Multiplex PCR-based strategy to detect contamination with mycotoxigenic Fusarium species in rice and fingermillet collected from southern India

BACKGROUND: The genus Fusarium comprises a diverse group of fungi including several species that produce mycotoxins in food commodities. In the present study, a multiplex PCR was standardised for the group‐specific detection of fumonisin‐producing and trichothecene‐producing strains of Fusarium species. Primers for genus‐level recognition of Fusarium spp. were designed from the internal transcribed spacer regions 1 and 2 of rDNA. Primers for group‐specific detection were designed from the tri5 and tri6 genes involved in trichothecene biosynthesis and the fum1 and fum13 genes involved in fumonisin biosynthesis. RESULTS: Among the various genera and their strains tested, all the 85 confirmed Fusarium strains were positive for rDNA gene and the rest stayed negative. From among the Fusarium strains, 15 had amplification for trichothecene‐ and 20 for fumonisin‐encoding genes. All PCR positive trichothecene chemotypes of Fusarium species tested were positive for chemical analysis but in the case of fumonisins, of the 20 PCR positive cultures, only 13 showed positive for chemical analysis by HPTLC. CONCLUSION: The assay described here provided a rapid and reliable detection of trichothecene‐ and fumonisin‐producing Fusarium directly from natural food grains and the results were always comparable with a conventional HPTLC detection method. It can, therefore, be used by the food industry to monitor quality and safety. Copyright © 2011 Society of Chemical Industry     

On the Role of Contact Resistance and Electrode Modification in Organic Electrochemical Transistors

Contact resistance is renowned for its unfavorable impact on transistor performance. Despite its notoriety, the nature of contact resistance in organic electrochemical transistors (OECTs) remains unclear. Here, by investigating the role of contact resistance in n‐type OECTs, the first demonstration of source/drain‐electrode surface modification for achieving state‐of‐the‐art n‐type OECTs is reported. Specifically, thiol‐based self‐assembled monolayers (SAMs), 4‐methylbenzenethiol (MBT) and pentafluorobenzenethiol (PFBT), are used to investigate contact resistance in n‐type accumulation‐mode OECTs made from the hydrophilic copolymer P‐90, where the deliberate functionalization of the gold source/drain electrodes decreases and increases the energetic mismatch at the electrode/semiconductor interface, respectively. Although MBT treatment is found to increase the transconductance three‐fold, contact resistance is not found to be the dominant factor governing OECT performance. Additional morphology and surface energy investigations show that increased performance comes from SAM‐enhanced source/drain electrode surface energy, which improves wetting, semiconductor/metal interface quality, and semiconductor morphology at the electrode and channel. Overall, contact resistance in n‐type OECTs is investigated, whilst identifying source/drain electrode treatment as a useful device engineering strategy for achieving state of the art n‐type OECTs.     

The role of environmental factors and medium composition on bacteriocin production by an aquaculture probiotic Enterococcus faecium MC13 isolated from fish intestine

The aim of this study was to optimize medium composition for higher yield of total viable cells and bacteriocin by Enterococcus faecium MC13. The factors such as peptone, meat extract, yeast extract, lactose, glycerol, tween 80, triammonium citrate and K₂HPO₄ were selected based on the Lactobacillus MRS medium composition. Two level factorial designs (FD) and steepest ascent path were performed to identify vital factors among the variables. Through the 2^?8 FD, peptone, yeast extract and lactose were found to be significant factors involved in the enhanced production of viable cells and bacteriocin. Therefore, these three foremost factors were further optimized by central composite design to achieve efficient yield. The optimum MRS composition was found to be peptone (40.0 g/L), meat extract (30.0 g/L), yeast extract (40.0 g/L), lactose (24.0 g/L), glycerol (5.8 g/L), Tween 80 (3.0 g/L), triammonium citrate (1.0 g/L), K₂HPO₄ (2.5 g/L), MgSO₄·7H₂O (0.10 g/L), MnSO₄·7H₂O (0.05 g/L) and dipotassium PO₄ (2.0 g/L). The optimized growth medium allowed higher amount of bacteriocin activity (36,100 AUml^?1) and total viable cells (14.22 LogCFUml^?1) production which were two-times higher than the commercial MRS medium.     

The effect of the shape and size of the pores on the mechanical properties of porous HAP-based bioceramics

In this study, the influence of the shape and size of the pores on the mechanical properties of the obtained porous HAP-based bioceramics was investigated. The porous HAP-based bioceramics were obtained starting from spherical calcium hydroxyapatite powder, obtained by hydrothermal syntheses. The number of shapeless inter-agglomerate pores decreased and amount of spherical intra-agglomerate pores increased on increasing the sintering temperature from 1100 °C to 1250 °C. The shape of pores also changed with thermal treatment of specimens; the small pores remained spherical while the larger pores became more spherical in shape, as was proved by image analysis. A three-dimensional, finite element unit cell model was applied to evaluate the influence of pore shape on the mechanical strength of HAP ceramics. By analyzing the effect of the shape of pores to the fracture toughness of sintered porous HAP bioceramics, it was observed that the more spherical the pores were, the tougher became the bioceramics. After sintering at 1250 °C for 2 h, measured toughness was 1.31 MPa m^1/2, which is a relatively high value for this type of bioceramics.     

The Potential Role of Kallistatin in the Development of Abdominal Aortic Aneurysm

Abdominal aortic aneurysm (AAA) is a vascular condition that causes permanent dilation of the abdominal aorta, which can lead to death due to aortic rupture. The only treatment for AAA is surgical repair, and there is no current drug treatment for AAA. Aortic inflammation, vascular smooth muscle cell apoptosis, angiogenesis, oxidative stress and vascular remodeling are implicated in AAA pathogenesis. Kallistatin is a serine proteinase inhibitor, which has been shown to have a variety of functions, potentially relevant in AAA pathogenesis. Kallistatin has been reported to have inhibitory effects on tumor necrosis factor alpha (TNF-α) signaling induced oxidative stress and apoptosis. Kallistatin also inhibits vascular endothelial growth factor (VEGF) and Wnt canonical signaling, which promote inflammation, angiogenesis, and vascular remodeling in various pre-clinical experimental models. This review explores the potential protective role of kallistatin in AAA pathogenesis.     

TrkB Receptor Signalling: Implications in Neurodegenerative,Psychiatric and Proliferative Disorders

The Trk family of receptors play a wide variety of roles in physiological and disease processes in both neuronal and non-neuronal tissues. Amongst these the TrkB receptor in particular has attracted major attention due to its critical role in signalling for brain derived neurotrophic factor (BDNF), neurotrophin-3 (NT3) and neurotrophin-4 (NT4). TrkB signalling is indispensable for the survival, development and synaptic plasticity of several subtypes of neurons in the nervous system. Substantial evidence has emerged over the last decade about the involvement of aberrant TrkB signalling and its compromise in various neuropsychiatric and degenerative conditions. Unusual changes in TrkB signalling pathway have also been observed and implicated in a range of cancers. Variations in TrkB pathway have been observed in obesity and hyperphagia related disorders as well. Both BDNF and TrkB have been shown to play critical roles in the survival of retinal ganglion cells in the retina. The ability to specifically modulate TrkB signalling can be critical in various pathological scenarios associated with this pathway. In this review, we discuss the mechanisms underlying TrkB signalling, disease implications and explore plausible ameliorative or preventive approaches.     

Additive manufacturing of barium titanate based ceramic heaters with positive temperature coefficient of resistance (PTCR)

Lanthanum/manganese doped barium titanate (BT) based PTCR functional heater elements/structures were fabricated with desirable electrical properties for the first time using Additive Manufacturing (AM). 3D printed components of varying size and shape and prototype honeycomb lattices with high density were achieved through AM. Aqueous, less organic containing (2.5 wt% additives versus 10–30 wt% added typically), eco-friendly ink formulations were developed with suitable rheological properties for 3D printing. For BT prints, the sintered densities of the 3D ceramic parts were found to be >99% TD, highest reported value so far. The microstructure, electrical properties and heating characteristics of the printed PTCR components were studied in detail and their thermal stability evaluated using infrared imaging and benchmarked against commercial PTCR heating element. The heating behaviour of the solid and porous 3D printed components was demonstrated to be similar, paving the way for light weight (?47% reduction in weight) heaters suitable for automotive/aerospace applications and less materials wastage during device fabrication.     

Artificial in-plane ordering of textured YBa2Cu3O7?x films deposited on polycrystalline yttria-stabilized zirconia substrates

Anisotropie surface texturing of the polycrystalline yttria-stabilized zirconia substrates, prior to YBa₂Cu₃O_7–x film deposition, is shown to promote in-plane (basal plane) ordering of the film growth in addition to thec-axis texturing. TheJ _c 's of the films in the weak-link-dominated low-field regime are enhanced considerably, and this result is attributed to the reduction of weak links resulting from a reduction in the number of in-plane large-angle grain boundaries.The authors acknowledge the support and encouragement of V. G. Keramidas and P. L. Key. This work was supported by the Electric Power Research Institute (Contract No. RP 7911-13).     

Gate bias polarity dependence of charge trapping and time-dependentdielectric breakdown in nitrided and reoxidized nitrided oxides

The gate bias polarity dependence of charge trapping and time-dependent dielectric breakdown (TDDB) in nitrided and reoxidized nitrided silicon dioxides prepared by rapid thermal processing (RTP) is reported. Charge trapping during high-field injection can be reduced by rapid thermal nitridation for both substrate and gate injection. While reoxidation of nitrided oxides shows further reduction in charge trapping for substrate injection, degradation is observed for gate injection. Similar effects are observed for TDDB: reoxidized nitrided oxides show charge-to-breakdown in excess of 300 C/cm² for substrate injection, but less than 30 C/cm² for gate injection. These effects are related to the nitrogen and hydrogen profiles in the oxides. By tailoring the process conditions, a symmetric behavior of NO and RONO films with low charge trappings and Q _BD in excess of 50 C/cm² is possible, making them attractive as long-lifetime dielectrics from EEPROM (electrically erasable programmable ROM) and flash EEPROM technologies