MVCSLAM: Mono-Vision Corner SLAM for Autonomous Micro-Helicopters in GPS Denied Environments

We present a real-time vision navigation and ranging method (VINAR) for the purpose of Simultaneous Localization and Mapping (SLAM) using monocular vision. Our navigation strategy assumes a GPS denied unknown environment, whose indoor architecture is represented via corner based feature points obtained through a monocular camera. We experiment on a case study mission of vision based SLAM through a conventional maze of corridors in a large building with an autonomous Micro Aerial Vehicle (MAV). We propose a method for gathering useful landmarks from a monocular camera for SLAM use. We make use of the corners by exploiting the architectural features of the manmade indoors

Estimation of Steam Turbine Shafts Fatigue Damage Caused by Torsional Vibrations

В Україні 74 енергоблоки потужністю 150-800 МВт теплових електростанцій із 102 перебувають на межі перевищення паркового ресурсу (220 тис. Годин). З них 17 енергоблоків наближаються до кінця ресурсу парку, а 11 енергоблоків досягли передбачуваного ресурсу (100 тис. Годин). Статистика аварій на електростанціях у різних країнах показує, що більшість з них спричинені тривалим накопиченням збитків від втоми. Серед основних причин пошкодження втоми - пульсація високотемпературних потоків пари в циліндрах турбіни, поперечні та крутильні коливання валів при тривалій експлуатації тощо. Це обумовлює розробку обчислювальних та експериментальних методів визначення втомних пошкоджень вали турбінних установок при динамічних навантаженнях. Оцінка втомних пошкоджень вала парової турбіни К-200-130 базується на 3D-моделі кінцевих елементів. Розрахунки враховують експериментально визначені втомні властивості роторної сталі. Розраховано втомну пошкодження в результаті крутильних коливань валу турбіни, спричинених аномальною роботою турбінного генератора. Зони концентрації напружень в обертових елементах парової турбіни типу К-200-130 встановлені для різних режимів роботи. Запропоновано процедуру прогнозування впливу втоми від пошкоджень на розрахунковий ресурс турбінного агрегату.In Ukraine, 74 power units with a capacity of 150-800 MW of thermal power plants out of 102 are on the verge of exceeding the park resource (220 thousand hours). Of these, 17 power units are close to the end the park resource, and 11 units have reached their estimated resource (100 thousand hours). Statistics of power plants accidents in different countries indicates that most of them are caused by the long term accumulation of fatigue damage. Among the main causes of fatigue damage are the pulsating of high-temperature steam flows in the turbine cylinders, transverse and torsional vibrations of shafts during long-term operation etc. This causes the development of computational and experimental methods for the determination of fatigue damage of turbine units’ shafts under dynamic loads. The evaluation of fatigue damage of steam turbine K-200-130 shaft is based on the 3D finite element model. The calculations take into account experimentally determined fatigue properties of rotor steel. The fatigue damage as a result of torsional vibrations of turbine shaft caused by the abnormal operation of turbine generator is calculated. Zones of stress concentration in the rotating elements of the steam turbine type K-200-130 are established for various operating modes. The procedure to predict the effect of fatigue damage on the estimated resource of turbine unit is proposed.В Украине 74 энергоблока мощностью 150-800 МВт тепловых электростанций из 102 находятся на грани превышения ресурса парка (220 тыс. Часов). Из них 17 энергоблоков близки к исчерпанию ресурса парка, а 11 энергоблоков вышли на расчетный ресурс (100 тыс. Часов). Статистика аварий на электростанциях в разных странах показывает, что большинство из них вызвано длительным накоплением усталостных повреждений. Среди основных причин усталостных повреждений - пульсации высокотемпературных потоков пара в цилиндрах турбины, поперечные и крутильные колебания валов при длительной эксплуатации и т. Д. Это вызывает развитие расчетных и экспериментальных методов определения усталостных повреждений. валы турбоагрегатов при динамических нагрузках. Оценка усталостных повреждений вала паровой турбины К-200-130 проводится на основе трехмерной конечно-элементной модели. В расчетах учтены экспериментально определенные усталостные свойства роторной стали. Рассчитано усталостное повреждение в результате крутильных колебаний вала турбины, вызванных ненормальной работой турбогенератора. Установлены зоны концентрации напряжений во вращающихся элементах паровой турбины типа К-200-130 для различных режимов работы. Предложена методика прогнозирования влияния усталостных повреждений на расчетный ресурс турбоагрегата

Progress towards elimination of onchocerciasis in the Region du Sud-Ouest of Burkina Faso which was previously subject to a recrudescence event after vector control

Background The Sud-Ouest region of Burkina Faso (especially the Bougouriba valley) has been historically problematic with respect to onchocerciasis control, with a recrudescence of infections after vector control carried out the WHO Onchocerciasis Control Programme was halted in 1989. After 1996, mass drug administration of ivermectin was instigated to control the recrudescence so that it would no longer constitute a public health problem. However, in 2010 WHO changed its recommended policy from control to elimination, and in 2013 biannual Community-Directed Treatment with Ivermectin (CDTI) was instigated. Epidemiological surveys were carried-out in 2011 and 2018 to determine whether CDTI was producing a decline in infection levels and progress towards elimination. Methodology/Principal findings A cross-sectional study was conducted across 20 villages in four health districts in 2011 and 29 villages in 2018. Individuals aged five years and above were examined by skin-snip, and the prevalence and microfilarial load was determined for each village. In 2011, 75% of villages had some infections and 20% had prevalences >5%, with a mean prevalence across all villages of 2.63% (range 0.0–9.7%), and community microfilarial load ranging from 0 to 0.25 microfilariae per biopsy. In 2018, nine villages (= 31% of total) had some infections, with prevalences ranging from 0.41% to 3.54%, and a mean prevalence across all villages of 0.37%. Community microfilarial load ranged from 0 to 0.1. Amongst those people found to be microfilarial positive, 87% had a history of migration. Conclusions/significance The endemicity of onchocerciasis infection in the Sud-Ouest region has declined to low levels and seems to be progressing towards elimination. Our findings indicated that biannual CDTI is having good effect, but it should continue for a number of years to ensure elimination of transmission. However, progress towards elimination has a troublesome history in this region, and it would be advisable to select more sentinel villages to have confidence in any future epidemiological and entomological surveys, especially Stop-MDA surveys. With positive individuals migrating between countries, cross-border collaboration needs more attention to ensure effective treatment for onchocerciasis elimination

Identification of Leishmania Proteins Preferentially Released in Infected Cells Using Change Mediated Antigen Technology (CMAT)

Although Leishmania parasites have been shown to modulate their host cell's responses to multiple stimuli, there is limited evidence that parasite molecules are released into infected cells. In this study, we present an implementation of the change mediated antigen technology (CMAT) to identify parasite molecules that are preferentially expressed in infected cells. Sera from mice immunized with cell lysates prepared from L. donovani or L. pifanoi-infected macrophages were adsorbed with lysates of axenically grown amastigotes of L. donovani or L. pifanoi, respectively, as well as uninfected macrophages. The sera were then used to screen inducible parasite expression libraries constructed with genomic DNA. Eleven clones from the L. pifanoi and the L. donovani screen were selected to evaluate the characteristics of the molecules identified by this approach. The CMAT screen identified genes whose homologs encode molecules with unknown function as well as genes that had previously been shown to be preferentially expressed in the amastigote form of the parasite. In addition a variant of Tryparedoxin peroxidase that is preferentially expressed within infected cells was identified. Antisera that were then raised to recombinant products of the clones were used to validate that the endogenous molecules are preferentially expressed in infected cells. Evaluation of the distribution of the endogenous molecules in infected cells showed that some of these molecules are secreted into parasitophorous vacuoles (PVs) and that they then traffic out of PVs in vesicles with distinct morphologies. This study is a proof of concept study that the CMAT approach can be applied to identify putative Leishmania parasite effectors molecules that are preferentially expressed in infected cells. In addition we provide evidence that Leishmania molecules traffic out of the PV into the host cell cytosol and nucleus

Fusion between Leishmania amazonensis and Leishmania major Parasitophorous Vacuoles: Live Imaging of Coinfected Macrophages

Protozoan parasites of the genus Leishmania alternate between flagellated, elongated extracellular promastigotes found in insect vectors, and round-shaped amastigotes enclosed in phagolysosome-like Parasitophorous Vacuoles (PVs) of infected mammalian host cells. Leishmania amazonensis amastigotes occupy large PVs which may contain many parasites; in contrast, single amastigotes of Leishmania major lodge in small, tight PVs, which undergo fission as parasites divide. To determine if PVs of these Leishmania species can fuse with each other, mouse macrophages in culture were infected with non-fluorescent L. amazonensis amastigotes and, 48 h later, superinfected with fluorescent L. major amastigotes or promastigotes. Fusion was investigated by time-lapse image acquisition of living cells and inferred from the colocalization of parasites of the two species in the same PVs. Survival, multiplication and differentiation of parasites that did or did not share the same vacuoles were also investigated. Fusion of PVs containing L. amazonensis and L. major amastigotes was not found. However, PVs containing L. major promastigotes did fuse with pre-established L. amazonensis PVs. In these chimeric vacuoles, L. major promastigotes remained motile and multiplied, but did not differentiate into amastigotes. In contrast, in doubly infected cells, within their own, unfused PVs metacyclic-enriched L. major promastigotes, but not log phase promastigotes - which were destroyed - differentiated into proliferating amastigotes. The results indicate that PVs, presumably customized by L. major amastigotes or promastigotes, differ in their ability to fuse with L. amazonensis PVs. Additionally, a species-specific PV was required for L. major destruction or differentiation – a requirement for which mechanisms remain unknown. The observations reported in this paper should be useful in further studies of the interactions between PVs to different species of Leishmania parasites, and of the mechanisms involved in the recognition and fusion of PVs

Cooperation between Apoptotic and Viable Metacyclics Enhances the Pathogenesis of Leishmaniasis

Mimicking mammalian apoptotic cells by exposing phosphatidylserine (PS) is a strategy used by virus and parasitic protozoa to escape host protective inflammatory responses. With Leishmania amazonensis (La), apoptotic mimicry is a prerogative of the intramacrophagic amastigote form of the parasite and is modulated by the host. Now we show that differently from what happens with amastigotes, promastigotes exposing PS are non-viable, non-infective cells, undergoing apoptotic death. As part of the normal metacyclogenic process occurring in axenic cultures and in the gut of sand fly vectors, a sub-population of metacyclic promastigotes exposes PS. Apoptotic death of the purified PS-positive (PSPOS) sub-population was confirmed by TUNEL staining and DNA laddering. Transmission electron microscopy revealed morphological alterations in PSPOS metacyclics such as DNA condensation, cytoplasm degradation and mitochondrion and kinetoplast destruction, both in in vitro cultures and in sand fly guts. TUNELPOS promastigotes were detected only in the anterior midgut to foregut boundary of infected sand flies. Interestingly, caspase inhibitors modulated parasite death and PS exposure, when added to parasite cultures in a specific time window. Efficient in vitro macrophage infections and in vivo lesions only occur when PSPOS and PS-negative (PSNEG) parasites were simultaneously added to the cell culture or inoculated in the mammalian host. The viable PSNEG promastigote was the infective form, as shown by following the fate of fluorescently labeled parasites, while the PSPOS apoptotic sub-population inhibited host macrophage inflammatory response. PS exposure and macrophage inhibition by a subpopulation of promastigotes is a different mechanism than the one previously described with amastigotes, where the entire population exposes PS. Both mechanisms co-exist and play a role in the transmission and development of the disease in case of infection by La. Since both processes confer selective advantages to the infective microorganism they justify the occurrence of apoptotic features in a unicellular pathogen

Minimal information for studies of extracellular vesicles (MISEV2023): From basic to advanced approaches

© 2024 The Authors. Journal of Extracellular Vesicles, published by Wiley Periodicals, LLC on behalf of the International Society for Extracellular Vesicles. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY), https://creativecommons.org/licenses/by/4.0/Extracellular vesicles (EVs), through their complex cargo, can reflect the state of their cell of origin and change the functions and phenotypes of other cells. These features indicate strong biomarker and therapeutic potential and have generated broad interest, as evidenced by the steady year-on-year increase in the numbers of scientific publications about EVs. Important advances have been made in EV metrology and in understanding and applying EV biology. However, hurdles remain to realising the potential of EVs in domains ranging from basic biology to clinical applications due to challenges in EV nomenclature, separation from non-vesicular extracellular particles, characterisation and functional studies. To address the challenges and opportunities in this rapidly evolving field, the International Society for Extracellular Vesicles (ISEV) updates its 'Minimal Information for Studies of Extracellular Vesicles', which was first published in 2014 and then in 2018 as MISEV2014 and MISEV2018, respectively. The goal of the current document, MISEV2023, is to provide researchers with an updated snapshot of available approaches and their advantages and limitations for production, separation and characterisation of EVs from multiple sources, including cell culture, body fluids and solid tissues. In addition to presenting the latest state of the art in basic principles of EV research, this document also covers advanced techniques and approaches that are currently expanding the boundaries of the field. MISEV2023 also includes new sections on EV release and uptake and a brief discussion of in vivo approaches to study EVs. Compiling feedback from ISEV expert task forces and more than 1000 researchers, this document conveys the current state of EV research to facilitate robust scientific discoveries and move the field forward even more rapidly.Peer reviewe

The use of complementary and alternative medicine by 7427 Australian women with cyclic perimenstrual pain and discomfort: A cross-sectional study

© 2016 Fisher et al. Background: To assess the prevalence of cyclic perimenstrual pain and discomfort and to detail the pattern of complementary and alternative (CAM) use adopted by women for the treatment of these symptoms. Methods: Data from the 2012 national Australian Longitudinal Study of Women's Health (ALSWH) cross-sectional survey of 7427 women aged 34-39 years were analysed to estimate the prevalence of endometriosis, premenstrual syndrome (PMS), irregular or heavy periods and severe dysmenorrhoea and to examine the association between their symptoms and their visits to CAM practitioners as well as their use of CAM therapies and products in the previous 12 months. Results: The prevalence of endometriosis was 3.7 % and of the perimenstrual symptoms assessed, PMS was most prevalent at 41.2 % whilst irregular bleeding (22.2 %), heavy periods (29.8 %) and severe period pain (24.1 %) were reported at lower levels. Women with endometriosis were more likely than non-sufferers to have consulted with a massage therapist or acupuncturist and to have used vitamins/minerals, yoga/meditation or Chinese medicines (p < 0.05). PMS sufferers were more likely to consult with an osteopath, massage therapist, naturopath/herbalist or alternative health practitioner and to have used all forms of CAM therapies except Chinese medicines than women who had infrequent PMS (all p < 0.05). Women with irregular periods did not have different patterns of CAM use from non-sufferers and those with heavy periods did not favour any form of CAM but were less likely to visit a massage therapist or use yoga/meditation than non-sufferers (p < 0.05). For women with severe dysmenorrhoea there was no difference in their visits to CAM practitioners compared to non-sufferers but they were more likely to use aromatherapy oils (p < 0.05) and for more frequent dysmenorrhoea also herbal medicines, Chinese medicines and other alternative therapies compared to non-sufferers (all p < 0.05). Conclusions: There is a high prevalence of cyclic perimenstrual pain and discomfort amongst women in this age group. Women were using CAM differentially when they had specific symptoms of cyclic perimenstrual pain and discomfort. The use of CAM needs to be properly assessed to ensure their safe, effective use and to ascertain their significance as a treatment option enabling women with menstrual problems and their care providers to improve their quality of life

Interaction of Hydrogen with Graphitic Surfaces, Clean and Doped with Metal Clusters

Producción CientíficaHydrogen is viewed as a possible alternative to the fossil fuels in transportation. The technology of fuel-cell engines is fully developed, and the outstanding remaining problem is the storage of hydrogen in the vehicle. Porous materials, in which hydrogen is adsorbed on the pore walls, and in particular nanoporous carbons, have been investigated as potential onboard containers. Furthermore, metallic nanoparticles embedded in porous carbons catalyze the dissociation of hydrogen in the anode of the fuel cells. For these reasons the interaction of hydrogen with the surfaces of carbon materials is a topic of high technological interest. Computational modeling and the density functional formalism (DFT) are helping in the task of discovering the basic mechanisms of the interaction of hydrogen with clean and doped carbon surfaces. Planar and curved graphene provide good models for the walls of porous carbons. We first review work on the interaction of molecular and atomic hydrogen with graphene and graphene nanoribbons, and next we address the effects due to the presence of metal clusters on the surface because of the evidence of their role in enhancing hydrogen storage.Ministerio de Economía, Industria y Competitividad (Grant MAT2014-54378-R