933 research outputs found

    Ultrasound-activated ciliary bands for microrobotic systems inspired by starfish

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    Cilia are short, hair-like appendages ubiquitous in various biological systems, which have evolved to manipulate and gather food in liquids at regimes where viscosity dominates inertia. Inspired by these natural systems, synthetic cilia have been developed and utilized in microfluidics and microrobotics to achieve functionalities such as propulsion, liquid pumping and mixing, and particle manipulation. Here, we demonstrate ultrasound-activated synthetic ciliary bands that mimic the natural arrangements of ciliary bands on the surface of starfish larva. Our system leverages nonlinear acoustics at microscales to drive bulk fluid motion via acoustically actuated small-amplitude oscillations of synthetic cilia. By arranging the planar ciliary bands angled towards (+) or away (−) from each other, we achieve bulk fluid motion akin to a flow source or sink. We further combine these flow characteristics with a physical principle to circumvent the scallop theorem and realize acoustic-based propulsion at microscales. Finally, inspired by the feeding mechanism of a starfish larva, we demonstrate an analogous microparticle trap by arranging + and − ciliary bands adjacent to each other

    THE IMPACT OF THE DEVELOPMENT OF MARITIME AUTONOMOUS SYSTEMS ON THE ETHICS OF NAVAL CONFLICTS

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    Robotic systems are believed to be the elements of conceptual inflexion in the conduct of future military conflicts. The progress made by the military industry in the field of robotics science and engineering, coupled with the practical results obtained in theatres of operations, have led us to the hypothesis of a paradigm shift regarding the role that autonomous systems will have not only in designing military operations but also in approaching the ethics of military action

    Magnitude and correlates of moderate to severe anemia among adult HIV patients receiving first line HAART in Northwestern Tanzania: a cross sectional clinic based study

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    Introduction: Moderate to severe anemia is an important clinical problem in HIV patients on Highly Active Antiretroviral Therapy. The rate of progression and mortality in this sub group of patients is high compared to non anemic patients. In sub Saharan Africa with scale up of Anti retroviral therapy, the magnitude of this problem is not known especially in Tanzania. This study aimed at determining the magnitude and correlates of moderate to severe anemia in HIV patients receiving first line ART in northwestern Tanzania. Methods: This was a cross sectional clinic based study, involving adult HIV patients on first line Highly Active Antiretroviral Therapy at Bugando Medical Centre Care and Treatment Center. The patients' data were analyzed using STATA version 11 to determine the prevalence of moderate to severe anemia and risk factors that could predict occurrence of anemia. Results: In this study 346 patients on Highly Active Anti-Retroviral Therapy were enrolled, of whom 100(40.46%) had moderate to severe anemia. The odds of being anemic were strongly predicted by Zidovudine based regime, low baseline CD4 count (< 200 cells/μl) and HIV stage 3&4 at enrollment. Most of the anemic patients had mean corpuscular volume of >100fl. Conclusion: The prevalence of moderate to severe anemia is significantly high in this cohort of HIV-infected patients on first line Anti Retroviral Therapy and it is strongly predicted by Zidovudine based regime, low baseline CD4 and HIV stage 3 and 4. On clinical grounds this suggests that patients who are initiated on Zidovudine based regimen and those in advanced HIV at enrollment should have regular haemoglobin follow up to identify anemia at its earliest stage to improve the clinical outcome of these patients.Pan African Medical Journal 2016; 2

    Mini-Invasive Extraarticular Stabilization of the Cranial Cruciate Deficient Stifle in Dogs

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    The purpose of this work was to describe three mini-invasive techniques for extraarticular stabilization of the deficient stifle based of bone anchores inserted in quasi-isometric sites.Suture stabilization of the stifle consisted of placing a monofilament nylon leader line or polyethylene suture between femoral site adjacent to the distal poles of the fabella, and tibial site immediately cranial to the long digital extensor tendon, using two anchor types. Each stifle was tested (cranial drawer test and tibial compression test) before and after arthroscopic transection of the cranial cruciate ligament and after performing the assigned procedure. Surgical approach, order of procedural steps, drill hole entrance and exit points, and techniques for anchors placement, tensioning, and securing were described.The results of the cranial drawer test and tibial compression test do not show statistically significant differences between the three applied techniques. All three techniques provide passive stability to the deficient stifle

    Monthly average daily global and diffuse solar radiation based on sunshine duration and clearness index for Brasov, Romania

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    The main objective of this study is to develop single location appropriate models for the estimation of the monthly average daily global and diffuse horizontal solar radiation for Brasov, Romania. The study focuses particularly on models based on the sunshine duration and clearness index. The data used for the calibration of the models were collected during a period of 4 yr, between November 2008 and October 2012, at the Transilvania University of Brasov. The testing and validation of the models was carried out using data from the online SoDa database for Brasov for the year 2005. Different statistical error tests were applied to evaluate the accuracy of the models. The predicted values are also compared with values from three other known models concerning the global and diffuse solar radiation. A new mixed model was developed for the estimation of monthly average daily global horizontal solar radiation. The data processing was performed by means of a real-time interface developed with LabVIEW graphical programming language. The parameters taken into account were the relative sunshine, the clearness index, the extraterrestrial radiation, the latitude and the longitude. The methodology is simple and effective and may be applied for any region. Its effectiveness was proven through comparison with global models

    Peculiarities of the comparative metallograms of the uroconcrements having urates as dominant component and phosphates as dominant component

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    Investigations were made on uroconcrements collected from two groups of subjects (patients) with kidney stones and admitted in the hospital. In the first step, using Fourier Transformed Infrared Spectroscopy (FT-IR) the types of uroconcrements were defined. Further on, a limited number of uroconcrements were analyzed by means of atomic absorption spectroscopy (AAS) in order to determine the concentration of the some alkaline (Na, K) and alkaline-earth (Ca, Mg) metals in their composition. From the first group only the uroconcrements having urates as dominant components and from the second group only the uroconcrements having phosphates as dominant components were selected. The comparison of the obtained metallograms revealed aspects about the types of lithiasis and their specificity
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