The use of microorganisms to assay mycotoxins and the eucidation of their mechanisms of action.

A method was developed for monitoring the growth of a range of bacteria and fungi in the Bactometer 32 impedimeter. 195 yeast strains, 74 strains of mould and 20 strains of bacteria were screened for sensitivity to 1 mug ml[-1] of T-2 toxin. Growth inhibition was assessed impedimetrically. Twelve bacteria, 20 moulds and 38 yeast strains were tested against roridin A, verrucarin A, deoxynivalenol, and diacetoxyscirpenol each at 1 mum ml[-1] . Deoxynivalenol was found to be only slightly toxic. Roridin A and verrucarin A were markedly more toxic than the others to the fungi, but not to the bacteria. Four microorganisms (Bacillus subtilis, Candida albicans. Hansenula fabianii and Pichia burtonii)were selected for further study. No obvious pattern of response could be discerned for the effects of different carbohydrates on microbial sensitivity to T-2 toxin. The effects of T-2 toxin on B. subtilis and C. albicans were greater if chloroform rather than dichloromethane and methanol (95:5, v/v) was used as the toxin carrying solvent, the reverse was true for H. fabianii and P. burtonii. Dose-response curves were constructed, based on impedimetric responses, and no-effect levels were determined for each species. For B. subtilis the no-effect level was 0.35 mum ml[-1], for C. albicans it was 0.40 mum ml[-1], for H. fabianii it was 0.012 mum ml[-1] and for P. burtonii it was 0.018 mum ml[-1]. H. fabianii was selected for further studies. This strain was found to be auxotrophic for proline. The effect of T-2 toxin and verrucarin A on the uptake of radiolabelled proline in H. fabianii cultures was studied. Dose-response curves were constructed for each toxin. It was found that both toxins reduced proline uptake in a dose dependent manner, the no-effect levels were 0.025 mum ml[-1] for T-2 toxin and 0.0125 mum ml[-1] for verrucarin A

A New Computational Methodology to Find Appropriate Solutions of Fuzzy Equations

In this paper, a new computational methodology to get an appropriate solution of a fuzzy equation of the form. In support of that some propositions with proofs and theorems are presented. A different approach of the definition of positive fuzzy number and negative fuzzy number have been focused. Also, the concept of half-positive and half-negative fuzzy number has been introduced. The solution of the fuzzy equation can be positive fuzzy number or negative fuzzy number or half positive or half negative fuzzy number which is computed by using the methodology focused in the proposed propositions. Keywords: Fuzzy number, Fuzzy equation, Positive fuzzy number, Negative fuzzy number, half positive and half negative fuzzy number, a fuzzy number

Deformation Induced Phase Transformation of 304L Stainless Steel and its Structural Characterization

This report aims to examine deformation induced phase transformation in 304L stainless steel up on compressive loading at room temperature of 300K. For this, compression tests were carried out using specimens of varying length to diameter ratios. To avoid effects of any friction, teflon tapes were use at the specimen platen interfaces. The results indicate that homogenous deformation takes place up to 15% of total compressive engineering strain. X-ray diffraction and scanning electron microscopic studies indicate that metastable austenite transforms to martensite due to compressive loading. “The volume fraction of martensite increases with increase in percentage of deformation.” Post deformation hardness also increases monotonically. Nature of homogenous deformation also gets reduced due to prevailing friction at the interfaces. In the course of the study, the amounts of particular phase fractions have also been calculated from the integrated intensity of XRD results. The results are then correlated with the extent of deformation in the respective samples and the behavior is compared as-against tensile loading conditions

Parametric optimization for hardness of tig welded duplex stainless steel

Achieving optimal mechanical properties in welding joints hinges on employing precise parametric conditions. This is particularly crucial for Tungsten Inert Gas (TIG) welding of ASTM/UNS 2205 Duplex Stainless Steel (DSS), where attributes like hardness, ultimate tensile strength, and yield strength are paramount. Maintaining high Hardness Value (HV) demands proper welding parameters such as welding current, gas flow rate, and welding speed. To enhance DSS welding quality, especially hardness, this study utilizes the Taguchi method to optimize welding process parameters. The importance of each factor is assessed through Annova statistical analysis. The outcomes highlight the positive impact of parametric optimization on HV, as evidenced by the analysed data. Parametric optimization proves to be a potent approach for refining industrial processes like welding, with particular relevance in TIG welding of duplex stainless steel due to its mechanical robustness and corrosion resistance. Nevertheless, challenges arise due to the material's elevated hardness and low thermal conductivity, resulting in potential defects like cracks and porosity. The identification of optimal welding parameters, encompassing current, voltage, speed, and gas flow rate, helps address these challenges and advances high-quality welds. Through systematic variations and analysis of these parameters, researchers and engineers can pinpoint the optimal combination that mitigates defects while maximizing desired joint attributes. Within the realm of TIG welding of duplex stainless steel, metric optimization holds the potential to elevate welding quality, curtail costs and waste, and heighten productivity and safety. Consequently, organizations can attain enhanced performance, efficiency, and profitability within their welding processe

Tuning intermetallic electronic coupling in polyruthenium systems via molecular architecture

A large number of polynuclear ruthenium complexes encompassing selective combinations of spacer (bridging ligand,BL) and ancillary (AL) functionalities have been designed. The extent of intermetallic electronic communication in mixed-valent states and the efficacy of the ligand frameworks towards the tuning of coupling processes have been scrutinised via structural, spectroelectrochemical, EPR, magnetic and theoretical investigations. Moreover, the sensitive oxidation state features in the complexes of non-innocent quinonoid bridging moieties have also been addressed