Hybrid extractive scintillator resin for simultaneous concentration and detection of plutonium from aqueous solutions.

A scoping study of a commercially available resin selective for aqueous plutonium (Pu), AnaLig® Pu-02, modified with scintillator was investigated as a scheme to simultaneously concentrate and detect Pu in aquatic matrices. The extractive scintillating resin was comprised of a silica base, functionalized for plutonium extraction, grafted with plastic scintillator of polyvinyl toluene (PVT) and 2-(1-naphthyl)-4-vinyl-5- phenyloxazole (vNPO) fluor. Scintillator was incorporated onto the AnaLig® Pu-02 resin in a two-step process of silanization followed by surface-polymerization. Successful modification was facilitated by grinding the resin beads prior to silanization to expose cleaved silica surface sites appropriate for scintillator grafting. The modified resin was subjected to initial characterization of batch uptake and radioluminosity measurements where a total detection efficiency of 32.5% was observed. The modified resin was then subjected to pH 1 simulants containing environmental relevant groundwater constituents of varying concentration. Concentrations of 0.001M Fe(III) interfered with Pu uptake, while concentrations of up to 0.01M Ca(II) and 0.001 mM concentration of natural uranium and thorium had minimal influence on plutonium uptake. A translucent column packed with the modified AnaLig® Pu-02 was placed in a commercial flow-cell radiation detector for real-time detection of plutonium; a total detection efficiency of 20.4% was achieved for on-line measurements. The modification of AnaLig® Pu-02 results in a minimum detection limit capable of meeting the EPA limit for gross alpha activity in drinking water given a sufficient counting time of 15 min and approximately 300 mL of solution volume.

Hybrid extractive scintillator resin for simultaneous concentration and detection of radiocesium from aqueous solutions.

A hybrid extractive scintillating resin (HESR) was developed for the concentration and detection of radiocesium. The HESR comprised a cesium-selective potassium ferrierite ion-exchange powder embedded in porous polymeric scintillating beads. It was prepared by carrying out suspension polymerization of 4-methylstyrene with divinylbenzene, 2-(1-naphthyl)-4-vinyl-5-phenyloxazole fluor and ferrierite-K powder. A translucent column packed with the HESR was placed in a commercial flow-cell radiation detector for real-time detection of radiocesium. Measurements using the HESR detection system were compared with an on-line gamma-ray measurement using a NaI:Tl well detector containing a column of ferrierite-K powder/SiO2 or potassium-nickel ferrocyanate-polyacrylonitrile (KNiFC-PAN). The NaI:Tl well detector configuration quantified the gamma-ray from 137mBa, while the flow-cell detector primarily quantified the beta particles and conversion electrons of 137Cs. The minimum detectable concentration of the two detection modalities were calculated and shown to be lower than the maximum contaminant level in drinking water of 7.4 Bq/L (200 pCi/L).

sIL7R concentrations in the serum reflect disease activity in the lupus kidney.

OBJECTIVES: Evaluation of disease activity in systemic lupus erythematosus (SLE) nephritis is a challenge, and repeated renal biopsies are usually needed in order to confirm a suspicion of flare. In a previous cross-sectional study, we reported that serum soluble form of the interleukin-7 receptor (sIL7R) levels is strongly associated with nephritis in SLE patients. In the present study, we wanted to confirm the association between changes in serum sIL7R concentrations and renal disease activity in a large longitudinal cohort of SLE nephritis patients. METHODS: Sera were harvested longitudinally in 105 SLE nephritis patients. Serum sIL7R cut-off value for the detection of SLE nephritis activity was determined as the mean sIL7R concentration in non-nephritis SLE patients + 2 SDs using data collected in our previous study. Patients with glomerular filtration rate (GFR) <60 mL/min/1.73 m(2) (n=17) were excluded from the study due to persistently elevated serum sIL7R values. RESULTS: Serum sIL7R concentrations above the renal cut-off value were observed in 25 (out of 88) patients with a normal GFR. These patients had significantly higher serum double-stranded DNA (dsDNA) Ab and urinary protein to creatinine (UPC) ratio. Strikingly, 12 of them developed a renal British Isles Lupus Assessment Group index (BILAG) A within the next 3 months, while this was only the case in four out of the 63 other patients (p<0.0001). The test had 75.0% sensitivity and 81.9% specificity for the detection of a renal BILAG A. Combination of serum sIL7R with any of the classical tests (anti-dsDNA Ab titres, UPC ratio, serum C3) resulted in an increased specificity for the detection of a renal flare. Administration of immunosuppressive therapy resulted in a significant decrease in serum sIL7R concentrations. CONCLUSIONS: Serum sIL7R is a sensitive and specific marker of renal disease activity in SLE. Elevated serum sIL7R values in SLE patients are associated with or predict the occurrence of an SLE nephritis flare.

Feasibility of real-time 3D echocardiography in weightlessness during parabolic flight.

Aim of the study was to test the feasibility of transthoracic real-time 3D (Philips) echocardiography (RT3D) during parabolic flight, to allow direct measurement of heart chambers volumes modifications during the parabola. One RT3D dataset corresponding to one cardiac cycle was acquired at each gravity phase (1 Gz, 1.8 Gz, 0 Gz, 1.8 Gz) during breath-hold in 8 unmedicated normal subjects (41 +/- 8 years old) in standing upright position. Preliminary results, obtained by semi-automatically tracing left ventricular (LV) and left atrial (LA) endocardial contours in multiple views (Tomtec), showed a significant (p<0.05) reduction, compared to 1 Gz, of LV and LA volumes with 1.8 Gz, and a significant increase with 0 Gz. Further analysis will focus on the right heart.

[Embryological study of the mechanism of antenatal lower urinary tract obstruction]. / Obstruction anténatale du bas appareil urinaire: étude embryologique de son mécanisme.

Closure of the embryonic bladder based on the results of the study of 25 human embryos (Crown-Rump length: 5mm-60mm) and 8 Born's reconstructions, is presented. It is a complex but well regulated stage of organogenesis. Division of the cloaca depends on caudal regression, development of the genital tubercle and growth of the urorectal fold which joins the cloacal membrane. The didermal cloacal membrane (composed of the ecto and endodermal layers) opens on its caudal part. On the cranial part, there is a cloacal plug, composed of packed cells, which strengthens the inferior part of the genital tubercle. After progressive vacuolation, this plug is colonized by mesodermal tissue derived from the urorectal fold, which assumes the development of the anterior perineum. This stage depends on cranial growth of the genital tubercle. On a human embryo (31 mm Crown-Rump length, 52 days, 10 Weeks of amenorrhea), the bladder is closed, urachus obturated and urethra patent. The vesico-ureteral junction, and prostatic utricle are present and the colliculus seminalis is well developed. A temporary obstruction (caused by asynchronism between urachus closure and urethral opening) can induce antenatal vesicoureteral reflux which could regress after birth. However if urethral obstruction is definitive (posterior urethral valves or atresia), reflux persists. Antenatal sonographic bladder identification is possible after 10 weeks of amenorrhea with visualisation of the two umbilical arteries by color duplex ultrasound. If the urachus remains patent, it can be visualized inside the arterial umbilical triangle, on a transverse view.

Prenatal echographic diagnosis of corpus callosum agenesis. The Nancy experience 1982-1989.

In this report we present the Nancy experience on the prenatal echographic diagnosis of corpus callosum agenesis in a consecutive series of 17 patients. The pitfalls and difficulties in the prenatal echographic diagnosis of ACC is emphasized. They are related with the particular development of the corpus callosum and the limitations of diagnostic procedures. Moreover, the variability of corpus callosum anomalies is illustrated, and the difficulties in establishing long term prognosis in the individual patient documented.