The Supercritical Water Reactor (SCWR) is one of the six reactor concepts being investigated under the framework of the Generation IV International Forum (GIF). Research on materials and chemistry ...for supercritical water-cooled reactors dates back to the 1960s when a number of reactor concepts using water at supercritical temperatures but sub-critical pressures (nuclear steam) were studied. There is also significant experience available from the operation of supercritical fossil-fired power plants. In this paper, the materials requirements of the various SCWR concepts are introduced, with a focus on the European Union pressure vessel concept and the Canadian pressure tube concept. The current understanding of the key materials degradation issues is reviewed, and knowledge gaps identified.
•International cooperation under Generation IV led to major advances in SCWR materials and chemistry.•The selection and qualification of a suitable fuel cladding alloy remains the biggest challenge.•The general corrosion of iron- and nickel-based alloys in SCWR conditions is now fairly well understood.•The SCC behavior is less clear and sometimes results of different groups are even contradictory.•The biggest gap in knowledge remains in the behavior of the candidate alloys under irradiation.
The lead tungstate crystal (PbWO 4 , PWO) is one of the widely used scintillation materials for electromagnetic calorimeters (EMCs) in high-energy physics experiments. The degradation of the optical ...transmittance in the range of the luminescence spectrum under ionizing radiation leads to losses of the light output resulting in the deterioration of the energy resolution and limiting the lifetime of the calorimeter. A possible way to restore radiation damage is the in situ illumination by visible or near-infrared light of the whole crystal volume. It allows recovering the transmittance losses due to the depopulation of the color centers. Such a kind of stimulated recovery subsystem based on a blue light-emitting diode is considered for the EMC of the PANDA detector at Facility for Antiproton and Ion Research (FAIR) (Darmstadt, Germany). Here, we report on the stimulated recovery studies of the lead tungstate radiation damage induced by external light from laser diodes at different wavelengths. The level of technological development of laser diodes allows increasing the efficiency of the stimulated recovery.
A new inorganic scintillation material based on Ba-Gd silica glass doped with cerium (BGS) is fabricated and studied. With the highest light yield among heavy glasses at the level of 2500 ph/MeV and ...fast scintillation response, the new scintillator ensures a good coincidence time resolution of < 230 ps FWHM for 511 keV γ-quanta from a 22Na source and SiPM readout. In addition to good performance in γ-quanta detection, the material demonstrates capability for efficient detection of low-energetic neutrons. The scintillator is produced by exploiting the standard industrial glass technology, which allows for an unlimited scaling up the conversion of raw material into a high-quality scintillator at a high rate. The glass can be casted in application-specific molds, so minimizing the material losses. The presented glass scintillator has potential for further improvement of its light output and scintillation response time.
General corrosion tests in SCW were carried out at 650°C/25MPa up to 3000h for four 316L tube samples with different surface finishes.The corrosion behavior of these samples was studied using SEM ...and EDS and in addition using FIB and TEM for selected samples.A thin and apparently more protective oxide film formed on surface cold worked (machined) 316L sample compared to ground ones.Cold working of the surface region of 316L appears to suppress oxidation for a substantial exposure time, at least up to 3000h.It seems that oxidation resistance is enhanced by the high dislocation density of cold worked (machined) sample surface.
This work summarizes the results of corrosion studies of a surface treated austenitic stainless steel 316L at relevant operating conditions of SCWR (Supercritical Water Reactor). Different surface treatments were conducted for austenitic stainless steel 316L tube samples in order to study the effect of cold work in sample surface on corrosion resistance. Samples were exposed in supercritical water (SCW) at 650°C/25MPa, up to 3000h. The corrosion rate was evaluated by measuring the weight change of the samples and by cross-section examinations using a Scanning Electron Microscope (SEM) in conjunction with Energy Dispersive X-ray Spectroscopy (EDS). Additional investigations using a Focused Ion Beam (FIB) microscope and a Transmission Electron Microscopy (TEM) were also performed on selected samples. It is observed that in machined sample, with a fine-grained microstructure and higher dislocation density in the sub-surface zone formed a very thin Cr-rich oxide film which suppresses the inward oxygen and outward iron diffusion.
Context: Lack of sun exposure is widely accepted as the primary cause of epidemic low vitamin D status worldwide. However, some individuals with seemingly adequate UV exposure have been reported to ...have low serum 25-hydroxyvitamin D 25(OH)D concentration, results that might have been confounded by imprecision of the assays used.
Objective: The aim was to document the 25(OH)D status of healthy individuals with habitually high sun exposure.
Setting: This study was conducted in a convenience sample of adults in Honolulu, Hawaii (latitude 21°).
Participants: The study population consisted of 93 adults (30 women and 63 men) with a mean (sem) age and body mass index of 24.0 yr (0.7) and 23.6 kg/m2 (0.4), respectively. Their self-reported sun exposure was 28.9 (1.5) h/wk, yielding a calculated sun exposure index of 11.1 (0.7).
Main Outcome Measures: Serum 25(OH)D concentration was measured using a precise HPLC assay. Low vitamin D status was defined as a circulating 25(OH)D concentration less than 30 ng/ml.
Results: Mean serum 25(OH)D concentration was 31.6 ng/ml. Using a cutpoint of 30 ng/ml, 51% of this population had low vitamin D status. The highest 25(OH)D concentration was 62 ng/ml.
Conclusions: These data suggest that variable responsiveness to UVB radiation is evident among individuals, causing some to have low vitamin D status despite abundant sun exposure. In addition, because the maximal 25(OH)D concentration produced by natural UV exposure appears to be approximately 60 ng/ml, it seems prudent to use this value as an upper limit when prescribing vitamin D supplementation.
Despite expectant management, preeclampsia remote from term usually results in preterm delivery. Antithrombin, which displays antiinflammatory and anticoagulant properties, may have a therapeutic ...role in treating preterm preeclampsia, a disorder characterized by endothelial dysfunction, inflammation, and activation of the coagulation system.
This randomized, placebo-controlled clinical trial aimed to evaluate whether intravenous recombinant human antithrombin could prolong gestation and therefore improve maternal and fetal outcomes.
We performed a double-blind, placebo-controlled trial at 23 hospitals. Women were eligible if they had a singleton pregnancy, early-onset or superimposed preeclampsia at 23 0/7 to 30 0/7 weeks’ gestation, and planned expectant management. In addition to standard therapy, patients were randomized to receive either recombinant human antithrombin 250 mg loading dose followed by a continuous infusion of 2000 mg per 24 hours or an identical saline infusion until delivery. The primary outcome was days gained from randomization until delivery. The secondary outcome was composite neonatal morbidity score. A total of 120 women were randomized.
There was no difference in median gestational age at enrollment (27.3 weeks’ gestation for the recombinant human antithrombin group range, 23.1–30.0 and 27.6 weeks’ gestation for the placebo group range, 23.0–30.0; P=.67). There were no differences in median increase in days gained (5.0 in the recombinant human antithrombin group range, 0–75 and 6.0 for the placebo group range, 0–85; P=.95). There were no differences between groups in composite neonatal morbidity scores or in maternal complications. No safety issues related to recombinant human antithrombin were noted in this study, despite the achievement of supraphysiological antithrombin concentrations.
The administration of recombinant human antithrombin in preterm preeclampsia neither prolonged pregnancy nor improved neonatal or maternal outcomes.
The aim of the study was to evaluate the usability of different fixative fluids in the detection of mast cells in ovaries and uteri of female dogs and cats.
Samples were fixed in 4% formaldehyde, ...Carnoy's fluid, Mota's basic lead acetate and isotonic formaldehyde-acetic acid (IFAA).
Mast cells (MCs) were detected by acidified toluidine blue staining and counted for various parts of the ovaries and uteri. In the ovaries of both species, the numbers of MCs were significantly (p < 0.05) higher in Carnoy than in formalin. No significant differences were found between Carnoy and Mota (tested only in cats). In the uterus, numbers of MCs were significantly (p < 0.05) higher in Carnoy, Mota and IFAA compared to formalin (canine endometrium, feline endometrium and feline myometrium), in Carnoy and Mota compared to formalin (canine myometrium) and in Mota compared to IFAA (feline myometrium). The majority of MCs were formalin-sensitive in the canine and feline uterus, in the canine ovary and in the feline cortex ovarii. In the feline medulla ovarii, the majority of MCs were formalin-resistant. No formalin-resistant MCs were detected in the feline tunica albuginea ovarii.
Thus, using Mota's or Carnoy's fluid in the canine or feline female reproductive organs is recommended. This study improves methodology for all studies which clarify the role of MCs in the reproductive organs of the domestic and laboratory animals.
Surgery is still the only curative therapy for locoregional gastric cancer. Hereby it is important to achieve negative margins (R0 resection) and to perform an adequate lymph-node dissection (D2 ...lymphadenectomy). Unfortunately most cases of gastric cancer are diagnosed in a locally advanced tumor stage. The poor prognosis of patients with these tumors is due to the frequent recurrences after primary resection in curative intent. This observation led to the development of (neo)adjuvant treatment concepts. Beginning with the end of the 1980s, more and more patients with locally advanced tumors were subjected to a preoperative, perioperative, or postoperative treatment in order to improve the prognosis after curative resection. However, in different regions of the world, different regiments are preferred. While adjuvant chemotherapy is the established treatment in Asia, adjuvant chemoradiotherapy is favored in the USA and perioperative chemotherapy is considered the treatment of choice in Europe. However, recently a certain convergence of the different philosophies is to be observed. This article covers the relevant studies dealing with neoadjuvant and adjuvant treatment concepts and gives an overview on the latest developments in this field.
The future P¯ANDA experiment with a next generation detector will focus on hadron spectroscopy. It will use cooled anti-proton beams with a momentum between 1.5 GeV/c and 15 GeV/c interacting with ...various targets. This allows to directly form all states of all quantum numbers and measure their widths with an accuracy of a few tens of keV. The experiment will be located at the exceptional Facility for Anti-proton and Ion Research in Germany (FAIR), which is currently under construction. The electromagnetic target calorimeter of the P¯ANDA experiment has the challenging aim to detect high energy photons with excellent energy resolution over the full dynamic range from 15 GeV down to a few tens of MeV within a 2 T solenoid. The target calorimeter itself is divided into a barrel and two endcaps. The individual crystals will be read out with two precisely matched large area avalanche photo diodes. In the very inner part of the forward endcap vacuum phototetrodes will be used instead. To reach the demands of the experiment, improved PbWO4 (PWO) scintillator crystals, cooled down to −25°C have been chosen. They provide a fast decay time for highest count rates, short radiation length for compactness, improved light yield for lowest thresholds and excellent radiation hardness 1. The main part of the 15,740 crystals needed have been produced by the Bogoroditsk Plant of Technochemical Products (BTCP) in Russia. After stopping their business, a new potential producer for the missing 41% of crystals have been found. The company Crytur in Czech Republic provided 150 promising preproduction crystals so far. Except some of the very first produced crystals, all samples exceed the required high quality parameters. Most of them have already been used for the first major assembly stage of assembling one of the 16 barrel slice segments, which will be presented as well.
Contents
This study is the first description of the distribution of mast cells in various phases of the oestrous cycle in the ovary of cat. Furthermore, this is the first description in species with ...an induced ovulation. The aim was to describe the distribution of mast cells and variability of their numbers in the feline ovaries in different phases of the oestrous cycle. The number of mast cells in medulla ovarii was affected by the estradiol and progesterone level in the blood serum because the lowest number was detected in anoestrus when the levels of hormones were basal. Nevertheless, both high and low numbers of mast cells were found in oestrus and dioestrus. To conclude, mast cells seem to be essential for the induction of spontaneous ovulation, but they do not play the same role for ovulation itself in cats with induced ovulation.
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