Biological Control Of Mycotoxigenic Fungi And Associated Mycotoxins By The Application Of Bacterial And Yeast Antifungal Compounds

Mycotoxins are secondary metabolites of mycotoxigenic fungi and are considered as a serious threaten to the life of humans and animals, since some of these mycotoxins are carcinogenic compounds. In this M.Sc research project, we demonstrated that the low fermenting yeast L. thermotolerans 751 has a great antifungal potential through the synthesis of Volatile Organic Compounds (VOC) that are able to act against the mycotoxigenic fungi and the synthesis of their mycotoxins. L. thermotolerans 751 has also shown a great adsorption potential to mycotoxins in in-vitro experiments. In addition, these VOCs were applied in in-vitro experiments to inhibit the fungal growth and spores’ germination and protection of fungi inoculated tomato fruit, for more than one month. On the other hand, our second biocontrol agent, the Qatari bacterial strain Burkholderia cepacia (QBC03) has shown a broad antifungal spectrum and a very efficient inhibition of the synthesis of mycotoxins.This research work was made possible by the sponsorship of Qatar National Research Foundation; NPRP grant #8-392-4-00

Avoiding the exactness of the Jacobian matrix in Rosenbrock formulae

AbstractA new class of methods, for solving stiff systems, which avoids the exactness of the Jacobian matrix is introduced. The order conditions for methods of order p ⩽ 5 are given. The linear stability properties for such methods are analysed; numerical testing are also included

Modelling fibre-reinforced concrete for predicting optimal mechanical properties

Fibre-reinforced cementitious composites are highly effective for construction due to their enhanced mechanical properties. The selection of fibre material for this reinforcement is always challenging as it is mainly dominated by the properties required at the construction site. Materials like steel and plastic fibres have been rigorously used for their good mechanical properties. Academic researchers have comprehensively discussed the impact and challenges of fibre reinforcement to obtain optimal properties of resultant concrete. However, most of this research concludes its analysis without considering the collective influence of key fibre parameters such as its shape, type, length, and percentage. There is still a need for a model that can consider these key parameters as input, provide the properties of reinforced concrete as output, and facilitate the user to analyse the optimal fibre addition per the construction requirement. Thus, the current work proposes a Khan Khalel model that can predict the desirable compressive and flexural strengths for any given values of key fibre parameters. The accuracy of the numerical model in this study, the flexural strength of SFRC, had the lowest and most significant errors, and the MSE was between 0.121% and 0.926%. Statistical tools are used to develop and validate the model with numerical results. The proposed model is easy to use but predicts compressive and flexural strengths with errors under 6% and 15%, respectively. This error primarily represents the assumption made for the input of fibre material during model development. It is based on the material’s elastic modulus and hence neglects the plastic behaviour of the fibre. A possible modification in the model for considering the plastic behaviour of the fibre will be considered as future work

Identification of early stage and metastatic prostate cancer using electrochemical detection of beta-2-microglobulin in urine samples from patients

Abstract To improve prostate cancer (PCa) diagnosis, it is imperative to identify novel biomarkers and establish effective screening techniques. Here, we introduce electrochemical biosensing of β-2-Microglobulin (β2M) in urine as a potential diagnostic tool for PCa. The immunosensor is composed of a screen-printed graphene electrode coated with anti β2M antibodies. The sensor is capable of detecting the protein directly in urine without any sample pretreatment within 45 min including sample incubation and a lower limit of detection of 204 µg/L. The sensor demonstrated a significant difference in the β2M-creatinine ratio in urine between control and both local- and metastatic PCa (mPCa) (P = 0.0302 and P = 0.0078 respectively), and between local- and mPCa (P = 0.0302). This first example of electrochemical sensing of β2M for the diagnosis of PCa may set the stage for an affordable, on-site screening technique for PCa

Candida albicans and Napkin Dermatitis: Relationship and Lesion Severity Correlation

Introduction: Napkin Dermatitis (ND) is a common problem in infancy that affects almost every child during the early months and years of their lifetime. It is a skin disease that becomes a challenge for both parents and physicians because of its frequency and difficulty in eliminating all of the causative factors in diapered infants. Usually Napkin dermatitis is self-limiting but when associated with Candida albicans (C. albicans) seems to be moderate to severe.Aim: The aim of the present study was to determine the colonization of C. albicans in children with Napkin dermatitis and to correlate between intensity of C. albicans colonization and the severity of napkin rash.Patients and Methods: This case-controlled study was conducted at Qassim University pediatric outpatient clinics, during the period from August 2014 to July 2015. Sixty patients with diaper dermatitis and 33 healthy controls were enrolled to this study. Sociodemographic and clinical data were obtained from the parents of each participant using questionnaires Paired (stool and skin) samples were collected from all cases and healthy control children. The samples were cultured on differential and selective chromogenic medium for isolation and initial identification of candida species. Identification confirmation of the isolates was determined by the Vitek 2 compact automated system.Results: Diaper dermatitis shows significant outcome to washing diaper area (per day) (P=0.001), History of diarrhea last 7 Days (P˂0.001), skin lab results (+/-) for Candida albicans, (P˂0.001), skin colony count, (P˂0.001), However, there is no correlation to age (P=0.828), gender (P=0.368) and feeding style (P=0.401).Conclusion: The severity score of napkin dermatitis was significantly observed among cases with diaper dermatitis (p-value<0.001) and control children (p-value<0.001) respectively.Keywords: Candida albicans; Napkin dermatitis; Diaper dermatitis; Vitek 2 compact system; Qassim

Description of the Magnetic Field and Divergence of Multisolenoid Aharonov-Bohm Potential

Explicit formulas for the magnetic field and divergence of multisolenoid Aharonov-Bohm potential are obtained; the mathematical essence of this potential is explained. It is shown that the magnetic field and divergence of this potential are very singular generalized functions concentrated at a finite number of thin solenoids. Deficiency index is found for the minimal operator generated by the Aharonov-Bohm differential expression

Applications of Rare Earth Metals in Al-Si Cast Alloys

The present article reviews a large number of research publications on the effect of mischmetal (MM), rare earth metals (RE), La or Ce, and combinations of La + Ce on the performance of Al-Si cast alloys mainly 319, 356, 380, 413, and 390 alloys. Most of these articles focused on the use of rare earth metals as a substitute for strontium (Sr) as a eutectic silicon (Si) modifier if added in low percentage ( 1 wt.%) is required to achieve a noticeable reduction in grain size, however at the cost of alloy brittleness

PTCH1+/− Dermal Fibroblasts Isolated from Healthy Skin of Gorlin Syndrome Patients Exhibit Features of Carcinoma Associated Fibroblasts

Gorlin's or nevoid basal cell carcinoma syndrome (NBCCS) causes predisposition to basal cell carcinoma (BCC), the commonest cancer in adult human. Mutations in the tumor suppressor gene PTCH1 are responsible for this autosomal dominant syndrome. In NBCCS patients, as in the general population, ultraviolet exposure is a major risk factor for BCC development. However these patients also develop BCCs in sun-protected areas of the skin, suggesting the existence of other mechanisms for BCC predisposition in NBCCS patients. As increasing evidence supports the idea that the stroma influences carcinoma development, we hypothesized that NBCCS fibroblasts could facilitate BCC occurence of the patients. WT (n = 3) and NBCCS fibroblasts bearing either nonsense (n = 3) or missense (n = 3) PTCH1 mutations were cultured in dermal equivalents made of a collagen matrix and their transcriptomes were compared by whole genome microarray analyses. Strikingly, NBCCS fibroblasts over-expressed mRNAs encoding pro-tumoral factors such as Matrix Metalloproteinases 1 and 3 and tenascin C. They also over-expressed mRNA of pro-proliferative diffusible factors such as fibroblast growth factor 7 and the stromal cell-derived factor 1 alpha, known for its expression in carcinoma associated fibroblasts. These data indicate that the PTCH1+/− genotype of healthy NBCCS fibroblasts results in phenotypic traits highly reminiscent of those of BCC associated fibroblasts, a clue to the yet mysterious proneness to non photo-exposed BCCs in NBCCS patients