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Yi Hu, Xiangjie Chen, Kun Yang, Daohui Lin
Toxicity of silver nanoparticles (AgNPs) has been studied in various culture media. However, these media notably differ from the natural aquatic system, thus the conclusions may be inapplicable for real environment condition. The toxicity and its underlying mechanism of AgNPs in surface waters warrant more investigations. This study investigated the acute toxicity, chronic toxicity, bioaccumulation, and alga-daphnia food chain transfer of citrate-coated AgNPs (C-AgNPs) and Ag(+) (from AgNO3) to D. magna in a culture medium (M4) and a surface water sample...
October 17, 2017: Science of the Total Environment
Nicolas Lemercier, Volker Middel, Didier Hentsch, Serge Taubert, Masanari Takamiya, Tanja Beil, Jean-Luc Vonesch, Tilo Baumbach, Patrick Schultz, Claude Antony, Uwe Strähle
Many areas of biological research demand the combined use of different imaging modalities to cover a wide range of magnifications and measurements or to place fluorescent patterns into an ultrastructural context. A technically difficult problem is the efficient specimen transfer between different imaging modalities without losing the coordinates of the regions-of-interest (ROI). Here, we report a new and highly sensitive integrated system that combines a custom designed microscope with an ultramicrotome for in-resin-fluorescence detection in blocks, ribbons and sections on EM-grids...
October 19, 2017: Scientific Reports
Ninni Persson, Catarina Lavebratt, Natalie C Ebner, Håkan Fischer
Dopaminergic pathways play a crucial role in reward processing, and advanced age can modulate its efficiency. DARPP-32 controls dopaminergic function and is a chemical nexus of reward processing. In 61 younger (20-30 years) and older adults (54% ♀) (65-74 years), we examined how blood-oxygen-level dependent (BOLD) activation to emotional faces, vary over genotypes at three single nucleotide polymorphism (SNPs), coding for DARPP-32 (rs879606; rs907094; 3764352). We also assessed age-magnification of DARPP-32 effects on BOLD activation...
October 1, 2017: Social Cognitive and Affective Neuroscience
Xuemin Cheng, Maolin Li, Jialing Zhou, Hui Ma, Qun Hao
We previously developed a Mueller matrix microscope by combining a dual-rotating-retarder device with a commercial microscope, which holds promise for pathologic diagnosis applications. In practical applications, the signals to be measured are sensitive to systematic errors, and the measurement accuracy and the instrument calibration affect the capacity to characterize the data. In conventional calibration, the initial positions of the rotating devices are constrained, causing calibration instability. To improve the calibration, we examine the mathematical model of the calibration process using previous studies, and derive a calibration algorithm with reduced error magnification...
September 1, 2017: Applied Optics
Stephane Perrin, Audrey Leong-Hoï, Sylvain Lecler, Pierre Pfeiffer, Ivan Kassamakov, Anton Nolvi, Edward Hæggström, Paul Montgomery
In the present work, we have investigated the combination of a superresolution microsphere-assisted 2D imaging technique with low-coherence phase-shifting interference microscopy. The imaging performance of this technique is studied by numerical simulation in terms of the magnification and the lateral resolution as a function of the geometrical and optical parameters. The results of simulations are compared with the experimental measurements of reference gratings using a Linnik interference configuration. Additional measurements are also shown on nanostructures...
September 1, 2017: Applied Optics
Yajun Niu, Jun Chang, Fengxiang Lv, Benlan Shen, Weilin Chen
Foveated imaging systems have the ability to capture local high-resolution or high-magnification images with wide field of view (FOV); thus, they have great potential for applications in the field of monitoring and remote sensing of unmanned aerial vehicles. Hence, foveated optical systems are in strong demand. However, the existing foveated imaging systems either are equipped with expensive modulators or require fixing the local high resolution imaging field, which is not suitable for mass production or object tracking in industrial applications...
October 1, 2017: Applied Optics
Cristina M Gómez-Sarabia, Luis M Ledesma-Carrillo, Cipriano Guzmán-Cano, Miguel Torres-Cisneros, Rafael Guzmán-Cabrera, Jorge Ojeda-Castañeda
We present an alignment technique that exploits angular correlations by employing a pair of masks, which encode in an angular format pseudo-random sequences. The angular correlator generates peaked irradiance distributions on-axis, provided that the elements of the pair are aligned. Otherwise, the on-axis irradiance distribution decreases to a minimum value. Since the proposed angular correlator is independent of the lateral magnification, it is useful for testing the performance of varifocal lenses. A merit function describes the tolerance to focus errors associated with the location of a small size detector...
October 1, 2017: Applied Optics
Antonín Mikš, Jiří Novák
A method is described for the first-order analysis of a two-conjugate zoom lens composed of three movable elements. Such an optical system satisfies the requirement that the object, image, and pupil planes are fixed within the change of its magnification. General formulas are derived for the calculation of parameters of a three-component two-conjugate zoom lens system, which enable us to calculate the optical power of individual optical elements and their distances for a different range of magnification and imposed conditions...
June 20, 2017: Applied Optics
Tim Stangner, Hanqing Zhang, Tobias Dahlberg, Krister Wiklund, Magnus Andersson
Wide field-of-view imaging of fast processes in a microscope requires high light intensities motivating the use of lasers as light sources. However, due to their long spatial coherence length, lasers are inappropriate for such applications, as they produce coherent noise and parasitic reflections, such as speckle, degrading image quality. Therefore, we provide a step-by-step guide for constructing a speckle-free and high-contrast laser illumination setup using a rotating ground glass diffuser driven by a stepper motor...
July 1, 2017: Applied Optics
Kensuke Umehara, Junko Ota, Takayuki Ishida
In this study, the super-resolution convolutional neural network (SRCNN) scheme, which is the emerging deep-learning-based super-resolution method for enhancing image resolution in chest CT images, was applied and evaluated using the post-processing approach. For evaluation, 89 chest CT cases were sampled from The Cancer Imaging Archive. The 89 CT cases were divided randomly into 45 training cases and 44 external test cases. The SRCNN was trained using the training dataset. With the trained SRCNN, a high-resolution image was reconstructed from a low-resolution image, which was down-sampled from an original test image...
October 18, 2017: Journal of Digital Imaging: the Official Journal of the Society for Computer Applications in Radiology
Tatiana Novikova
This paper provides an overview of the current research in the field of optical techniques for cervical neoplasia detection and covers a wide range of the existing and emerging technologies. Using colposcopy, a visual inspection of the uterine cervix with a colposcope (a binocular microscope with 3- to 15-fold magnification), has proven to be an efficient approach for the detection of invasive cancer. Nevertheless, the development of a reliable and cost-effective technique for the identification of precancerous lesions, confined to the epithelium (cervical intraepithelial neoplasia) still remains a challenging problem...
2017: Beilstein Journal of Nanotechnology
Ashish Arjun Ahuja, Piyush Kohli, Sonali Lomte
No abstract text is available yet for this article.
October 2017: Indian Journal of Ophthalmology
Ali Al-Naji, Javaan Chahl
Most existing non-contact monitoring systems are limited to detecting physiological signs from a single subject at a time. Still, another challenge facing these systems is that they are prone to noise artifacts resulting from motion of subjects, facial expressions, talking, skin tone, and illumination variations. This paper proposes an efficient non-contact system based on a digital camera to track the cardiorespiratory signal from a number of subjects (up to six persons) at the same time with a new method for noise artifact removal...
2017: IEEE Journal of Translational Engineering in Health and Medicine
David Lalande, Jeffrey A Hodd, John S Brousseau, Van Ramos, Daniel Dunham, Frederick Rueggeberg
STATEMENT OF PROBLEM: Because crowns with open margins are a well-known problem and can lead to complications, it is important to assess the accuracy of margins resulting from the use of a new technique. Currently, data regarding the marginal fit of computer-aided design and computer-aided manufacturing (CAD-CAM) technology to fabricate a complete gold crown (CGC) from a castable acrylate resin polymer block are lacking. PURPOSE: The purpose of this in vitro study was to compare marginal discrepancy widths of CGCs fabricated by using either conventional hand waxing or acrylate resin polymer blocks generated by using CAD-CAM technology...
October 14, 2017: Journal of Prosthetic Dentistry
E Kornemann, O Márkus, A Opolka, T Zhou, I Greving, M Storm, C Krywka, A Last, J Mohr
We introduce the concept of a miniaturized compound refractive X-ray zoom lens consisting of SU-8 lenses fabricated by deep X-ray lithography. The focal length can be varied by changing the number of lens elements placed in the beam. We use suitable actuators to move single lens elements reversibly out of the beam. The X-ray zoom lens can accept different X-ray energies while keeping a fixed working distance, or vary the focal distance for a fixed energy. The latter is useful in tuning the magnification factor in full field microscopy...
September 18, 2017: Optics Express
Heejung Lee, Philjun Jeon, Dugyoung Kim
Digital in-line holographic microscopy (DIHM) has attracted attention because of its simple but powerful three-dimensional (3D) imaging capability. To improve the spatial resolution, 3D image reconstruction algorithms use numerical magnification, which generates distortions in the generated images. We propose a method to overcome this problem by using the simple relation between the object and image positions in 3D space. Several holograms were taken while translating a resolution target at different axial positions by a motorized stage...
September 4, 2017: Optics Express
Ronghuan Chen, Hua Liu, Haolin Zhang, Wenjuan Zhang, Jia Xu, Wenbin Xu, Jinhuan Li
The resolution of digital micro-mirror device (DMD) scanning lithography is limited in the transverse direction (the scanning direction is vertical) as a result of the compacted size of the DMD micro-mirror and the low magnification of the projection lens. Above-stated restrictions lead to an unsatisfactory saw-tooth edge (size ~one DMD pixel) after the lithography process within all directions except for the scanning orientation. In order to smooth the edge, an optimized sub-pattern construction method, described as the combination of wobulation techniques and the continuous scanning lithography process, is proposed...
September 4, 2017: Optics Express
Julie Benard, Jérôme Rivory, Florian Rostain, Céline Montuclard, Valérie Hervieu, Thierry Ponchon, Mathieu Pioche
No abstract text is available yet for this article.
October 17, 2017: Endoscopy
Josko Viskic, Drazen Jokic, Suzana Jakovljevic, Lana Bergman, Sladana Milardovic Ortolan, Senka Mestrovic, Ketij Mehulic
OBJECTIVE: To evaluate the surface of glazed lithium disilicate dental ceramics after irradiation under different irradiation settings of Nd:YAG and Er:YAG lasers using a scanning electron microscope (SEM). MATERIALS AND METHODS: Three glazed-press lithium disilicate ceramic discs were treated with HF, Er:YAG, and Nd:YAG, respectively. The laser-setting variables tested were laser mode, repetition rate (Hz), power (W), time of exposure (seconds), and laser energy (mJ)...
October 17, 2017: Angle Orthodontist
Bianca F Hettlich
Minimally invasive spine surgery (MISS) seems to have many benefits for human patients and is currently used for various minor and major spine procedures. For MISS, a change in access strategy to the target location is necessary and it requires intraoperative imaging, special instrumentation, and magnification. Few veterinary studies have evaluated MISS for canine patients for spinal decompression procedures. This article discusses the general requirements for MISS and how these can be applied to veterinary spinal surgery...
October 13, 2017: Veterinary Clinics of North America. Small Animal Practice
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