Efficacy of Antimicrobial Pullulan‐Based Coating to Improve Internal Quality and Shelf‐Life of Chicken Eggs During Storage

There has been a growing interest in the use of natural materials as a delivery mechanism for antimicrobials and coatings in foods. The aim of the present study was to evaluate the effectiveness of pullulan coatings to improve internal quality and shelf‐life of fresh eggs during 10 wk of storage at 25 and 4 °C. Three treatments of eggs were evaluated as follows; non‐coated (control; C), coated with pullulan (P), and coated with pullulan containing nisin (N). The effects of the pullulan coatings on microbiological qualities, physical properties, and freshness parameters were investigated and compared with non‐coated eggs. For non‐coated eggs, as storage time increased, yolk index, albumen index, and Haugh unit value decreased and weight loss increased. However, pullulan coatings (P or N) minimized weight loss (<1.5%) and preserved the albumen and yolk quality of eggs (with a final B grade) 3 wk longer than non‐coated eggs at 25 °C. At 4 °C, both P‐ and N‐coated eggs went from AA to A grade after 9 wk and maintained the grade for 10 wk (4 wk longer than that of non‐coated eggs). This study is the first to demonstrate that pullulan coatings can preserve the internal quality, prolong the shelf‐life, and minimize weight loss of fresh eggs.     

Electrospinning of biopolymer nanofibers encapsulated with functional nanoparticles toward core-shell fluorescence encoding

Photochromism has been an efficient approach to improve authenticity of commercial products. In order to prepare an authentication nanofibrous film with mechanical reliability, it has been crucial to improve the engineering production route of the authentication materials. Herein, we electrospun photoluminescent nanofibrous film with a fiber diameter of 50–200 nm from the environmentally-friendly polylactic acid embedded with nanoparticles of rare-earth activated strontium aluminate (NRESA; 10–15 nm). The created nanocomposite film was colorless in daylight, and became an intense green in ultraviolet light. The strontium aluminate photochromic agent must be applied in the nanoparticle form to ensure film transparency by enhancing its dispersion without aggregation in the electrospun polylactic acid nanofiber bulk. An emission peak was observed at 518 nm after excitation of the pigment-polylactic acid nanofibers at 365 nm. Raising NRESA ratio increased the hydrophobic properties of the pigment-polylactic acid nanofibers without changing their visual or mechanical properties. The transparent films showed high photochromic reversibility without exhaustion under numerous exposure cycles of ultraviolet light and darkness. The nanofibrous mats were elastic and flexible. The current technique is an effective strategy for making a variety of anti-counterfeiting substances.     

A wall-incorporated valve for preserving continence: an experimental evaluation of a new technique

The purpose of the present study was to analyse whether sex, age, skin test reactivity, cigarette smoking and occupational exposure were related to the total serum immunoglobulin (Ig)E concentrations (kU x L[-1]), in a general population sample. We studied 1,905 subjects (915 males, 990 females) of a general population sample (n=2,841, 8-73 yrs) participating in the second cross-sectional respiratory epidemiological survey in the rural Po Delta area (near Venice, North Italy). Distribution of total serum IgE concentrations was skewed, thus a log-transformation was performed to obtain a Gaussian shape. Significantly higher values of IgE were found in males compared to females. In general, a peak of IgE concentration was found at 8-14 yrs. IgE values tended to be lower in older than younger adults. Significantly higher serum IgE levels were shown in subjects with a positive skin-prick test index (ST+) than in those with a negative skin-prick test index (ST-). There was a significant relationship of total IgE levels with skin reactivity to pollens and house-dust mites. In both sexes higher values of IgE were found in current smokers than in ex-nonsmokers, regardless of skin-test reactivity. There was no significant difference in IgE values between ex- and nonsmokers. Passive smoking and occupational exposure were significantly related to increased IgE values. Our results confirm that in a general population sample immunoglobulin E concentrations are related not only to skin-prick test reactivity to common aeroallergens, but also to other risk factors for chronic obstructive lung diseases, such as sex, active/ passive smoking and occupational exposure.     

Infection of sheep with adult and larval Ostertagia circumcincta: gastrin

OBJECTIVE: To determine the prevalence, incidence and risk factors for Mycobacterium tuberculosis infection, as well as to assess TB knowledge and attitudes, among a group of known drug users in a city with low TB incidence (11.3 per 100,000 in 1995). METHODS: Patients of an urban drug treatment facility enrolled in opioid substitution, opioid antagonist and other drug treatment programs were screened for TB, including tuberculin skin testing and standardized data collection on TB risk factors. A subsample of clients was interviewed about TB knowledge and attitudes. RESULTS: Between 1 June 1995 and 31 May 1996, 1055 individuals were screened. The prevalence of infection was 15.7% (CI: 13.2-18.2%). PPD positivity was associated with older age (per annum, OR = 1.08, CI: 1.05-1.11), non-white race (OR = 2.81, CI: 1.72-4.60), foreign birth (OR = 4.24, CI: 2.35-7.62) and a history of injecting drug use (OR = 1.89, CI: 1.14, 3.12). The incidence of infection was 2.9 per 100 person-years (CI: 1.8-4.7). Thirty-two per cent of 79 drug users interviewed about TB knowledge and attitudes thought TB could be prevented by bleaching or not sharing needles/syringes. Fifty-one per cent thought anyone with a positive TB skin test was contagious. CONCLUSION: M. tuberculosis infection was common in this population and associated with injecting drugs and several demographic factors. The incidence of new infection was relatively low. In this non-endemic environment, the detection and treatment of latent infection are important aspects of TB control. Misconceptions about TB transmission were also widespread in this population. Drug treatment programs can play a key role by undertaking screening programs that educate about TB and identify infected subjects who would benefit from preventive therapy.     

Three-dimensional geotechnical modeling of the soils in Riyadh city,KSA

A standard penetration test (SPT) was carried out for 700 samples from 143 boreholes in four districts in Riyadh city, Kingdom of Saudi Arabia (KSA). Rock quality designation (RQD) and unconfined compression strength (UCS) tests were also performed for 238 samples from 154 boreholes in 15 districts of the city. Three-dimensional (3D) models of the SPT, RQD, and UCS were produced using the Voxler 3 software package. Further, 333 soil samples collected from 106 boreholes in 11 districts were examined to spatially model the distinctive geotechnical patterns of the alluvial soils in two dimensions. Tests were carried out to determine the soil grain size distribution, natural water content (NWC%), Atterberg’s consistency limits [liquid limit (LL%), plastic limit (PL%), and plasticity index (PI%)], and soil–water chemical components (pH Cl⁻, SO₃²⁻, and CO₃⁻). Spatial maps of the geotechnical parameters were produced by applying the geostatistical ordinary kriging implemented in ArcGIS. Soil samples were classified according to the unified soil classification system (USCS), and a thickness of the silty clay layer was produced. Plasticity charts indicated that the soils are inorganic cohesive clays with low and moderate plasticity (CL). Soil strength parameters showed wide ranges of UCS (average 220, range 21.3–618 kg/cm²), SPT (average 39, 0–100 N), and RQD (average 44, 11–78%). UCS and SPT 3D models clarified a regional southeastward trend of increase. RQD 3D models showed poor to fair engineering quality of rocks (25–75%). The results presented here can help to establish geohazard zonation maps with construction favorability ratings for safe urban expansion.

     

Recognition of the DNA Minor Groove by Thiazotropsin Analogues

Solution‐phase self‐association characteristics and DNA molecular‐recognition properties are reported for three close analogues of minor‐groove‐binding ligands from the thiazotropsin class of lexitropsin molecules; they incorporate isopropyl thiazole as a lipophilic building block. Thiazotropsin B (AcImPy^iPrThDp) shows similar self‐assembly characteristics to thiazotropsin A (FoPyPy^iPrThDp), although it is engineered, by incorporation of imidazole in place of N‐methyl pyrrole, to swap its DNA recognition target from 5′‐ACTA GT‐3′ to 5′‐ACGC GT‐3′. Replacement of the formamide head group in thiazotropsin A by nicotinamide in AIK‐18/51 results in a measureable difference in solution‐phase self‐assembly character and substantially enhanced DNA association characteristics. The structures and associated thermodynamic parameters of self‐assembled ligand aggregates and their complexes with their respective DNA targets are considered in the context of cluster targeting of DNA by minor‐groove complexes.     

Maintenance Strategies and Failure‐Cost Model for Medical Equipment

This paper proposes a mathematical maintenance model that analyses the effect of maintenance on the survival probability of medical equipment based on maintenance history and age of the equipment. The proposed model is simulated in Scilab using real data extracted from maintenance history of anaesthesia machine from Draeger. The analysis using survival approach reveals that conducting preventive maintenance on the selected medical equipment had a positive impact on survival of equipment. The model is then used to analyse the cost of maintenance scenarios, and an appropriate scenario is proposed for anaesthesia machine. A new failure‐cost model is developed, which may be used to calculate the number of failures of equipment and the annual maintenance cost. The proposed models may be used as a planning tool for selecting maintenance strategies for various medical equipments. Copyright © 2014 John Wiley & Sons, Ltd.     

Adsorption of diuron and its degradation products from aqueous solution by surfactant-modified pillared clays

Adsorption of the herbicide diuron and its three degradation products: 3-(3,4-dichlorophenyl)-1-methylurea, 1-(3,4-dichlorophenyl) urea and 2,4-dichloroanilin on three organo–inorgano-clay minerals, was investigated. These surfactant-modified pillared clays (SMPC) were prepared by intercalation of polycations of aluminum(III), iron(III) or titanium(IV) into the interlamellar space of a montmorillonite, followed by co-adsorption of cetyl trimethylammonium bromide. The adsorption capacity of these new microporous solids was considerably enhanced especially with Ti- or Fe-SMPC. The adsorption isotherms of diuron and its derivatives at different pH were performed on each SMPC. These isotherms are typically S-type curves and suggested a hydrophobic adsorption mechanism. A comparative study of adsorption of the four compounds on each SMPC adsorbent shows the high adsorption capacity of diuron in comparison with its degradation products. This new generation of adsorbents could thus be considered as powerful competitors to activated carbon for the water treatment of industrial effluents in acidic medium.     

Photocatalysis with Ti-pillared clays for the oxofunctionalization of alkylaromatics by O2

Ti-pillared montmorillonite clays (Ti-PILCs) have been investigated as photocatalysts for the selective oxygenation of the following liquid alkylaromatics: toluene, para-xylene and ortho-xylene. The photocatalytic processes occur using O₂ as oxidizing species, upon near UV light, in mild pressure and temperature conditions and with good stability of the catalytic materials. Accumulation of valuable carbonylic derivatives is possible since their over-oxidation to carbon dioxide is negligible. In particular, proper reaction conditions are found for obtaining carbonylic compounds with about 90% selectivity, which is significantly higher than that obtained when the same experiments are carried out with commercial TiO₂ Degussa P25. Detailed results on the chemical–physical characterization of these materials are also presented. In this regard, particular attention is devoted to the effects of surface interaction with substrates and reaction intermediates on efficiency and selectivity of the photocatalytic processes. In particular, the hydrophobic nature of the Ti-PILCs as well as adsorption phenomena are beneficial for alkylaromatics to reach the photoactive sites. The results obtained in mixed alkylaromatics/cyclohexane reaction media show that the Ti-PILCs are also able to discriminate among the substrates in favour of the aromatic compounds.     

Effect of mixture strength and injection timing on combustion characteristics of a direct injection hydrogen-fueled engine

An experimental investigation was performed to characterize the hydrogen combustion in a spark-ignition direct-injection engine. It was focused on the effects of mixture strength and injection timing on the characteristics of hydrogen combustion. For this purpose, the practical tests were carried out on an experimental test rig. It is originally designed for optimization of the direct-injection natural-gas engine. The experimental test-rig results comprised the traces for the in-cylinder pressure, mass fraction burned, and heat release rate under the different operation conditions. The results obtained show that the richer mixture condition produced higher pressure trends at all tested points. Besides that, it exhibited a faster rate of increase in combustion rate due to the increase of flame speed. However, the combustion characteristics deteriorated due to the lack of mixture stratification with earlier injection timing. It is concluded that direct-injection timing is essential to achieve better combustion performance. Moreover, retarding the spark ignition timing is also crucial to avoid abnormal combustion in the case of a richer mixture and early start on injection.