Iron requirements and iron balance during pregnancy. Is iron supplementation needed for pregnant women?

Among fertile, nonpregnant, Danish women, 33% have absent or reduced iron stores; 22% have serum ferritin values above 70 micrograms/l, i.e., iron reserves of more than 530 mg, corresponding to the net iron losses during a normal pregnancy. During pregnancy, the demands for absorbed iron increase from 0.8 to 7.5 mg/day. Controlled studies show that iron-treated pregnant women have higher serum ferritin levels, i.e., larger iron stores, and higher haemoglobin levels than placebo-treated women. A supplement of 66 mg ferrous iron daily from the beginning of the 2nd trimester prevents iron deficiency anaemia. In Denmark, general iron prophylaxis with 60-70 mg ferrous iron daily from 20 weeks of gestation is recommended by the health authorities.     

Test Results of an Active System for Reducing Vibration Forces and Pressure Pulsations

Technical Physics Letters - The absence of literature data on active reduction of the transmission of vibrations and pulsations of pressure through pipeline compensators with liquid is noted. A...     

Hardware for new methods of radiation control

Designs of the prototypes of two dosimetry systems that are widely used in the modern international practice of the dosimetry of ionizing radiation, in one of which the ability for real-time measurements of radiation field parameters exists, are presented. The nature of optically stimulated luminescence (OSL) and radioluminescence (RL), on which the operation of the systems is based, is described. The results of tests of prototypes of OSL and RL dosimetry systems are given. Key specifications and advantages over traditional thermoluminescent systems are identified for the Korund-101-OSL OSL system prototype.     

Constitution of the Al Corner in the Ternary Al–Ge–Mg Phase Diagram

Powder Metallurgy and Metal Ceramics - A fragment of the Al corner in the ternary Al–Ge–Mg phase diagram has been constructed. Experimental methods have shown that the tie-line of the L...     

Technical Note - Inversion of systems of quadratic equations

Inversion of linear systems of equations is straightforward, although there are some complications when the equations represent a physical process and there is noise in the measurements of the dependent variables. This paper extends the linear inversion method to systems of quadratic equations. Using this method, we can devise better inversion algorithms, and better estimates of the error in the inversion process, by including quadratic terms explicitly. Two different ways that quadratic terms can be included are suggested. The method used will depend largely on the relative sizes of the various non-linear terms. This method will also greatly improve our ability to evaluate the potential performance of proposed sensor systems. I believe that this is a new approach to this problem.     

Optimization approach to the suppression of vibration errors in phase-shifting interferometry

An optimization-based strategy is introduced for suppressing errors due to vibration in phase-shifting-interferometry algorithms. A norm-square integral criterion of the error as a function of vibration frequency is used as the basis of the optimization procedure. Analytical results are obtained for certain classes of problems, and numerical algorithms are used when these are not available. It is also shown that the effect of vibration-induced errors in the computation of a time-averaged phase estimate diminishes as the measurements are averaged. Simulations are used to validate the analysis and demonstrate the overall efficacy of the approach. Generalizations to multiple objective optimization problems are briefly discussed.     

Thermoluminescent dosemeters based on TLD-500 detectors for control of neutron fields

The results of a study dealing with detection of neutrons in thermoluminescent (TL) photon radiation detectors, type TLD-500, based on an anion-defective corundum have been reported. The detection method uses the transformation of neutron radiation into gamma radiation arising when neutrons are captured by cadmium nuclei. A comparative analysis of the data obtained with the TL detectors and results of radiometric measurements suggested applicability of this method. A sensor with an optimal embodiment providing a relatively high sensitivity has been developed.     

Is there theoretical evidence for a metallic carbon polymorph with space group symmetry at ambient conditions?

Quantum mechanical calculations based on density functional theory and the generalised gradient approximation show that the equilibrium lattice parameter of a carbon polymorph with space group symmetry would be 3.08 Å, and hence very different from that of diamond. No local minimum in the dependence of the total energy on the lattice parameter has been found. Such a polymorph would be approximately 5 eV atom⁻¹ less stable than diamond, suggesting that its synthesis is very unlikely. This finding is consistent with older density functional calculations and contradicts recent results of LCAO calculations, which have been used to support the interpretation of experimental data as showing the existence of a metallic carbon polymorph with space group symmetry .     

The Korund-201-TL dosimetry system for radiation monitoring

This paper presents a brief overview of existing personal dosimetric systems that are based on thermally stimulated luminescence. The new Korund-201-TL automated thermoluminescence system is described.