Phase Equilibria in the Fe-Nb System

A review of the literature revealed that recently published phase diagrams of the Fe-Nb system show considerable discrepancies regarding phase equilibria with the melt and the homogeneity ranges of the intermetallic phases, specifically of the Laves phase Fe₂Nb. Therefore the system has been reinvestigated by metallography, electron probe microanalysis (EPMA), and differential thermal analysis (DTA). Temperatures of invariant reactions were determined and the homogeneity ranges of the two intermetallic phases, Fe₂Nb Laves phase and Fe₇Nb₆ μ phase, which both exist within a wide composition range, were established.     

High concentrations of essential and toxic elements in infant formula and infant foods – A matter of concern

This study assessed concentrations in and intake of toxic and essential elements from formulas and foods intended for infants during their first 6 months of life. Concentrations of the essential elements Ca, Fe, Zn, Mn and Mo were significantly higher in most formulas than in breast milk. Daily intake of Mn from formula varies from ten up to several hundred times the intake of the breast fed infant, levels that may be associated with adverse health effects. One portion of infant food provided significantly more Fe, Mn, Mo, As, Cd, Pb and U than one feeding of breast milk, but less Ca, Cu and Se. Rice-based products in particular contained elevated As concentrations. Drinking water used to mix powdered formula may add significantly to the concentrations in the ready-made products. Evaluation of potentially adverse effects of the elevated element concentrations in infant formulas and foods are warranted.     

The Fe-A1-Ti system

An extensive experimental investigation of the Fe-Al-Ti system by metallography, microprobe analysis, and XRD on quenched specimens and on diffusion couples is presented. Two isothermal sections at 800 and 1000 °C were established; they differ substantially from the existing (800 °C) or partly determined (1000 °C) diagrams. From these results, existence of the τ₁ phase (Fe₂AlTi) can be ruled out. Existence of the ternary compounds, τ₂ (Al₂FeTi) and τ₃ (Al₂₂Fe₃Ti₈), is confirmed. The composition limits of both phases were determined; they differ considerably from those given in earlier reports. The τ₂ phase apparently exists in a cubic and a tetragonal polymorph, depending on composition. The cubic form exists at high titanium contents. At 1000 °C, the two polymorphs are separated by a miscibility gap. At compositions where the “X phase” (Al₆₉Fe₂₅Ti₆) was previously reported, single-phase samples were obtained at both temperatures. From the present results, there is no evidence to assume that this is a new ternary phase rather than the ternary homogeneity range of the Al₃Fe phase. In addition, extensions of the binary intermetallic phases into the ternary system were determined.     

Integrative socio‐economic planning of measures in the context of the water framework directive

The European Water Framework Directive (WFD) constitutes a milestone for the protection of aquatic ecosystems. With respect to the challenging objectives of the WFD and the connected financial burdens, which may possibly exceed the capabilities of some regions, it is essential to establish a targeted and integrated view of the economic aspects, which are applicable within the implementation process of the WFD. This is necessary to provide for a sustainable and acceptable implementation of the WFD with regard to the affected parties. However up to now there are many undefined legal concepts and few specific procedural developments, which often do not correspond to the required interdisciplinary and practical approach but are based on complex scientific methods. Hence the purpose of the present article should consist in providing an approach for the integration of the different economic aspects of the WFD in the establishment of the programme of measures and for the concretisation of the river basin specific environmental objectives to be reached.     

Improved results in patients who have congenital diaphragmatic hernia using preoperative stabilization, extracorporeal membrane oxygenation, and delayed surgery

Congenital diaphragmatic hernia (CDH) is associated with pulmonary hypoplasia. The pulmonary vascular bed may be extremely reactive to various stimuli, and in the treatment it is important to avoid pulmonary vasospasm. The strategy in our institution since 1990 has involved a prolonged preoperative stabilization with gentle mechanical ventilation. Pressures have been kept as low as possible, and slight hypercarbia has been accepted. Peak inspiratory pressures exceeding 35 cm H2O have been avoided. Extracorporeal membrane oxygenation (ECMO) has been used according to standard inclusion criteria. Nitric oxide and high-frequency oscillation have been added to the therapeutic modalities during the study period. When the patient was considered stabilized, surgical repair was undertaken after a delay of 24 to 96 hours. In patients on ECMO who could not be decannulated, surgical repair was undertaken while on ECMO. From 1990 through 1995, 52 patients were admitted with a diagnosis of CDH. Forty-three of these were risk group patients presenting with respiratory distress within 6 hours after birth. A total of 48 patients survived (survival rate 92%), and 39 of the risk group patients (survival rate 91%). There were only four hospital deaths, all with contraindications to ECMO. It is suggested that the adopted protocol is beneficial in the treatment of CDH and that the fraction of patients who have pulmonary hypoplasia incompatible with life is smaller than previously believed.     

Pediatric ECMO for pulmonary support: experience from 12 cases

Extracorporeal membrane oxygenation (ECMO), which can be described as treatment with a modified heart-lung machine over a prolonged period of time, is used to support patients with life-threatening but potentially reversible lung failure. ECMO by itself does not cure the patient but gives the lungs a chance to rest while awaiting spontaneous or therapeutic healing. The method is well documented in the neonatal age group. In the non-neonatal age group, however, experience is less extensive. This report of the initial result from our hospital with 12 non-neonatal pediatric cases shows high survival and low morbidity. Nine of the 12 patients were able to be weaned from ECMO (75% survival) and 8 of these 9 patients were long-term survivors. Medium time on the ventilator after discontinuation of ECMO was 4 days. At follow-up, all long-term survivors had no signs of neurological or pulmonary sequelae. These encouraging results point to the fact that ECMO should be considered more often in cases of life-threatening but potentially reversible pulmonary failure.     

"Ergonomics"--OSHA's next regulatory frontier?

Ergonomics is an increasing health concern for all work environments in the 1990s. Ergonomic stresses do exist in the dental office for all personnel, and proposed regulatory activity will include dentistry. Hopefully, the pace of regulation will be met by scientific investigation that quantifies these stresses and defines their proper management and prevention. If so, ergonomics will become well-understood and will not develop as a new frontier of misapplied regulation.     

Selenium regulation of selenium-dependent glutathione peroxidases in animals and transfected CHO cells

Glutathione peroxidase (GPX1) was the first identified selenium-dependent enzyme, and this enzyme has been most useful as a biochemical indicator of selenium (Se) status and the parameter of choice for determining Se requirements. We have continued to study Se regulation of GPX1 to better understand the underlying mechanism and to gain insight into how cells themselves regulate nutrient status. In progressive Se deficiency in rats, GPX1 activity, protein and mRNA all decrease in a dramatic, coordinated and exponential fashion such that Se-deficient GPX1 mRNA levels are 6-15% of Se-adequate levels. mRNA levels for other Se-dependent proteins are far less decreased in the same animals. The mRNA levels for a second Se-dependent peroxidase, phospholipid hydroperoxide glutathione peroxidase (GPX4), are little affected by Se deficiency, demonstrating that Se regulation of GPX1 is unique. Se regulation of GPX1 activity in growing male and female rats shows that the Se requirement is 100 ng/g diet, based on liver GPX1 activity; use of GPX1 mRNA as the parameter indicates that the Se requirement is nearer to 50 ng Se/g diet in both male and female rats. This approach will readily detect an altered dietary Se requirement, as shown by the incremental increases in dietary Se requirement by 150, 100 or 50 ng Se/g diet in Se-deficient rat pups repleted with Se for 3, 7 or 14 d, respectively. Studies with CHO cells stably transfected with recombinant GPX1 also show that overexpression of GPX1 does not alter the minimum level of media Se necessary for Se-adequate levels of GPX1 activity or mRNA. We hypothesize that classical GPX1 has an integral biological role in the mechanism used by cells to regulate Se status, making GPX1 an especially useful and effective parameter for determining Se requirements in animals.     

Evaluation of a patient teaching skills course disseminated through staff developers

Effective Patient Teaching (EPT), a course designed to improve health professionals' and health professions students' teaching skills, reliably produces gains in participants' skills when presented by its developers. The objective of this dissemination research study was to investigate whether, using a 'training of trainers' approach, seven nurses with staff development responsibilities in five different sites could teach EPT with similar effectiveness. The evaluation included pre- and post-course analysis of audiotaped patient education sessions conducted by 48 health professional participants who took EPT from one of the trainers in their home institutions. Post-course participant satisfaction surveys were also administered. EPT resulted in teaching skill improvements in four of five sites, and overall teaching skills scores improved significantly (P < 0.01). EPT can improve participants' teaching skills when taught by health professional trainers with staff development responsibilities who have recently received EPT training.