<h2 class="jove_title"><a href="https://www.jove.com/video/53388">A Simple Method for the Size Controlled Synthesis of Stable Oligomeric Clusters of Gold Nanoparticles under Ambient Conditions</a></h2>Marlon Lawrence1, Anze Testen1, Tilen Koklic2, Oliver Smithies11Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, 2Condensed Matter Physics Department, Laboratory of Biophysics, Jozef Stefan Institute
We describe a simple method for producing highly stable oligomeric clusters of gold nanoparticles via the reduction of chloroauric acid (HAuCl4) with sodium thiocyanate (NaSCN). The oligoclusters have a narrow size distribution and can be produced with a wide range of sizes and surface coats.<h2 class="jove_title"><a href="https://www.jove.com/video/52272">A Basic Positron Emission Tomography System Constructed to Locate a Radioactive Source in a Bi-dimensional Space</a></h2>Luis Manuel Monta&#241;o-Zetina, Omar Villalobos-MoraPhysics Department, Centro de Investigacion y de Estudios Avanzados del IPN (Cinvestav)We present a simple but well-constructed Positron Emission Tomography (PET) system and elucidate its basic working principles. The goal of this protocol is to guide the user in constructing and testing a simple PET system.<h2 class="jove_title"><a href="https://www.jove.com/video/53604">Tracking Cells in GFP-transgenic Zebrafish Using the Photoconvertible PSmOrange System</a></h2>Carlo A. Beretta1,2,3, Nicolas Dross2, Ulrike Engel2, Matthias Carl11Medical Faculty Mannheim, Department of Cell and Molecular Biology, Heidelberg University, 2COS and Nikon Imaging Center at the University of Heidelberg, Heidelberg University, 3University of Heidelberg, Excellenzcluster CellNetworksWe established the photoconvertible PSmOrange system as a powerful, straight-forward and cost inexpensive tool for in vivo cell tracking in GFP transgenic backgrounds. This protocol describes its application in the zebrafish model system.<h2 class="jove_title"><a href="https://www.jove.com/video/53645">Modeling Chemotherapy Resistant Leukemia In Vitro</a></h2>William L. Slone*1, Blake S. Moses*1, Rebecca Evans1, Debbie Piktel1, Karen H. Martin1,2, William Petros1, Michael Craig1, Laura F. Gibson1,31Alexander B. Osborn Hematopoietic Malignancy and Transplantation Program of the Mary Babb Randolph Cancer Center, Robert C. Byrd Health Sciences Center, West Virginia University School of Medicine, 2Department of Neurobiology and Anatomy, Robert C. Byrd Health Sciences Center, West Virginia University School of Medicine, 3Department of Microbiology, Immunology and Cell Biology, Robert C. Byrd Health Sciences Center, West Virginia University School of MedicineThe current report summarizes a protocol that can be utilized to model the influence of the bone marrow microenvironment niche on leukemic cells with emphasis placed on enrichment of the most chemoresistant subpopulation.

february 2016 - this month in jove: photoconvertible proteins, gold nanoparticles, pet principles, and bone marrow microenvironments

Here's a look at what's coming up in the <a href="http://www.jove.com/archive/108">February 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>, the transparent, rapidly developing zebrafish embryo is ideal for visualizing developmental processes. When cells of interest are labeled with fluorescent photoconvertible proteins, they allow precise tracking of defined structures-highlighting specific cells while leaving other transgenic cells in the dark. <a href="http://www.jove.com/video/53604/tracking-cells-gfp-transgenic-zebrafish-using-photoconvertible?status=a55610k">Beretta et al.</a> have established the photoswitchable monomeric orange (PSmOrange) system for zebrafish. This protein's orange-to-red spectrum allows it to visible in existing transgenic lines expressing green fluorescent protein (GFP). Microinjection of nuclear-targeted PSmOrange mRNA labels all cell nuclei with orange/red fluorescence, and targeted photoconversion switches its emission spectrum to far red. The quantum efficiency and stability of PSmOrange makes it a superb cell-tracking tool for living zebrafish during embryonic development and disease.
In <a href="http://www.jove.com/chem">JoVE Chemistry</a>, few materials have found as many uses in so many diverse fields as gold nanoparticles. Their applications range from biological sensors to radio frequency-based cancer treatments. Gold nanoparticles are valued for their unique structural, optical and electronic properties. These special attributes caught the interest of Oliver Smithies, who won the Nobel Prize in Physiology or Medicine in 2007. This month, he and his colleagues describe a simple method for producing highly stable oligomeric clusters of gold nanoparticles, and present models that can predict particle size with great accuracy.
In <a href="http://www.jove.com/eng">JoVE Engineering</a>, we look at the principles of positron emission tomography (PET), a non-invasive technique for imaging the body's inner tissues and organs. <a href="http://www.jove.com/video/52272">Monta&#241;o-Zetina and Villalobos-Mora</a> present a guide for constructing a simple, homemade PET system for fully characterizing its basic working principles. This prototype demonstrates the primary functions of PET, and serves as an elegant model for teaching its principles to the academic public. 
In <a href="http://www.jove.com/med">JoVE Medicine</a>, it is well established that the bone marrow microenvironment provides a haven for hematopoietic diseases. This month, <a href="http://www.jove.com/video/53645/">Slone et al.</a> use cell types from the bone marrow niche in an in vitro co-culture model. This supports the generation of a subpopulation of chemoresistant tumor cells. These calls can be used to investigate the underlying pathways of tumor development and to test novel therapeutic strategies.
You've just had a sneak peek of the <a href="http://www.jove.com/archive/108">February 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 February 2016 - This Month in JoVE: Photoconvertible Proteins, Gold Nanoparticles, PET Principles, and Bone Marrow Microenvironments at JoVE.com

February 2016 - This Month in JoVE: Photoconvertible Proteins, Gold Nanoparticles, PET Principles, and Bone Marrow Microenvironments

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

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1.7K Views.  Massachusetts Eye and Ear. February 2016 - This Month in JoVE: Photoconvertible Proteins, Gold Nanoparticles, PET Principles, and Bone Marrow Microenvironments

Video: February 2016 - This Month in JoVE: Photoconvertible Proteins, Gold Nanoparticles, PET Principles, and Bone Marrow Microenvironments

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.

أغسطس 2012: من هذا الشهر في [جوف]

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

Research

JoVE Journal

Biology

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: A السنة قيد الاستعراض

 
 
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 ...