Interaction of Salmonella spp. with the Intestinal Microbiota

Salmonella spp. are major cause of human morbidity and mortality worldwide. Upon entry into the human host, Salmonella spp. must overcome the resistance to colonization mediated by the gut microbiota and the innate immune system. They successfully accomplish this by inducing inflammation and mechanisms of innate immune defense. Many models have been developed to study Salmonella spp. interaction with the microbiota that have helped to identify factors necessary to overcome colonization resistance and to mediate disease. Here we review the current state of studies into this important pathogen/microbiota/host interaction in the mammalian gastrointestinal tract

What traits are carried on mobile genetic elements, and why?

Although similar to any other organism, prokaryotes can transfer genes vertically from mother cell to daughter cell, they can also exchange certain genes horizontally. Genes can move within and between genomes at fast rates because of mobile genetic elements (MGEs). Although mobile elements are fundamentally self-interested entities, and thus replicate for their own gain, they frequently carry genes beneficial for their hosts and/or the neighbours of their hosts. Many genes that are carried by mobile elements code for traits that are expressed outside of the cell. Such traits are involved in bacterial sociality, such as the production of public goods, which benefit a cell's neighbours, or the production of bacteriocins, which harm a cell's neighbours. In this study we review the patterns that are emerging in the types of genes carried by mobile elements, and discuss the evolutionary and ecological conditions under which mobile elements evolve to carry their peculiar mix of parasitic, beneficial and cooperative genes

Mutual Optimism as a Rationalist Explanation for War

Blainey (1988) argued that crises are more likely to end in war when two nations disagree about their relative power. Fey and Ramsay (2007) claim that this widely used “mutual optimism” explanation is theoretically incoherent. Their criticism neglects the need to specify a behavioral causal mechanism that links beliefs to the outbreak of war. We show how the rationalist game-theoretic work on the causes of war provides such mechanisms: the risk-return trade-off and costly signaling, and demonstrate that these models are immune to Fey and Ramsay’s critiques. We also show that the class of models Fey and Ramsay propose make the substantively unwarranted assumption that an actor can unilaterally impose peace on an opponent who strictly prefers war. Their finding that war does not occur in equilibrium has nothing to do with mutual optimism. We conclude that the mutual optimism explanation can be grounded on firm rationalist foundations

Experimental Results of the Tribology of Aluminum in the Presence of Polytron Additive

Friction is an ever-present obstacle that causes energy loss in mechanical parts. To alleviate this nuisance, we carried out experimental studies on a brand new additive called Polytron to assess its role in the minimization of friction and wear. The wear, the volume wear rate, the wear coefficient, and the coefficient of friction of the aluminum surface were measured at room temperature with pin-on-disk tribometer without and with 10% Polytron in Helix oil. In the base oil Helix, their values were found to be 70 μm, 1.28×10−3mm3/min, 1.27×10−10m2/N, and 0.012, respectively, which with the incorporation of Polytron additive in the Helix oil correspondingly reduced to 20μm, 6.08×10−5mm3/min, 4.22×10−11m2N, and 0.004. The experimental verdict points to an ionic character of the additive in that it impregnates the crystal structure of the metal, thereby prompting a hard surface layer which subsequently curtails wear and friction

Reliability based Topological Optimization of Computer Networks - Part II: Iterative Techniques

Topological optimization of computer networks is concerned with the design of a network by selecting a subset of the available set of links such that the fault tolerance and reliability aspects are maximized while a cost constraint is met. A number of enumerative and iterative based techniques were proposed to solve this problem. In this paper (Part II), we present and compare the different proposed iterative techniques for optimizing different aspects (reliability, fault tolerance, and cost) of the designed networks

Bullying of medical students in Pakistan: a cross-sectional questionnaire survey.

Background: Several studies from other countries have shown that bullying, harassment, abuse or belittlement are a regular phenomenon faced not only by medical students, but also junior doctors, doctors undertaking research and other healthcare professionals. While research has been carried out on bullying experienced by psychiatrists and psychiatry trainees in Pakistan no such research has been conducted on medical students in this country. Methodology/Principal Findings: We conducted a cross-sectional questionnaire survey on final year medical students in six medical colleges of Pakistan. The response rate was 63%. Fifty-two percent of respondents reported that they had faced bullying or harassment during their medical education, about 28% of them experiencing it once a month or even more frequently. The overwhelming form of bullying had been verbal abuse (57%), while consultants were the most frequent (46%) perpetrators. Students who were slightly older, males, those who reported that their medical college did not have a policy on bullying or harassment, and those who felt that adequate support was not in place at their medical college for bullied individuals, were significantly more likely to have experienced bullying. Conclusion: Bullying or harassment is faced by quite a large proportion of medical students in Pakistan. The most frequent perpetrators of this bullying are consultants. Adoption of a policy against bullying and harassment by medical colleges, and providing avenues of support for students who have been bullied may help reduce this phenomenon, as the presence of these two was associated with decreased likelihood of students reporting having being bullied

Reliability based Topological Optimization of Computer Networks - Part II: Iterative Techniques

Topological optimization of computer networks is concerned with the design of a network by selecting a subset of the available set of links such that the fault tolerance and reliability aspects are maximized while a cost constraint is met. A number of enumerative and iterative based techniques were proposed to solve this problem. In this paper (Part II), we present and compare the different proposed iterative techniques for optimizing different aspects (reliability, fault tolerance, and cost) of the designed networks

An audit of secondary peritonitis at a tertiary care university hospital of Sindh, Pakistan

OBJECTIVE: Peritonitis is the most common life threatening surgical emergency, which requires urgent surgical intervention and is a significant cause of morbidity and mortality. The objective of this study was to highlight the frequency of secondary peritonitis and to analyze the site and causes of perforation, in our tertiary care setup. METHODS: A retrospective analysis of 311 patients of secondary peritonitis was done from July 2008 to June 2010 at Liaquat University Hospital Jamshoro, Hyderabad, Sindh, Pakistan. All cases found to have peritonitis as a result of perforation of any part of gastrointestinal tract at the time of surgery were included in the study. All cases with either primary peritonitis or that due to anastomotic dehiscence were excluded. RESULTS: A total of 311 patients were studied. Most of the patients were males (77%) and (89%) were in the third and fourth decades of life. Majority of the patients presented with pain (97%) associated with bowel symptoms. Most common site of perforation was small bowel (ileal 59%, jujenal 2%). In this series, most common risk factor of perforation was typhoid (43%). Ileostomy was the most commonly performed procedure. Overall morbidity was 48.5% and mortality was 17%. CONCLUSION: Considering the relatively higher rate of typhoid perforation quoted in this study, it is vital that typhoid fever ought to be eliminated by improved sanitation and immunizing programmes, otherwise surgeons will be confronted with its complications

Association between antipsychotics and weight gain among psychiatric outpatients in Pakistan: a retrospective cohort study

<p>Abstract</p> <p>Background</p> <p>It has been known for a long time that use of antipsychotics, particularly atypical antipsychotics, is associated with weight gain and increase in risk of metabolic disturbances. In this study we have tried to find out if use of antipsychotics is associated with increase in weight and body mass index (BMI) in the Pakistani population.</p> <p>Methods</p> <p>We performed a case note review of all patients who had been prescribed antipsychotic medication at the psychiatry outpatient clinic of a tertiary care university hospital in Pakistan over a 4-year period.</p> <p>Results</p> <p>A total of 50% of patients had a BMI in the overweight or higher range at baseline. Patients showed a mean weight gain of 1.88 kg from baseline in 3 months and 3.29 kg in 6 months. Both of these values were statistically significant. The increase in mean BMI from baseline was 0.74 and 1.3 in 3 months and 6 months, respectively. In patients for whom we had at least one further weight measurement after baseline, 48% (39/81) showed a clinically significant weight gain.</p> <p>Conclusion</p> <p>Pakistani patients are just as likely to put on weight during antipsychotic treatment as patients from other countries. Considering that this population already has a much higher prevalence of diabetes mellitus compared to the Western countries, the consequences of increased weight may be even more serious in terms of increased morbidity and mortality.</p