727 research outputs found

    Eye in the Sky

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    This project is separated into two parts: an unmanned aerial vehicle (UAV) and a corresponding capsule. The UAV will be stored in the capsule as the pair is released from underwater and floats to the surface where the capsule will autonomously open and discharge the drone. Following release, the UAV will fly up and record video surveillance of the surrounding area. Finally, the UAV will record the data onto a micro SD card inserted in the monitor that shows the camera’s live feed. The objective is to design, build, test, and finalize a UAV and capsule that meet NUWC’s, the customer, specifications as much as possible. The overarching design for this system consists of a cylindrical capsule with chambers for the drone, electronic controls, controlled air flow, and the tank of compressed air. An Arduino UNO is programmed to trigger the flow of air that pushes the drone out after a certain number of seconds. The UAV is a quadcopter whose arms spread open by a simple spring mechanism once ejected from the capsule but sits linearly while inside the capsule. The capsule has been manufactured from aluminum and the drone uses the Vortex 250 Pro as a base but has been modified to feature the required fold-able arms. Testing has shown that the capsule functions as expected. It floats to the surface, maintains a vertical position, and ejects the UAV after the programmed number of seconds. Testing has also shown that the UAV’s physical body also functions as expected in terms of its arms springing open when no longer constrained within the capsule. Photos and videos have been successfully recorded onto the monitor. The drone’s flight was not tested due to unforeseen and currently unresolved software issues. Overall, if the drone was capable of flight, the team would expect the system to work well as a whole

    STING-dependent recognition of cyclic di-AMP mediates type I interferon responses during Chlamydia trachomatis infection.

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    UnlabelledSTING (stimulator of interferon [IFN] genes) initiates type I IFN responses in mammalian cells through the detection of microbial nucleic acids. The membrane-bound obligate intracellular bacterium Chlamydia trachomatis induces a STING-dependent type I IFN response in infected cells, yet the IFN-inducing ligand remains unknown. In this report, we provide evidence that Chlamydia synthesizes cyclic di-AMP (c-di-AMP), a nucleic acid metabolite not previously identified in Gram-negative bacteria, and that this metabolite is a prominent ligand for STING-mediated activation of IFN responses during infection. We used primary mouse lung fibroblasts and HEK293T cells to compare IFN-β responses to Chlamydia infection, c-di-AMP, and other type I IFN-inducing stimuli. Chlamydia infection and c-di-AMP treatment induced type I IFN responses in cells expressing STING but not in cells expressing STING variants that cannot sense cyclic dinucleotides but still respond to cytoplasmic DNA. The failure to induce a type I IFN response to Chlamydia and c-di-AMP correlated with the inability of STING to relocalize from the endoplasmic reticulum to cytoplasmic punctate signaling complexes required for IFN activation. We conclude that Chlamydia induces STING-mediated IFN responses through the detection of c-di-AMP in the host cell cytosol and propose that c-di-AMP is the ligand predominantly responsible for inducing such a response in Chlamydia-infected cells.ImportanceThis study shows that the Gram-negative obligate pathogen Chlamydia trachomatis, a major cause of pelvic inflammatory disease and infertility, synthesizes cyclic di-AMP (c-di-AMP), a nucleic acid metabolite that thus far has been described only in Gram-positive bacteria. We further provide evidence that the host cell employs an endoplasmic reticulum (ER)-localized cytoplasmic sensor, STING (stimulator of interferon [IFN] genes), to detect c-di-AMP synthesized by Chlamydia and induce a protective IFN response. This detection occurs even though Chlamydia is confined to a membrane-bound vacuole. This raises the possibility that the ER, an organelle that innervates the entire cytoplasm, is equipped with pattern recognition receptors that can directly survey membrane-bound pathogen-containing vacuoles for leaking microbe-specific metabolites to mount type I IFN responses required to control microbial infections

    The Effectiveness of Injury-Prevention Programs in Reducing the Incidence of Anterior Cruciate Ligament Sprains in Adolescent Athletes

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    Clinical Scenario: There is a high incidence of anterior cruciate ligament (ACL) injury in adolescents participating in pivoting sports such as soccer, basketball, and handball. Most ACL injuries in athletes are noncontact injuries, with a mechanism of sudden deceleration, change in direction, or landing from a jump. These mechanisms coupled with an increase in contraction of the quadriceps have been shown as risk factors for ACL injuries. Injuries to the ACL may require surgery, a long rehabilitation, and the potential for reinjury. Studies have shown reductions in lower extremity injury rates using training protocols that focus on landing mechanics, balance training, strength training, and/or agility training. There has been some thought that starting preventive training programs with adolescent athletes may be the most effective approach to reducing adolescent ACL injuries. Focused Clinical Question: Can lower extremity injury-prevention programs effectively reduce ACL injury rates in adolescent athletes

    Genetic mutations in pfcrt and pfmdr1 at the time of artemisinin combination therapy introduction in South Pacific islands of Vanuatu and Solomon Islands

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    Background: Chloroquine (CQ), alone or in combination with sulphadoxine-pyrimethamine, was widely used for the treatment of Plasmodium falciparum and Plasmodium vivax for several decades in both Vanuatu and Solomon Islands prior to the introduction of artemether-lumefantrine (AL) in 2008. However, the effect of chloroquine selection on parasite population, which may affect the efficacy of lumefantrine or other partner drugs of artemisinin, has not been well assessed. This study aims to provide baseline data on molecular markers (pfcrt and pfmdr1), along with the origins of pfcrt, prior to the introduction of AL. Methods: Blood spots were obtained from epidemiological surveys conducted on Tanna Island, Tafea Province, Vanuatu and Temotu Province, Solomon Islands in 2008. Additional samples from Malaita Province, Solomon Islands were collected as part of an artemether-lumefantrine efficacy study in 2008. Plasmodium falciparum pfcrt and pfmdr1 genes were examined for polymorphisms. Microsatellite markers flanking pfcrt were also examined to ascertain origins of CQ resistance. Results: Pfcrt analysis revealed 100% of parasites from Tafea Province, Vanuatu and Malaita Province, Solomon Islands and 98% of parasites from Temotu Province, Solomon Islands carried the K76T polymorphism that confers CQ resistance. Comparison of pfcrt allelic patterns and microsatellite markers flanking pfcrt revealed six haplotypes with more than 70% of isolates possessing haplotypes very similar to those observed in Papua New Guinea. The dominant (98.5%) pfmdr1 allele across all island groups was YYCND. Conclusions: Prior to the introduction of AL in the Solomon Islands and Vanuatu, P. falciparum isolates possessed point mutations known to confer CQ resistance and possibly associated with a decreased susceptibility to quinine and halofantrine, but an increased susceptibility to artemisinin and lumefantrine. Overall, pfcrt allelic types and the flanking microsatellite markers exhibited similarities to those of Papua New Guinea, suggesting these parasites share a common ancestry. The current use of AL for both P. falciparum and P. vivax infections will enable changes in these markers, in the absence of CQ pressure, to be monitored

    Fetal Hematopoietic Stem Cell Transplantation Fails to Fully Regenerate the B-Lymphocyte Compartment

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    B cells are key components of cellular and humoral immunity and, like all lymphocytes, are thought to originate and renew from hematopoietic stem cells (HSCs). However, our recent single-HSC transfer studies demonstrate that adult bone marrow HSCs do not regenerate B-1a, a subset of tissue B cells required for protection against pneumonia, influenza, and other infections. Since B-1a are regenerated by transfers of fetal liver, the question arises as to whether B-1a derive from fetal, but not adult, HSCs. Here we show that, similar to adult HSCs, fetal HSCs selectively fail to regenerate B-1a. We also show that, in humanized mice, human fetal liver regenerates tissue B cells that are phenotypically similar to murine B-1a, raising the question of whether human HSC transplantation, the mainstay of such models, is sufficient to regenerate human B-1a. Thus, our studies overtly challenge the current paradigm that HSCs give rise to all components of the immune system
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