Wendy Chao

JoVE - Year in Review: 2015

In January 2015, JoVE Developmental Biology became the newest addition to the JoVE family, and featured a live-imaging protocol for visualizing the developing Drosophila eye. In February, JoVE Medicine showed state-of-the-art cranial ultrasound imaging in neonates. Advances in this technique have improved its diagnostic value, allowing timely therapeutic intervention. In March, JoVE Environment featured dendroecology, the science of using tree rings to study ecological effects of specific environmental factors. In April, JoVE Biology examined a mode of bacterial motility called swarming with a two-phase swarm assay. that can be used to study various aspects of bacterial growth. In May, JoVE Chemistry described the self-assembly of single-stranded DNA tiles into complex 2D shapes. This demonstrated the principles of DNA tiling as an approach for making programmable nanostructures. June 2015 marked the release of JoVEs 100th issue, and in JoVE Behavior, we featured protocols for assessing cognition, including a method of quantifying learning in young infants by tracking leg movements. In July, JoVE Medicine presented a method for measuring halitosis in dogs by taking breath samples, and performing gas chromatography. This assay could be used in trials of dog food formulated to fight bad breath in our canine companions. In August, JoVE Bioengineering contained a protocol for bioengineering kidney tissues. Kidneys are decellularized by perfusion, and repopulated with human renal cells, This promising technology can lead to kidney grafts made from a patients own cells. In September, JoVE Environment examined herbicide resistance, which threatens commercial crop production. An excised leaf assay determines the rates of herbicide metabolism, which is useful for studying the metabolic basis of resistance. In October, JoVE Neuroscience featured a method for interfacing 3D neuronal cultures to micro-electrode arrays. The complex 3D assemblies closely approximate in vivo neural networks. Novembers edition of JoVE Behavior showcased the natural human ability to acquire new motor skills, which is central in a structured rehabilitation program for amputees as they learn how to use multifunctional prosthetics. In December, JoVE Immunology & Infection prepared us for the impending flu season with an easy protocol for sampling influenza in pigs. Because swine are important hosts for flu viruses, this method helps to monitor virus evolution and currently circulating strains. This Year in Review was just a sampling of more than 900 video-articles that JoVE published in 2015. Browse the JoVE archives for thousands of other videos, and come back each week to see brand-new material in JoVE: The Journal of Visualized Experiments.

March 2015: This Month in JoVE - Solving Crime with Science, Applying Technology to Understand Trees, and Studying Protein Synthesis on a Chip

Heres a look at whats coming up in the March 2015 issue of JoVE: The Journal of Visualized Experiments.

February 2015: This Month in JoVE - Tracking Down Foodborne Illness, Imaging Baby Brains, and Paying Scientific Attention to Attention

Heres a look at whats coming up in the February 2015 issue of JoVE: The Journal of Visualized Experiments. In JoVE Environment we have a method for tracing outbreaks of food poisoning to insects. Everyone knows that insects can deposit diseasecausing organisms on our food. Not surprisingly, insects are important vectors of foodborne illnesses caused by pathogens like Salmonella, E. coli, and Listeria. However, its hard to link an outbreak of food poisoning to a specific type of insect. This is because individual insects are not usually collected aseptically in environmental sampling programs. Therefore, Pava-Ripoli et al. from the U.S. Food and Drug Administration take microbial samples from individual flies under aseptic conditions and use PCR to detect specific pathogens. PCR-positive samples are then confirmed by plating on selective or differential media and through commercial biochemical assays. Using this method, public health officials can better determine how insects contribute to foodborne outbreaks. JoVEs Clinical & Translational Medicine section features cranial ultrasound-an indispensable technique for safely imaging the neonatal brain. Ecury-Goossen et al. demonstrate optimal settings that provide better imaging quality, and color Doppler techniques for visualizing intracerebral vessels. They also demonstrate how alternate acoustic windows can improve detection of brain injuries. These advances in cranial ultrasound have improved its diagnostic value-allowing timely therapeutic intervention. In JoVE Behavior we have two articles that deal with attention. One involves attentional set shifting, or the ability to direct attention to informative cues and away from irrelevant ones. Heisler et al. perform this test in mice that have been trained to dig in pots for a food reward. The test cues are different digging materials and different scents. The mice learn to pay attention to a single relevant cue to find their food. The neural circuits behind attentional set shifting are highly conserved between rodents and humans; therefore, this model can be used to preclinically evaluate cognitive deficits and potential therapies. In another article in JoVE Behavior, Yung et al. perform two well-known attention tests in an online platform. The multiple object tracking (MOT) task studies the motion-based tracking of multiple objects by the visual system, and the Useful Field of View (UFOV) Task assesses attention and processing speed of visual stimuli from a brief glance. Our authors collected data from over 1,700 participants in a Massive Online Open Course. The results were highly consistent with controlled laboratory-based measures of the same tests, showing the usefulness of behavior studies done entirely online.

August 2015 - This Month in JoVE: Isolating Stem Cells, Bioengineering the Kidney, and Getting Kids to eat Carrots

Heres a look at whats coming up in the August 2015 issue of JoVE: The Journal of Visualized Experiments. In JoVE Developmental Biology, a major goal in stem cell research is to grow human pluripotent stem cells (hPSCs) in fully humanized conditions without using feeder cells, exogenous supplements, or synthetic substrates. This will eliminate the risk of contamination by animal cells and facilitate economical mass production for therapeutic applications. Jung and Kim previously showed that chorionic cells from the human placenta could support the propagation of hPSCs. So this month, they isolate and culture placental chorionic cells and use the placentaconditioned media to culture the hPSCs. The result is an almost completely humanized culture system that can advance stem cell research and

JoVE 2013: The Year in Review

In this Year in Review, we take a look at some of the biggest moments from the year 2013 in JoVE: The Journal of Visualized Experiments. January featured two articles that used optical methods to selectively control individual neurons genetically encoded with light-sensitive proteins. These optogenetic techniques were used to study how specific neurons control certain behaviors, such as the escape response in fruit flies (de Vries and Clandinin) and the touch response in zebrafish larvae (Palanca and Sagasti). In February we launched JoVE Chemistry, with subjects ranging from complex biochemistry, to assay development, to chemical engineering, and organic synthesis. This section also includes the design and preparation of materials for advanced biomedical applications. In March, in the Applied Physics section, Truscott et al. demonstrated techniques for three-dimensional imaging of fluid flow fields, such as the airflow passing over a set of synthetic vocal folds, and other pressing questions in the area of fluid mechanics. April brought the launch of JoVE Science Education, a revolutionary video database dedicated to teaching the fundamentals of scientific research. including General Laboratory Techniques, Basic Methods in Cellular and Molecular Biology, and Model Organisms like yeast, Drosophila and C. elegans. In the May issue, Mata-Martinez et al. showed several fluorometric techniques to monitor Ca2+ dynamics in human sperm. Sample collection was not included in this procedure for obvious reasons, so viewers will just have to improvise. June brought another new section: JoVE Behavior, which explores various behavioral aspects of humans and animals. These include addiction, learning & memory, social interaction, and emotion. Julys Bioengineering section showcased the incredible ability of nucleic acids to self-assemble into two-dimensional and three-dimensional structures, with Ben-Ishay, et al. designing DNA origami nanorobots that harness the remarkable features of DNA. In August, in the JoVE Behavior section, Morris et al. presented a method for studying the brains response to cigarette smoking. In September, Gfrerer et al. used zebrafish to study cleft palate and related developmental malformations, observing the formation of craniofacial structures through time-lapse confocal microscopy. October was when we launched JoVE Environment, a multidisciplinary section devoted to research methods in areas like biofuels, oceanography, atmospheric sciences, and natural resources. In Novembers Clinical and Translational Medicine section, Ebinger et al. featured the STEMO, or stroke emergency mobile, an ambulance with specialized equipment to allow vital diagnostics and interventions to be performed during patient transport. In December, from JoVE Applied Physics, a technique called digital fringe projection was demonstrated by Ekstrand et al. to provide dense, superfast 3D measurements of dynamic surfaces. This Year in Review was just a sampling of more than 700 video articles that JoVE offered in 2013. Browse the JoVE archives for thousands of other videos, and come back each week to see brand-new material in JoVE: The Journal of Visualized Experiments.

July 2014: This Month in JoVE - Shrinkage Stress in Dental Fillings, Olfactory Learning in Honeybees, Age-related Balance Changes, and Chemical Distribution in the Environment

Heres a look at whats coming up in the July 2014 issue of JoVE: The Journal of Visualized Experiments. Going to the dentist to get a cavity filled is pretty unpleasant. Even worse, the resin composites used in dental fillings shrink as they set. This can cause the filling to debond-allowing new cavities to form under the filling. Alternatively, the shrinkage may cause the tooth to crack. These problems call all result in more trips to the dentist. In JoVE Clinical & Translational Medicine, Li et al. analyze the shrinkage strain and stress of polymerizing fillings. They do this by making a glass model of a tooth cavity and filling it with a resin composite. Then they use digital image correlation to show the areas and types of shrinkage strain, such as horizontal tensile strain or contraction strain. This method can help scientists develop improved resin composites that will hopefully result in fewer trips to the dentist. In JoVE Neuroscience, Brill et al. demonstrate how honeybees learn through olfaction, or the sense of smell. They stimulate the bees with odors and pheromones while using electrodes to record from two tracts in their olfactory pathway. This technique allows stable long-term recordings for hours or even days. Our authors use these recordings to reconstruct the neuronal architecture in 3D. This method can help scientists better understand how olfaction contributes to learning and memory. In JoVE Behavior, we feature two standard behavioral tests for assessing balance performance in mice. In the rotarod test, mice walk along rotating and accelerating dowels; when they lose their balance, they fall. In the balance beam test, mice walk along a narrow, circular rod into the shelter of a dark box. Trials are recorded with a video camera for later analysis. Tung et al. use both of these tests to show how balance changes with age. Older mice will fall faster on the rotarod test and take longer to traverse the balance beam. These simple and non-invasive tests can provide insight into age-related changes. They can also be used to study neuromuscular and inner ear disorders. In JoVE Environment, chemical management is a major concern as more and more chemicals end up in our soil. These include pesticides, fertilizers, biological hazards, and industrial waste. This month, Matteson et al. integrate two methods for studying the fate of chemicals in the environment: lysimetry and porewater sampling. The lysimeters in this protocol are made of rolled and welded steel sheets. They are driven into the test site, and the porewater samplers are pushed into the lysimeter. At the desired time points, the lysimeters are extracted, and samples are taken for analysis. This technique can establish the distribution and potential risks of chemicals in the environment.

August 2013: This Month in JoVE

Here’s a look at what’s coming up in the August 2013 issue of JoVE: The Journal of Visualized Experiments. Honey is an age-old anti-aging product; according to legend, Cleopatra, the Queen of the Nile, bathed in honey to preserve her ageless beauty. But did you know that honeybees themselves might hold the secret to slowing or even reversing aging? The honeybee is an established model for studying how social and environmental factors can affect the aging process. Nurse bees, which stay in the hive to tend the growing larvae, age more slowly than forager bees, which venture out to collect nectar and pollen. Munch et al. expand classical experimental paradigms with three new techniques for studying aging in honeybees: distinguishing chronological aging from work-induced senescence, reverting forager bees into nurse bees by taking them to a new hive, and quantifying aging by measuring lipofuscin (a known biomarker of cellular senescence). It smells like smoke over in the JoVE Behavior section, where we feature a method for studying the brain’s response to cigarette smoking. Morris et al. use positron emission tomography (PET) to non-invasively image the dopaminergic system during smoking. They also make dopamine movies to illustrate how smoking causes dopamine levels to fluctuate in the striatal area of the brain. Because the rise and fall of striatal dopamine levels contribute to addiction and withdrawal, this is a powerful technique for studying the addictive effects of smoking. In JoVE Applied Physics, we feature an article in the field of microwave photonics, which studies the interaction between microwaves and optical waves. Coillet et al. build microwave photonics systems based on whispering gallery modes (WGMs), which are waves that can travel around a concave surface. To make the resonator, Coillet et al. grind down a commercially available crystalline optical window, polish it with extremely fine particles, and verify its smoothness using interferometric measurements. Then, they draw a fiber taper, which couples light in the resonator. Finally, they show how to excite a WGM. This is a promising technology with many potential applications in aerospace, telecommunications, and other areas. In JoVE Bioengineering, Moll et al. build upon classic two-dimensional cell culture with an engineered three-dimensional tumor test system. In this biological vascularized scaffold, a metal insert containing decellularized small intestinal submucosa serves as a scaffold for culturing cancer cells or other cell types. These than be grown statically or as a dynamic culture in a flow bioreactor, which exposes cells to shear stress. This allows a lifelike model for studying tumor development and potential treatments. You’ve just had a sneak peek of a few highlights from the August 2013 issue of JoVE. Visit the website to see the full-length articles, plus many more, in JoVE: The Journal of Visualized Experiments.

March 2013: This Month in JoVE

Here are some highlights from the March 2013 issue of Journal of Visualized Experiments (JoVE). This month, JoVE features several video articles in the Clinical and Translational Medicine section. In the ophthalmology department, Connors et al. of Massachusetts Eye & Ear and Harvard Medical School have developed an audio-based virtual environment simulator to help blind people improve their navigation skills. The simulator allows users to build cognitive maps of three-dimensional spaces in the context of a video game-using only audio cues. The users were not aware that the virtual building in the game represents an actual building; furthermore, the users were never asked to recall the building layout while playing. Nonetheless it appears that the game can help them navigate through unfamiliar spaces. At Massachusetts General Hospital and Harvard Medical School, Lin et al. are developing an improved method to noninvasively measure brain metabolism and blood flow in newborns. This method combines measurements of hemoglobin oxygen saturation (SO2) with cerebral blood flow index (CBFi), which provides accurate measurements of cerebral metabolism and hemodynamics. This method also complies with neonatal ICU policies, making it potentially useful for assessing brain health, development, and response to therapy in newborns. Also in this section, Lee et al. of UC San Francisco/VA Medical Center demonstrate how a biopolymer gel, derived from polysaccharides found in brown algae, can help patients with heart failure. The alginate-based biopolymer is injected into the area between the base and apex of the left ventricle free wall. This reduces left ventricle size and thickens its free wall; it also reduces left ventricular wall stress, as assessed by mathematical modeling. This therapy, called Algisyl-LVR, is currently in clinical development for treating patients with dilated cardiomyopathy. In JoVE Immunology and Infection, Robinson et al. of University of Texas Health Science Center-Houston demonstrate a noninvasive technique for imaging lymphatic vessels, which are involved in many physiological and disease processes. A near-infrared fluorescent dye, such as indocyanine green (ICG), is injected intradermally-allowing the lymphatic vasculature to be visualized using a near-infrared fluorescence imaging system. The JoVE Applied Physics section features a method in the field of fluid mechanics, developed at Brigham Young University in collaboration with the Naval Undersea Warfare Center of Newport, Rhode Island. Truscott et al. describe a novel technique for quantitative three-dimensional imaging of fluid flow fields, such as the airflow passing over a set of synthetic vocal folds, or bubbly flow fields. This method can help resolve a range of problems in the area of fluid mechanics. This summary provides a preview of the cutting-edge video publications appearing this month in JoVE. Visit the website and check out the full-length articles, plus many more, in JoVE: The Journal of Visualized Experiments.

September 2012: This Month in JoVE

This September in JoVE, researchers from the School of Medicine at the Free University of Berlin demonstrate a novel method for studying how stroke patients compensate for visual field defects. To do this, our authors make use of a driving simulator complete with brakes, a steering wheel, and turn signals. Using driving simulation software and sophisticated eye tracking, researchers can compare the gaze behavior of stroke patients as they navigate through virtual driving courses with varying degrees of complexity. Though posterior cerebral artery infarction can lead to similar visual deficits in patients, some are able to navigate through the driving courses by developing compensatory eye movements, while others crash into dangerous obstacles, like wild boars. Through the analysis of compensatory gaze behavior employed by patients, our authors see great potential for using driving simulation as a tool to rehabilitate stroke patients trying to overcome the blind spots in their visual fields. In collaboration with the University of Southern California, researchers in the Department of Ophthalmology at Oregon Health and Science University present a method for measuring total blood flow in the retina using Doppler optical coherence tomography (OCT). The retina contains millions of neurons that capture visual images and convert them into electrical signals, which travel through the optic nerve to the brain. Blood vessels enter the retina at the optic disk, where the optic nerve connects to the retina. These vessels supply oxygen and nutrients, and also remove waste. In some retinal diseases (such as diabetic retinopathy) or glaucoma (which affects the optic nerve), the retinal vasculature may be abnormal. Because these diseases are leading causes of irreversible vision loss, measurements of retinal blood flow can be very useful in clinical practice and research. Unlike traditional optical imaging methods, like laser Doppler and ultrasound color Doppler, laser Doppler OCT can provide absolute measurements of retinal blood flow; these are based on Doppler-shifted light, which is backscattered from red blood cells as they flow through vessels. Our authors demonstrate how to scan the retina and optic disc with Doppler OCT; the scans are then graded and analyzed with DOCTORC software, which our authors developed. This method shows good reproducibility between graders and methods. Furthermore, in eyes with glaucoma, retinal blood flow measurements are highly correlated with vision loss. Thus, Doppler OCT represents a powerful tool that can be used in ophthalmology research and clinical practice. Coinciding with mosquito season, researchers in the Department of Entomology at Virginia Tech demonstrate a simple and robust technique for chromosome mapping of mosquito genomes. Out of more than 40 mosquito genera containing thousands of species, researchers are particularly interested in the genera Anopheles, Aedes, and Culex because they contain species that transmit harmful human diseases. About 90% of the Anopheles gambia genome has been mapped to chromosomal locations; however, it is extremely difficult to prepare suitable chromosome spreads for the Aedes genus or the Culex genus using cell lines and standard techniques. To overcome this problem, our authors use 4th instar mosquito larvae, which have imaginal discs that produce high-quality chromosomal spreads. The researchers show how to dissect the imaginal discs and prepare suitable chromosome preparations for fluorescence in situ hybridization (FISH). Genome mapping is thus possible for mosquitoes in the Aedes, Culex, and Anopheles genera. This technique paved the way for entomologists to make precise chromosomal maps for not only mosquitoes, but also for other insects. In the Center for Research at Quebecs University of Laval, researchers demonstrate a method for tracking neuronal migration in the murine forebrain. One important site of neurogenesis in the mammalian brain is the subventricular zone, and newly born neurons migrate away from this area via the rostral migratory stream to the olfactory bulb. The cells are labeled with a stereotaxically injected retrovirus encoding a green fluorescent protein; then, using a combination of acute slice preparation, timelapse imaging, and image analysis, our authors can calculate the migration speed of labeled neuroblasts. Through careful tracking of cell trajectories along blood vessels, this method can help elucidate the different molecular cues and cellular mechanisms that influence cell migration. This brief summary highlights just a few notable video-articles that will be released this September in JoVE. We also feature methods for tracking cell fate in zebrafish with photoconvertible fluorescent proteins, using micropipettes to test cell stiffness, and imaging the behavior of proteins that respond to DNA damage.

November 2012: This Month in JoVE

In this issue, Oestreicher et al. show us how to isolate magnetotactic bacteria from freshwater samples, and concentrate the bacteria at one end of a glass capillary. The magnetotactic bacteria can then be visualized by light and transmission electron microscopy, and used for various other assays. Also in the November 2012 issue, Boland et al. demonstrate how to reprogram fibroblasts into induced pluripotent stem cells (iPSCs), and how to isolate iPSC lines for injecting into tetraploid blastocysts, as demonstrated previously in JoVE. While mouth pipetting is generally not recommended because it can have adverse effects, this protocol requires the technique, executed carefully, to manipulate the embryos. This is one of the rare occasions when its actually OK to mouth pipet in the lab. If the induced cells are fully pluripotent, they can result in full-term mice derived completely from iPSCs. In JoVE Neuroscience, Heermann and Krieglstein demonstrate a method for visualizing Schwann cell development along growing axons. To do this, our authors culture cervical ganglia explants onto collagen matrices, and treat the explants with nerve growth factor or other substances. The collagen gels can then be visualized using time-lapse imaging with fluorescence or bright-field microscopy, migrating along axons towards the periphery. Also in JoVE Neuroscience, Hoffmann et al. put tiny headphones on songbirds to study how they use auditory feedback to adjust their singing. The authors demonstrate how to construct the headphones and attach them to the birds head; then, by adjusting the acoustic signal, they can study the computational and neurophysiological basis of vocal learning in birds. In JoVE Clinical & Translational Medicine, Iyengar et al. use a zebrafish tumor model to study genes that can modify the pathogenesis of melanoma. This is done by first creating transgenic zebrafish that express a gene of interest. Various assays can then be performed to study how different genes affect melanoma, including onset, invasion, and transplantability. In JoVE Bioengineering, Martin et al. demonstrate a gliding assay to measure the flexural rigidity of biopolymers (such as microtubules). By attaching motor proteins to a microscope slide, and adding fluorescently labeled microtubules, our authors can analyze the dynamics of cytoskeletal polymers. This preview summarizes just a few notable video-articles in the November 2012 issue of JoVE. Stop by throughout the month of November to check out the full length versions of these articles and many more.