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Stainless steels containing both C and N have unique characteristics while requiring unconventional manufacturing methods. This latter feature also translates into a lack of systematic investigations into their properties. In this work, a series of 13 wt%Cr steels with various interstitial solid solutions of C and N was synthesized by high temperature solution nitriding, HTSN, of commercial 13 wt%Cr martensitic steels. Light optical microscopy was applied to reveal the microstructural features, which consisted of a combination of martensite and austenite in various ratios depending on the C and N content. The mechanical response was characterized by nanoindentation. Data analysis assumed a fixed hardening exponent and provided an estimate of the yield strength and Young’s modulus of the synthesized steels and their microstructural components. The comparison with literature data indicated that this estimate is sound for martensite, while the data for austenite suggests an underestimation of the hardening exponent for this phase. The investigation demonstrates the potential of HTSN for the synthesis of novel 13 wt%Cr steels alloyed with both C and N. Moreover, it suggests that the use of nanoindentation for extracting the mechanical properties is limited by the non-uniqueness of the method with regard to the hardening exponent.

While maraging steels are excellent candidates for additive manufacturing of high-strength materials, most of them provide little to no corrosion resistance. In this study, the surface of additively manufactured maraging steel is augmented with diffusion-based chromizing. The diffusion of chromium into the surface results in the formation of α-Cr, σ-phase and austenite depending on the chromium content at the respective distance from the surface. The bulk consists of a ductile bcc martensite hardened by precipitation of intermetallics during a low temperature ageing treatment. The σ-case provides a very high hardness, while the austenite phase is rather soft and unaffected by the ageing treatment. The chromizing treatment significantly reduced the corrosion rate of the maraging steel up to a factor of 14. Decomposition of the σ-case into a uniform case of austenite (austenitic stainless steel) further improved the corrosion resistance almost 24 times. This showed the strong potential of the chromizing treatment on a highstrength material to obtain a combination of their beneficial properties.

The medical device industry demands unique device identification (UDI) tags on metallic components applied via laser marking. A common issue is that the visual appearance of the marking becomes poorly legible over time due to loss of contrast. Nanosecond pulsed laser irradiation was used to grow an oxide layer on two different martensitic stainless steels AISI 420F mod and 420B to compare the influences of the chemical composition of the steel (with and without S), power density, and energy input. The corrosion behavior was found to depend strongly on laser energy input. The presence of sulfur negatively affected the corrosion resistance and narrowed the applicable window for the laser processing parameters significantly. For the sulfur-containing AISI 420F steel, 3‒5 μm wide craters formed on the surface after laser marking, which is interpreted as thermal degradation of protruding MnS inclusions resulting from the laser marking process. Also, substantial cracking in the oxide layer was observed. The marked specimens suffered from corrosion in a thin zone below the formed oxide layer. This behavior is attributed to Cr-depletion in the zone adjacent to the oxide layer, resulting from providing Cr to the growing oxide layer.

The case study is on the use of pulverized anthracite and coke oven gas as a fuel for the twin shaft regenerative kiln in quick lime manufacture. The study has successfully proved the suitability of the above fuels as economic and practical alternatives.

In the cement, lime and power generation sectors, the most commonly used method for burning solid fuels is pulverized fuel combustion. The article includes extensive discussion of twin shaft regenerative lime kilns.

Cimprogetti SpA has commissioned its anthracite-fired CIM Reversy NS 45 kiln with a capacity of 200 t/d. The kiln has been installed at the Plena Plant, Bulgaria, and is equipped with an inertisation system for CO2 to avoid dust explosion risks. The company has also installed a CIM-Twin D NS55 kiln, fired on coke oven gas, with a capacity of 260 t/d at the Kardemir Plant, Turkey. The two kilns demonstrate the suitability of pulverized coal and coke oven gas as fuels and both produce consistent quicklime quality.

Italy's Cimprogetti has developed two hydration plants which allow lime producers to comply with increasingly stringent environmental requirements. The Cim-Hydrax comprises pre-hydration, hydration and finishing units and the TG-Third generation incorporates a bladed twin shaft high speed pre-mixer. The two systems remove particulates to

This article addresses an investigation of the influence of plastic deformation on low temperature surface hardening by gaseous nitriding of three commercial austenitic stainless steels: AISI 304, EN 1.4369 and Sandvik Nanoflex® with various degrees of austenite stability. The materials were plastically deformed to different equivalent strains by uniaxial tension. Gaseous nitriding of the strained material was performed in ammonia gas at atmospheric pressure at 703 K (430 °C) and 693 K (420 °C) depending on the material. Microstructural characterization of the as-deformed states and the nitrided case included X-ray diffraction analysis, reflected light microscopy and microhardness. The results demonstrate that a case of expanded austenite develops and that, in particular, strain-induced martensite has a large influence on the nitrided zone. ▪

Low-temperature carburizing dramatically enhances the inherently low wear resistance of austenitic stainless steels due to the formation of a carbon-supersaturated solid solution, i.e. expanded austenite. The formation of expanded austenite from low-temperature carburizing has been intensively investigated. However, the influence of chemical composition of the stainless steel on the carburizing response has not received the same interest. This contribution addresses the effect of the chemical composition on low-temperature carburizing in terms of carbon solubility, decomposition of expanded austenite upon exceeding the solubility limit and the elasto-plastic accommodation of the carbon-induced lattice expansion. The results demonstrate that the carbon solubility increases with an increasing Cr-equivalent and that higher Cr- and Ni-equivalents favor the formation of Cr-based M7C3over Fe-based Hägg (M5C2) carbide.

This contribution provides an overview of the concepts of high temperature solution nitriding (HTSN) and the state of the art of the technology. It shows how HTSN can be applied to different classes of stainless steels. New advances of HTSN are presented, in particular the combination of HTSN with low temperature surface hardening, LTSH, is addressed: HTSN is an excellent “pre-treatment” for LTSH for austenitic, duplex, ferritic and martensitic stainless steels. Examples of combined HTSN + LTSH treatments of duplex and martensitic stainless steels are shown.

AbstractThe present work investigates the corrosion resistance of Ni and Ni2Al3coated austenitic stainless steel (TP347H) tubes, which were exposed in a biomass-fired boiler with an outlet steam temperature of 540 °C for 6757 h. The Ni2Al3coating was produced by electroplating Ni followed by low temperature pack cementation. After exposure, microstructural investigations were performed by light optical and electron microscopy (SEM-EDS). Electroplated Ni coatings were not protective in straw firing power plants and exhibited similar corrosion morphology as uncoated tubes. For Ni2Al3coatings, the nickel aluminide layer was no longer adherent to the tube and was only found within the deposit. However, Ni2Al3coatings had provided some protection compared to uncoated and Ni coated tubes. The formation of nickel chloride binds aggressive chlorine and slows down the active oxidation mechanism. In local areas, sulphidation corrosion attack of Ni was detected.

Work carried out for Rugby Jamaica Lime and Minerals Ltd on lime kilns of a regenerative twin shaft type is examined in detail.

Die Austenit-zu-Martensit-Umwandlungunterhalb Raumtemperatur wurde in situ mit Magnetometrie in Fe-N-, Fe-Cr-C- und Fe-Cr-Ni-basierten Legierungen untersucht. Nach dem Abschrecken von der Austenitisiertemperatur auf Raumtemperatur wurden die Legierungen in siedendem Stickstoff abgeschreckt. Anschließend wurde die martensitische Umwandlung während der Erwärmung auf Raumtemperatur verfolgt. Verschiedene konstante Erwärmraten zwischen 0,5 K/min und 10 K/min wurden untersucht. Eine Probe wurde als Referenz schockartig in Wasser aufgeheizt, um zu überprüfen, ob die Martensitbildung bei einer hohen Erwärmrate unterdrückt werden kann. Thermisch aktivierte Bildung von Martensit während dem Erwärmen wurde für alle getesteten Legierungen mit einer von der Erwärmrate abhängigen Umwandlungskinetik überzeugend demonstriert. Außerdem konnte mittels Magnetometrie gezeigt werden, dass die Erwärmrate den Martensitanteil während der Wärmebehandlung beeinflusst. Die Aktivierungsenergie für thermisch aktivierte Martensitbildung wurde mit der Methode nach Kissinger zu 11–18 kJ/mol bestimmt und nimmt mit dem Anteil der Zwischengitterelemente zu.

Shielding gas flow is essential to the additive manufacturing (AM) process, and the effects of argon shielding gas flow variation on the macroscopic homogeneity of additive manufactured stainless steel parts have been studied using an open-architecture AM system. Such a variation manifests itself layer-by-layer within one part and part-by-part across the build plate. Within one build, a combination of balling behavior, conduction melting and keyhole melting is observed across the build plate using the same laser parameters. Quantitative characterization of the melt pool shapes show that the melt pool width and the penetration depth exhibit the largest variations. Possible relations between the gas flow condition and macroscopic structure variations are discussed and guidelines for improved design of a gas flow system as well as future research directions are suggested for achieving macroscopically uniform metal AM.

Gaseous carburising of self-passivating Fe–Cr–Ni alloys in acetylene–hydrogen was investigated for temperatures up to 823 K. Acetylene–hydrogen gas mixtures allow both the activation of the surface and the subsequent carburising at a high and adjustable carburising potential. For relatively low temperatures, carbon stabilised expanded austenite develops, which has high hardness, while retaining the corrosion performance of the untreated alloy; for relatively high temperatures, Cr based carbides develop, and eventually, the material deteriorates by metal dusting corrosion.

The present contribution gives an overviewof some of the technological aspects of low temperature thermochemical treatment of stainless steel. Examples of low temperature gaseous nitriding, carburising and nitrocarburising of stainless steel are presented and discussed. In particular, the morphology, microstructure and characteristics of so-called expanded austenite “layers” on stainless steel are addressed.

The present workinvestigates the possibility of nitrocarburising in ammonia-acetylene-hydrogen and ammonia-propene-hydrogen gas mixtures, where unsaturated hydrocarbon gas is the carbon source during nitrocarburising. Consequently, nitrocarburising is carried out in a reducing atmosphere and straightforward control of the carburising and nitriding potentials is in principle possible. The nitrocarburising response of unalloyed (ARMCO) Fe was investigated in a thermobalance during controlled nitrocarburising at 580°C. The “cases” obtained on nitrocarburised iron were characterized by reflected light microscopy and X-ray diffraction analysis. It is shown that the use of unsaturated hydrocarbon gas in nitrocarburising processes is a viable alternative to traditional nitrocarburising methods.

In diesem Beitrag wird ein Überblick über neue wissenschaftliche und technologische Entwicklungen auf dem Gebiet des Gasnitrierens und Gascarburierens von austenitischem rostfreien Stahl bei niedrigen Temperaturen, d.h. unter etwa 723 K für das Gasnitrieren und unter etwa 823 K für das Gascarburieren, gegeben. Diese thermochemischen Oberflächenbehandlungen werden durch eine neu patentierte Vorbehandlung ermöglicht, wobei die passive Chromoxidschicht durch eine sehr dünne katalytische Nickelschicht ersetzt wird. Bei der nachfolgenden thermochemischen Behandlung spalten stickstoff- und kohlenstoffhaltige Gaskomponenten bevorzugt an der Nickeloberfläche. Dabei werden Stickstoff- und Kohlenstoffatome vom darunterliegenden Substrat unter Bildung von aufgeweitetem Austenit aufgenommen. Kristallografische Daten, Absorptionsisotherme, Diffusionskoeffizienten und die thermische Stabilität wurden an homogenen Folien aufgeweiteten Austenits unterschiedlicher Stickstoffgehalte untersucht. Härte- und Eigenspannungs-Tiefenverläufe wurden an aufgeweitetem Austenit in Schichten ermittelt, die durch Gasnitrierung und Gascarburierung von austenitischen Stählen erzeugt wurden. Dabei wurde festgestellt, dass eine Kombination von Gasnitrierung und Gascarburierung die Möglichkeit bietet, optimale Härte- und Eigenspannungs-Tiefenverläufe einzustellen.

OBJECTIVE: First-degree relatives (FDR) of type 2 diabetic patients are often insulin resistant. Visceral obesity is closely linked to both insulin resistance and type 2 diabetes. We therefore hypothesized that the inheritance of an increased tendency to store fat in visceral fat depots may be a characteristic phenotypic feature in FDR contributing to their insulin resistance. DESIGN AND METHODS: We measured fat distribution in 20 FDR and 14 age-, gender- and body mass index (BMI)-matched controls employing dual energy X-ray absorbtiometry (DEXA)- and computed tomography (CT)-scanning. Insulin-stimulated glucose uptake (ISGU) was determined by a hyperinsulinemic clamp and maximal aerobic work capacity (VO2 max) by a bicycle ergometer test. Baseline lipolysis was measured using [3H]palmitate. The activity level of the hypothalamic-pituitary-adrenal axis was assessed as the 24 h urinary (u)-cortisol/creatinine ratio. RESULTS: All subjects had a normal oral glucose tolerance test (OGTT), but FDR were insulin resistant (ISGU: 6.64+/-0.48 vs 9.12+/-0.98 mg/kg ffm/min, P=0.01). Despite similar BMI (25.2+/-0.5 vs 24.8+/-0.7 kg/m2, P=0.61) and overall fat mass (26.4+/-1.6 vs 24.2+/-2.1%, P=0.41) in FDR vs controls, the amount of visceral adipose tissue was substantially increased (65.9+/-10.0 vs 40.1+/-11.3 cm2, P<0.05) and VO2 max was reduced (52.2+/-3.1 vs 63.3+/-3.9 ml/kg ffm/min, P<0.05) in FDR. Visceral adiposity was inversely correlated with ISGU (FDR: r=-0.52, P<0.05; controls: r=-0.65, P<0.01) and in multiple regression analysis visceral adiposity (P<0.01), VO2 max (P<0.001) and a family history of type 2 diabetes (P<0.05) (r2=0.64) all significantly and independently contributed to the level of ISGU. Baseline palmitate appearance (145+/-10 vs 139+/-15 micromol/min, P=0.74) and the 24 h u-cortisol/creatinine ratio ((24.9+/-1.3 vs 27.4+/-2.0).10(-6), P=0.28) were both comparable in the two groups. CONCLUSION: Healthy but insulin-resistant FDR have enhanced visceral obesity and reduced VO2 max compared with people without a family history of diabetes, despite similar BMI and overall fat mass. Both the visceral adiposity and reduced aerobic fitness are strongly associated with and may contribute to their insulin resistance.

We prove some sharp upper bounds on the number of resonances associated with the Laplacian, or Laplacian plus potential, on a manifold with infinite cylindrical ends.

Glucose-limited chemostats were used to determine the growth yields of biomass of Bacillus clausiiPP 473-8 producing an alkaline serine protease Savinase (Novozymes A/S, Bagsværd, Denmark) and a low yield of biomass on oxygen was observed. The energy metabolism was investigated further by setting up simple stoichiometric models for growth on glucose and citrate. In order to determine the parameters in the models, a macromolecular biomass composition was determined based on measured values of protein and RNA combined with literature data. From the macromolecular composition of the biomass the theoretical co-factor and building block requirements needed for biomass formation were calculated. Using the stoichiometric models and data for growth on glucose and citrate the amount of ATP needed for biomass synthesis was estimated to 42.0 mmol ATP/gDW, the P/O ratio to 0.68 and the ATP maintenance to 2.93 mmol ATP/gDW/h. From these values it is concluded that the high oxygen consumption compared with other Bacillusspecies is due to a low efficiency in respiration resulting in a low P/O ratio. Finally, the energetic parameters were estimated for different architectures of the respiratory chain.

We describe the spectrum of the Laplacian on a manifold with asymptotically cusp ends and find asymptotics of a corresponding spectral shift function. Here the spectral shift function is the difference of the eigenvalue counting function and the scattering phase.

The aim of the present study was to assess the safety, pharmacokinetics and pharmacodynamics (including specificity) of NN703 (tabimorelin), a growth hormone (GH) secretagogue, in healthy male subjects following treatment for 7 days once-daily. This was a randomized, double-blind and placebo-controlled study with four active dose levels: 1.71, 3.0, 4.5 and 6.86 mg/kg body weight. There was a dose-related increase for GH area under the curve (AUC) (0–12 h) and GHCmax(0–12 h); these were significantly higher on both days 1 and 7 as compared with placebo treatment (P= 0.04 to P< 0.0001); however, an overall significant decrease in GH release was found from day 1 to day 7 (P< 0.001). Insulin-like growth factor-I (IGF-I) and IGF binding protein 3 (IGFBP-3) increased at all dose levels (including placebo); however, a significantly higher increase as compared with placebo treatment was observed at the three highest dose levels for IGF-I (P= 0.04–0.0006) and at the highest dose level for IGFBP-3 (P= 0.03). There was no statistically significant increase in AUC (0–5 h) for follicle-stimulating hormone, luteinizing hormone and cortisol between active and placebo treatment for day 1 or 7. On day 1 only, a statistically significant increase in AUC (0–5 h) was found for prolactin at 1.71 and 6.86 mg/kg (P< 0.05), for thyroid-stimulating hormone (TSH) at 3.0 mg/kg (P< 0.01) and for adrenocorticotrophic hormone (ACTH) at 4.5 mg/kg (P< 0.05); however, no dose–response relationship was observed for TSH or ACTH. In addition, a statistically significant decrease in AUC (0–5 h) for ACTH (3.0 and 6.86 mg/kg) and cortisol (1.71 mg/kg) was observed on day 7 (P< 0.05). Thus, NN703 is a promising candidate for treatment of absolute or relative GH deficiency.

The aim of the present study was to investigate the pharmacodynamics, pharmacokinetics, safety and tolerability of a single dose of NN703 (tabimorelin), a growth hormone secretagogue in healthy male subjects. The study design was double blind, randomized and placebo-controlled, with eight escalating dose levels (0.05–12mg/kg bodyweight (BW)). NN703 was well tolerated by the subjects. The GH area under the curve (AUC) (0–24h) was significantly higher when compared to placebo for the three highest dose levels (3.0mg/kg: P= 0.027, 6.0mg/kg: P= 0.0023, 12mg/kg: P< 0.0001), and for GH maximal concentration Cmaxthe four highest dose levels were also significantly higher when compared to placebo (1.5mg/kg: P= 0.04, 3.0mg/kg: P= 0.0143, 6.0mg/kg: P= 0.0053, 12mg/kg: P= 0.0007). Furthermore, there was a significant increase in IGF-1 levels when compared to placebo for the 6.0 and 12.0mg/kg BW dose levels (P< 0.0001). Statistical analysis comparing the AUC (0–24h) of the NN703 (four highest dose levels) and placebo-treated groups showed no significant increases following NN703 for ACTH, LH, FSH, TSH, prolactin, and cortisol, however, subtle individual changes were noted in ACTH, cortisol and prolactin at doses above 3.0mg/kg. In conclusion, NN703 is a promising potential candidate for treatment of GH deficiency/insufficiency.

Abstract:: For scattering on the modular surface and on the hyperbolic cylinder, we show that the solutions of the wave equations can be expanded in terms of resonances, despite the presence of trapping. Expansions of this type are expected to hold in greater generality but have been understood only in non-trapping situations.

The use of heparin in a liquid form to measure ionized calcium (Ca+ +) in plasma or whole blood can induce preanalytical errors by dilution and by changing the original Ca+ +value by binding or by re-equilibration with calcium in the anticoagulant solution.To quantify these errors, Ca+ +was measured on serum pools under different sampling conditions. Incomplete syringe filling and specimen volume/syringe nominal volume ratio effects were tested. Syringes were rinsed with saline to yield pure dilution effects, with sodium heparinate to study binding and with calcium-titrated heparinate to evaluate ‘calcium-distortion’. Detailed tables provide percentage error values for all sampling conditions. Dilution errors could reach − 5% and binding was always important (− 14 to − 50%). Distortion was minimal around 1·25 mmol/L but could reach − 4% for high and + 8% for low Ca+ +values. Errors increased when syringes were not filled to their nominal volume, especially with small-sized specimens.

Thirty-three patients with undisplaced fractures of the distal radius were included in a clinical controlled trial with the purpose of evaluating whether it was safe to reduce the time of immobilisation in a plaster splint from 5 to 3 weeks. We did not find any difference in radiological healing at 3 months or in the functional scores after 3 and 9 months.

The incidence of severe duodenal anomalies (MD) has been investigated in 458 patients submitted to barium meal examination and in 176 subjects comprising various clinical subgroups. The incidence of MD in patients submitted to barium meal examination was 11.6%. The incidence of MD in 25 normals was 4%, which was not significantly different from the incidence (10%) of MD in patients with gastro-oesophageal reflux symptoms. Compared with in normals, MD occurred with a significantly higher incidence in 45 patients with X-ray-negative dyspepsia (24%), in 36 patients with the irritable bowel syndrome (44%), and in 37 patients with asthma (38%). It is concluded that demonstration of MD in a patient is only indicative of a possible disorder.

Jepsen JM, Persson M, Jakobsen NO, Christiansen T, Skoubo-Kristensen E, Funch-Jensen P, Kruse Å, Thommesen P. Prospective study of prevalence and endoscopic and histopathologic characteristics of duodenal polyps in patients submitted to upper endoscopy. Scand J Gastroenterology 1994;29:483-487.Background: Retrospective studies of duodenal polyps have shown a prevalence of 0.3%-1.5% in patients referred to upper endoscopy, and histopathologic classifications have been inconsistent. Hook Methods: A prospective consecutive study was carried out in 584 patients referred to diagnostic upper endoscopy. Symptoms were registered on a questionnaire, endoscopic and histopathologic findings on standard forms. The same pathologist evaluated all biopsy specimens.Results: Twenty-seven patients had polyps in the first and/or second part of the duodenum, for a prevalence 4.6%. Sixteen polyps were either inflammatory (nine polyps) or ectopic gastric mucosa (seven polyps). Both of these polyp types were practically always non-solitary, sessile, small, and located in the duodenal bulb. Seven polyps were covered by normal mucosa, three being endoscopically typical lipomas. Two polyps were adenomas (0.4% of all the patients and 7% of the polyps), and both were found in the descending part. One hyperplastic polyp of the gastric type and one case of fibrosis were found. Conclusions: 1) Duodenal polyps are found in 4.6% of patients referred to upper endoscopy and should therefore be looked for. 2) Multiple, small polyps in the duodenal bulb are always benign and need neither biopsy nor treatment (in patients with familial polyposis biopsy is recommended). 3) In the descending duodenum polyps are rare, but a substantial number of them are adenomas. Biopsy is therefore mandatory in this localization.

Let X be compact manifold with boundary and exact b-metric, so X has asymptotically cylindrical ends. Let Δ be the Laplacian on X. In this paper it is shown that where ℱ− 1 is the inverse Fourier transform, b-Tr is a regularization of the integral of the restriction of the Schwartz kernel to the diagonal, and Ψ is the scattering matrix. The first term is analogous to the case of a compact manifold without boundary, and the rest are similar to terms in a trace formula for one-dimensional scattering.Copyright 1995, 1999 Academic Press, Inc.

In a prospective study, 26 patients with symptoms of reflux oesophagitis underwent a barium examination for gastro-oesophageal reflux after food stimulation, and endoscopy with biopsy from different levels of the oesophagus. Radiologic grading of the gastro-oesophageal reflux depending on the height of the reflux into the oesophagus was performed, and this was correlated to the microscopic appearance at different levels in the oesophagus. Complete agreement between the radiologic grading and the histology was found in 69 per cent of the cases, and when ***gastro-oesophageal reflux was demonstrated the agreement was 75 per cent. Accordingly, the results showed a good accordance between the two variants, indicating that the height of the reflux during the food stimulated test may be truly indicative of the reflux height under non-test conditions.

The aim of the present study was to use magnetic resonance imaging as a non-invasive measure of renal enlargement and regression in experimental diabetes in rats. Rats were randomized into three groups: (1) non-diabetic control animals, (2) diabetic animals, untreated for 30 days after streptozotozin treatment and (3) diabetic animals treated with insulin from day 21 to day 30 after streptozotocin administration. Magnetic resonance images were obtained from anaesthetized rats and kidney, cortex, medulla and pelvis volumes were calculated throughout the experiment until day 30. In untreated diabetic animals, a marked increase in kidney volume was seen 4 days after the induction of diabetes (P<0·05) and after 30 days this increase amounted to 73%, with similar increases in the cortex (63%) and medulla (69%). No change was seen in the pelvis volume. Insulin administration on day 21 to untreated diabetic rats abruptly reduced kidney volume by 21%, cortex volume by 27% and medulla volume by 18%, and after 4 days all three parameters were similar to those seen in non-diabetic controls. In conclusion, the present study has demonstrated the applicability of magnetic resonance imaging as a non-invasive measure of renal enlargement and regression in experimental diabetes in rats. In untreated hyperglycaemic diabetic rats, with manifest diabetic renal enlargement, acute regression in renal volume was observed concomitant with insulin-induced normoglycaemia.Journal of Endocrinology(1997) 153,193–198

The substance concentration of ionized calcium (cCa2+ ) in blood, plasma or serum preanalytically may be affected by pH changes of the sample, calcium binding by heparin, and dilution by the anticoagulant solution.

1. Normal subjects showed an average increase in serum ionized calcium (Ca2+) concentration of 0·11 mmol/l in peripheral venous blood 10 min after onset of bicycle exercise at 70% of maximum aerobic capacity. The corresponding mean rise in serum total calcium concentration was 0·21 mmol/l. 2. The change in serum Ca2+ as result of acidification was studied in 20 normal subjects by carbon dioxide equilibration in vitro followed by measurement of serum Ca2+. The log serum Ca2+ was inversely proportional to serum pH. 3. The ?log serum Ca2+/?pH in vitro was similar to the ?log serum Caa+/?pH in vivo during exercise, this ratio, however, being somewhat greater during the first minute of exercise. 4. Serum Ca2+ returned to normal values about 20 min after stopping exercise as the pH returned to normal, but the fall immediately after stopping exercise was more pronounced than that due to the change in pH, as predicted from the studies in vitro. 5. Blood lactate concentration rose from 0·86 to 8·41 mmol/l after 10 min exercise, but the rise in blood lactate during exercise was slower than the rise in serum Ca2+. Also the fall during the recovery period was delayed compared with the fall in serum Ca2+. 6. It is suggested that the rise in serum Ca2+ during severe muscular exercise might be important for the physiological adaptations during work, and for bone metabolism.

A prospective investigation on gastro-oesophageal reflux in 97 consecutive patients has been carried out by means of a barium examination employing the conventional method and after food stimulation. Gastro-oesophageal reflux was observed in 38 patients with and 15 patients without oesophageal symptoms. Gastro-oesophageal reflux was induced by two mechanisms, an active component after food stimulation and a passive component after the conventional method including respiratory manoeuvres and leg raising. In 32 patients, only the active component could be demonstrated and in 6 patients only the passive component. In the remaining 15 patients both active and passive components occurred. The clinical significance of the active and passive components in gastro-oesophageal reflux needs further investigation.

Several letters to the editor are presented in response to articles in previous issues including "Why the U.S. still has not cracked NTT" in the January 11, 1982 issue, "Give steel a fair hearing" in the February 1, 1982 issue, and "Not enough for Japan" in the February 15, 1982 issue.

We investigated the diagnostic value of two different ultrasound scanning methods for the early diagnosis of acute scaphoid fractures. Fifty-seven patients with ten scaphoid fractures were assessed within a week of injury. The accuracy of the ultrasound assessment was 84% and its specificity was 91%. However, its sensitivity was only 50%. We conclude that ultrasound examination is unreliable for the diagnosis of acute scaphoid fractures.

Summary: Intracranial oncotic aneurysms are very rare. Only twelve reported cases were from choriocarcinoma. We present a new case with two aneurysms disappearing after chemotherapy, the second in the literature but the first case with persistence of all arteries.

This article illustrates the plethora of different possibilities in thermochemical surface engineering (TSE) and the close interlink between science and innovation. Three widely different examples of gaseous TSE are presented: surface engineering of austenitic stainless steel by high- and low- temperature surface treatment, surface hardening of titanium by incorporation of nitrogen, oxygen and carbon, and direct synthesis of magnetic iron-nitride a"-Fe16N2. It is shown how 3D printed materials made of stainless steel and titanium can benefit from TSE.

Circulating BDNF is higher in women than in men and suggested to be affected by changes in food intake, body weight, and exercise. The purpose of this study was to compare BDNF concentrations in women and men during a 12-week weight loss intervention. Using a previously published 12-week randomized study, serum BDNF was assessed at baseline and after 12 weeks using an enzyme-linked immunosorbent assay method. Fifty overweight or obese but healthy individuals (26 women, mean age of 36.4 ± 7.9 years; 24 men, mean age of 38.0 ± 5.9 years) were included and allocated into three groups: exercise-only (EXO; 12 weeks of aerobic exercise and isocaloric diet), diet-only (DIO; 8 weeks of very low energy diet (VLED 600 kcal/day) followed by a 4-week weight maintenance diet), or diet and exercise (DEX; 12 weeks of aerobic exercise in parallel with 8 weeks of VLED (800 kcal/day) followed by a 4-week weight maintenance diet). At baseline, BDNF levels were 25% higher in women compared to men (p=0.006). Body weight was reduced in all intervention groups (p<0.006). Exercise (EXO group) induced a 22% reduction in circulating BDNF in men (p=0.037) and women (p=0.080). In the DIO and DEX groups, a significant reduction in BDNF levels (29.9%; p=0.035 and 32.5%; p=0.003, respectively) was observed in women but not in men. In conclusion, circulating BDNF was significantly changed by diet alone or combined with exercise in women and only by exercise alone in men. This suggests that changes in circulating BDNF depend on weight loss methods (diet/exercise) as well as sex.