very low density lipoprotein, and heart. Noteworthy, CMTTD accumulated more in the heart, plasma, and VLDL particles compared to the liver, and in the VLDL particle alpha-linolenic acid (18:3n-3) decreased whereas eicosatetraenoic acid (20:4n-3) increased. In addition, linoleic acid (18:2n-6) and the total amount of polyunsaturated fatty acids decreased, the latter mainly due to a decrease in n-6 fatty acids. The present data show that CMTTD was detected in plasma and incorporated into VLDL, liver, and heart. The relative incorporation (mol%) of CMTTD was heart > VLDL > liver. In conclusion, CMTTD causes both a hypocholesterolemic and hypotriacylglycerolemic effect in hyperlipidemic hamsters.     

Regulation of beta 2-adrenergic receptor mRNA and gene transcription in rat C6 glioma cells: effects of agonist, forskolin, and protein synthesis inhibition

The human CDX1 gene has been isolated from a small intestine cDNA library using a murine Cdx1 cDNA probe. The nucleotide sequence of CDX1 is 81% identical to murine Cdx1 and predicts a 265-amino-acid protein with 85% identity to the mouse protein (98% identity, including conservative amino acid changes). The CDX1 locus has been mapped to a cosmid contig from chromosome 5q31-q33, placing CDX1 approximately 100 kb distal to CSFIR. Expression of CDX1 in adults appears to be limited to the intestine and colon by Northern analysis, suggesting a possible role in the terminal differentiation of the intestine. Further analysis of CDX1 should elucidate the function of caudal-type homeobox genes in human development.     

Gender and haplotype effects upon hematological manifestations of adult sickle cell anemia

We evaluated the rates of short-term neonatal complications, neonatal brain damage or mortality in a group of 96 singleton pregnancies complicated by hypertension and electively delivered before 36 weeks gestation. The neonatal outcome of these pregnancies was compared with that of a matched control group of 192 uneventful pregnancies delivered because of spontaneous preterm labor or premature rupture of membranes. Although the rates of acidosis, apneoic crises, bradycardia and ventilatory support were higher among cases than controls, the risk of intraventricular hemorrhage, severe brain damage (grade III-IV intraventricular hemorrhage or periventricular leucomalacia) or neonatal mortality were comparable between the two groups. Neonatal complications were more frequent among infants born to mothers with severe hypertension or severe proteinuria. In conclusion, this study has shown that short term neonatal complications after elective preterm delivery in hypertensive pregnancies are increased in comparison with low risk controls. However, these complications, which were well managed in our intensive care nursery, did not affected neonatal mortality or severe brain damage.