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Depth of field

Christian Baeumer, Martin Janson, Beate Timmermann, Jörg Wulff
AIM: To assess if apertures shall be mounted upstream or downstream of a range shifting block if these field-shaping devices are combined with the pencil-beam scanning delivery technique (PBS). The lateral dose fall-off served as a benchmark parameter. Both options realizing PBS-with-apertures were compared to the uniform scanning mode. We also evaluated the difference regarding the out-of-field dose caused by interactions of protons in beam-shaping devices.
 Methods: The potential benefit of the downstream configuration over the upstream configuration was estimated analytically...
March 19, 2018: Physics in Medicine and Biology
K C Ringsberg, E Olander, P Tillgren, N Thualagant, A Trollvik
BACKGROUND: Health literacy is an essential social determinant for promoting and maintaining the health of a population. AIM: From a health promotion perspective, explore health literacy issues, concerns and future challenges among Nordic practitioners and researchers. METHODS: Data were collected in a workshop at the 8th Nordic Health Promotion Conference, and in a literature review, with articles from five databases. The search included title and abstract with the search terms health literacy* and health literacy as a MeSH term and all the Nordic countries...
February 2018: Scandinavian Journal of Public Health
Hinnerk Schulz-Hildebrandt, Mario Pieper, Charlotte Stehmar, Martin Ahrens, Christian Idel, Barbara Wollenberg, Peter König, Gereon Hüttmann
Intravital microscopy (IVM) offers the opportunity to visualize static and dynamic changes of tissue on a cellular level. It is a valuable tool in research and may considerably improve clinical diagnosis. In contrast to confocal and non-linear microscopy, optical coherence tomography (OCT) with microscopic resolution (mOCT) provides intrinsically cross-sectional imaging. Changing focus position is not needed, which simplifies especially endoscopic imaging. For in-vivo imaging, here we are presenting endo-microscopic OCT (emOCT)...
February 1, 2018: Biomedical Optics Express
Bo Cai, Xiaomin Zhai, Zeguan Wang, Yan Shen, Ronald Xu, Zachary J Smith, Quan Wen, Kaiqin Chu
Monitoring and manipulating neuronal activities with optical microscopy desires a method where light can be focused or projected over a long axial range so that large brain tissues (>100 [Formula: see text] thick) can be simultaneously imaged, and specific brain regions can be optogenetically stimulated without the need for slow optical refocusing. However, the micron-scale resolution required in neuronal imaging yields a depth of field of less than 10 [Formula: see text] in conventional imaging systems...
February 1, 2018: Biomedical Optics Express
Raimund Lechner, Thomas Küpper, Markus Tannheimer
INTRODUCTION: History is full of examples of the influence of the mountain environment on warfare. The aim of this article is to identify the main environmental hazards and summarize countermeasures to mitigate the impact of this unique environment. METHODS: A selective PubMed and Internet search was conducted. Additionally, we searched bibliographies for useful supplemental literature and included the recommendations of the leading mountain medicine and wilderness medicine societies...
March 15, 2018: Wilderness & Environmental Medicine
Juntao Xia, Lin Ye, Hongqiang Ren, Xu-Xiang Zhang
Aerobic granular sludge (AGS), a self-immobilized microbial consortium containing different functional microorganisms, is receiving growing attention, since it has shown great technological and economical potentials in the field of wastewater treatment. Microbial community is crucial for the formation, stability, and pollutant removal efficiency of aerobic granules. This mini-review systematically summarizes the recent findings of the microbial community structure and function of AGS and discusses the new research progress in the microbial community dynamics during the granulation process and spatial distribution patterns of the microbiota in AGS...
March 17, 2018: Applied Microbiology and Biotechnology
Valérie Leclair, Ingrid E Lundberg
PURPOSE OF REVIEW: Idiopathic inflammatory myopathy (IIM) classification criteria have been a subject of debate for many decades. Despite several limitations, the Bohan and Peter criteria are still widely used. The aim of this review is to discuss the evolution of IIM classification criteria. RECENT FINDINGS: New IIM classification criteria are periodically proposed. The discovery of myositis-specific and myositis-associated autoantibodies led to the development of clinico-serological criteria, while in-depth description of IIM morphological features improved histopathology-based criteria...
March 17, 2018: Current Rheumatology Reports
Nils Gessert, Matthias Schlüter, Alexander Schlaefer
Tracking the pose of instruments is a central problem in image-guided surgery. For microscopic scenarios, optical coherence tomography (OCT) is increasingly used as an imaging modality. OCT is suitable for accurate pose estimation due to its micrometer range resolution and volumetric field of view. However, OCT image processing is challenging due to speckle noise and reflection artifacts in addition to the images' 3D nature. We address pose estimation from OCT volume data with a new deep learning-based tracking framework...
March 10, 2018: Medical Image Analysis
Nicola Pinto, S Javad Rezvani, Andrea Perali, Luca Flammia, Milorad V Milošević, Matteo Fretto, Cristina Cassiago, Natascia De Leo
Superconducting and normal state properties of Niobium nanofilms have been systematically investigated as a function of film thickness, on different substrates. The width of the superconducting-to-normal transition for all films is remarkably narrow, confirming their high quality. The superconducting critical current density exhibits a pronounced maximum for thickness around 25 nm, marking the 3D-to-2D crossover. The magnetic penetration depth shows a sizeable enhancement for the thinnest films. Additional amplification effects of the superconducting properties have been obtained with sapphire substrates or squeezing the lateral size of the nanofilms...
March 16, 2018: Scientific Reports
Ping Yang, Derrick Y F Lai, Jia F Huang, Chuan Tong
Aquaculture ponds are dominant features of the landscape in the coastal zone of China. Generally, aquaculture ponds are drained during the non-culture period in winter. However, the effects of such drainage on the production and flux of greenhouse gases (GHGs) from aquaculture ponds are largely unknown. In the present study, field-based research was performed to compare the GHG fluxes between one drained pond (DP, with a water depth of 0.05m) and one undrained pond (UDP, with a water depth of 1.16m) during one winter in the Min River estuary of southeast China...
March 2018: Journal of Environmental Sciences (China)
Xiangsheng Xie, Huichang Zhuang, Hexiang He, Xiaoqing Xu, Haowen Liang, Yikun Liu, Jianying Zhou
Human ability to visualize an image is usually hindered by optical scattering. Recent extensive studies have promoted imaging technique through turbid materials to a reality where color image can be restored behind scattering media in real time. The big challenge now is to recover objects in a large field of view with depth resolving ability. Based on the existing research results, we systematically study the physical relationship between speckles generated from objects at different planes. By manipulating a given single point spread function, depth-resolved imaging through a thin scattering medium can be extended beyond the original depth of field (DOF)...
March 15, 2018: Scientific Reports
A G Ramos, V J García-Garrido, A M Mancho, S Wiggins, J Coca, S Glenn, O Schofield, J Kohut, D Aragon, J Kerfoot, T Haskins, T Miles, C Haldeman, N Strandskov, B Allsup, C Jones, J Shapiro
Transoceanic Gliders are Autonomous Underwater Vehicles (AUVs) for which there is a developing and expanding range of applications in open-seas research, technology and underwater clean transport. Mature glider autonomy, operating depth (0-1000 meters) and low energy consumption without a CO2 footprint enable evolutionary access across ocean basins. Pursuant to the first successful transatlantic glider crossing in December 2009, the Challenger Mission has opened the door to long-term, long-distance routine transoceanic AUV missions...
March 15, 2018: Scientific Reports
Long Chen, Wen Tang, Nigel W John, Tao Ruan Wan, Jian Jun Zhang
BACKGROUND AND OBJECTIVE: While Minimally Invasive Surgery (MIS) offers considerable benefits to patients, it also imposes big challenges on a surgeon's performance due to well-known issues and restrictions associated with the field of view (FOV), hand-eye misalignment and disorientation, as well as the lack of stereoscopic depth perception in monocular endoscopy. Augmented Reality (AR) technology can help to overcome these limitations by augmenting the real scene with annotations, labels, tumour measurements or even a 3D reconstruction of anatomy structures at the target surgical locations...
May 2018: Computer Methods and Programs in Biomedicine
Longchao Yao, Jun Chen, Paul E Sojka, Xuecheng Wu, Kefa Cen
Dynamic stringy objects such as liquid rims and ligaments are frequently observed in important applications such as the multiphase breakup of fuel droplets. We develop a new method based on digital in-line holography to automatically measure complicated stringy objects. A static spring mounted on a rotator is measured to validate the effectiveness and accuracy of the method. The sections are extracted along the skeleton of the spring in a depth-of-field extended image and then sized and located as individual particles using a hybrid method...
March 15, 2018: Optics Letters
Bicheng Luo, Feng Xu, Christian Richardt, Jun-Hai Yong
We propose a novel 360° scene representation for converting real scenes into stereoscopic 3D virtual reality content with head-motion parallax. Our image-based scene representation enables efficient synthesis of novel views with six degrees-of-freedom (6-DoF) by fusing motion fields at two scales: (1) disparity motion fields carry implicit depth information and are robustly estimated from multiple laterally displaced auxiliary viewpoints, and (2) pairwise motion fields enable real-time flow-based blending, which improves the visual fidelity of results by minimizing ghosting and view transition artifacts...
April 2018: IEEE Transactions on Visualization and Computer Graphics
M B Agranat, O V Chefonov, A V Ovchinnikov, S I Ashitkov, V E Fortov, P S Kondratenko
We report on the experimental observation of high-power terahertz-radiation-induced damage in a thin aluminum film with a thickness less than a terahertz skin depth. Damage in a thin metal film produced by a single terahertz pulse is observed for the first time. The damage mechanism induced by a single terahertz pulse could be attributed to thermal expansion of the film causing debonding of the film from the substrate, film cracking, and ablation. The damage pattern induced by multiple terahertz pulses at fluences below the damage threshold is quite different from that observed in single-pulse experiments...
February 23, 2018: Physical Review Letters
Yan Shen, Neil McLaughlin, Xiaoping Zhang, Minggang Xu, Aizhen Liang
Crop residue return is imperative to maintain soil health and productivity but some farmers resist adopting conservation tillage systems with residue return fearing reduced soil temperature following planting and crop yield. Soil temperatures were measured at 10 cm depth for one month following planting from 2004 to 2007 in a field experiment in Northeast China. Tillage treatments included mouldboard plough (MP), no till (NT), and ridge till (RT) with maize (Zea mays L.) and soybean (Glycine max Merr.) crops...
March 14, 2018: Scientific Reports
Silvia Zingg, Patrick Dolle, Maarten Jeroen Voordouw, Maren Kern
BACKGROUND: Ticks and tick-borne pathogens are a global problem for the health of humans and their livestock. Wood ants are important ecosystem engineers in forests worldwide. Although both taxa are well studied, little is known about their interactions under natural conditions. The purpose of the present field study was to test whether European red wood ants (Formica polyctena) influence the abundance of Ixodes tick populations in temperate forests. METHODS: Data collection took place in 130 sampling plots located at 26 ant nest sites paired with 26 control sites in northwestern Switzerland...
March 15, 2018: Parasites & Vectors
Adélaïde Compaoré, Sabine Gies, Bernard Brabin, Halidou Tinto, Loretta Brabin
BACKGROUND: Iron deficiency remains a prevalent adolescent health problem in low income countries. Iron supplementation is recommended but improvement of iron status requires good adherence. OBJECTIVES: We explored factors affecting adolescent adherence to weekly iron and/or folic acid supplements in a setting of low secondary school attendance. METHODS: Taped in-depth interviews were conducted with participants in a randomised, controlled, periconceptional iron supplementation trial for young nulliparous women living in a rural, malaria endemic region of Burkina Faso...
March 14, 2018: Reproductive Health
Jitendra B Maurya, Alexandre François, Yogendra K Prajapati
One-dimensional photonic crystal (1DPC) sensors have emerged as contenders for traditional surface plasmon resonance sensors, owing to their potential for the detection of bigger molecules and particles due to their higher interaction volume in the sensing medium. Two-dimensional layered nanomaterials, most notably graphene and dichalcogenides (e.g., MoS₂, MoSe₂, WS₂, and WSe₂), have shown higher refractive index sensitivity because of their absorption as well as adsorption property. The proposed configuration of 1DPC presented consists of alternate layers of the aforementioned nanomaterials and silicon...
March 14, 2018: Sensors
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