Characterisation of Wolbachia-like bacteria isolated from the parthenogenetic stored-product pest psocid Liposcelis bostrychophila (Badonnel) (Psocoptera)

The widespread psocid, Liposcelis bostrychophila, is a stored-product pest of grain and farinaceous foods. Its ubiquity is in part due to its parthenogenetic reproduction which is shown to be the result of the presence of rickettsial bacteria in the ovaries and developing oocytes. Based on similarities in 16S rDNA sequences, the bacteria are identified as Wolbachia-like. There is little difference in these sequences among a number of L. bostrychophila populations from around the UK and there was no correlation with patterns of similarity among the insect 12S rDNA sequences.Treatment with antibiotics and heat reduced or removed the bacterial infections. Rifampicin (1%) produced aposymbiotic psocids within 4 weeks and the egg production in such treated individuals was greatly reduced. Tetracycline and maintenance at a temperature of 37°C reduced the bacterial loads in the oocytes but did not significantly impact egg production. Closely related bisexual psocid species have no detectable 16S rDNA, which supports EM observations, and were unaffected by the antibiotic treatments.     

Overcoming the limitations of current meta-analysis of randomised controlled trials

For a meta-analysis to give definitive information, it should meet at least the minimum standards that would be expected of a well-designed, adequately powered, and carefully conducted randomised controlled trial. These minimum standards include both qualitative characteristics--a prospective protocol, comparable definitions of key outcomes, quality control of data, and inclusion of all patients from all trials in the final analysis--and quantitative standards--an assessment of whether the total sample is large enough to provide reliable results and the use of appropriate statistical monitoring guidelines to indicate when the results of the accumulating data of a meta-analysis are conclusive. We believe that rigorous meta-analyses undertaken according to these principles will lead to more reliable evidence about the efficacy and safety of interventions than either retrospective meta-analysis or individual trials.     

K and Ca content of fresh green tea, black tea, and tea residue determined by X-ray fluorescence analysis

Summary X-Ray fluoresence (XRF) can be successfully used for the qualitative and quantitative elemental analysis of various agricultural products. Its simplicity, high throughput and the possibility of automation make it useful for screening large numbers of samples. The K and Ca content of 138 samples of fresh green tea, black tea and black tea residues were determined by applying the XRF system. Such a method of mineral analysis of food products is not very common. Tea from different teagrowing areas of Turkey, green tea of different shooting periods, black tea processed at different tea plants and tea residues from these black tea were analysed. The K content of green tea, processed black tea and tea residues after brewing were found to have ranges of 19,049–26,254 mg/kg, 21,904–26,883 mg/kg and 9,468–13,778 mg/kg, respectively. In the same samples the Ca content was determined as 3,580–4,799 mg/kg, 3,370–4,823 mg/kg, and 3,743–5,733 mg/kg, respectively. These findings were compared with the results of atomic emission techniques and it was concluded that the XRF system could be effectively used for quantitative analysis of the K and Ca content of tea samples.

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Die Bestimmung des K- und Ca-Gehaltes von frischem Tee, schwarzem Tee und Teerückstand durch die X-Ray-Fluoreszenz-Technik

Zusammenfassung Mit der X-Ray Fluoreszenztechnik können die qualitativen und quantitativen Bestimmungen der Mineralstoffe in verschiedenen Produkten erfolgreich durchgeführt werden. Mit dieser Methode wurde der Ca- und K-Gehalt von 138 Proben untersucht, und zwar frischer Tee, schwarzer Tee und Teerückstand. Diese Methode ist in der Lebensmitteltechnologie, insbesondere bei der Mineralstoffbestimmung nicht üblich. Die Teeproben stammten aus verschiedenen Teeanbaugebieten der Türkei. In dieser Arbeit wurden die Wirkung der Sproßperiode, der Verarbeitungstechnik und des Anbaugebietes auf den Ca- und K-Gehalt der Teeproben untersucht. Der durchschnittliche K-Gehalt betrug: in frischem Tee 19049–26254 mg/kg, in schwarzem Tee 21904–26883 mg/kg, in Teerückstand 9468–13778 mg/kg; der Ca-Gehalt 3580–4799 mg/kg, 3370–4823 mg/kg und 3473–5733 mg/kg.

     

Effects of Combined Heat and Mass Transfer on Entropy Generation due to MHD Nanofluid Flow over a Rotating Frame

The current investigation aims to explore the combined effects of heat and mass transfer on free convection of Sodium alginate-Fe3O4 based Brinkmann type nanofluid flow over a vertical rotating frame. The Tiwari and Das nanofluid model is employed to examine the effects of dimensionless numbers, including Grashof, Eckert, and Schmidt numbers and governing parameters like solid volume fraction of nanoparticles, Hall current, magnetic field, viscous dissipation, and the chemical reaction on the physical quantities. The dimensionless nonlinear partial differential equations are solved using a finite difference method known as Runge-Kutta Fehlberg (RKF-45) method. The variation of dimensionless velocity, temperature, concentration, skin friction, heat, and mass transfer rate, as well as for entropy generation and Bejan number with governing parameters, are presented graphically and are provided in tabular form. The results reveal that the Nusselt number increases with an increase in the solid volume fraction of nanoparticles. Furthermore, the rate of entropy generation and Bejan number depends upon the magnetic field and the Eckert number.     

Covariance matrix-based fire and flame detection method in video

This paper proposes a video-based fire detection system which uses color, spatial and temporal information. The system divides the video into spatio-temporal blocks and uses covariance-based features extracted from these blocks to detect fire. Feature vectors take advantage of both the spatial and the temporal characteristics of flame-colored regions. The extracted features are trained and tested using a support vector machine (SVM) classifier. The system does not use a background subtraction method to segment moving regions and can be used, to some extent, with non-stationary cameras. The computationally efficient method can process 320?× 240 video frames at around 20 frames per second in an ordinary PC with a dual core 2.2 GHz processor. In addition, it is shown to outperform a previous method in terms of detection performance.     

Aqueous polymerization of acrylamide initiated by 4,4′-azobis (4-cyano pentanol) and chain extension of polyacrylamide by means of ceric ion redox systems

Summary The polymerization of acrylamide (AA) initiated by 4,4-azobis (4 cyanopentanol) (ACP) was investigated in aqueous solution at 60°C. The molecular weight and the conversion depend on polymerization duration and initiator concentration. Polymerization of AA initiated by ACP yields polyacrylamide (PAA) with hydroxyl terminal groups. Redox polymerization of AA initiated by hydroxyl terminated PAA in conjuction with Ce(IV) provided increase in the molecular weight of the initial polymer.     

The use of neural networks for the prediction of the settlement of one-way footings on cohesionless soils based on standard penetration test

In this study, artificial neural networks (ANNs) were used to predict the settlement of one-way footings, without a need to perform any manual work such as using tables or charts. To achieve this, a computer programme was developed in the Matlab programming environment for calculating the settlement of one-way footings from five traditional settlement prediction methods. The footing geometry (length and width), the footing embedment depth, the bulk unit weight of the cohesionless soil, the footing applied pressure, and corrected standard penetration test varied during the settlement analyses, and the settlement value of each one-way footing was calculated for each traditional method by using the written programme. Then, an ANN model was developed for each method to predict the settlement by using the results of the analyses. The settlement values predicted from each ANN model developed were compared with the settlement values calculated from the traditional method. The predicted values were found to be quite close to the calculated values. Additionally, several performance indices such as determination coefficient, variance account for, mean absolute error, root mean square error, and scaled percent error were computed to check the prediction capacity of the ANN models developed. The constructed ANN models have shown high prediction performance based on the performance indices calculated. The results demonstrated that the ANN models developed can be used at the preliminary stage of designing one-way footing on cohesionless soils without a need to perform any manual work such as using tables or charts.     

Photoactive epichlorohydrin, 2. Photoinitiated free-radical and promoted cationic polymerization by using polyepichlorohydrin with benzoin terminal groups

The photoinitiated free-radical polymerization of methyl methacrylate (MMA) and the radical-promoted cationic polymerization of cyclohexene oxide (CHO) in the presence of low-molecular-weight polyepichlorohydrin terminated with groups containing benzoin derivatives were studied. Benzoin-terminated polyepichlorohydrin was prepared by Activated Monomer (AM) polymerization. Upon photolysis. polymer-bound alkoxy benzyl radicals were generated, initiating the radical polymerization of MMA. In the case of radical-promoted cationic polymerization of CHO, the cationic initiating species were formed by the oxidation of photochemically generated polymeric radicals by N-ethoxy-2-methylpyridinium hexafluorophosphate.     

Studying the sol-gel transition of styrene-divinyl benzene crosslinking co-polymerization via excimer forming dye molecules

A novel method based on the steady state fluorescence technique was used to study the sol-gel transition in the free radical crosslinking reaction between styrene (St) and divinyl benzene (DVB) with 2,2′-azobisisobutyronitrile (AIBN) as initiator. N-(4-(pyrenyl methylene)-oxycarbonyl phenyl)maleimide (Py-MI) was used as a fluorescence probe. The possible enchainment of Py-MI in alternating sequences occurred randomly in polymer clusters produced modifications in the fluorescence spectra, namely the shift at the higher wavelengths due to the excimer formation. The fluorescence spectra of Py-MI's excimers allowed both to monitor the sol-gel transition and to test the critical exponents as function of co-monomer's concentration. The gel fraction exponent β and the weight average degree of polymerization exponent γ agreed best with the static percolation values. Although this technique was applied for St-DVB co-polymerization, it may be generalized for the other monomers that are able to bind chemically to Py-MI monomer during the polymerization.     

Investigation of milling characteristics of alumina powders milled with a newly designed vibratory horizontal attritor

In this study, a vibratory horizontal attritor was designed, constructed and used to produce alumina powders. The effects of process parameters, such as milling time, ball-powder weight ratio (BPR) and rotational speed (RS) of the attritor on the mean particle size and particle size distribution have been investigated. Milling times of 1, 5, 10 and 15 h and ball-powder weight ratios of 5:1, 10:1, 20:1 and 40:1 were considered in the present study. Rotational speeds of the attritor were selected as 500, 700 and 900 rpm and distilled water was used as milling media.The experimental results show that increasing milling time and ball-powder weight ratio resulted in finer particles. Optimum rotational speed of the attritor was found as 700 rpm. The mean particle size of attrited powders were in the range of 2.05-6.82 μm, depending on process parameters.