The History of ICRP and the Evolution of its Policies

Within 12 months of the discovery of X rays in 1895, papers appeared in the literature reporting adverse effects from high exposure. In 1925, the first International Congress of Radiology, held in London, considered the need for a protection committee, which it established at its second congress in Stockholm in 1928. This paper celebrates the 80^th anniversary of ICRP by tracing the history of the development of its policies, and identifying a few of the personalities involved from its inception up to the modern era. The paper follows the progress from the early controls on worker doses to avoid deterministic effects, through the identification of stochastic effects, to the concerns about public exposure and increasing stochastic risk estimates. The key features of the recommendations made by ICRP from 1928 up to the most recent in 2007 are identified.     

The effect of levitated water on fermentation kinetics

The rate of anaerobic glucose fermentation by baker's yeast is found to be altered when tap water is replaced with "levitated" (i.e., hydrodynamically processed) water. To analyze the effect in more detail, we developed a fermentation kinetics model that differentiates between (i) nutrient transport into the cell, (ii) the "catabolic" and (iii) the "anabolic" reactions. As a result, the levitated water affects specifically the glucose uptake kinetics, whereas the other kinetic parameters remain unchanged. Remarkably, the sign of the effect changes with the water used to prepare the culture. When levitated water is used for both the culture preparation and the fermentation, the rate constant of glucose transport is increased by (67+/-25)%, relative to ordinary tap-water. When the culture is prepared in ordinary water and only the fermentation is performed in levitated water, the rate constant of glucose transport decreased by (50+/-12)%. Three-week old levitated water has no discernable effect any more.     

Bulge-Forming miRNases Cleave Oncogenic miRNAs at the Central Loop Region in a Sequence-Specific Manner

The selective degradation of disease-associated microRNA is promising for the development of new therapeutic approaches. In this study, we engineered a series of bulge-loop-forming oligonucleotides conjugated with catalytic peptide [(LeuArg)₂Gly]₂ (BC–miRNases) capable of recognizing and destroying oncogenic miR-17 and miR-21. The principle behind the design of BC–miRNase is the cleavage of miRNA at a three-nucleotide bulge loop that forms in the central loop region, which is essential for the biological competence of miRNA. A thorough study of mono- and bis-BC–miRNases (containing one or two catalytic peptides, respectively) revealed that: (i) the sequence of miRNA bulge loops and neighbouring motifs are of fundamental importance for efficient miRNA cleavage (i.e., motifs containing repeating pyrimidine–A bonds are more susceptible to cleavage); (ii) the incorporation of the second catalytic peptide in the same molecular scaffold increases the potency of BC–miRNase, providing a complete degradation of miR-17 within 72 h; (iii) the synergetic co-operation of BC–miRNases with RNase H accelerates the rate of miRNA catalytic cleavage by both the conjugate and the enzyme. Such synergy allows the rapid destruction of constantly emerging miRNA to maintain sufficient knockdown and achieve a desired therapeutic effect.     

Mechanics-aided digital image correlation for the investigation of piezoelectric and ferroelectric behaviour of a soft PZT

The strain response of a polarised PZT was characterised using Digital Image Correlation (DIC). The DIC algorithm is based on a global approach and regularises the displacement field using the balance equations of solid mechanics. The measurement error is reduced by correcting the displacements that are mechanically not admissible. A ferroelectric test showed that the standard deviations of strain fields remain mostly under 1.2 × 10^?4 for an element size of 64 px. The standard deviation on the average value is 3 × 10^?6. The strain field is homogeneous and its average value is consistent with the strain obtained from a CCD laser measurement device. The longitudinal strain, transverse strain and polarisation response of the PZT were measured for bipolar and unipolar loadings ranging from 50 to 5000 V/mm. Material properties were extracted from these measurements. This work shows the advantages of a novel 2D-DIC algorithm for piezoelectric strain characterisation.     

Detection of CO<Subscript>2</Subscript> and O<Subscript>2</Subscript> by iron loaded LTL zeolite films

Detection of oxygen and carbon dioxide is important in the field of chemical and biosensors for atmosphere and biosystem monitoring and fermentation processes. The present study reports on the preparation of zeolite films doped with iron nanoparticles for detection of CO₂ and O₂ in gas phase. Pure nanosized LTL type zeolite with monomodal particle size distribution loaded with iron (Fe-LTL) was prepared under hydrothermal condition from colloidal precursor suspensions. The zeolite was loaded with iron to different levels by ion exchange. The Fe-LTL suspensions were used for preparation of thin films on silicon wafers via spin coating method. The reduction of the iron in the zeolite films was carried out under H₂ flow (50% H₂ in Ar) at 300 °C. The presence of iron nanoparticles is proved by in situ ultra-violet-visible spectroscopy. The properties of the films including surface roughness, thickness, porosity, and mechanical stability were studied. In addition, the loading and distribution of iron in the zeolite films were investigated. The Fe-LTL zeolite films were used to detect O₂ and CO₂ in a concentration dependent mode, followed by IR spectroscopy. The changes in the IR bands at 855 and 642 cm^–1 (Fe?O?H and Fe?O bending vibrations) and at 2363 and 2333 cm^–1 (CO₂ asymmetric stretching) corresponding to the presence of O₂ and CO₂, respectively, were evaluated. The response to O₂ and CO₂ was instant, which was attributed to great accessibility of the iron in the nanosized zeolite crystals. The saturation of the Fe-LTL films with CO₂ and O₂ at each concentration was reached within less than a minute. The Fe-LTL films detected both oxygen and carbon dioxide in contrast, to the pure LTL zeolite film.

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Recovery of Phosphoric Acid from Spent Petrochemical Catalysts

Petrochemical catalysts are widely used in the industry. For the production of cumene, zeolite-based catalysts containing phosphoric acid are applied. Over the time, coking deactivates the surface, and the catalyst has to be exchanged and disposed of. Different process approaches for recycling the phosphoric acid-containing catalysts were investigated. Related preliminary investigations have shown that calcination of the used catalyst is necessary prior to reprocessing. By digesting the catalyst with hydrofluoric acid, ∼96 % phosphate was recovered. However, this process is very costly in terms of process technology. More promising is digestion by basic or acidic routes. Several options are possible here, and digestion with H₃PO₄ proved to be particularly suitable. Here, phosphate yields reached up to 98.8 %, with a positive balance of economic efficiency at the same time. The catalyst can be produced and recycled in the same plant with the same reagents, what constitutes a major breakthrough towards sustainability in industrial catalysis.     

Use of chitosan complex with aminophosphonic groups and cobalt for the removal of Sr2+ ions

We briefly describe the adsorbent performance of the chitosan complex with aminophosphonic groups and cobalt in the removal process of Sr²⁺ ions from aqueous solutions. The strontium adsorption was studied as a function of pH, contact time, and initial strontium concentration. Adsorption isotherms such as Langmuir, Freundlich, Dubinin–Radushkevich, and Temkin were used to analyze the equilibrium data at different concentrations. The kinetics of the Sr²⁺ sorption was analyzed using the pseudo-first-order and pseudo-second-order kinetic models. The results clearly indicate that the chitosan complex with aminophosphonic groups and cobalt is an efficient adsorbent with respect to its capacity to absorb Sr²⁺ ions from aqueous solutions.