Hyper-rook Domain Inequalities

A hyper-rook domain of an element x in the space (words of length n over alphabets with k elements) is a sphere with center x and fixed radius j in Hamming distance. The number j determines the dimension of the hyper-rook domain. The classical (and far from solved) problem of covering by rook domains (here considered as the 1-dimensional case) is the problem of finding minimal coverings of by such spheres. Very few results are known in the literature for dimensions ≥ 2. We prove in this paper certain classes of inequalities based on coverings using matrices, which give upper and lower bounds for several cases of the problem for higher dimensions.     

Some results on polarized partion relations of higher dimension

Several types of polarized partition relations are considered. In particular we deal with partitions defined on cartesian products of more than two factors. MSC: 03E05.     

New Dimensions on Translations Between Logics

After a brief promenade on the several notions of translations that appear in the literature, we concentrate on three paradigms of translations between logics: (conservative) translations, transfers and contextual translations. Though independent, such approaches are here compared and assessed against questions about the meaning of a translation and about comparative strength and extensibility of a logic with respect to another. Dedicated to the memory of Mário Tourasse Teixeira and Antonio Mário Sette     

Surfactant protein C metabolism in human infants and adult patients by stable isotope tracer and mass spectrometry

Surfactant protein C (SP-C) is deemed as the surfactant protein most specifically expressed in type II alveolar epithelial cells and plays an important role in surfactant function. SP-C turnover in humans and its meaning in the clinical context have never been approached. In this study, we used mass spectrometry to investigate SP-C turnover in humans. We studied four infants and eight adults requiring mechanical ventilation. All patients had no lung disease. Patients received a 24-h continuous infusion of ¹³C-leucine as precursor of SP-C, and serial tracheal aspirates and plasma samples were obtained every 6 h till 48 h. SP-C was isolated from tracheal aspirates by sorbent-phase chromatography. ¹³C-leucine SP-C enrichment could be successfully measured in three infant and in four adult samples by using mass spectrometry coupled with a gas chromatographer. Median SP-C fractional synthesis rate, secretion time, and peak time were 15.7 (14.1–27.5) %/day, 6.0 (4.7–11.5) h, and 24 (20–27) h. In conclusion, this study shows that it is feasible to accurately determine SP-C turnover in humans by stable isotopes.     

Simplified method for microlitre deuterium measurements in water and urine by gas chromatography-high-temperature conversion-isotope ratio mass spectrometry

Deuterium (2H) in water and urine can be measured by off-line and, more recently, on-line techniques using isotope ratio mass spectrometry (IRMS). We describe a new simple on-line pyrolysis method for the analysis of 2H/1H in water and urine samples by continuous flow IRMS, normally used for 2H/1H measurements in organic compounds. A deactivated column connected the split injector to a high-temperature conversion reactor (TC HD), and 0.5 microL of sample was injected. Accuracy and precision were determined with Vienna Standard Mean Ocean Water (VSMOW), Standard Light Antarctic Precipitation (SLAP), and Greenland Ice Sheet Precipitation (GISP). The range of linearity was measured with a calibration curve of enriched water from 0 up to 0.1 atom percent excess (APE) (i.e. -72 up to 6323 delta per mil (deltaD per thousand)) with a precision of <5 per thousand and accuracy ranging between 1 and 55 per thousand. Blinded reanalysis of urine samples by an equilibration device (Gas Bench) and by a dedicated pyrolysis system (TC/EA) was performed and results compared by the Bland-Altman test. Enrichments ranged between 600 and 2400 per thousand deltaD(VSMOW) with a precision of +/-5 per thousand. Urine enrichments described by our method were strongly correlated with values obtained by Gas Bench and TC/EA (p < 0.0001). There was a significant memory effect that was reduced by injecting the sample 15 times and discarding the first 10 injections, together with accurate furnace conditioning and appropriate cleaning of the syringe. Data indicate that the method is accurate, and that it can be used for water and urine deuterium determination when a Gas Bench or TC/EA instrument is not available and the amount of sample is limited.     

Surfactant protein B amount and kinetics in newborn infants: an optimized procedure

Surfactant protein B (SP‐B) plays a key role in surfactant homeostasis affecting its biophysical properties and physiological function. Recently, a method to measure SP‐B amount and kinetics from tracheal aspirates (TAs) became available. The main objective of this study was to improve the critical steps of the procedure to obtain a better SP‐B sensitivity. We administered a 24 h continuous infusion of 1 mg/kg/h of 1¹³ C‐leucine to ten newborn infants. SP‐B was isolated from serial TAs and its fractional synthesis rate, secretion time, peak time and half life were derived from ¹³ C enrichment curves obtained by gas chromatography mass spectrometry. SP‐B amount in TAs was also assessed. During the extraction step, acidification and organic solvent ratio optimization doubled the recovery of SP‐B from TAs, so did the elongation of the propylation time (from 20 min to 1 h) with enhanced leucine derivatization yield. Measurement of ¹³ C leucine enrichments, and therefore all SP‐B kinetics parameters, were successfully calculated in all TAs samples due to the increase of SP‐B yield. SP‐B amount was 0.29 (0.16–0.41) % of total phospholipids with a minimum value of 0.08% belonging to one of the respiratory distress syndrome (RDS) patients. In conclusion, this new procedure enables accurate determination of SP‐B kinetics even in the presence of low protein amount like in preterm RDS patients. Copyright © 2012 John Wiley & Sons, Ltd.     

Simultaneous measurement of phosphatidylglycerol and disaturated-phosphatidylcholine palmitate kinetics from alveolar surfactant. Study in infants with stable isotope tracer, coupled with isotope ratio mass spectrometry

Disaturated-phosphatidylcholine (DSPC) and phosphatidylglycerol (PG) are respectively the first and the third most abundant phospholipid in human alveolar surfactant. Their concentration decreases in airway surfactant of adults and infants with respiratory distress syndrome and cystic fibrosis. In this study, we used mass spectrometry (IRMS) to investigate the turnover of DSPC and PG in tracheal aspirates (TA) obtained from infants with normal or diseased lungs. We studied eight infants requiring mechanical ventilation: two with no lung disease, four with diaphragmatic hernia, one with ATP-binding cassette sub-family A member 3 heterozygote mutation and one with sepsis. Patients received deuterated water for 48 h as metabolic precursors of palmitate-DSPC and palmitate-PG. Serial TAs were obtained every 6 h for five days or until extubation. DSPC and PG were isolated from TA by column and high-performance thin layer chromatography. Deuterium enrichments of palmitate-DSPC and PG residues were measured by IRMS coupled with a gas chromatographer. Median secretion time (ST), peak time (PT) and fractional synthesis rate (FSR) were 3.7 [0.9- 13.4] h, 71.0 [52.2 - 85.2] h and 6.6 [6.3 - 11.1] %/day for DSPC and 19.3 [6.4 - 22.8] h, 49.0 [33.0 - 52.5] h and 5.8 [4.8 - 10.9] %/day for PG. This study shows that it is feasible to use deuterium derived from body water to trace simultaneously airway surfactant DSPC and PG in humans. When compared within the same patient, DSPC and PG had similar fractional synthesis rates, but PG had a shorter PT, suggesting differences in the life cycle of these essential surfactant components.