A SOFTWARE SENSOR FOR IN-SITU MONITORING OF THE 5-DAY BIOCHEMICAL OXYGEN DEMAND

Prikazana su dva senzora temeljena na tehnikama umjetne inteligencije. Namijenjeni su opažanju tijekom petodnevnoga, tj. vremenski zahtjevnoga, postupka određivanja biokemijske potrošnje kisika (BPK5). Vrijednost se tako može, nakon mjerenja, izračunati gotovo trenutačno. Upotrijebljene su mreža usmjerene vrste i mreža temeljena na radijalnoj funkciji (skr. UUNM, RFUNM), kojima se odredila najveća vrijednost te potrošnje (BPK5(maks)). To je funkcija srednje, najveće i najmanje vrijednosti otopljenoga kisika (OKsred, OKnajveći, OKnajmanji). Mjerenje je načinjeno u rijeci Sefidrood. Nadalje, mreža je optimizirana primjenom Levenberg-Marquardtova (LM), elastičnoga, povratnoga (EP) i algoritma skaliranoga, konjugiranoga gradijenta (SKG). Rezultati su pokazali kako je za uvježbavanje i provjeru najbolji Levenberg-Marquadtov algoritam. Također, svaka je mreža ocijenjena uporabom srednje kvadratne pogrješke, koeficijentom korelacije te omjerom odstupanja. Rezultati su pokazali kako su obje mreže, usmjerena i radijalna, postigle približno jednake rezultate.Due to the time-consuming procedure for determining the 5-day biochemical oxygen demand (BOD5), the present study developed two software sensors based on artificial intelligence techniques to estimate this indicator instantaneously. For this purpose, feed-forward and radial basis function neural networks (FFANN and RBFANN, respectively) were tuned to estimate the maximum values of BOD5 (BOD5(max)) as a function of average, maximum and minimum dissolved oxygen in the Sefidrood River. Also, Levenberg-Marquardt (LM), resilient back propagation (RP), and scaled conjugate gradient (SCG) algorithms were used to optimize the FFANN parameters. The results demonstrated that the performance of LM algorithm in tuning the FFANN was better than others, in verification step. Besides, the performance of both FFANN and RBFANN models for prediction of the BOD5(max) was approximately the same

Global gene-expression analysis of the response of Salmonella Enteritidis to egg-white exposure reveals multiple egg-white-imposed stress responses

Chicken egg white protects the embryo from bacterial invaders by presenting an assortment of antagonistic activities that combine together to both kill and inhibit growth. The key features of the egg-white anti-bacterial system are iron restriction, high pH, antibacterial peptides and proteins, and viscosity. Salmonella enterica serovar Enteritidis is the major pathogen responsible for egg-borne infection in humans, which is partly explained by its exceptional capacity for survival under the harsh conditions encountered within egg white. However, at temperatures up to 42 ˚C, egg white exerts a much stronger bactericidal effect on S. Enteritidis than at lower tempertaures, although the mechanism of egg-white-induced killing is only partly understood. Here, for the first time, the impact of exposure of S. Enteritidis to egg white under bactericidal conditions (45 ˚C) is explored by global-expression analysis. A large-scale (18.7% of genome) shift in transcription is revealed suggesting major changes in specific aspects of S. Enteritidis physiology: induction of egg-white related stress-responses (envelope damage, exposure to heat and alkalinity, and translation shutdown); shift in energy metabolism from respiration to fermentation; and enhanced micronutrient provision (due to iron and biotin restriction). Little evidence of DNA damage or redox stress was obtained. Instead, data are consistent with envelope damage resulting in cell death by lysis. A surprise was the high degree of induction of hexonate/hexuronate utilisation genes, despite no evidence indicating the presence of these substrates in egg white

Egg-white proteins have a minor impact on the bactericidal action of egg white toward Salmonella Enteritidis at 45°C

Salmonella enterica serovar Enteritidis is noted for its ability to survive the harsh antibacterial activity of egg white which is presumed to explain its occurrence as the major food-borne pathogen associated with the consumption of eggs and egg products. Liquid egg white is a major ingredient for the food industry but, because of its thermal fragility, pasteurization is performed at the modest temperature of 57 °C (for 2 to 6 min). Unfortunately, such treatment does not lead to sufficient reduction in S. Enteritidis contamination, which is a clear health concern when the product is consumed without cooking. However, egg white is able to limit S. Enteritidis growth due to its alkaline pH, iron deficiency and multiple antimicrobial proteins. This anti-Salmonella activity of egg white is temperature dependent and becomes bactericidal once the incubation temperature exceeds 42°C. This property is exploited in highly-promising pasteurization treatment (42-45 °C for 1 to 5 days) which achieves complete killing of S. Enteritidis. However, the precise mechanism and the role of the egg-white proteins are not fully understood. Here, the impact of exposure of S. Enteritidis to egg white-based media, with or without egg-white proteins (>10 kDa), under bactericidal conditions (45 °C) was explored by measuring survival and global expression. Surprisingly, the bactericidal activity of egg white at 45 °C was only slightly affected by egg-white proteins indicating that they play a minor role in the bactericidal activity observed. Moreover, egg-white proteins had minimal impact on the global-gene-expression response to egg white such that very similar, major regulatory responses (20% genes affected) were observed both with and without egg-white proteins following 45 min at 45°C. Egg-white proteins caused a significant change in expression for just 64 genes, including the psp and lysozyme-inhibitor responses genes which is suggestive of an early membrane perturbation effect. Such damage was supported by disruption of the proton motive force by egg-white proteins. In summary, the results suggest that low-mass components of egg white are largely responsible for the bactericidal activity of egg white at 45 °C

Egg white versus Salmonella Enteritidis! A harsh medium meets a resilient pathogen

Salmonella enterica serovar Enteritidis is the prevalent egg-product-related food-borne pathogen. The egg-contamination capacity of S. Enteritidis includes its exceptional survival capability within the harsh conditions provided by egg white. Egg white proteins, such as lysozyme and ovotransferrin, are well known to play important roles in defence against bacterial invaders. Indeed, several additional minor proteins and peptides have recently been found to play known or potential roles in protection against bacterial contamination. However, although such antibacterial proteins are well studied, little is known about their efficacy under the environmental conditions prevalent in egg white. Thus, the influence of factors such as temperature, alkalinity, nutrient restriction, viscosity and cooperative interactions on the activities of antibacterial proteins in egg white remains unclear. This review critically assesses the available evidence on the antimicrobial components of egg white. In addition, mechanisms employed by S. Enteritidis to resist egg white exposure are also considered along with various genetic studies that have shed light upon egg white resistance systems. We also consider how multiple, antibacterial proteins operate in association with specific environmental factors within egg white to generate a lethal protective cocktail that preserves sterility

دراسة تأثير الحقن بمعلَّق غبار أفران الإسمنت (CKD) على مقاومة التربة الرملية الساحلية للضغط الحر

إنَّ تقنية الحقن من أحدث التقنيات المستخدمة لتحسين ترب التأسيس، وهي تُصنّف في عدة أنماط، حيث يُعتبر نوع التربة هو العامل الأهم في اختيار نمط الحقن. يُستعمل الحقن التغلغلي ((Permeation Grouting عموماً، لتحسين الخصائص الهندسية للترب الحبيبية، ويتم بضخ مادة الحقن بشكل سائل إلى تربة التأسيس تحت تأثير الضغط، فتتغلغل في فراغاتها ثم تتصلب مشكّلةً مادة تربط بين حبيبات التربة، فتتحسن خصائص التربة المعالجة بالحقن بدون تغيير بنيتها الطبيعية، وهو النمط المتبع في هذا البحث. يهدف البحث إلى دراسة تأثير الحقن Permeation Grouting)) بمعلَّق غبار أفران الإسمنت (CKD) على مقاومة الضغط الحر (الغير محصور) للتربة الرملية في المنطقة الساحلية في سوريا، ولتحقيق ذلك تم تصميم وتصنيع نموذج حقن مخبري، من ثم تم حقن عينات التربة بمعلَّق مكوَّن من نسب مئوية مختلفة من (CKD) وهي (2, 4, 6, 8, 10,12) % من الوزن الجاف للتربة المعالجة، ونسب خلط (ماء: غبار إسمنت) وهي {W:CKD= (2:1, 4:1, 6:1, 8:1, 10:1)} من ثم تم اجراء تجارب الضغط البسيط على العينات المحقونة من أجل مدتي معالجة (7) و(28) يوم.   بيَّنت النتائج أن التربة الرملية المعالجة بالحقن بغبار أفران الإسمنت قد اكتسبت مقاومة عالية على الضغط الحر، وأن قيم مقاومة الضغط الحر  وقيم معامل المرونة المماسي الابتدائي  ازدادت بشكل ملحوظ بازدياد نسبة (CKD)% في معلَّق الحقن وبازدياد مدة المعالجة، بينما نقصت تلك القيم بازدياد نسبة (W:CKD) في معلَّق الحقن، كما بيّنت أن المعامل  ازداد بازدياد  وأن العلاقة بينهما خطية

دراسة عددية لظاهرة التسيل في الترب الرملية المفككة المشبعة تحت تأثير الزلازل باستخدام برنامج FLAC3D

توضّح هذه الدراسة كيفية التنبؤ بقابلية الترب المفككة المشبعة للتسيل  من خلال حساب ضغط الماء المسامي المتولد عن الزلزال والاجهادات الفعالة ومقارنة هذه الاجهادات مع قيم ضغط الماء المسامي حيث أن التربة تتسيل عندما يصبح ضغط الماء المسامي مساوٍ لقيمة الإجهاد الفعال أو أكبر منه وعندما تنعدم الإجهادات الفعالة تكون التربة قد تسيلت بشكل تام وفقدت مقاومتها على القص. تتضمن الدراسة إجراء دراسة بارامترية للعوامل المؤثرة على التسيل(خواص التربة والزلزال) باستخدام برنامج FLAC3D ، وتمت مناقشة وتحليل النتائج التي تم الوصول اليها ووضع بعض الاستنتاجات والتوصيات الهامة

Use of pulsed-field gel electrophoresis for the discrimination of Bacillus cereus group isolates in liquid egg products collected in french egg breaking companies

Bacteria belonging to the Bacillus cereus group are commonly found in soil, air, dust, water and in many raw and processed foods. Several strains of this group have been implicated in food-borne illness. These bacteria are also prolific enzyme producers (lipases, proteases) and are recognised as causing spoilage in several pasteurised foodstuffs. Some strains exhibit psychrotrophic properties, causing an increasing problem during refrigerated storage and distribution of perishable food products. The monitoring and control of these bacteria are then of high importance for the egg breaking industry. For a better understanding of their diversity and ecological distribution, successful molecular typing methods are needed.Among the methods described for the typing of B. cereus group strains, the pulsed-field gel electrophoresis (PFGE) has already been carried out in order to build B. cereus genetic maps, to show the genomic diversity among B. cereus and B. thuringiensis, to discriminate B. anthracis from B. cereus and B. thuringiensis, and for several epidemiologic investigations.The aim of the present study was to discriminate, by a PFGE method adapted in our laboratory from the work of Gautier et al. (1996), a collection of psychrotrophic bacteria belonging to the B. cereus group collected in 6 egg breaking companies during a period covering a warm and a cold season

Global Gene-expression Analysis of the Response of Salmonella Enteritidis to Egg White Exposure Reveals Multiple Egg White-imposed Stress Responses

Chicken egg white protects the embryo from bacterial invaders by presenting an assortment of antagonistic activities that combine together to both kill and inhibit growth. The key features of the egg white anti-bacterial system are iron restriction, high pH, antibacterial peptides and proteins, and viscosity. Salmonella enterica serovar Enteritidis is the major pathogen responsible for egg-borne infection in humans, which is partly explained by its exceptional capacity for survival under the harsh conditions encountered within egg white. However, at temperatures up to 42°C, egg white exerts a much stronger bactericidal effect on S. Enteritidis than at lower temperatures, although the mechanism of egg white-induced killing is only partly understood. Here, for the first time, the impact of exposure of S. Enteritidis to egg white under bactericidal conditions (45°C) is explored by global-expression analysis. A large-scale (18.7% of genome) shift in transcription is revealed suggesting major changes in specific aspects of S. Enteritidis physiology: induction of egg white related stress-responses (envelope damage, exposure to heat and alkalinity, and translation shutdown); shift in energy metabolism from respiration to fermentation; and enhanced micronutrient provision (due to iron and biotin restriction). Little evidence of DNA damage or redox stress was obtained. Instead, data are consistent with envelope damage resulting in cell death by lysis. A surprise was the high degree of induction of hexonate/hexuronate utilization genes, despite no evidence indicating the presence of these substrates in egg white

Environmental conditions and molecular fractions involved in the antimicrobial activity of egg white against S. Enteritidis

In Europe, the species Salmonella enterica, particularly the serovar S. Enteritidis, represents the major human pathogen related to egg consumption. Consequently, it is mainly used as a model in most studies interested in the antimicrobial activity of egg white. In order to explain this antimicrobial activity, the main hypotheses are, on the one hand, the involvement of antimicrobial egg white proteins (ovotransferrin, lysozyme…), and, on the other hand, physicochemical factors such as alkaline pH, and viscous and heterogeneous structure. However, data are conflicting in the literature, and it is difficult to compare the studies because of the use of various strains, various inoculum sizes, various incubation times and temperatures and eggs with varying freshness.Hence, we have investigated the incubation conditions enhancing the antimicrobial activity of egg white against S. Enteritidis by carrying a complete factorial design analysis comprising 180 experimental conditions. Three different media were chosen in order to evaluate the effect of the macromolecular fraction of egg white: whole egg white, egg white filtrate, and egg white filtrate supplemented with 10 % egg white. The other tested factors were the temperature (37°C to 48°C), pH (9.3 versus 7.8) and initial inoculum size (3 to 8 log cfu.mL-1). This study clearly identified the temperature and the presence of macromolecules as the main factors involved in the bactericidal activity of egg white against S. Enteritidis