Buckling of orthotropic webs in process machinery

Many webs in web process machinery exhibit out-of-plane deformations, defined as troughs, in free web spans between rollers. In other cases when the troughs become severe the out-of-plane web deformations will begin to transcend rollers. Any out-of-plane web deformations that transcend rollers are defined as wrinkles. Troughs and wrinkles in webs are often undesirable as they can interfere with web processes such as coating, they can result in web breaks and thereby decreased productivity, or these deformations may become permanent and result in quality loss.Many plastic film, paper, tissue and nonwoven webs are highly anisotropic either by design or just as a result of the process by which the web is made. The first objective of this paper is to show how anisotropic web properties affect the buckling and wrinkling tendencies of these webs. Previously algorithms have been developed that show how roller misalignment can induce troughs and wrinkles. The second objective of this paper is to demonstrate how web orthotrophy can affect the allowable roller misalignment in a web span and the web tension required to sustain a wrinkle upon a roller.Mechanical and Aerospace Engineerin

Analysis of trough formation and lateral steering of a web due to a tapered downstream roller

Cylindrical rollers are never perfectly cylindrical. A common defect of a cylindrical roller is radial taper. A roller with a radial taper will induce a lateral shear force into the web. This shear force will cause a steering effect as well as a cross machine direction compressive stress which can lead to the formation of troughs and wrinkles in a web. This publication addresses these topics and presents a model to help determine the specification for taper in "cylindrical" rollers. An analytical model is presented, experiments were performed, and the data was compared to predictions from the proposed model.Mechanical and Aerospace Engineerin

Predicting web wrinkles on rollers

There are two levels of web instability in web lines. The first level of web instability is called web troughs. Web troughs are due to the instability of webs that occur in free web spans. Web troughs have been shown to be predictable using traditional buckling theory. Closed form expressions have been developed and verified in the lab that predict when web troughs will result from roller misalignment and roller taper. Web troughs can be a nuisance in web processes where the web must be planar. The troughs themselves may not damage the web but can be responsible for reductions in web quality after processing that can result in lost profit.The next level of instability is called web wrinkles. Web wrinkles are due to the instability of webs that are transiting rollers. When webs transit rollers they assume the shape of a sector of a cylindrical shell. A cylindrical shell of web is much more stable than the web in free spans. Compressive stresses which are two to three orders of magnitude larger than those required to induce web troughs are necessary to buckle the cylindrical shell. This paper will demonstrate that web wrinkles are a post buckling phenomena that result from web troughs. The source of the high compressive stresses needed to buckle the web into wrinkles on rollers will be shown. We will show how web wrinkles can be predicted and we will show experimental verification for the cases where a misaligned or tapered rollers were the source of the troughs and wrinkles. Web wrinkles can damage the web as a result of inelastic deformation, fold-overs, and in the worst case may cause full separation or failure of the web. When web wrinkles can be predicted, they can also be prevented.Mechanical and Aerospace Engineerin

STIR: software for tomographic image reconstruction release 2

We present a new version of STIR (Software for Tomographic Image Reconstruction), an open source object-oriented library implemented in C++ for 3D positron emission tomography reconstruction. This library has been designed such that it can be used for many algorithms and scanner geometries, while being portable to various computing platforms. This second release enhances its flexibility and modular design and includes additional features such as Compton scatter simulation, an additional iterative reconstruction algorithm and parametric image reconstruction (both indirect and direct). We discuss the new features in this release and present example results. STIR can be downloaded from http://stir.sourceforge.net

Design principles for riboswitch function

Scientific and technological advances that enable the tuning of integrated regulatory components to match network and system requirements are critical to reliably control the function of biological systems. RNA provides a promising building block for the construction of tunable regulatory components based on its rich regulatory capacity and our current understanding of the sequence–function relationship. One prominent example of RNA-based regulatory components is riboswitches, genetic elements that mediate ligand control of gene expression through diverse regulatory mechanisms. While characterization of natural and synthetic riboswitches has revealed that riboswitch function can be modulated through sequence alteration, no quantitative frameworks exist to investigate or guide riboswitch tuning. Here, we combined mathematical modeling and experimental approaches to investigate the relationship between riboswitch function and performance. Model results demonstrated that the competition between reversible and irreversible rate constants dictates performance for different regulatory mechanisms. We also found that practical system restrictions, such as an upper limit on ligand concentration, can significantly alter the requirements for riboswitch performance, necessitating alternative tuning strategies. Previous experimental data for natural and synthetic riboswitches as well as experiments conducted in this work support model predictions. From our results, we developed a set of general design principles for synthetic riboswitches. Our results also provide a foundation from which to investigate how natural riboswitches are tuned to meet systems-level regulatory demands

Interleukin 7 from Maternal Milk Crosses the Intestinal Barrier and Modulates T- Cell Development in Offspring

Background Breastfeeding protects against illnesses and death in hazardous environments, an effect partly mediated by improved immune function. One hypothesis suggests that factors within milk supplement the inadequate immune response of the offspring, but this has not been able to account for a series of observations showing that factors within maternally derived milk may supplement the development of the immune system through a direct effect on the primary lymphoid organs. In a previous human study we reported evidence suggesting a link between IL-7 in breast milk and the thymic output of infants. Here we report evidence in mice of direct action of maternally-derived IL-7 on T cell development in the offspring. Methods and Findings  We have used recombinant IL-7 labelled with a fluorescent dye to trace the movement in live mice of IL-7 from the stomach across the gut and into the lymphoid tissues. To validate the functional ability of maternally derived IL- 7 we cross fostered IL-7 knock-out mice onto normal wild type mothers. Subsets of thymocytes and populations of peripheral T cells were significantly higher than those found in knock-out mice receiving milk from IL-7 knock-out mothers. Conclusions/Significance Our study provides direct evidence that interleukin 7, a factor which is critical in the development of T lymphocytes, when maternally derived can transfer across the intestine of the offspring, increase T cell production in the thymus and support the survival of T cells in the peripheral secondary lymphoid tissue

The Sputum Microbiome in Pulmonary Tuberculosis and Its Association With Disease Manifestations: A Cross-Sectional Study.

Each day, approximately 27,000 people become ill with tuberculosis (TB), and 4,000 die from this disease. Pulmonary TB is the main clinical form of TB, and affects the lungs with a considerably heterogeneous manifestation among patients. Immunomodulation by an interplay of host-, environment-, and pathogen-associated factors partially explains such heterogeneity. Microbial communities residing in the host's airways have immunomodulatory effects, but it is unclear if the inter-individual variability of these microbial communities is associated with the heterogeneity of pulmonary TB. Here, we investigated this possibility by characterizing the microbial composition in the sputum of 334 TB patients from Tanzania, and by assessing its association with three aspects of disease manifestations: sputum mycobacterial load, severe clinical findings, and chest x-ray (CXR) findings. Compositional data analysis of taxonomic profiles based on 16S-rRNA gene amplicon sequencing and on whole metagenome shotgun sequencing, and graph-based inference of microbial associations revealed that the airway microbiome of TB patients was shaped by inverse relationships between Streptococcus and two anaerobes: Selenomonas and Fusobacterium. Specifically, the strength of these microbial associations was negatively correlated with Faith's phylogenetic diversity (PD) and with the accumulation of transient genera. Furthermore, low body mass index (BMI) determined the association between abnormal CXRs and community diversity and composition. These associations were mediated by increased abundance of Selenomonas and Fusobacterium, relative to the abundance of Streptococcus, in underweight patients with lung parenchymal infiltrates and in comparison to those with normal chest x-rays. And last, the detection of herpesviruses and anelloviruses in sputum microbial assemblage was linked to co-infection with HIV. Given the anaerobic metabolism of Selenomonas and Fusobacterium, and the hypoxic environment of lung infiltrates, our results suggest that in underweight TB patients, lung tissue remodeling toward anaerobic conditions favors the growth of Selenomonas and Fusobacterium at the expense of Streptococcus. These new insights into the interplay among particular members of the airway microbiome, BMI, and lung parenchymal lesions in TB patients, add a new dimension to the long-known association between low BMI and pulmonary TB. Our results also drive attention to the airways virome in the context of HIV-TB coinfection

Full-length haplotype reconstruction to infer the structure of heterogeneous virus populations

Next-generation sequencing (NGS) technologies enable new insights into the diversity of virus populations within their hosts. Diversity estimation is currently restricted to single-nucleotide variants or to local fragments of no more than a few hundred nucleotides defined by the length of sequence reads. To study complex heterogeneous virus populations comprehensively, novel methods are required that allow for complete reconstruction of the individual viral haplotypes. Here, we show that assembly of whole viral genomes of ∼8600 nucleotides length is feasible from mixtures of heterogeneous HIV-1 strains derived from defined combinations of cloned virus strains and from clinical samples of an HIV-1 superinfected individual. Haplotype reconstruction was achieved using optimized experimental protocols and computational methods for amplification, sequencing and assembly. We comparatively assessed the performance of the three NGS platforms 454 Life Sciences/Roche, Illumina and Pacific Biosciences for this task. Our results prove and delineate the feasibility of NGS-based full-length viral haplotype reconstruction and provide new tools for studying evolution and pathogenesis of viruse