Chest Pain and Costochondritis Associated with Vitamin D Deficiency: A Report of Two Cases

Vitamin D is integral for bone health, and severe deficiency can cause rickets in children and osteomalacia in adults. Although osteomalacia can cause severe generalized bone pain, there are only a few case reports of chest pain associated with vitamin D deficiency. We describe 2 patients with chest pain that were initially worked up for cardiac etiologies but were eventually diagnosed with costochondritis and vitamin D deficiency. Vitamin D deficiency is known to cause hypertrophic costochondral junctions in children (“rachitic rosaries”) and sternal pain with adults diagnosed with osteomalacia. We propose that vitamin D deficiency may be related to the chest pain associated with costochondritis. In patients diagnosed with costochondritis, physicians should consider testing and treating for vitamin D deficiency

Technology assessment of biomass ethanol : a multi-objective, life cycle approach under uncertainty

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 2006.Includes bibliographical references (p. 210-219).A methodology is presented for assessing the current and future utilization of agricultural crops as feedstocks for the production of transportation fuels, specifically, the use of corn grain and stover for ethanol production. The generic methodology integrates chemical process design and decision analysis tools. Four primary concepts are incorporated to address the performance of technologies and policies: 1) expansion of the system boundaries to include the entire process life cycle, 2) incorporation of both economic and environmental metrics for multi-objective optimization with tradeoff analysis using Pareto curves, 3) explicit incorporation of uncertainty analysis using Bayesian updating, and 4) integration of multiple feedstocks, processes, and products, in a network optimization framework, with subsequent decomposition to more refined models, for an improvement assessment of specific research and development goals. The first step is an assessment of the emerging corn grain ethanol industry in the U.S. Using life cycle assessment with Bayesian uncertainty propagation, the net energy balance of corn grain ethanol production is calculated and shown to be slightly positive.(cont.) The variability in the system suggests that this variance is dependent primarily on corn production location, distribution requirements, and ethanol conversion and purification efficiency lead to the significant variance. From an economic performance, an optimized facility can produce ethanol competitively with gasoline at $55/barrel, on an unsubsidized and energy equivalent basis. The life cycle greenhouse gas emissions decrease of - 5% - 30% between gasoline and ethanol on a miles driven basis. A potential modification to the process is the use of an alternative feedstock, such as lignocellulosic waste and residues, which have larger resource availability and lower economic cost. Compared to the original case, cellulosic ethanol would have a higher net energy ratio with lower greenhouse gas emissions, but the current projected economic costs are prohibitive. An improvement analysis of potential technology advancements using multiple object network optimization across the entire supply chain suggests that research and development should focus on feedstock logistics and the pretreatment stage.by Jeremy C. Johnson.Ph.D

A Framework to Manage the Complex Organisation of Collaborating: Its Application to Autonomous Systems

In this paper we present an analysis of the complexities of large group collaboration and its application to develop detailed requirements for collaboration schema for Autonomous Systems (AS). These requirements flow from our development of a framework for collaboration that provides a basis for designing, supporting and managing complex collaborative systems that can be applied and tested in various real world settings. We present the concepts of "collaborative flow" and "working as one" as descriptive expressions of what good collaborative teamwork can be in such scenarios. The paper considers the application of the framework within different scenarios and discuses the utility of the framework in modelling and supporting collaboration in complex organisational structures

Richer concepts are better remembered: number of features effects in free recall

Many models of memory build in a term for encoding variability, the observation that there can be variability in the richness or extensiveness of processing at encoding, and that this variability has consequences for retrieval. In four experiments, we tested the expectation that encoding variability could be driven by the properties of the to-be-remembered item. Specifically, that concepts associated with more semantic features would be better remembered than concepts associated with fewer semantic features. Using feature listing norms we selected sets of items for which people tend to list higher numbers of features (high NoF) and items for which people tend to list lower numbers of features (low NoF). Results showed more accurate free recall for high NoF concepts than for low NoF concepts in expected memory tasks (Experiments 1–3) and also in an unexpected memory task (Experiment 4). This effect was not the result of associative chaining between study items (Experiment 3), and can be attributed to the amount of item-specific processing that occurs at study (Experiment 4). These results provide evidence that stimulus-specific differences in processing at encoding have consequences for explicit memory retrieval

Solving the Wolbachia Paradox: Modeling the Tripartite Interaction between Host, Wolbachia, and a Natural Enemy

Wolbachia is one of the most common symbionts of arthropods. Its establishment requires lateral transfer to and successful transmission within novel host species. However, Wolbachia performs poorly when introduced into new host species, and models predict that Wolbachia should seldom be able to establish from low initial frequencies. Recently, various symbionts, including Wolbachia, have been shown to protect their hosts from natural enemies. Hence, Wolbachia invasion may be facilitated by the dynamic interaction between it, its host, and a natural enemy. We model such an interaction whereby Wolbachia induces either complete resistance, partial resistance, or tolerance to a host-specific pathogen and also induces the common manipulation phenotype of cytoplasmic incompatibility (CI). We show that the presence of the pathogen greatly facilitates Wolbachia invasion from rare and widens the parameter space in which "imperfect" Wolbachia strains can invade. Furthermore, positive frequency-dependent selection through CI can drive Wolbachia to very high frequencies, potentially excluding the pathogen. These results may explain a poorly understood aspect of Wolbachia biology: it is widespread, despite performing poorly after transfer to new host species. They also support the intriguing possibility that Wolbachia strains that encode both CI and natural-enemy resistance could potentially rid insects, including human disease vectors, of important pathogens

Wolbachia-Mediated Antibacterial Protection and Immune Gene Regulation in Drosophila

The outcome of microbial infection of insects is dependent not only on interactions between the host and pathogen, but also on the interactions between microbes that co-infect the host. Recently the maternally inherited endosymbiotic bacteria Wolbachia has been shown to protect insects from a range of microbial and eukaryotic pathogens. Mosquitoes experimentally infected with Wolbachia have upregulated immune responses and are protected from a number of pathogens including viruses, bacteria, Plasmodium and filarial nematodes. It has been hypothesised that immune upregulation underpins Wolbachia-mediated protection. Drosophila is a strong model for understanding host-Wolbachia-pathogen interactions. Wolbachia-mediated antiviral protection in Drosophila has been demonstrated for a number of different Wolbachia strains. In this study we investigate whether Wolbachia-infected flies are also protected against pathogenic bacteria. Drosophila simulans lines infected with five different Wolbachia strains were challenged with the pathogenic bacteria Pseudomonas aeruginosa PA01, Serratia marcescens and Erwinia carotovora and mortality compared to paired lines without Wolbachia. No difference in mortality was observed in the flies with or without Wolbachia. Similarly no antibacterial protection was observed for D. melanogaster infected with Wolbachia. Interestingly, D. melanogaster Oregon RC flies which are naturally infected with Wolbachia showed no upregulation of the antibacterial immune genes TepIV, Defensin, Diptericin B, PGRP-SD, Cecropin A1 and Attacin D compared to paired flies without Wolbachia. Taken together these results indicate that Wolbachia-mediated antibacterial protection is not ubiquitous in insects and furthermore that the mechanisms of antibacterial and antiviral protection are independent. We suggest that the immune priming and antibacterial protection observed in Wolbachia-infected mosquitoes may be a consequence of the recent artificial introduction of the symbiont into insects that normally do not carry Wolbachia and that antibacterial protection is unlikely to be found in insects carrying long-term Wolbachia infections

Antiviral protection and the importance of Wolbachia density and: tissue tropism in Drosophila simulans

Wolbachia, a maternally transmitted endosymbiont of insects, is increasingly being seen as an effective biological control agent that can interfere with transmission of pathogens, including dengue virus. However, the mechanism of antiviral protection is not well understood. The density and distribution of Wolbachia in host tissues have been implicated as contributing factors by previous studies with both mosquitoes and flies. Drosophila flies infected with five diverse strains of Wolbachia were screened for the ability to mediate antiviral protection. The three protective Wolbachia strains were more closely related and occurred at a higher density within whole flies than the two nonprotective Wolbachia strains. In this study, to further investigate the relationship between whole-fly Wolbachia density and the ability to mediate antiviral protection, tetracycline was used to decrease the abundance of the high-density, protective Wolbachia strain wAu prior to viral challenge. Antiviral protection was lost when the density of the protective Wolbachia strain was decreased to an abundance similar to that of nonprotective Wolbachia strains. We determined the Wolbachia density and distribution in tissues of the same five fly-Wolbachia combinations as used previously. The Wolbachia density within the head, gut, and Malpighian tubules correlated with the ability to mediate antiviral protection. These findings may facilitate the development of Wolbachia biological control strategies and help to predict host-Wolbachia pairings that may interfere with virus-induced pathology