172 research outputs found

    Manganese Doped Fluorescent Paramagnetic Nanocrystals for Dual-Modal Imaging

    Get PDF
    In this work, dual-modal (fluorescence and magnetic resonance) imaging capabilities of water-soluble, low-toxicity, monodisperse Mn-doped ZnSe nanocrystals (NCs) with a size (6.5 nm) below the optimum kidney cutoff limit (10 nm) are reported. Synthesizing Mn-doped ZnSe NCs with varying Mn2+ concentrations, a systematic investigation of the optical properties of these NCs by using photoluminescence (PL) and time resolved fluorescence are demonstrated. The elemental properties of these NCs using X-ray photoelectron spectroscopy and inductive coupled plasma-mass spectroscopy confirming Mn2+ doping is confined to the core of these NCs are also presented. It is observed that with increasing Mn2+ concentration the PL intensity first increases, reaching a maximum at Mn2+ concentration of 3.2 at% (achieving a PL quantum yield (QY) of 37%), after which it starts to decrease. Here, this high-efficiency sample is demonstrated for applications in dual-modal imaging. These NCs are further made water-soluble by ligand exchange using 3-mercaptopropionic acid, preserving their PL QY as high as 18%. At the same time, these NCs exhibit high relaxivity (approximate to 2.95 mM(-1) s(-1)) to obtain MR contrast at 25 degrees C, 3 T. Therefore, the Mn2+ doping in these water-soluble Cd-free NCs are sufficient to produce contrast for both fluorescence and magnetic resonance imaging techniques

    Economic Performance of Pre-Crops in a Three-Year Rotation Program for Organic Vegetable Production

    Get PDF
    A four year experiment is being carried out, at Ege University Department of Horticulture, in which three different pre-crops are tested under an organic management system as compared to fallow. The aim of the experiment is to identify the most suitable rotation program for organic vegetable production in Turkey. Vicia sativa (common vetch), Brassica oleracea var. italica (broccoli), Vicia faba ‘Sevilla’ (faba bean) and fallow are tested as preceding (winter) crops. During the experiment carried out between 2007 and 2009, the main crops were tomato (2007), zucchini (2008) and pepper (2009). Broccoli represented the farmers’ choice as a winter vegetable. Vetch (incorporated) and faba bean (partially harvested and incorporated) were selected as legumes well adapted to the regional conditions. Soil fertility was maintained by incorporation of the crop residues at the end of both cycles and addition of organic-certified commercial compost (Bioaktif) and compost tea during the main cycle. All the management, including disease and pest management, was carried out according to the organic regulations valid in Turkey and the EU. During the production seasons, all variable costs and revenue, during both the pre-crop and main crop cycles, were recorded and gross margin calculated for each treatment. Economic analysis showed that broccoli as a pre-crop required the highest variable costs followed by faba bean, vetch and fallow, in all three years. Total revenue was the highest in plots where broccoli was the pre-crop. It is followed by faba bean plots mostly because higher yields were obtained in main crop plots following faba bean. The least profitable was fallow – main crop rotation. Broccoli plants also have some extra benefits like adding a high amount of biomass to soil and suppressing weed growth due to shading and allelopathic effects

    Determinación de los efectos de algunas pastillas peletizadas en el rumen pH y temperaturas con sensores de rumen inalámbricos

    Get PDF
    Objective. This study was conducted with the aim of determination of the effects of pellets prepared with addition of different additives (molasses, guar meal and sepiolite) on changes in  in vitro rumen pH and temperature. Materials and methods. In the current study sixteen pelleted feeds were prepared with wheat and soybean straws. The Daisy incubator was used for maintaining (mimicing) rumen conditions and feed was incubated for 48 hours. The wireless rumen sensors were used for determination of the changes in in vitro rumen pH and temperature. The data were subjected to one way variance analysis. Results. The tested boluses were found to show similar temperature and pH measurements to digital pH metre measurements. The effect of sepiolite addition on pH and temperature was found insignificant in all treatments. The lowest pH value was determined for wheat straws. Control groups and molasses added in soybean straws and wheat straws were similar in terms of ruminal pH values. Guar meal and guar meal+molasses added in soybean straws was shown to increase pH (p<0.01). In vitro rumen temperatures in soybean straws were found lower compared to those in wheat straws in all treatments (p<0.001). Conclusions. It was concluded that boluses integrated to Daisy incubator can be safely used for determining the effects of feeds on rumen fermentation in in vitro studies. Objetivo. Este estudio se realizó con el fin de determinar los efectos de los pellets preparados con adición de diferentes aditivos (melaza, harina de guar y sepiolita) sobre los cambios en el pH y temperatura in vitro del rumen. Materiales y métodos. En este estudio, se prepararon dieciséis alimentos peletizados con pajas de trigo y soya. La incubadora Daisy se usó para mantener (imitar) las condiciones del rumen y la alimentación se incubó durante 48 horas. Los sensores de rumen inalámbricos se usaron para la determinación de los cambios en el pH y la temperatura in vitro del rumen. Los datos fueron sometidosa análisis de varianza de una vía. Resultados. Se encontró que los bolos evaluados muestran mediciones de temperatura y pH similares a las mediciones del medidor de pH digital. El efecto de la adición de sepiolita sobre el pH y la temperatura fue insignificante en todos los tratamientos. El valor de pH más bajo se determinó para pajas de trigo. La adición de grupos de control y melazas en pajas de soya y paja de trigo fue similar en términos de valores de pH ruminal. Se demostró que la adición de harina de guar y harina de guar + melazas en pajas de soya aumenta el pH (p <0.01). Las temperaturas in vitro del rumen en las pajuelas de soya fueron menores en comparación con las pajas de trigo en todos los tratamientos (p <0.001). Conclusiones Se concluyó que los bolos integrados a la incubadora Daisy se pueden utilizar de forma segura para determinar los efectos de los alimentos en la fermentación ruminal en estudios in vitro

    ORGANİK ÜRETİMDE FİĞ (Vicia sativa) İLE YAPILAN YEŞİL GÜBRELEMENİN BAZI SEBZE TÜRLERİNİN VERİMİNE VE TOPRAK ÖZELLİKLERİNE ETKİSİ

    Get PDF
    Organik tarımda yeşil gübreleme toprak sağlığının korunması açısından vazgeçilmez bir uygulamadır. Çalışmada nadasa bırakma ve fiğ ile yapılan yeşil gübrelemenin sonrasında yetiştirilen sebze türleri (domates, kabak, biber ve patlıcan) üzerine olan etkisi ile uzun vadede toprak organik maddesi ve bazı bitki besin elementlerinin değişimi incelenmiştir. 2006-2010 yılları arasında yürütülen çalışmada, fiğ ile yapılan yeşil gübreleme ve nadas uygulamasının yanı sıra (CT) kompost çayı ve (CF) "Powhumus" ticari isimli organik gübreler alt faktör olarak yer almışlardır. Fiğ ile yapılan yeşil gübreleme biber verimini istatistiksel olarak arttırmıştır, CF gübreleme ise domates ve kabak verimi üzerinde etkili olmuştur. Buna karşılık, yeşil gübreleme domates ve kabak verimi üzerinde etkisiz kalmıştır. Patlıcan verimi ise hem CF gübre hem de fiğ ile yapılan yeşil gübrelemeden olumlu etkilenmişti. Dikim öncesi uygulanan CF gübresi toprak organik maddesini de artırmıştır. Toprakta azot miktarı yeşil gübreleme ve gübre tiplerinden etkilenmese de yıllar bazında artış göstermiştir. Toprakta fosfor miktarı fiğ ile yapılan gübrelemeden olumsuz etkilenirken, potasyum miktarı yetiştirilen sebze türlerine bağlı olarak değişiklikler göstermiştir

    Percutaneous management of complicated parapneumonic effusion and empyema after surgical tube thoracostomy failure in children: a retrospective study

    Get PDF
    PurposeWe aimed to evaluate the results of percutaneous management of complicated parapneumonic effusions (PPE) and empyema after surgical tube thoracostomy failure in children.MethodsA total of 84 children treated percutaneously after surgical tube thoracostomy failure between 2004 and 2019 were included to this retrospective study. Technical success was defined as appropriate placement of the drainage catheter. Clinical success was defined as complete resolution of infection both clinically and radiologically. Management protocol included imaging-guided pigtail catheter insertion, fibrinolytic therapy, serial ultrasonographic evaluation, catheter manipulations as necessary (revision, exchange, or upsizing), and appropriate antibiotherapy. All patients were followed up at least 6 months.ResultsTechnical success rate was 100%. Unilateral single, unilateral double, and bilateral catheter insertions were performed in 73, 9, and 2 patients, respectively. Inserted catheter sizes ranged from 8 F to 16 F. Streptokinase, urokinase, and tissue plasminogen activator were used as fibrinolytic agent in 29 (34%), 14 (17%), and 41 (49%) patients, respectively. In order to maintain effective drainage, 42 additional procedures (catheter exchange, revision, reposition, or additional catheter placement) were performed in 20 patients (24%). Clinical success was achieved in 83 of 84 patients (99%). Median catheter duration was 8 days (4–32 days). Median hospital stay during percutaneous management was 11.5 days (7–45 days). Factors affecting the median catheter duration were the presence of necrotizing pneumonia (p < 0.001) and bronchopleural fistulae (p < 0.001).ConclusionPercutaneous imaging-guided catheterization with fibrinolytic therapy should be the method of choice in pediatric complicated PPE and empyema patients with surgical tube thoracostomy failure. Percutaneous treatment is useful in avoiding more aggressive surgical options

    Circular High-Q Resonating Isotropic Strain Sensors with Large Shift of Resonance Frequency under Stress

    Get PDF
    We present circular architecture bioimplant strain sensors that facilitate a strong resonance frequency shift with mechanical deformation. The clinical application area of these sensors is for in vivo assessment of bone fractures. Using a rectangular geometry, we obtain a resonance shift of 330 MHz for a single device and 170 MHz for its triplet configuration (with three side-by-side resonators on chip) under an applied load of 3,920 N. Using the same device parameters with a circular isotropic architecture, we achieve a resonance frequency shift of 500 MHz for the single device and 260 MHz for its triplet configuration, demonstrating substantially increased sensitivity

    Value CMR: Towards a comprehensive, rapid, cost-effective cardiovascular magnetic resonance imaging

    Get PDF
    Cardiac magnetic resonance imaging (CMR) is considered the gold standard for measuring cardiac function. Further, in a single CMR exam, information about cardiac structure, tissue composition, and blood flow could be obtained. Nevertheless, CMR is underutilized due to long scanning times, the need for multiple breath-holds, use of a contrast agent, and relatively high cost. In this work, we propose a rapid, comprehensive, contrast-free CMR exam that does not require repeated breath-holds, based on recent developments in imaging sequences. Time-consuming conventional sequences have been replaced by advanced sequences in the proposed CMR exam. Specifically, conventional 2D cine and phase-contrast (PC) sequences have been replaced by optimized 3D-cine and 4D-flow sequences, respectively. Furthermore, conventional myocardial tagging has been replaced by fast strain-encoding (SENC) imaging. Finally, T1 and T2 mapping sequences are included in the proposed exam, which allows for myocardial tissue characterization. The proposed rapid exam has been tested in vivo. The proposed exam reduced the scan time from \u3e1 hour with conventional sequences to \u3c20 minutes. Corresponding cardiovascular measurements from the proposed rapid CMR exam showed good agreement with those from conventional sequences and showed that they can differentiate between healthy volunteers and patients. Compared to 2D cine imaging that requires 12-16 separate breath-holds, the implemented 3D-cine sequence allows for whole heart coverage in 1-2 breath-holds. The 4D-flow sequence allows for whole-chest coverage in less than 10 minutes. Finally, SENC imaging reduces scan time to only one slice per heartbeat. In conclusion, the proposed rapid, contrast-free, and comprehensive cardiovascular exam does not require repeated breath-holds or to be supervised by a cardiac imager. These improvements make it tolerable by patients and would help improve cost effectiveness of CMR and increase its adoption in clinical practice

    A Soft+Rigid Hybrid Exoskeleton Concept in Scissors-Pendulum Mode: A Suit for Human State Sensing and an Exoskeleton for Assistance

    Get PDF
    In this paper, we present a novel concept that can enable the human aware control of exoskeletons through the integration of a soft suit and a robotic exoskeleton. Unlike the state-of-the-art exoskeleton controllers which mostly rely on lumped human-robot models, the proposed concept makes use of the independent state measurements concerning the human user and the robot. The ability to observe the human state independently is the key factor in this approach. In order to realize such a system from the hardware point of view, we propose a system integration frame that combines a soft suit for human state measurement and a rigid exoskeleton for human assistance. We identify the technological requirements that are necessary for the realization of such a system with a particular emphasis on soft suit integration. We also propose a template model, named scissor pendulum, that may encapsulate the dominant dynamics of the human-robot combined model to synthesize a controller for human state regulation. A series of simulation experiments were conducted to check the controller performance. As a result, satisfactory human state regulation was attained, adequately confirming that the proposed system could potentially improve exoskeleton-aided applications
    corecore