Two primer pairs to detect OTA producers by PCR method

Fungi contaminating foods and feeds may produce many mycotoxins including ochratoxin A (OTA). Early and rapid detection of potential OTA producing fungi is important to reduce the negative impacts of OTA. In this study, two PCR specific primer pairs, AoLC35-12L/AoLC35-12R and AoOTAL/AoOTAR, were designed from a DNA sequence of a polyketide synthase gene in Aspergillus ochraceus NRRL 3174. On 14 different fungi tested by PCR, AoLC35-12L/AoLC35-12R amplified a unique band from either OTA or citrinin producers while AoOTAL/AoOTAR amplified one PCR product only from A. ochraceus. So these primers could be used to detect both OTA and citrinin producing fungi (AoLC35-12L/AoLC35-12R) or only A. ochraceus (AoOTAL/AoOTAR) from foodstuffs using PCR method.     

Isolation and characterization of a psychrotolerant toxin producer, Bacillus weihenstephanensis, in liquid egg products

A psychrotolerant bacteria of the Bacillus cereus group was found responsible for the spoilage of whole liquid egg products. By sequencing a 16S rRNA region and performing a PCR amplification of specific 16S rRNA and cspA signatures, a Bacillus weihenstephanensis was identified. Characterization of this strain shows its ability to grow in defined medium as well as in whole liquid egg at refrigerated temperatures. The strain isolated possesses genes encoding for hemolysin BL, nonhemolytic enterotoxin, and B. cereus enterotoxins and produces enterotoxins with cytotoxic activity in whole liquid egg, even at refrigerated temperatures. The isolate exhibits a clear ability to stick and form biofilms on stainless steel, the most common material used in egg breaking factories, as well as on model hydrophilic (glass) and hydrophobic (polytetrafluoroethylene) materials. These findings show the necessity to monitor for Bacillus contamination in egg products that are often used in the composition of particularly susceptible finished products such as cream, dessert, dairy, meat, and seafood.     

Experimental study of mass transfer in a dense bubble swarm

We consider the liquid-side mass transfer coefficient k_L in a dense bubble swarm for a wide range of gas volume fraction (0.45%≤α_G≤16.5%). The study is performed for an air–water system in a square column. Bubble size, shape and velocity have been measured for different gas flow rates by means of a high speed camera. Gas volume fraction and bubble velocity have also been measured by a dual-tip optical probe. Both of these measurements show that the bubble vertical velocity decreases when increasing α_G in agreement with previous investigations. The mass transfer is measured from the time evolution of the dissolved oxygen concentration, which is obtained by the gassing-out method. The mass transfer coefficient is found to be very close to that of a single bubble provided the bubble Reynolds number is based on the average equivalent diameter 〈d_eq〉 and the vertical slip velocity 〈V_z〉.     

Isolation and Characterization of Starch from Pearl Millet (Pennisetum typhoidium) Flours

Pearl millet, an underutilized crop, is a relatively good source of nutrients and has varied uses over cereals. New applications must be explored to popularize the millet. In the present study, flour and isolated starch from pearl millet cultivars—Kalukombu and Maharashtra Rabi Bajra (MRB)—were investigated for physicochemical properties, nutritionally important starch fractions and x-ray diffraction. The yield of starch was significantly low (Kalukombu: 34.5 g/100 g and MRB: 39.4 g/100 g) with traces of non-starch components (protein, fat, and ash) indicating its purity. Starch could be classified as non-waxy type based on low amylose content (2.86–4.96 g/100 g). Low amylose lead to fragility of swollen starch granules which disintegrated easily at 65°C as observed in swelling power and solubility. Isolated starch was characterized with low water- and oil-holding capacity which could be attributed to the low protein content and absence of fiber in the starch. However, MRB starch showed higher oil uptake compared to flour, possibly due to its larger surface area that increased oil uptake. X-ray diffraction patterns showed sharp peaks at 2θ values 15 and 23º and a diffused peak at 2θ of 17 and 18º which is characteristic of A-type pattern. Low resistant starch (RS) and high readily digestible starch (RDS) content observed in the isolated starch could be attributed to the A-type pattern of starch which is more susceptible to enzyme hydrolysis and also due to elimination of structural obstruction to amylase hydrolysis during the process of starch isolation and gelatinization.     

Endothelial Colony-Forming Cells Dysfunctions Are Associated with Arterial Hypertension in a Rat Model of Intrauterine Growth Restriction

Infants born after intrauterine growth restriction (IUGR) are at risk of developing arterial hypertension at adulthood. The endothelium plays a major role in the pathogenesis of hypertension. Endothelial colony-forming cells (ECFCs), critical circulating components of the endothelium, are involved in vasculo-and angiogenesis and in endothelium repair. We previously described impaired functionality of ECFCs in cord blood of low-birth-weight newborns. However, whether early ECFC alterations persist thereafter and could be associated with hypertension in individuals born after IUGR remains unknown. A rat model of IUGR was induced by a maternal low-protein diet during gestation versus a control (CTRL) diet. In six-month-old offspring, only IUGR males have increased systolic blood pressure (tail-cuff plethysmography) and microvascular rarefaction (immunofluorescence). ECFCs isolated from bone marrow of IUGR versus CTRL males displayed a decreased proportion of CD31+ versus CD146+ staining on CD45− cells, CD34 expression (flow cytometry, immunofluorescence), reduced proliferation (BrdU incorporation), and an impaired capacity to form capillary-like structures (Matrigel test), associated with an impaired angiogenic profile (immunofluorescence). These dysfunctions were associated with oxidative stress (increased superoxide anion levels (fluorescent dye), decreased superoxide dismutase protein expression, increased DNA damage (immunofluorescence), and stress-induced premature senescence (SIPS; increased beta-galactosidase activity, increased p16^INK4a, and decreased sirtuin-1 protein expression). This study demonstrated an impaired functionality of ECFCs at adulthood associated with arterial hypertension in individuals born after IUGR.     

Neural classification of Lamb wave ultrasonic weld testing signalsusing wavelet coefficients

This paper presents an ultrasonic nondestructive weld testing method based on the wavelet transform (WT) of inspection signals and their classification by a neural network (NN). The use of Lamb waves generated by an electromagnetic acoustic transducer (EMAT) as a probe allows us to test metallic welds. In this work, the case of an aluminum weld is treated. The feature extraction is made by using a method of analysis based on the WT of the ultrasonic testing signals; a classification process of the features based on a neural classifier to interpret the results in terms of weld quality concludes the process. The aim of this complete process of analysis and classification of the testing ultrasonic signals is to lead to an automated system of weld or structure testing. Results of real-world ultrasonic Lamb wave signal analysis and classifications for an aluminum weld are presented; these demonstrate the feasibility and efficiency of the proposed method     

Analysis of the infrared transmission data of hydrogenated amorphous silicon film fabricated by high rate PECVD

The optical properties of hydrogenated amorphous silicon thin films prepared by a new thermocatalytic plasma enhanced chemical vapor deposition (PECVD) method are here reported for the first time. The transmission spectrum of the film, deposited at a rate of 1.5 nm/s, was measured between 500 and 1100 nm. The envelopes of the transmission spectrum interference maxima and minima were analyzed to reveal the absorption coefficient α(λ@#@), the refractive indexn(λ), the average thickness of the film (791 nm) and the variation of the thickness (11.4 nm), using an analysis which takes into account film inhomogeneity. The modified Newton's method of numerical analysis was used to obtain the optical parameters. The optical band gap ε₀} was determined to be 1.69 eV from the absorption coefficient spectrum, commensurate with values quoted for lower deposition rate PECVD films. The value for ε₀}, the small variation of the film thickness, and a value for the defect density of 3.7 x 10¹⁵}cm^-3} determined for similar material in other work indicate that the thermocatalytic PECVD method can produce acceptable quality films at a high deposition rate.     

Predicting the Academic Performance of Construction Engineering Students by Teaching and Learning Approaches: Case Study

There are various teaching approaches that instructors may adopt in their quest to teach effectively, and students can choose from a range of learning approaches to help them achieve good grades. This study investigates the effectiveness of personal learning approaches adopted by undergraduates and the teaching approaches employed by instructors in the context of construction engineering courses. The research questions are as follows. (1)?What are the students’ learning approaches that lead to better academic achievement? (2)?What are the instructors’ teaching approaches that give rise to better academic achievement? The study also aims to construct a model to predict a student’s likely academic performance in a construction engineering course. The research design is a self-administered survey. Using a structured questionnaire consisting of questions relating to learning strategies and teaching approaches, data were collected from undergraduates who majored in construction engineering. Statistical analyses undertaken include Pearson correlation and multiple linear regression modeling. Pearson correlation analysis shows that both the Growing Teaching approach and the students’ Achieving Motive learning approach are significantly correlated with academic performance. A robust grade prediction model was developed, whereby a student’s grade in a construction engineering course may be predicted using one teaching approach (Growing Teaching) and three learning approaches (Achieving Motive, Achieving Strategy, and Deep Motive). To help students obtain higher grades in a construction engineering course, instructors should adopt the Growing Teaching approach, and students should adopt the Achieving Motive learning approach. Because students who adopt the Deep Motive learning approach are penalized with lower grades, it is recommended that instructors modify their teaching methods and approaches so that students do not take shortcuts in their learning without deeper regard for higher-order learning outcomes.     

A novel optimization-based bandwidth-aware minimum power multicast routing algorithm in green wireless networks

Multicast routing in wireless networks that possess the wireless multicast advantage could significantly reduce the power and energy consumption. However, this kind of multicast routing that only addresses the transmission radius coverage might not be able to meet the bandwidth requirement of the users. As a result, additional transmissions are required to incur more energy consumption and carbon dioxide emissions that make existing algorithms not applicable to bandwidth constrained applications. In this paper, for the first time, we address the bandwidth aware minimum power multicast routing problem in wireless networks where the objective function is to minimize the total power consumption subject to the users?? bandwidth requirements. This problem is a challenging cross-layer design problem that requires seamless and sophisticated integrated design in the network layer (multicast routing) and physical layer (bandwidth-aware wireless transmission and power control). We first formulate this problem as a mixed integer linear programming problem and then propose a Lagrangian relaxation based algorithm to solve this problem. Numerical results demonstrate that the proposed approach is a sound green networking algorithm that outperforms the existing power efficient multicast routing approaches under all tested cases, especially in large bandwidth request, fine radius granularity, large group size and sparse network.     

Mass Spectrometry,Ion Mobility Separation and Molecular Modelling: A Powerful Combination for the Structural Characterisation of Substituted Cyclodextrins Mixtures

When working on the synthesis of substituted cyclodextrins (CDs), the main challenge remains the analysis of the reaction media content. Our objective in this study was to fully characterise a complex isomers mixture of Lipidyl-βCDs (LipβCD) obtained with a degree of substitution 1 (DS = 1) from a one-step synthesis pathway. The benefit of tandem mass spectrometry (MS/MS) and ion mobility separation hyphenated with mass spectrometry (IM-MS) was investigated. The MS/MS fragment ion‘s relative intensities were analysed by principal component analysis (PCA) to discriminate isomers. The arrival time distribution (ATD) of each isomer was recorded using a travelling wave ion mobility (TWIM) cell allowing the determination of their respective experimental collision cross section (CCS_exp). The comparison with the predicted theoretical CCS (CCS_th) obtained from theoretical calculations propose a regioisomer assignment according to the βCD hydroxyl position (2, 3, or 6) involved in the reaction. These results were validated by extensive NMR structural analyses of pure isomers combined with molecular dynamics simulations. This innovative approach seems to be a promising tool to elucidate complex isomer mixtures such as substituted cyclodextrin derivatives.