Genome Degradation in Brucella ovis Corresponds with Narrowing of Its Host Range and Tissue Tropism

Brucella ovis is a veterinary pathogen associated with epididymitis in sheep. Despite its genetic similarity to the zoonotic pathogens B. abortus, B. melitensis and B. suis, B. ovis does not cause zoonotic disease. Genomic analysis of the type strain ATCC25840 revealed a high percentage of pseudogenes and increased numbers of transposable elements compared to the zoonotic Brucella species, suggesting that genome degradation has occurred concomitant with narrowing of the host range of B. ovis. The absence of genomic island 2, encoding functions required for lipopolysaccharide biosynthesis, as well as inactivation of genes encoding urease, nutrient uptake and utilization, and outer membrane proteins may be factors contributing to the avirulence of B. ovis for humans. A 26.5 kb region of B. ovis ATCC25840 Chromosome II was absent from all the sequenced human pathogenic Brucella genomes, but was present in all of 17 B. ovis isolates tested and in three B. ceti isolates, suggesting that this DNA region may be of use for differentiating B. ovis from other Brucella spp. This is the first genomic analysis of a non-zoonotic Brucella species. The results suggest that inactivation of genes involved in nutrient acquisition and utilization, cell envelope structure and urease may have played a role in narrowing of the tissue tropism and host range of B. ovis

Candida glabrata : a review of its features and resistance

Candida species belong to the normal microbiota of the oral cavity and gastrointestinal and vaginal tracts, and are responsible for several clinical manifestations, from mucocutaneous overgrowth to bloodstream infections. Once believed to be non-pathogenic, Candida glabrata was rapidly blamable for many human diseases. Year after year, these pathological circumstances are more recurrent and problematic to treat, especially when patients reveal any level of immunosuppression. These difficulties arise from the capacity of C. glabrata to form biofilms and also from its high resistance to traditional antifungal therapies. Thus, this review intends to present an excerpt of the biology, epidemiology, and pathology of C. glabrata, and detail an approach to its resistance mechanisms based on studies carried out up to the present.The authors are grateful to strategic project PTDC/SAU-MIC/119069/2010 for the financial support to the research center and for Celia F. Rodrigues' grant

Marine Tar Residues: a Review

Abstract Marine tar residues originate from natural and anthropogenic oil releases into the ocean environment and are formed after liquid petroleum is transformed by weathering, sedimentation, and other processes. Tar balls, tar mats, and tar patties are common examples of marine tar residues and can range in size from millimeters in diameter (tar balls) to several meters in length and width (tar mats). These residues can remain in the ocean envi-ronment indefinitely, decomposing or becoming buried in the sea floor. However, in many cases, they are transported ashore via currents and waves where they pose a concern to coastal recreation activities, the seafood industry and may have negative effects on wildlife. This review summarizes the current state of knowledge on marine tar residue formation, transport, degradation, and distribution. Methods of detection and removal of marine tar residues and their possible ecological effects are discussed, in addition to topics of marine tar research that warrant further investigation. Emphasis is placed on ben-thic tar residues, with a focus on the remnants of the Deepwater Horizon oil spill in particular, which are still affecting the northern Gulf of Mexico shores years after the leaking submarine well was capped

Measuring the economic costs of traffic congestion

The main concern of this research is to examines traffic congestion costs related with the road passenger transportation. With the rapid urbanization, it is evident that commercial and socio economic activity tending to centralize only in few major cities in a country. This has led to increase in the number of the commuters daily traveling to the cities. Also the economy grows and real income of household & vehicle population also increasing. Those things are creating a major issue of congestion, especially within urban cities. Road traffic congestion interrupts and reduces productivity level and it is a symbol of economic depression. This research presents the complete methodological process from data collection to analysis of main two cost factors of road traffic congestion. Those cost factors are workforce productivity time loss & excess fuel energy consumption/ operating cost. The most important aspect of this study is that it provides a measure of the real monetary cost of congestion to local or regional economies

Life evaluation of critical members of steel bridges located in different atmospheres

Abstract: Most of the iron and steel bridges in Sri Lanka are more than 100 years old. Since many of them are reaching or exceeding their design lives, the risk of collapsing those bridges have increased. One of the probable damages which bridges experience due to increasing traffic volume as well as environmental degradations such as corrosion is the corrosion fatigue failure. This problem is severe in bridges located in industrial areas and along the coastal line of the country. Corrosion and corrosion fatigue made a huge attention in the recent past due to many failures of bridges all over the world. This paper presents a study conducted on assessing the corrosion fatigue damage of steel bridges. It proposes a procedure developed using existing fatigue and corrosion models for evaluating the remaining fatigue life. The procedure includes condition surveys, field loading tests, finite element modelling and analysis, developing S-N curves for different atmospheric conditions, use of corrosion rates and assessing cumulative fatigue damage. The paper also presents a case study: a century old iron and steel (mild steel and wrought iron) railway truss bridge damaged by both corrosion and fatigue. Using details of condition survey, load testing, appropriate corrosion data, finite element modelling and a corrosion fatigue assessment procedure, the remaining life of the bridge was evaluated for two atmospheric conditions; (i) corrosive atmosphere and (ii) noncorrosive atmosphere. The results of the evaluation were then compared to show the impact of the atmospheric condition on the fatigue life of the bridge

Application of meta-modeling based finite element solution conversion method to develop smart initial guess of conjugate gradient method for solid element simulation

Smart initial guess of Conjugate Gradient (CG) method for solid finite element simulation is developed by using the meta-modeling based finite element solution conversion method. The key feature of this solution conversion method is the rigorousness; the meta-modeling ensures that the most appropriate structural or solid element solution is the one that is close to the solid or structural element solution, respectively, since an error between structural and solid element solutions is accurately defined in a solution space of continuum mechanics. The initial guess of CG method of this study is developed by using an approximate solid element solution which is converted from a relevant structural element solution. Two numerical examples; a cantilever beam and frame problems, of the proposed CG method are presented. The results show that the computational cost is significantly reduced in the proposed CG method as compared to the ordinary CG method. There is an expectation that this reduction of computational cost of solid element simulation will become more significant with the size of the problem targeted

S-N curve for riveted details in corrosive environment and its application to a bridge

A formula for stress‐life curve is proposed to predict the fatigue life of riveted bridges located in corrosive environments. The corrosive environment‐dependent parameters of the S‐N curve are determined based on the corrosion fatigue testing results of different types of steel specimens in air, fresh water, and seawater. Eurocode detail category 71 and UK WI‐rivet detail category represent the fatigue strength of riveted members. The proposed S‐N curve formula is compared with full‐scale fatigue test results of riveted joints, plate girders, and truss girders, which were tested in a corrosive environment. Thus, the validity of the formula is confirmed. The formula does not require any material parameter other than the code‐given fatigue curve of riveted details. The fatigue life of a riveted railway bridge is estimated by using the proposed formula, and the results are compared with conventional approaches. The applicability and significance of the proposed curve are confirmed.publishedVersio