<h2 class="jove_title"><a href="https://www.jove.com/video/53792">Analyzing In Vivo Cell Migration using Cell Transplantations and Time-lapse Imaging in Zebrafish Embryos</a></h2>Florence A Giger1, Julien G Dumortier2, Nicolas B David11CNRS UMR8197 &ndash; INSERM U1024, IBENS, Institut de Biologie de l&#39;&#201;cole Normale Sup&#233;rieure, 2Department of Physiology Development and Neuroscience, University of CambridgeCombining cell transplantation, cytoskeletal labeling and loss/gain of function approaches, this protocol describes how the migrating zebrafish prospective prechordal plate can be used to analyze the function of a candidate gene in in vivo cell migration. <h2 class="jove_title"><a href="https://www.jove.com/video/53815">Comparing the Frequency Effect Between the Lexical Decision and Naming Tasks in Chinese</a></h2>Xin-Yu Gao*1, Meng-Feng Li*1, Tai-Li Chou*2, Jei-Tun Wu11Department of Psychology, National Taiwan University, 2Neurobiology and Cognitive Science Center, National Taiwan UniversityResearchers adopt both the lexical decision task and the naming task to investigate some important topics such as character/word recognition by comparing the frequency effect between these two tasks. This article introduces this approach through two exemplar experiments and elaborates on the underlying logic.<h2 class="jove_title"><a href="https://www.jove.com/video/53907">Development of an In Vitro Ocular Platform to Test Contact Lenses</a></h2>Chau-Minh Phan1, Hendrik Walther1, Huayi Gao2, Jordan Rossy1, Lakshman N. Subbaraman1, Lyndon Jones11School of Optometry and Vision Science, University of Waterloo, 2Medella HealthCurrent in vitro models for evaluating contact lenses (CLs) and other eye-related applications are severely limited. The presented ocular platform simulates physiological tear flow, tear volume, air exposure and mechanical wear. This system is highly versatile and can be applied to various in vitro analyses with CLs.<h2 class="jove_title"><a href="https://www.jove.com/video/53816">Visualization of Twitching Motility and Characterization of the Role of the PilG in Xylella fastidiosa</a></h2>Xiangyang Shi1, Hong Lin21<a>Department of Plant Science, University of California, Davis</a>, 2Agricultural Research Service, San Joaquin Valley Agricultural Sciences Center, United States Department of AgricultureIn this study, a nano-microfluidic flow chamber was employed to visualize and functionally characterize the twitching motility of Xylella fastidiosa, a bacterium that causes Pierce&#39;s disease in grapevine.

april 2016 - this month in jove: cell migration, bacterial motility, psycholinguistics, and in vitro eye model for contact lenses

Here's a look at what's coming up in the <a href="http://www.jove.com/archive/110">April 2016 issue</a> of <a href="http://www.jove.com/">JoVE: The Journal of Visualized Experiments</a>.
In <a href="http://www.jove.com/devbio">JoVE Developmental Biology</a>, cell migration is a vital process in multicellular organisms. It is not only essential during embryonic development, but also in adult life, when it contributes to physiological processes like wound healing and immunity. It is also involved in pathological situations, such as cancer growth and metastasis. Cell migration has been studied for decades in vitro; but in vivo studies have proven to be more difficult. This month <a href="http://www.jove.com/video/53792">Giger et al.</a> use cell transplantation to create mosaic zebrafish embryos, and taking advantage of the embryos' optical clarity, they analyze the migration of the prospective prechordal plate as a model system for studying gene function.
In <a href="http://www.jove.com/i2">JoVE Immunology &amp; Infection</a>, many bacteria can also move, and in some species, motility contributes to the capacity to invade and replicate in host tissues. The bacterium Xylella fastidiosa causes a number of diseases in economically important plants, and its twitching motility provides the means for long-distance travel and colonization. To study the mechanisms of twitching motility in X. fastidiosa, <a href="http://www.jove.com/video/53816">Shi and Lin</a> use a nano-microfluidic flow chamber integrated with a time-lapse image recording system. This allows long-term spatial and temporal observations of bacterial aggregation and migration. This system also provides a new approach for studying gene function in bacterial motility. 
In <a href="http://www.jove.com/behavior">JoVE Behavior</a>, it's well known that the more often a word occurs, the faster it can be identified. This phenomenon is known as the frequency effect. This month, <a href="http://www.jove.com/video/53815">Gao et al.</a> study the frequency effect using Chinese characters and two experimental paradigms in the field of psycholinguistic research: the lexical decision task, which measures how long it takes a subject to decide whether or not a character is an actual word; And the naming task, which measures how long it takes to speak a written word out loud. By using both methods, researchers can paint a more complete and precise picture of character and word recognition.
In <a href="http://www.jove.com/bioengineering">JoVE Bioengineering</a>, vision researchers have been striving to create an in vitro eye model to test contact lenses. Most models to date have many limitations in terms of physiological relevance, but this month <a href="http://www.jove.com/video/53907/">Phan et al.</a> present an ocular platform that simulates physiological tear flow, tear volume, air exposure and mechanical wear. This system is highly versatile and can be applied to various in vitro analyses with contact lenses.
You've just had a sneak peek of the <a href="http://www.jove.com/archive/110">April 2016 issue</a> of <a href="http://www.jove.com/">JoVE</a>. Visit the website to see the full-length articles, plus many more, in <a href="http://www.jove.com/">JoVE: The Journal of Visualized Experiments</a>.

Watch this Scientific Journal Video about April 2016 - This Month in JoVE: Cell Migration, Bacterial Motility, Psycholinguistics, and In Vitro Eye Model for Contact Lenses at JoVE.com

April 2016 - This Month in JoVE: Cell Migration, Bacterial Motility, Psycholinguistics, and In Vitro Eye Model for Contact Lenses

Here's a look at what's coming up in the April 2016 issue of JoVE: The Journal of Visualized Experiments.
In JoVE Developmental Biology, cell migration is ...

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August 2012: This Month in JoVE

Traditional microscopy requires lens objectives to magnify specimens, and can involve numerous optical components like additional objectives, filters, and mirrors to refract and direct light to optical sensors. The August 2012 issue of JoVE (Journal of Visualized Experiments) is marked by the third publication from the Ozcan Lab (University of California, Los Angeles) on their lens free lens-free "on-chip" microscopy platform, which they have pioneered.
Back in 2009, the Ozcan lab published their first article, which demonstrated the use of a lens-free imaging platform that could image cells within whole blood. This imaging technique involves placing a sample directly on an optoelectric sensor array, like the CCD or CMOS chips found in the standard camcorder. Then, LED illumination from above the sample casts shadows on the chip, which are recorded as digital holograms that can be subjected to image processing. Not only does this lensless imaging system allow for an extremely large field of view (FOV of 0.6-8 cm2), the lack of bulky optical components makes it excellent for microfluidic applications. The Ozcan group demonstrates this in their follow-up 2011 JoVE article, in which fluorescently labeled white blood cells are imaged within a microfluidic chip.
This August in JoVE, the Ozcan group demonstrates further advancements to their lens-free microscopy platform by applying it to tomographic imaging of the nematode, C. elegans. By changing the angle of illumination, using a motorized rotation stage, the Ozcan group shows how multiple holographic slices may be generated for a sample-which, following processing, can be combined into tomograms. The Ozcan group confirms that their 3D reconstruction of the worm is successful by citing that the pharyngeal tube, a 5-micron-thick structure, is only visible in a single slice and in a 3D reconstructed cross section.
The compact and inexpensive nature of the lens-free imaging systems - designed and assembled by the Ozcan group - make them well suited for point-of-care diagnostic applications, or even cell phone based microscopy that can be performed in the field.
At the Ernest Gallo Clinic and Research Center at University of California, San Francisco JoVE learns how to visualize morphological changes in single cells using three-dimensional fluorescence microscopy and computer analysis. In this procedure, cells are given agonist, antagonist plus agonist, or no treatment, and prepared for immunofluorescence microscopy. Three-dimensional images are acquired with the help of a two-photon laser system, and the fluorescence data are processed on the computer using Imaris and Matlab.
To demonstrate the power of this technique, our authors quantify single-cell phenotypic changes in transfected HEK293 cells. Three-dimensional morphometric analysis shows dramatic changes in cells treated with agonist. These changes are not always apparent when using conventional 2D analysis. This technique allows morphological changes in single cells to be quantified and characterized in response to pharmacologic stimuli, offering a powerful new assessment tool to the arsenal of drug discovery research.
This month, in JoVE Applied Physics, we travel to South Carolina to visit the School of Materials Science and Engineering at Clemson University. Here, researchers show us how to construct lithium batteries for laboratory research.
The basic components of a lithium coin cell are the working electrode, the lithium electrolyte, and a lithium foil counter electrode. The different components of the coin cell are carefully assembled and sealed with a crimping machine. The finished coin cell can then be characterized in a battery tester. Using their homemade coin cells, our researchers can experiment with using different materials to make the cathodes of lithium coin cells.
This month in JoVE Immunology and Infection, we head to Basel, Switzerland to witness two techniques for diagnosing helminth infections. We also see how investigators perform the shuttle run test in children, in order to assess the effects of these infections on physical fitness.
Helminths are parasitic worms that can live inside humans and animals. Many species infect the intestinal tract, and may be transmitted through soil. Our authors demonstrate the Kato-Katz technique, which is used for diagnosing several common soil-transmitted helminths. They also demonstrate the Baermann technique, which uses light to stimulate the migration of certain types of phototactic helminths out of sample preparations. The various types of helminth species can subsequently be determined based on morphology.
Our authors then demonstrate how to set up and perform a 20-meter shuttle run test for children, and to measure the impact of helminth infections on physical fitness. This method can help determine the true burden of soil-transmitted helminth infections on overall health.
This brief summary highlights but a few notable video-articles that will be released in August. We'll also feature articles that demonstrate how to express genes in the midbrain of the chick embryo, study neutrophil transmigration in parallel flow chambers lined with endothelial cells, and precisely measure proteolytic degradation of the extracellular matrix.

Traditional microscopy requires lens objectives to magnify specimens, and can involve numerous optical components like additional objectives, filters, and mirrors to refract and direct light to optical sensors. The August 2012 issue of JoVE (Journal of Visualized Experiments) is marked by the third publication from the Ozcan Lab (University of California, Los Angeles) on their lens-free "on-chip" microscopy platform, which they have pioneered.

Août 2012: Ce mois-ci dans JoVE

Traditional microscopy requires lens objectives to magnify specimens, and can involve numerous optical components like additional objectives, filters, and ...

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2012: A Year In Review

Here's a look at some of the milestones and highlights of the year 2012 in Journal of Visualized Experiments (JoVE).
At the start of 2012, JoVE reached a major milestone by publishing our 1500th article. In this publication, in JoVE Bioengineering, Yu et al. described a method for analyzing the free radical composition of cigarette smoke. This method simulated cigarette puffing with a single-port smoking device, and combined it with electron spin resonance (ESR) spectroscopy to measure the degree to which antioxidant compounds can scavenge free radicals in cigarette smoke. A possible outcome of this research is the creation of less harmful cigarettes.
JoVE Bioengineering also contained the most-viewed article of 2012. Owczarczak et al. described a method for hacking a standard inkjet printer, loading ink cartridges with a cell-suspension "bioink," and printing lines of live cells onto glass slides. The thermal inkjet printing process creates temporary pores in the cell membrane, visualized by the incorporation of fluorescently labeled actin monomers. This concept, called "bioprinting," has many potential applications in cell and tissue engineering.
Also in 2012, JoVE Bioengineering featured a protocol by Hsia et al. for isolating and purifying spider silk protein, spinning it into fibers, and assessing the fiber strength. This protocol for laboratory-scale production of spider silk, which is stronger than tensile steel, can potentially be extended to large-scale manufacturing.
In JoVE Clinical and Translational Medicine, we featured a number of articles related to stroke, one of which. In one article, M&ouml;bius-Winkler et al. demonstrated placement of the WATCHMAN left atrial appendage occlusion device from Boston Scientific. This device is designed to prevent strokes by trapping clots within the left atrial appendage of the heart before they exit. Our authors demonstrated how to insert the guide wire through the femoral artery into the heart, advance the device into the left atrium, and deploy the device in the left atrial appendage.
Another article focused on stroke, Hamel et al. described the use of a driving simulator to study how patients compensate for visual field defects following stroke. By analyzing the compensatory gaze behavior of patients as they navigated through virtual driving courses with varying degrees of complexity, our authors see great potential for the use of driving simulators in stroke rehabilitation.
In JoVE Immunology and Infection, we published an article by Keyel et al. describing the real-time kinetics of immune cell responses to bacterial toxins using live cell microscopy. Combined with high-speed 3D confocal microscopy, this technique can also visualize the cellular repair response.
Also in JoVE Immunology and Infection, we featured an article by Yap et al. describing methods for diagnosing helminth infections in children. Helminths are parasitic worms that can infect the intestinal tract of humans and animals, and may be distinguished based on their morphology. The same article demonstrated how to measure the impact of helminth infections on physical fitness in children, which is a measure of overall health.
In JoVE Neuroscience, we featured a method by Hoffmann et al., who used tiny headphones to alter the auditory feedback in songbirds, and analyzed the computational and neurophysiological basis of vocal learning in birds when they adjust their singing in response to altered acoustic signals.
Also in JoVE Neuroscience, we moved from birds to bees with a method that assesses associative and non-associative tactile learning in honeybees. This method, by Mujagi&#263; et al., allowed bees to scan different metal surfaces with their antennae, then conditioned them to expect sugar water when their antennae touched particular surfaces, and analyzed the corresponding changes in antennal movement.
In 2012, we launched a brand-new section: JoVE Applied Physics, which features articles on subjects ranging from plasma physics to material science. The Applied Physics section also contained JoVE's 2000th video article, filmed in a synchrotron radiation facility, where Borisenko et al. showed how to determine the electronic structure of complex materials using angle-resolved photoemission spectroscopy.
In the JoVE General section, we published an article by Artioli et al. demonstrating the use of a portable gas analyzer to measure oxygen consumption during complex exercise - such as judo. By analyzing oxygen consumption and collecting blood for measuring plasma lactate concentration, this method can determine the relative contributions of different energy systems to specific aspects of complex exercise.
Finally, JoVE followed Dolhi et al. to a permanently ice-covered saline lake in Antarctica. There, scientists drilled through the ice to study single-celled microorganisms called protists that live in the harsh conditions of Antarctica.
This Year in Review was just a brief glimpse of a few of over 600 video articles that JoVE offered in 2012. Browse the JoVE archives to see thousands of other videos, and stay tuned for what's coming up this year in JoVE: The Journal of Visualized Experiments.

Here's a look at some of the milestones and highlights of the year 2012 in Journal of Visualized Experiments (JoVE).

2012: Une année en revue

 
 
Here's a look at some of the milestones and highlights of the year 2012 in Journal of Visualized Experiments (JoVE).
At the start of 2012, JoVE ...

April 2016 - This Month in JoVE: Cell Migration, Bacterial Motility, Psycholinguistics, and In Vitro Eye Model for Contact Lenses

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Août 2012: Ce mois-ci dans JoVE

2012: Une année en revue