Proteomic Helicobacter pylori biomarkers discriminative of low-grade gastric MALT lymphoma and duodenal ulcer

To date no reliable diagnostic method exists to predict, among the very large and clinically heterogeneous group of Helicobacter pylori‐infected patients, the extremely small group at risk for developing low‐grade gastric MALT lymphoma (LG‐MALT). Search of proteomic biomarkers holds promise for the classification of the H. pylori strains with regard to this severe clinical outcome. In the present study 69 H. pylori strains isolated from patients with two different H. pylori‐associated diseases, duodenal ulcer (DU, n=29) and LG‐MALT (n=40) were used. Protein expression patterns of the strains were analyzed by using the high‐throughput methodology SELDI. Selected proteins were purified by means of chromatographic and electrophoretic methods in view of further sequencing by LC‐MS/MS. Univariate analysis (Mann–Whitney test) of the protein expression patterns generated nine significant biomarkers that can discriminate between H. pylori strains from patients with DU and LG‐MALT. These biomarkers are of low molecular weight, ranging from 6 to 26.6 kDa. Among them, two are overexpressed in LG‐MALT strains and seven – in DU strains. Two biomarker proteins, one overexpressed in LG‐MALT strains (13.2 kDa) and another one – overexpressed in DU strains (26.6 kDa), were purified to homogeneity and identified by using LC‐MS/MS as a 50S ribosomal protein L7/L12 and a urease subunit, respectively. These biomarkers can be included in novel protein arrays for the differential diagnosis of H. pylori‐associated clinical outcomes.     

Tunnel diode oscillator circuit for surface impedance measurement of thin films near 20 MHz

We describe and analyse a simple method for the measurement of thin film surface impedance in the frequency range 10–20 MHz. This method is based on the analysis of both the frequency shift and the amplitude variation of the signal in a tunnel diode oscillator circuit inductively coupled to the sample. The sensitivity of the method to the conducting properties of the thin films is a function which is greatly dependent on geometrical parameters and which can be easily optimized and included in the response calculation. The analysis is illustrated by examples with superconducting and normal metal films. The resolution of the measurements is also discussed.     

Structure,electrical, dielectric,and optical investigation on polyvinyl alcohol/metal chloride nanocomposites

Different concentrations of metal chlorides/polyvinyl alcohol nanocomposites have been prepared by the typical solvent cast technique. The prepared samples were investigated by different techniques such as X‐ray diffraction, differential scanning calorimetry, and scanning electron microscope. DC and AC conductivities are examined at different temperatures and frequencies. An activation process was found in the DC conductivity versus temperature relation and the activation energy was calculated. The AC conductivity obeyed the ω^S power law. The behavior of S with temperature was studied. Various dielectric parameters such as dielectric constant (ε′), dielectric loss (ε″) and loss tangent (tan δ) have been determined in the temperature range 303–443 K at different frequencies. The dielectric parameters were found to decrease with increasing frequency. The study of dielectric relaxation as a function of temperature at constant frequency shows two relaxation mechanisms. The optical band gaps and band tails were estimated from the measured absorption spectra. The applied photon energy found to affect the observed optical band gaps. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Biodegradable poly(lactic acid)-based scaffolds: synthesis and biomedical applications

Biodegradable polymers are identified as substantial materials for biomedical applications. These polymers have the ability to deteriorate through an unpretentious hydrolysis and eliminated through kidneys’ functions or metabolic processes. Among widely used biodegradable polymers in biomedical applications, poly(lactic acid) (PLA) is becoming one of the most paramount polymers. Synthesizing PLA through melt/solution polycondensation polymerizations makes it relatively easy to tailor properties of final product. However, their synthesis reactions are affected by several parameters such as polymerization time, temperature, pressure, catalysts, and the polarity of the solvent. Moreover, equilibrium reactions are controlled through utilizing a hydrophilic monomer such as ethylene glycol (EG). These factors can strongly impact final properties of PLA. Thus, it is indispensable to comprehend the effect of operating parameters during the polymerization process. Optimizing synthesis conditions can be accomplished through reducing side reactions. Furthermore, this can be achieved through racemization by utilizing chain extenders to build high molecular weight and enhance thermal stability. In this review, the design and fabrication of porous PLA scaffolds and their physicomechanical behavior are reviewed. Different PLA scaffold parameters were investigated thoroughly, which include biocompatibility, biodegradability, and mechanical properties for different porosity and pore sizes to mimic the complex architecture of the natural tissue regeneration.

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A supervised discriminant data representation: application to pattern classification

Neural Computing and Applications - The performance of machine learning and pattern recognition algorithms generally depends on data representation. That is why, much of the current effort in...     

Diurnal distribution of airborne bacteria and fungi in the atmosphere of Helwan area, Egypt

Airborne bacterial and fungal composition in an industrial town of Helwan, Egypt, was studied using a slit impactor sampler during the period from March 2006 to February 2007. Airborne bacterial concentrations were usually higher than fungi. Bacteria and fungi had similar diurnal variation patterns. Airborne microorganisms reached their concentration peaks in the evening and gradually decreased during the night time. The hourly concentration peaks of the bacteria and fungi appeared at 20:00 h. A significant difference (P ≤ 0.05) was found between the hourly mean concentrations of airborne fungi in winter compared to other seasons. Fungi concentrations were significantly higher (P ≤ 0.05) on working weekdays than weekends. Aspergillus, Penicillium, Alternaria and Cladosporium were the most predominant airborne fungal genera. Aspergillus showed double peak patterns whereas Penicillium, Alternaria and Cladosporium showed one peak pattern. The diurnal variations of the bacteria and fungi could be divided into four periods: 1) the morning maximum concentration (6:00 h-10:00 h), 2) midday to afternoon pattern (10:00 h-16:00 h), 3) the evening concentration peak (18:00 h-20:00 h) and 4) the gradual decrease of night time concentration (22:00 h-24:00 h). Geographical location, human activity, growth cycle of organisms and meteorological factors were the main criteria controlling the temporal variations of the air microorganisms in the Wadi Hof area.     

Intelligent system to support judgmental business forecasting: thecase of estimating hotel room demand

Forecasting is an instrumental tool for strategic decision-making in any business activity. Good forecasts can reduce the uncertainty about the future and, hence, help managers make better decisions. Virtually all statistical forecasting techniques depend on the continuity of historical data and time series and may not predict a discontinuous change in the business environment. Often times, this discontinuity is known to managers who then must rely on their judgment to make forecast adjustments. We discuss the role of judgmental forecasting and take the problem of estimating future hotel room demand as a practical business application. Next, we propose IS-JFK: an intelligent system to support judgmental forecasting and knowledge of managers. To account for vagueness in the knowledge elicited from managers and the approximate nature of their reasoning, the system is built around fuzzy IF-THEN rules and uses fuzzy logic for decision inference. IS-JFK supports two methods for forecast adjustments: 1) a direct approach and 2) an approach based on fuzzy intervention analysis. Actual data from a hotel property are used in some case-scenario simulations to illustrate the merits of the intelligent support system     

Mechanical and thermal properties of calcium carbonate‐filled PP/LLDPE composite

Polymer blends typically are the most economical means to develop new resins for specific applications with the best cost/performance balance. In this paper, the mechanical properties, melting, glass transition, and crystallization behavoir of 80 phr polypropylene (PP) with varying weights of linear low density polyethylene (LLDPE) at 10, 20/ 20 wt % CaCO₃, 30, 40, and 50 phr were studied. A variety of physical properties such as tensile strength, impact strength, and flexural strength of these blends were evaluated. The compatibility of these composite was examined by differential scanning calorimetry (DSC) to estimate T_m and T_c, and by dynamic mechanical analysis (DMA) to estimate T_g. The fractographic analysis of these blends was examined by scanning electron microscopy (SEM). It has been confirmed that increasing the LLDPE content trends to decreases the tensile strength and flexural strength. However, increasing the LLDPE content led to increases in the impact strength of PP/LLDPE blends. It was also found that up to 40 phr the corresponding melting point (T_m) was not effected with increasing LLDPE content. Each compound has more than one T_g, which was informed that there is a brittle‐ductile transition in fracture nature of these blends, the amount of material plastically deformed on the failure surface seems to increase with the increasing the LLDPE content. And PP/LLDPE blends at temperature (23°C) showed a ductile fracture mode characterized by the co‐existence of a shear yielding process; whereas at lower temperature (−20°C) the fractured surfaces of specimens appear completely brittle. The specimens broke into two pieces with no evidence of stress whitening, permanent macroscopic deformation or yielding. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Study of superconductors by a.c. susceptibility

An apparatus used for a.c. susceptibility measurements is described and the usefulness of a.c. susceptibility measurements for investigating superconductors is discussed. The importance of carefully studying the real and imaginary parts of a.c. susceptibility is pointed out as illustrated by the results obtained on A15 compounds (V₃Si) and on Nb-Ti samples.