Radioactivity measurements as tool for physics dissemination

In general people associate environmental radioactivity with the artificial radioactivity and knows very little about natural radioactivity. Thus there is a critical need to improve nuclear physics public education. From 2005 in Italy two programs were promoted from Ministry of Education and University and National Institute of Nuclear Physics (INFN) for scientific dissemination in the field of environmental radioactivity. High school students in many Italian regions were involved in particular in indoor radon measurements. With this program students acquired awareness about the risks of inhalation of radon and its progeny and at the same time contributed to carry out radon monitoring, participating to all the experimental phases, from detectors set-up to data analysis. In particular we report about the activities carried out at Catania University and INFN division regarding a survey in the eastern Sicily. The overall monitoring, spanned over a period of 5 years, was carried out using passive nuclear track detection technique, through CR-39 dosimeters. In total about 500 detectors were placed in dwellings and schools in 57 locations. The investigated area have shown medium–high indoor radon concentrations, higher than the Italian average (70 Bq/m³). From the evaluation of the participating teachers and students, this kind of activities represents a successful strategy to enhance dissemination of physics, in particular in radioactivity topics.     

Safety evaluation of single-use medical devices after submission to simulated reutilization cycles

Pyrogenic and toxic reactions, especially in immunologically compromised patients, are among the risks associated with reuse of single-use medical devices (SUDs) with recurrent damaged surfaces. These drawbacks have raised serious doubts about the true benefits of the reprocessing practice. Taking into consideration prolonged patients' stay in hospitals due to adverse reactions provoked by recycled SUDs, the safety of these reprocessed materials was evaluated. The reprocessing cycles were simulated after intentional contamination of selected test material such as intravenous catheters, 3-way stopcocks, and tracheostomy tubes with Bacillus subtilis var. niger ATCC 9372 spores (10(7) CFU/unit). The repeated reprocessing cycles consisted of subsequent wash with enzymatic detergent followed by drying and sterilization with ethylene oxide-CFC (12 + 88), 600 mg/L at 55 degrees C, relative humidity 60%, for 3 h. After each reprocessing cycle, specimen samples were evaluated by pour plate microbial counts, direct and indirect inoculation sterility tests, cytotoxicity evaluation, and scanning electron microscopy (SEM). Microbial counts as high as 10(3) CFU were evident even after the 10th reprocessing cycle, besides scratched and damaged surfaces observed by SEM. Risk-benefit viewpoints are discussed.     

An energy decomposition analysis for intramolecular non-covalent interaction in solvated environment

In this work, the intra-EDA method, which is a recently developed energy decomposition analysis scheme for intramolecular non-covalent interaction is extended from gas phase to solvated environment. It is the first analysis scheme that performs analysis for intramolecular interaction in solution. By fragmentation scheme, a molecule is divided into intramolecular interacting fragments and environmental fragments via single bond homolysis breaking. The solvent effect is taken into account by implicit solvation model. Intramolecular interaction free energy is estimated as the separated treatment of inter-fragment interactions in dielectric environment. The analysis results highlight the importance of solvent effects to intramolecular non-covalent interaction.     

An improved model for predicting hydrate phase equilibrium in marine sediment environment

Based on the models of hydrate phase equilibrium in bulk water and porous media, an improved model was proposed to predict the methane hydrate equilibrium in marine sediment environment. In the suggested model, mechanical equilibrium of force between the interfaces in hydrate-liquid-vapor system was considered. When electrolyte was present in pore water, interfacial energy between hydrate and liquid was corrected by an equation that is expressed as the function of temperature and electrolyte concentration. The activity of water is calculated based on the Pitzer model and the interfacial energy between liquid and gas is solved using the Li method. The prediction results show good agreement with the experimental data. By comparison with other models, it is proved that this model can improve the accuracy for predicting hydrate phase equilibrium in marine sediment environment.     

Evolution of an open-access quantitative bioanalytical mass spectrometry service in a drug discovery environment

Increased demand for assays for compounds at the early stages of drug discovery within the pharmaceutical industry has led to the need for open-access mass spectrometry systems for performing quantitative analysis in a variety of biological matrices. The open-access mass spectrometers described here are LC/MS/MS systems operated in 'multiple reaction monitoring' (MRM) mode to obtain the sensitivity and specificity required to quantitate low levels of pharmaceutical compounds in an excess of biological matrix. Instigation of these open-access systems has resulted in mass spectrometers becoming the detectors of choice for non-expert users, drastically reducing analytical method development time and allowing drug discovery scientists to concentrate on their core expertise of pharmacokinetics and drug metabolism. Setting up an open-access facility that effectively allows a user with minimal mass spectral knowledge to exploit the MS/MS capability of triple quadrupole mass spectrometers presents a significantly different challenge from setting up qualitative single stage mass spectrometry systems. Evolution of quantitative open access mass spectrometry within a pharmaceutical drug metabolism and pharmacokinetics group, from its beginnings as a single generic system to a series of specialist fully integrated walk-up facilities, is described.     

An unsymmetrical coordination environment leading to two slow relaxation modes in a Dy2 single-molecule magnet

A Dy(2) single-molecule magnet was isolated using a mixed ligand strategy in which the Dy(III) ions adopt distinct coordination environments. This leads to two unique relaxation modes due to a single-ion type relaxation mechanism. Energy barriers were obtained from individually fitting the overlapping peaks.     

An approach for decontamination of beta-lactam antibiotic residues or contaminants in the pharmaceutical manufacturing environment

An effective procedure for decontamination of beta-lactam antibiotic residues or contaminants in the pharmaceutical manufacturing environment was investigated. Decontamination with solutions of hydrochloric acid, sodium hydroxide, hydrogen peroxide and hydroxylamine as agents for degradation was assessed. According to the results, the beta-lactam antibiotics were significantly degraded with sodium hydroxide and hydroxylamine. From the structural analysis of the degradation products of a cephem antibiotic, cefpodoxime proxetil, it was found that hydroxylamine degraded the beta-lactam structure under mild conditions, while sodium hydroxide did not. Therefore, hydroxylamine was considered an appropriate decontamination agent for beta-lactam antibiotics.     

Web service infrastructure for chemoinformatics

The vast increase of pertinent information available to drug discovery scientists means that there is a strong demand for tools and techniques for organizing and intelligently mining this information for manageable human consumption. At Indiana University, we have developed an infrastructure of chemoinformatics Web services that simplifies the access to this information and the computational techniques that can be applied to it. In this paper, we describe this infrastructure, give some examples of its use, and then discuss our plans to use it as a platform for chemoinformatics application development in the future.     

An insight into the passivation of cupronickel alloys in chloride environment

Cupronickels offer enhanced corrosion protection in marine environments by the formation of passive films on the surface. Cyclic voltammetric studies were carried on cupronickels in chloride solutions at pH 6.3 to understand the role of chloride ions in passive film formation. Increase in nickel content of the alloy and of chloride ions in solution decreases film resistance. Chloride ions take part in reduction of the passive film to copper. A solid-state model for passive film formation involving chloride ions has been attempted.     

An evaluation of monovalent osmium supported by the PNP ligand environment

Nitrogen is essential to reaction of (PNP)OsI (PNP is N(SiMe(2)CH(2)P(t)Bu(2))(2)) and Mg powder in THF, to give equimolar (PNP)OsH(N(2)) and hydrido carbene [((t)Bu(2)PCH(2)SiMe(2))N(SiMe(2)CH(2)P(t)Bu(CMe(2)CH)]OsH. This reaction is attributed to H(2) evolution from solid magnesium, rather than high energy H atom transfer between molecules, but relies also on the strong π-basicity of Os in favoring α-H migration from the metallated (t)Bu group on Os to form the second product, the hydrido carbene species. The path to two different products begins because the simple N(2) adduct of (PNP)OsI undergoes spontaneous heterolytic H-C splitting of the (t)Bu methyl group, to produce a secondary amine intermediate [((t)Bu(2)PCH(2)SiMe(2))N(H)(SiMe(2)CH(2)P(t)Bu(CMe(2)CH(2))]OsI(N(2)) which can then be dehydrohalogenated by Mg. The analogous reaction for (PNP)RuCl shows production of only (PNP)RuH(N(2)), with none of the hydride carbene dehydrogenation product. Comparative (Ru vs. Os) DFT calculations reveal the reaction steps where the Os analog is much more exothermic, accounting for certain reaction selectivities.     

Trace element pathways from environment to man

The ultimate purpose of all studies on environmental contamination is to protect human life; as a consequence the knowledge of the trace element pathways from environment to man is of paramount importance because it allows the assessment of a clear relationship between any environmental contamination and its effects on man. To this extent two different kinds of environmental studies will be described in this paper: (a) Studies of the geographic variations on the whole national territory of the natural levels of trace elements in water, food and some human tissues. (b) Studies of selected areas where a critical population group is exposed to abnormal levels of some trace elements. The main trace elements considered are: Co, Cr, Cs, Fe, Hg, Ni, Rb, Sb, Sc, Se and Zn; all the measurements were performed by means of non-destructive neutron activation analysis.     

An INAA-based evaluation of the responses of epiphytic lichens to elemental inputs in an oceanic environment (Azores)

Within an extensive survey of prevalent lower and higher plants in the Azores’ islands, with a view to their monitoring potential for airborne elements at ground level, and then to an eventual use in evaluation routines for the archipelago, epiphytic lichens were collected from Cryptomeria japonica (Japanese cedar) trunks all across Terceira and Santa Maria islands. After suitable procedures, thalli samples were put through instrumental neutron activation analysis (INAA; k ₀-variant) for elemental concentrations. Providing an overall view of micro-and trace-element levels in representative foliose-and fruticose-type species, the data of high-level elements agree generally well for genera with distinct species, with a relatively low interspecies variability. Principal-component analysis of the whole set of results discriminates clearly between two morphological factors, corresponding to foliose and fruticose species, and likely among four major origins of elemental inputs: soil/dust (two factors), sea spray and an antimony-related source. All things considered, and accounting for its availability and ubiquity, Parmotrema bangii seems an adequate choice for further lichen-based, biomonitoring campaigns in the Azores archipelago.     

How to increase the service temperature of polystyrene

In this overview we describe more recent attempts to raise that temperature range of polymeric systems containing styrene as the major starting monomer in which an article will loose dimensional stability under specified conditions. A search in the literature, both in journals and patent applications, over the last five years reveals a wealth of possibilities to perform this task. However, only a few of these have reached the commercial status, mostly due to reasons.     

Cool garment leathers for hot environment

Journal of Thermal Analysis and Calorimetry - Traditionally garment leathers are used in cold environment to protect the humans from chill weather. This is because leather garments have low heat...     

A web service infrastructure for thermochemical data

W3C standardized Web Services are becoming an increasingly popular middleware technology used to facilitate the open exchange of chemical data. While several projects in existence use Web Services to wrap existing commercial and open-source tools that mine chemical structure data, no Web Service infrastructure has yet been developed to compute thermochemical properties of substances. This work presents an infrastructure of Web Services for thermochemical data retrieval. Several examples are presented to demonstrate how our Web Services can be called from Java, through JavaScript using an AJAX methodology, and within commonly used commercial applications such as Microsoft Excel and MATLAB for use in computational work. We illustrate how a JANAF table, widely used by chemists and engineers, can be quickly reproduced through our Web Service infrastructure.