Behavior of 316L stainless steel containing corrosion pits under cyclic loading

The environmental performance of 316L grade stainless steel, in the form of tensile specimens containing a single corrosion pit with various aspect ratios, under cyclic loading in aerated chloride solutions is investigated in this study. Results from environmental tests were compared and contrasted with those obtained using finite element analysis (FEA). Fractography of the failed specimens obtained from experiments revealed that fatigue crack initiation took place at the base of the shallow pit. The crack initiation shifted towards the shoulder and the mouth of the pit for pits of increasing depth. This process is well predicted by FEA, as the strain contour maps show that strain is the highest around the centric strip of the pit. However, for shallow pits, local strain is uniformly distributed around that strip but begins to concentrate more towards the shoulder and the mouth region for increasingly deep pits.     

Quantitative UPLC‐MS/MS analysis of chlorogenic acid derivatives in antioxidant fractionates from dandelion (Taraxacum officinale) root

While qualitative studies have identified chlorogenic acids in antioxidant extracts, particularly ethyl acetate‐derived extracts, of Taraxacum officinale, quantitative analysis of these phenolic compounds remains largely unreported for this species. In this study, bioactivity‐guided fractionation of an antioxidant crude ethyl acetate extract (DPPH = 295.481 ± 0.955 mg TE g^?1 extract) from T. officinale root resulted in a number of reverse‐phase fractions that demonstrated high antioxidant activity (DPPH = 1058.733–1312.136 mg TE g^?1 extract), stronger than that of the synthetic antioxidant Trolox^®. UPLC‐MS/MS screening of these fractions for the presence of selected mono‐ and di‐caffeoylquinic acids revealed large quantities of 1,5‐dicaffeoylquinic acid present in several fractions (853.052–907.324 μg mg^?1), respectively. Due to the antioxidant potency and high levels of 1,5‐dicaffeoylquinic acid observed in these fractions, it was concluded that specifically this chlorogenic acid derivative is a major contributor to the antioxidant efficacy of dandelion root.     

Anti-D in a D-positive renal transplant patient

PURPOSE: We report a case of postoperative reparalysis in the recovery room, following nebulized epinephrine. The patient was pharmacologically reversed with edrophonium after paralysis with rocuronium. CLINICAL FINDINGS: A 12-yr-old girl developed postoperative reparalysis following the intraoperative administration of rocuronium. A total of 0.92 mg.kg-1 rocuronium was administered. After surgery, pharmacological reversal was achieved with 20 mg edrophonium with 0.15 mg atropine sulfate iv 35 min after the last administration of rocuronium. Muscular relaxation was monitored using an ulnar peripheral nerve stimulator (PNS). After reversal, a full train-of-four and sustained tetanus at 50 Hz were present. In the recovery room, following nebulized epinephrine, the patient became apneic. The patient was paralyzed and an ulnar PNS demonstrated only one faint twitch. The paralysis was reversed with 1.5 mg neostigmine with 0.3 mg glycopyrrolate. CONCLUSION: Postoperative reparalysis following rocuronium may be a cause of postoperative respiratory distress. The definitive diagnosis is made using PNS and observing the response to pharmacological reversal. Nebulized epinephrine may have a previously undescribed role in the development of postoperative reparalysis.     

The pharmacokinetics and pharmacodynamics of the oral iron chelator deferiprone (L1) in relation to hemoglobin levels

Recently, we demonstrated that administration of the orally active iron chelating agent deferiprone (1,2-dimethyl-3-hydroxypyrid-4-one (L1)) at 6-hour intervals results in significantly greater urinary iron excretion than that induced during administration of the drug at 12-hour intervals. That study was conducted in thalassemia patients, all of whom had received a packed red cell transfusion of 15 cc/kg. 72 hours prior to evaluation of urinary iron excretion, at a time when endogenous erythropoiesis would be expected to be at its lowest. In clinical practice however, thalassemia patients, suppression of endogenous erythropoiesis is not sustained between transfusions. We set out to determine the influence that administration of deferiprone has on urinary iron excretion at lower hemoglobin concentrations, immediately prior to transfusion. We hypothesized that hemoglobin levels will affect the ability of deferiprone to chelate iron. Ten regularly transfused patients with homozygous beta-thalassemia (HBT) aged mean +/- SD, 20.9 +/- 4.7, range 13 - 27 years, receiving long-term therapy with deferiprone, were treated with deferiprone 75 mg/kg/day, administered every 6 hours (or every 12 hours) for 72 hours immediately prior to a blood transfusion in the first month. One month later each patient received the other of the 2 dosing regimens for 72 hours immediately prior to transfusion. The deferiprone-induced 24-hour urinary iron excretion was similar during both dosing regimens; 0.56 +/- 0.45 mg/kg when L1 was given every 6 hours and 0.48 +/- 0.52 mg/kg when L1 was administered every 12 hours (p = 0.79). However, the calculated 24-hour area under the plasma concentration-time curve (AUC0-24) of deferiprone was significantly lower when deferiprone was administered at 6-hour intervals (6,762.8 +/- 1,601.6 mg*min/l), than that observed when deferiprone was administered every 12 hours (8,250.1 +/- 1,235.7 mg*min/l) (p = 0.04). The pharmacokinetics of deferiprone when administered immediately prior to transfusions are different from those following transfusions. More studies assessing total body iron excretion are needed to determine the contribution of the fecal route in iron excretion.     

MISR in-flight camera geometric model calibration and georectification performance

In order to facilitate a unique georectification approach implemented for Multi-angle Imaging SpectroRadiometer (MISR) data, specific calibration datasets need to be derived during flight. In the case of the spaceborne MISR instrument, with its unique configuration of nine fixed pushbroom cameras, continuous and autonomous coregistration and geolocation of image data are required prior to the application of scientific retrieval algorithms. In-flight-generated calibration datasets are required to (a) assure accuracy, (b) reduce processing load, and (c) support autonomous aspects of the processing algorithm. This paper describes the in-flight geometric calibration approach with the focus on the first year of activities and the georectification performance achieved.     

Clumsiness in children: a defect of kinaesthetic perception?

The distribution of type I interleukin-1 receptor (IL-1R1) mRNA in the rat brain was examined by in situ hybridization technique. IL-1R1 mRNA was expressed in several brain regions including the anterior olfactory nucleus, medial thalamic nucleus, posterior thalamic nucleus, basolateral amygdaloid nucleus, ventromedial hypothalamic nucleus, arcuate nucleus, median eminence, mesencephalic trigeminal nucleus, motor trigeminal nucleus, facial nucleus and Purkinje cells of the cerebellum. Furthermore, we identified neuronal expression of IL-1R1 mRNA using simultaneous detection (double in situ hybridization) of IL-1R1 mRNA with neuron specific enolase mRNA. In addition to the expression in neuronal cells, IL-1R1 mRNA was also expressed on the vascular walls and the epithelial cells of the choroid plexus and the ventricles. These findings suggest the possibility that IL-1 produces its multiple effects on the central nervous system through the actions not only on neuronal cells but also on endothelial and epithelial cells.     

The effect of growth hormone replacement on cortisol metabolism and glucocorticoid sensitivity in hypopituitary adults

OBJECTIVE: Growth hormone (GH) replacement therapy in hypopituitary adults is associated with sodium and water retention. The underlying mechanisms are incompletely understood and a possible contribution of altered cortisol metabolism or action has not been evaluated. We have investigated the effect of GH replacement therapy on cortisol metabolism, cortisol binding globulin and in-vitro glucocorticoid sensitivity in a group of adult hypopituitary patients. DESIGN AND PATIENTS: We studied 19 adult hypopituitary patients (18 adult onset, M:F, 6:13), who were receiving conventional hydrocortisone (16 patients), thyroxine (14 patients), triiodothyronine (1 patient), sex steroid (9 patients), human chorionic gonadotrophin (1 patient) or desmopressin (6 patients) replacement during a 6-month, double blind controlled trial of GH therapy (active:placebo, 8:11) followed by a 6-month open phase of GH (mean dose: 0.2 IU/kg/week, range 0.051-0.27) and after a 6-week washout phase following discontinuation of GH therapy. MEASUREMENTS: Twenty-four-hour urine free cortisol, cortisol metabolites (CoM), ratio 11-hydroxy/11-oxo CoM (F/E) and ratio 5 alpha/beta tetrahydrocortisol were measured at 6 months, 12 months and after the 6 week washout phase. Serum cortisol binding globulin was measured basally, at 6 months, 12 months and after washout. Glucocorticoid sensitivity was determined in lymphocyte preparations from 8 patients, during GH therapy and after washout, using an in-vitro technique dependent on dexamethasone suppression of phytohaemagglutinin-stimulated thymidine incorporation into DNA. Plasma renin activity and aldosterone were measured after 6-12 months GH therapy and after washout. RESULTS: After 6 months of GH, in patients on hydrocortisone (n = 9), there were significant decreases in CoM (mean decrement 21%, P < 0.01), F/E (mean decreased from 1.27 to 1.0, P = 0.04; reference range 0.33-1.29) and 5 alpha/5 beta tetrahydrocortisol (mean decreased from 0.67 to 0.48, P = 0.01) and a subsequent increase after washout. Patients not on hydrocortisone (n = 2) demonstrated a normal basal F/E falling by 25% on GH therapy but no change in CoM. During 12 months of GH therapy, patients on hydrocortisone (n = 7) demonstrated a further trend to decrement in CoM (P = 0.09) which reversed after washout (P = 0.04). Urine free cortisol tended to fall during GH therapy and increased significantly following washout after 12 months treatment (P < 0.02). Serum cortisol binding globulin decreased by 20% (P < 0.05) during 12 months GH treatment but remained within the reference range. In-vitro studies demonstrated a trend to reduced glucocorticoid sensitivity on GH therapy; the maximum inhibition of phytohaemagglutinin by dexamethasone tended to be less on GH therapy (P = 0.052) and was also lower than in 29 normal volunteers (P < 0.05). There were no significant changes in plasma renin but there was a small increment in aldosterone in recumbent patients (P = 0.04) during the open phase of GH therapy in the placebo arm. CONCLUSIONS: GH therapy in hypopituitary adults is associated with an apparent reduction in availability of administered hydrocortisone as measured by urine cortisol metabolites and urine free cortisol. This effect is unlikely to be clinically significant except possibly in ACTH deficient subjects on suboptimal hydrocortisone replacement. The changes in F/E suggest that GH may directly or indirectly modulate the activity of 11 beta-hydroxysteroid dehydrogenase. The apparent decrease in glucocorticoid sensitivity during GH therapy, demonstrated in vitro, merits further investigation.