Prevalence of Listeria species in some foods and their rapid identification

Purpose: To investigate the occurrence of Listeria spp., (particularly L. monocytogenes), in different foods and to compare diagnostic tools for their identification at species level.Methods: Samples of high protein foods such as raw meats and meat products and including beef products, chicken, fish and camel milk were analysed for the presence of Listeria spp. The isolates were characterised by morphological and cultural analyses, and confirmed isolates were identified by protein profiling and verified using API Listeria system. Protein profiling by SDS-PAGE was also used to identify Listeria spp.Results: Out of 40 meat samples, 14 (35 %) samples were contaminated with Listeria spp., with the highest incidence (50 %) occurring in raw beef products and raw chicken. Protein profiling by SDSPAGE was used to identify Listeria spp. The results were verified with API Listeria system. Approximately 25 % of the identified isolates were Listeria seeligeri, Listeria welshimeri, and Listeria grayi (three positive samples), while 16.66 % of the isolates were Listeria monocytogenes (two positive samples); 16.6 % of the isolates were Listeria innocua (two positive samples), while 8.3 % of the isolates were Listeria ivanovii (one positive sample).Conclusion: High protein foods contain different types of Listeria species; whole-cell protein profiles and API Listeria system can help in the identification of Listeria at the species level.Keywords: Listeria spp, High protein food, Api Listeria, Protein profil

CLEAN RINGS OF SKEW HURWITZ SERIES

In this paper we study the transfer of some algebraic properties from the ring R to the ring of skew Hurwitz series T = (H R, σ ) where σ  is an automorphism of R and vice versa. We show that T = (H R, σ ) is a clean (strongly clean) ring if and only if R is clean (strongly clean). Different properties of skew Hurwitz series are studied such as simplicity, primeness and semiprime.In this paper we study the transfer of some algebraic properties from the ring R to the ring of skew Hurwitz series T = (HR,σ) where σ is anautomorphism of R and vice versa. We show that T = (HR,σ) is a clean(strongly clean) ring if and only if R is clean (strongly clean). Different properties of skew Hurwitz series are studied such as simplicity, primeness and semiprime

Proportional Hazard Bivariate Kumaraswamy Model Applied on Fish Mercury Concentration

International advisory bodies have developed guidelines for testing mercury and aquatic items to protect human health and international trade. The mercury absorption in fish has a great effect on human health. For modeling this problem, a new bivariate distribution using the proportional hazard rate (PHR) model with Kumaraswamy marginal called BKPH is derived and studied via statistical properties and reliability measures. Moreover, several methods of parameter estimation are discussed, including maximum likelihood estimation (MLE), method of moments estimation (MME), and inference function for margins estimation (IFM). In the simulation study, the performance of estimators depending on their estimation methodologies is compared. Finally, a comparative study of the proposed BKPH with several bivariate Kumaraswamy distributions via goodness of fit criteria was introduced. The results of the study proved the potentiality of the BKPH model and has a best fitting on mercury fish absorption data

3,7-Dinitro-1,3,5,7-Tetraazabicyclo[3,3,1]Nonane (DPT): An Important Intermediate in the Synthesis Route of one of the Most Powerful Energetic Materials (RDX/HMX)

Synthesis of Cyclotetramethylene Tetramine through the action of nitrating mixture formed of ammonium nitrate and fuming nitric acid on hexamine in presence of acetic acid, acetic anhydride and p-formaldehyde has been proven. The pathway is relatively long and Hexamine Dinitrate and Dinitro Pentamethylene Tetramine (DPT) are two of the main intermediate compounds. The former was prepared, purified, and then characterized. Conversion of this compound into the latter has been followed up experimentally. Herein, we report the Preparation of Dinitro Pentamethylene Tetramine (DPT) from Hexamine Dinitrate - as an alternative synthetic route - which is an important intermediate appears through preparation of DPT from Hexamine directly. DPT was prepared at different temperatures. The variation of some factors like: temperature and time has been investigated. The obtained results were reliable and consistent with the literature. The conversion of Hexamine Dinitrate to HMX as another synthetic route was not fully studied from the point of view of kinetics. In this paper, it is intended to study the effect of time and temperature on the conversion rate of hexamine dinitrate to DPT. This scientific approach is considered as a bridge through which we aim to initiate a complete kinetic study of an important intermediate in the synthesis route of one of the most powerful energetic materials. Index Terms: Energetic materials, Hexamine, DPT, Hexamine dinitrate, Preparation, Characterization, Analysis techniques, Synthesis, Nitramines, RDX, HMX

Follow-up And Kinetic Model Selection Of Dinitro Pentamethylene Tetramine (DPT)

The Synthetic route of Cyclotetramethylene Tetramine is implemented through the reaction of hexamine and nitrating mixture that is formed as a result of a reaction between ammonium nitrate and fuming nitric acid. The reaction medium includes acetic acid, acetic anhydride and p-formaldehyde. This synthetic pathway is relatively long and both of hexamine dinitrate and Dinitro Pentamethylene Tetramine (DPT) are considered as the two main intermediate compounds. The former compound (hexamine dinitrate) was prepared, purified, and then characterized. Conversion of hexamine dinitrate into DPT has been followed up experimentally at different temperatures. Various factors including temperature and time has been investigated. The obtained results were reliable and consistent with the literature. Different kinetic models have been tested. The unreacted core model proved to be applicable, and the surface reaction was found to be controlling

The Lateral Distortional Buckling of I-Plate Girders

This paper presents a numerical study for lateral distortional buckling of I-plate girders (LDBIPGs) by using the general-purpose finite element package ABAQUS (version 6.13) software. 3-D finite element (FE) models for simply supported IPGs subjected to two cases of loading are built. The first case of loading was uniform end moment that was introduced by a couple of forces applied at the top and bottom flanges of the IPGs. The second case of loading was a concentrated load at the shear center in the mid-span. First, shell finite element models are validated by comparing the FE critical bending moment (������,����) by the critical bending moment in EC3 code (������,��,������). The results indicate that the ������,���� was in good agreement with ������,��,������. Secondly, a preliminary analysis is conducted to the relative girder slenderness (��) where the LDB too place. Finally, a parametric study is carried out on simply supported IPGs regarding to the span length, the flange cross-section dimensions and the thickness of the web. The results showed that increasing the length of girders decreases ������.���� and increase in the bending coefficient factor (����). Also, decreasing in the web plate slenderness ratio (��������⁄) works on increasing in ������.���� values and ����. The results also showed that the increasing in the thickness of flange increases ������.���� and increase the value of ���� with small value. As a result of parametric study, the mean value and standard deviation of ���� for LDB mode are 1.16 and 0.08 respectively for �� limits (90:130). For �� limits (131:175), the mean value and standard deviation of ���� are 1.27 and 0.03 respectively. As for �� limits (176:221), the mean value and standard deviation of ���� are 1.32 and 0.02 respectively

Analysing greenhouse ventilation using Computational Fluid Dynamics (CFD)

This is the author accepted manuscript. The final version is available from UKACM via the link in this recordGreenhouses (GH) are used to shield the crops from excessive cold or heat. They are used for growing certain types of cultivations during the year round. The aim of this study is to design a greenhouse using solar-powered technology to produce a Zero-Liquid-Discharge (ZLD) by using Solar Stills and adding condensers to dehumidify the excess vapoured water. This allows to have small-scale plants to reduce the cost of water treatment while increasing its sustainability. Computational fluid dynamics was used to find the best locations for the dehumidifiers in the GH and design the necessary ventilation. This can help to plan ahead and evaluate the optimal amount of produced water for different sizes of greenhouse before they are constructed physically.British Council - EgyptScience & Technology Development Fund (STDF), Egyp