Platinum deposition from hydrogen-ion beam irradiated solid precursor

We report a particular method of Pt/glassy carbon (GC) surface formation, based on a 15 keV H^+/? ion beam irradiation of thin H₂PtCl₆ × nH₂O layer placed over the GC surface. Hydrogen-ion beam irradiation provided an excellent adherence of Pt deposit, unlike to any other Pt-deposition method. Furthermore, the morphology and electrochemical activity of GC/Pt catalyst obtained at the fluence of 5 × 10¹⁷ cm^? 2 was found to be sensitive to the sign of charge of hydrogen ions. The electrochemical activity of such obtained Pt/GC surface toward oxygen reduction and ethanol oxidation was compared with the activity of the Pt deposits obtained by other more common reduction procedures.     

An iterative sensory procedure to select odor-active associations in complex consortia of microorganisms: application to the construction of a cheese model

The aim of this study was to develop and validate an iterative procedure based on odor assessment to select odor-active associations of microorganisms from a starting association of 82 strains (G1), which were chosen to be representative of Livarot cheese biodiversity. A 3-step dichotomous procedure was applied to reduce the starting association G1. At each step, 3 methods were used to evaluate the odor proximity between mother (n strains) and daughter (n/2 strains) associations: a direct assessment of odor dissimilarity using an original bidimensional scale system and 2 indirect methods based on comparisons of odor profile or hedonic scores. Odor dissimilarity ratings and odor profile gave reliable and sometimes complementary criteria to select G3 and G4 at the first iteration, G31 and G42 at the second iteration, and G312 and G421 at the final iteration. Principal component analysis of odor profile data permitted the interpretation at least in part, of the 2D multidimensional scaling representation of the similarity data. The second part of the study was dedicated to 1) validating the choice of the dichotomous procedure made at each iteration, and 2) evaluating together the magnitude of odor differences that may exist between G1 and its subsequent simplified associations. The strategy consisted of assessing odor similarity between the 13 cheese models by comparing the contents of their odor-active compounds. By using a purge-and-trap gas chromatography-olfactory/mass spectrometry device, 50 potent odorants were identified in models G312, G421, and in a typical Protected Denomination of Origin Livarot cheese. Their contributions to the odor profile of both selected model cheeses are discussed. These compounds were quantified by purge and trap-gas chromatography-mass spectrometry in the 13 products and the normalized data matrix was transformed to a between-product distance matrix. This instrumental assessment of odor similarities allowed validation of the choice of G312 as the best 10-strain ecosystem.     

European perspectives of food safety

Food safety has been a growing concern among European Union (EU) citizens over the last decades. Despite the fact that food has never been safer, consumers are considerably uncertain and increasingly critical about the safety of their food. The introduction of new principles, such as the primary responsibility of producers, traceability, risk analysis, the separation of risk assessment and risk management provided a more transparent, science‐based system in Europe, which can help to restore consumers' lost confidence. The present EU integrated approach to food safety ‘from farm to fork’ aims to assure a high level of food safety within the EU. © 2014 Society of Chemical Industry     

Formation of thin boron nitride coating on multiwall carbon nanotube surfaces

Thin boron nitride films were deposited onto outer surfaces of multiwall carbon nanotubes (MWCNTs) by dip coating, which involves infiltration by boric acid solutions and subsequent nitridation of the boron oxide in ammonia flow at 1050 °C. The overall composition of the samples was determined by electron energy loss (EELS) and X-ray photoelectron spectroscopy (XPS), the surface composition and chemical structure of the BN coatings by XPS, the morphology of the BN/MWCNT composites by scanning and transmission electron microscopy (SEM, TEM), and the resistance against oxidation at elevated temperatures by thermal analysis (TGA). It was proved that single and multilayer BN coverage were achieved at the applied experimental conditions, and the coated samples showed significantly increased oxidation resistance compared to the uncoated MWCNTs.     

A Multiagent Based Scheme for Unlicensed Spectrum Access in CR Networks

In recent wireless network domains static spectrum access is a major concern. Generally, this access leads to spectrum scarcity problem by creating empty holes or white spaces. However, the scarcity is temporary and can be alleviated if spectrum access is performed dynamically and efficiently. One important step towards dynamic spectrum access is the development of cognitive radio (CR) technology, which senses nearby spectrum portions (or bands) and tries to use them either opportunistically or by negotiating with the neighboring users. Nonetheless, dynamic spectrum access raises several challenges which need to be addressed in detail. These challenges include efficient allocation of spectrum for users in order to maximize spectrum utilization and to avoid user level conflicts both under licensed and unlicensed bands. In this paper, considering the relative rarity of solutions for unlicensed spectrum access and their inadequacy, we propose a scheme, where the CR devices (equipped with agents) interact with their neighbors to form several coalitions over the unlicensed bands. These types of coalitions can provide a less-conflicted access as the agents mutually agree for spectrum sharing and they allow other CR users to enter in their vicinity of acquired spectrum via bilateral message exchanges. Further, we present continuous time Markov chains to model the spectrum access process in continuous time and derive important performance metric as the blocking probability for without and with queuing systems. Amongst others, the important comparisons we made between analytical and simulation results in terms of blocking probability verify that our proposed model is correct. In essence, our proposed solution aims to increase dynamic spectrum usage by enabling cooperation between the users.     

Zinc corrosion protection with 1,5-diphosphono-pentane

A set of identical measurement was performed to characterize the corrosion behaviour in Na₂SO₄ solution and surface structure of layers formed in aqueous and ethanol solutions of 1,5-diphosphonic acid on mechanically polished zinc substrates in order to understand the inhibition mechanism. Although, the protective layers formed in ethanol and in aqueous solution show substantial differences, their protection efficiency tends to the same value after about 4 h in corrosion tests. Based on EIS, XPS and GD-OES data, a simple oxide–hydroxide/diphosphonate model of the interface is proposed.     

Seasonal allergic rhinitis and pollen count (a 5-year survey in Budapest)

The authors compared the seasonal symptoms and the pollen allergen spectrum of pollen allergy with the 5-year aeropalynological data in Budapest. They summarized the average of symptom scores based on the diaries of 105 pollen allergic patients (mainly children) suffering from seasonal allergic rhinoconjunctivitis. The pollen allergen spectrum of the patients was defined. They constructed a local pollen calendar on the basis of the first regular pollen counting in Budapest, which had been done by them for 5 years. The symptom scores grew parallel with the increasing number of grass and ragweed pollen. Tree pollen allergy was found in 7.6 per cent of the patients. In spite of the high number of three pollen in the air in March and April the patients did not have too many complaints according to their symptom scores. Grass pollen allergy was found in 67.6 per cent of the patients and in the grass pollen season (May-July) the characteristic clinical symptoms were expressed. Weeds (in 64.8 per cent of the patients), especially ragweed (in 59.0 per cent of the patients) caused the most significant complaints in the late summer--autumn (August, September and partly October) period. Ragweed and other weeds play an important role in the etiology of seasonal allergic diseases in Hungary. The authors call the attention to the necessity of measures taken against the spread of ragweed.     

Efficacy of prevention of thromboembolic complications with LMW-heparin in experiment

The authors used an antithrombotic agent (Nadroparin Calcium) with anti-Xa effect in their experiments to prevent thromboembolic complications in the model of endoprosthetic replacement of the hip joint in mongrel dogs. 10 experimental animals (Group I.) were given doses of 100 A Xa ICU/kg/bwt of Nadroparin Calcium subcutaneously 4 hours prior to the operation and also once a day until the 3rd postoperative day; between the 4th and 10th postoperative days doses of 150 A Xa ICU/kg/bwt Nadroparin Calcium were given. The 10 control animals (Group II.) did not receive anticoagulant treatment. In both groups platelet count, activated partial thromboplastin times (APTT), prothrombin and fibrinogen levels as well as activated factor X inhibition (F Xa) were measured prior to surgery and also until the 14th postoperative day. No changes in APTT and prothrombin levels were detected during the experiment, however platelet count and fibrinogen levels as well as the extent of F Xa inhibition showed significant and different changes in groups I. and II. The Group I. which had received thromboembolic prophylaxis did not develop deep venous thrombosis or pulmonary embolism, but the control group did. Based on their investigations, the authors concluded that they had been able to achieve F Xa inhibition by giving the above mentioned doses of Nadroparin Calcium which was enough to prevent thromboembolic complications in their model experiment of implanting hip endoprosthesis.     

Effect of granulocyte proteases on human coagulation factors IX and X. The protective effect of calcium

The inactivation of the zymogen and active forms of Factors IX and X by the effect of granulocyte proteases was investigated. As deduced from the apparent first-order inactivation rate constants, Factors IXa and Xa were about ten times as sensitive to proteolytic inactivation as the zymogen factors. In the presence of 2.5mM CaCl2 the rate of inactivation of zymogens decreased to one half. With the active factors, calcium caused complete resistance to proteolysis, prevailing for 15 min. The analysis of resistance to proteolysis, prevailing for 15 min. The analysis of resistance to proteolysis led us to the conclusion that the observed phenomenon was related to the calcium binding ability of the factors studied and can probably be explained by the protection of the active sites of enzymes.