1,741 research outputs found

    Nanosized patterns as reference structures for macroscopic transport properties and vortex phases in YBCO films

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    This paper studies the striking correlation between nanosized structural patterns in YBCO films and macroscopic transport current. A nanosized network of parallel Josephson junctions laced by insulating dislocations is almost mimicking the grain boundary structural network. It contributes to the macroscopic properties and accounts for the strong intergranular pinning across the film in the intermediate temperature range. The correlation between the two networks enables to find out an outstanding scaling law in the (Jc,B) plane and to determine meaningful parameters concerning the matching between the vortex lattice and the intergranular defect lattice. Two asymptotic behaviors of the pinning force below the flux flow regime are checked: the corresponding vortex phases are clearly individuated.Comment: 4 pages, 4 figure

    Hydrodynamic lift of vesicles under shear flow in microgravity

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    The dynamics of a vesicle suspension in a shear flow between parallel plates has been investigated under microgravity conditions, where vesicles are only submitted to hydrodynamic effects such as lift forces due to the presence of walls and drag forces. The temporal evolution of the spatial distribution of the vesicles has been recorded thanks to digital holographic microscopy, during parabolic flights and under normal gravity conditions. The collected data demonstrates that vesicles are pushed away from the walls with a lift velocity proportional to γ˙R3/z2\dot{\gamma} R^3/z^2 where γ˙\dot{\gamma} is the shear rate, RR the vesicle radius and zz its distance from the wall. This scaling as well as the dependence of the lift velocity upon vesicle aspect ratio are consistent with theoretical predictions by Olla [J. Phys. II France {\bf 7}, 1533--1540 (1997)].Comment: 6 pages, 8 figure

    Tuberculosis treatment in a refugee and migrant population: 20 years of experience on the Thai-Burmese border.

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    Although tuberculosis (TB) is a curable disease, it remains a major global health problem and an important cause of morbidity and mortality among vulnerable populations, including refugees and migrants

    Humans running in place on water at simulated reduced gravity

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    On Earth only a few legged species, such as water strider insects, some aquatic birds and lizards, can run on water. For most other species, including humans, this is precluded by body size and proportions, lack of appropriate appendages, and limited muscle power. However, if gravity is reduced to less than Earth's gravity, running on water should require less muscle power. Here we use a hydrodynamic model to predict the gravity levels at which humans should be able to run on water. We test these predictions in the laboratory using a reduced gravity simulator

    The velo-uvulo-pharyngeal lift or "roman blinds" technique for treatment of snoring: a preliminary report

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    Snoring is caused by vibrating anatomical structures in the upper aerodigestive tract. It can be treated surgically and non-surgically, although resective procedures are associated with high postoperative morbidity and failure rate. We describe a new non-resective surgical procedure called the velo-uvulo-pharyngeal lift in which the soft palate is lifted, shortened, advanced and stiffened by means of permanent threads anchored to fibro-osseous attachments at the level of the posterior nasal spine and both pterygoid hamuli. Four adult patients (median age 44.5 years; range 42-65) affected by snoring and mild obstructive sleep apnoea-hypopnoea syndrome (apneoa-hypopnoea index, AHI < 20) requiring septal surgery under general anesthesia also underwent velo-uvulo-pharyngeal lift. There were no significant intra- or post-operative complications, and all of the patients reported immediate snoring relief. The main complaints were slight pain and a sensation of local fullness, both of which spontaneously disappeared within two days. The subjective clinical improvement in snoring was confirmed during post-operative follow-up (median 15.5 months; range 6-25), as was the stable reshaping of the soft velo-uvulo-pharyngeal tissues and enlargement of the mesopharyngeal space. There was also a decrease in daytime sleepiness. Our preliminary results suggest that velo-uvulo-pharyngeal lift is a simple, cost-effective and minimally invasive means of widening the mesopharyngeal space in snoring patients with or without mild sleep apnoea-hypopnoea syndrome. The widening of the mesopharyngeal space prevents contact-induced wall vibrations and its inspiratory obstruction causing hypopnoea and apnoea. It can also be combined with other procedures if indicated

    A Superhydrophobic Cone to Facilitate the Xenomonitoring of Filarial Parasites, Malaria, and Trypanosomes Using Mosquito Excreta/Feces

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    Background: Molecular xenomonitoring (MX), the testing of insect vectors for the presence of human pathogens, has the potential to provide a non-invasive and cost-effective method for monitoring the prevalence of disease within a community. Current MX methods require the capture and processing of large numbers of mosquitoes, particularly in areas of low endemicity, increasing the time, cost and labour required. Screening the excreta/feces (E/F) released from mosquitoes, rather than whole carcasses, improves the throughput by removing the need to discriminate vector species since non-vectors release ingested pathogens in E/F. It also enables larger numbers of mosquitoes to be processed per pool. However, this new screening approach requires a method of efficiently collecting E/F. Methods: We developed a cone with a superhydrophobic surface to allow for the efficient collection of E/F. Using mosquitoes exposed to either Plasmodium falciparum, Brugia malayi or Trypanosoma brucei brucei, we tested the performance of the superhydrophobic cone alongside two other collection methods. Results: All collection methods enabled the detection of DNA from the three parasites. Using the superhydrophobic cone to deposit E/F into a small tube provided the highest number of positive samples (16 out of 18) and facilitated detection of parasite DNA in E/F from individual mosquitoes. Further tests showed that following a simple washing step, the cone can be reused multiple times, further improving its cost-effectiveness. Conclusions: Incorporating the superhydrophobic cone into mosquito traps or holding containers could provide a simple and efficient method for collecting E/F. Where this is not possible, swabbing the container or using the washing method facilitates the detection of the three parasites used in this study

    Case-Control Study of Risk Factors for Sporadic Giardiasis and Parasite Assemblages in North West England

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    Giardia duodenalis is a major cause of infectious gastroenteritis worldwide, and it is diversified into eight genetic assemblages (A to H), which are distinguishable only by molecular typing. There is some evidence that the assemblages infecting humans (assemblages A and B) may have different transmission routes, but systematically acquired data, combining epidemiological and molecular findings, are required. We undertook a case-control study with Giardia genotyping in North West England, to determine general and parasite assemblage-specific risk factors. For people without a history of foreign travel, swimming in swimming pools and changing diapers were the most important risk factors for the disease. People infected with assemblage B reported a greater number of symptoms and higher frequencies of vomiting, abdominal pain, swollen stomach, and loss of appetite, compared with people infected with assemblage A. More importantly, keeping a dog was associated only with assemblage A infections, suggesting the presence of a potential zoonotic reservoir for this assemblage. This is the first case-control study to combine epidemiological data with Giardia genotyping, and it shows the importance of integrating these two levels of information for better understanding of the epidemiology of this pathogen

    A new apparatus for deep patterning of beam sensitive targets by means of high-energy ion beam

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    The paper reports on a high precision equipment designed to modify over 3-dimensions (3D) by means of high-energy gold ions the local properties of thin and thick films. A target-moving system aimed at creating patterns across the volume is driven by an x-y writing protocol that allows one to modify beam sensitive samples over micrometer-size regions of whatever shape. The apparatus has a mechanical resolution of 15 nm. The issue of the local fluence measurement has been particularly addressed. The setup has been checked by means of different geometries patterned on beam sensitive sheets as well as on superconducting materials. In the last case the 3D modification consists of amorphous nanostructures. The nanostructures create zones with different dissipative properties with respect to the virgin regions. The main analysis method consists of magneto-optical imaging that provides local information on the electrodynamics of the modified zones. Features typical of non-linear current flow hint at which pattern geometry is more functional to applications in the framework of nanostructures across superconducting films.Comment: 7 page

    Laboratory evaluation of molecular xenomonitoring using mosquito excreta/feces to amplify Plasmodium, Brugia, and Trypanosoma DNA

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    Background: Results from an increasing number of studies suggest that mosquito excreta/feces (E/F) testing has considerable potential to serve as a supplement for traditional molecular xenomonitoring techniques. However, as the catalogue of possible use-cases for this methodology expands, and the list of amenable pathogens grows, a number of fundamental methods-based questions remain. Answering these questions is critical to maximizing the utility of this approach and to facilitating its successful implementation as an effective tool for molecular xenomonitoring. Methods: Utilizing E/F produced by mosquitoes or tsetse flies experimentally exposed to Brugia malayi, Plasmodium falciparum, or Trypanosoma brucei brucei, factors such as limits of detection, throughput of testing, adaptability to use with competent- and incompetent-vector species, and effects of additional blood feedings post parasite-exposure were evaluated. Two platforms for the detection of pathogen signal (quantitative real-time PCR and digital PCR [dPCR]) were also compared, with strengths and weaknesses examined for each. Results: Experimental results indicated that high throughput testing is possible when evaluating mosquito E/F for the presence of either B. malayi or P. falciparum from both competent- and incompetent-vector mosquito species. Furthermore, following exposure to pathogen, providing mosquitoes with a second, uninfected bloodmeal did not expand the temporal window for E/F collection during which pathogen detection was possible. However, this collection window did appear longer in E/F collected from tsetse flies following exposure to T. b. brucei. Testing also suggested that dPCR may facilitate detection through its increased sensitivity. Unfortunately, logistical obstacles will likely make the large-scale use of dPCR impractical for this purpose. Conclusions: By examining many E/F testing variables, expansion of this technology to a field-ready platform has become increasingly feasible. However, translation of this methodology from the lab to the field will first require the completion of field-based pilot studies aimed at assessing the efficacy of E/F screening
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