JoVE Behavior Research Articles

JoVE Monthly Highlights: February 2018

Here’s a look at what has been featured in the February 2018 issue of JoVE: The World’s Premier Video Journal. As wearable fitness trackers become more integrated into our daily lives, our authors in JoVE Engineering present a specs-tacular protocol describing glasses that can detect motion in the temporalis muscle while subjects read, exercise, and eat. Using this technique, researchers can get a closer look at ingestive behaviors and physical activity patterns in practical settings. From 3D printed glasses to 3D printed lungs, JoVE Bioengineering showcases a methodology to fabricate optical tissue phantoms. These tissue-mimicking optical phantoms provide a standard to evaluate and calibrate optical systems - circumventing expensive animal studies. This technique is highly adaptable and allows scientists to create phantoms of any structure that can be made with a 3D printer. Moving over to JoVE Behavior, our authors describe a novel model of contagious depression in animals. While some studies have investigated social contagion of psychiatric illnesses, the phenomenon is not fully recognized. Using this technique, our authors successfully induced depression-like symptoms in naive rats exposed to depressed rats. Finally, over in JoVE Chemistry, our authors added a splash of color to this month’s issue with a simple chemical spot test to identify an emerging class of drugs. Using only three reagents and a hotplate, our authors confirmed the presence of synthetic cathenones with a color change from light blue to yellow-orange. With further development, this technique could be utilized for law enforcement in both laboratory and field testing settings. You’ve just had a snapshot of the February 2018 issue of JoVE. Visit our website to see the full-length articles, plus many more, in JoVE: The World’s Premier Video Journal.

2017: JoVE's Year in Review

In January 2017, JoVE Behavior got off to a fetching start with a protocol to monitor the effects of a special diet for dogs with anxiety. This streamlined approach even uses a tool that most of us already have in our pockets: a smartphone! (54878) JoVE Biology helped us keep up with our New Year's fitness goals well into February with an article investigating the link between aerobic exercise and autophagy. (55099) In March, JoVE Bioengineering showed us that paper isn't going the way of the dinosaurs just yet! Our authors showcased 3-dimensional paper microfluidic devices that could be used to make cheap and simple immunoassays. (55287) JoVE Environment was buzzing about honey bees during April. Here, our authors demonstrated a protocol that can be used to investigate the effects of pesticides on honey bee colonies. (55296) In May, JoVE Behavior reminded us all to take a deep breath. Our authors used electroencephalography and electrocardiography to investigate traditional spiritual stress reduction techniques. (55455) During June, JoVE Science Education released an astonishing 8 new collections covering topics in Clinical Skills, Psychology, and Physics! Meanwhile, in the video journal, our authors gained the upper against infectious disease with a protocol to compare different hand washing techniques. (55604) In July, we were treated to a real spectacle in JoVE Medicine when our authors demonstrated a new way to use a smartphone and lens to record images of the fundus - and we can all see how smart that is. (55958) We all fawned over this protocol in the August issue of JoVE Environment. Here, our researchers relocated wild white-tailed deer to controlled habitats to examine the effects of environment and genetics on development. (56059) In September, JoVE Science Education continued its impressive growth trajectory and released 5 new collections covering topics in Chemistry and Biology. Over in the video journal, our authors in JoVE Bioengineering gave us a smashing protocol for simulating high speed collisions with bicycle helmets. (56288) Then, JoVE Neuroscience got a move on in October with an automated gait analysis for mice with nerve injuries. Here, our authors had mice strut their stuff on a glass runway to illuminate their footprints for the camera. (56402) During November, JoVE Engineering really turned up the heat as our authors described wind tunnel experiments that simulate forest fires in chaparral shrubs. (56591) Finally, in December JoVE finished the year with a bang. Not only did we publish our 7,000th video but in JoVE Chemistry our authors showcased laboratory experiments designed to simulate a nuclear reactor core meltdown and improve the safety of nuclear power plants - that's actually pretty cool. (54807) This year in review is just a sampling of more than 1,000 video protocols that JoVE published during 2017. Browse the JoVE archives for thousands of other videos and visit our website every week to see brand-new content.

JoVE Monthly Highlights: October 2017

Here's a look at what's coming up in the October 2017 issue of JoVE: The World's Premier Video Journal. From the bubbling cauldron of science emerges our first featured article, from JoVE Environment. Here, our Authors demonstrate how to build and deploy double-decker traps to attract and capture emerald ash borers - the most destructive forest insect to invade North America. These traps capture significantly more emerald ash borers than any other trap type in sites with relatively low EAB densities, allowing for effective detection and management of this invasive insect. Even more than giant creepy spiderwebs! Moving from pests to pets, our next study from JoVE Behavior takes a look at man's best friend. Here, our Authors describe eight different experimental tasks to analyze the relationship between dogs and their owners. The results of this standardized study suggest that owner warmth is the greatest source of behavioral variance - and that dogs belonging to more controlling owners tend to be more aggressive towards strangers. And good doggies get treats...no tricks! Switching gears, in JoVE Bioengineering this month our Authors use a custom built mechanical testing device to measure the flexural behavior of load bearing biological structures. The successful execution of this three-point bending test on the skeletal elements from marine sponges shows that this method can be used to understand the remarkable mechanical functions of a host of similar structures. That's heavy stuff! Finally, JoVE Chemistry zooms in on nanoparticle self-assembly processes in real time. Using uniformly sized platinum and lead selenide nanoparticles, our Authors produced liquid cells with silicon or silicon nitride or windows. Liquid-cell transmission electron microscopy analysis reveals that changes in the solvent boundaries, caused by evaporation, affects nanoparticle self-assembly by driving them to form amorphous aggregates. These aggregates then flatten, producing spellbinding two-dimensional self-assembled structures. You've just had a sneak peek of the October 2017 issue of JoVE. Visit the website to see the full-length articles, plus many more, in JoVE: The World's Premier Video Journal.

JoVE Monthly Highlights: September 2017

From a body of great articles this month, our first article, in JoVE Neuroscience, takes a peep at your peepers. Here, our Authors describe a method to perform spectral domain optical coherence tomography on mouse retinas, to study optic neuropathies. This technique concentrates on retinal ganglion cells in the peripapillary region, and provides a fast and accurate assessment of retinal thickness - allowing for changes, and possible signs of ophthalmic diseases, to be tracked. That's blinking marvelous! Zooming out from the eyes, JoVE Engineering switches focus to protecting the head. Using an anthropometric test device and high-speed cameras, our Authors simulate helmeted cranial impacts at speeds up to 8.3 m/s. When compared to established human tolerance curves, the data can be used to estimate the risk of diffuse brain and osteoligamentous neck injuries. In turn, this can help determine which helmets provide the best protection - and safety never goes out of style. Moving from head to toe our next study, from JoVE Behavior, describes a method to synchronously capture lower-limb joint movements and ground reaction force while wearing high-heels. Using three-dimensional motion analysis and a configured force platform, our Authors observe noticeable differences in the biomechanical adaptations adopted by Experienced versus Inexperienced Wearers. This suggests that further studies evaluating gait and footwear biomechanics should take individual experience into account. Finally, from footwear to the ground beneath, JoVE Environment takes a look at soil erosion. Here, our Authors describe a simple method to map patterns of soil erosion and deposition in agricultural land. The authors use a ground-based differential GPS to accurately measure elevation and then collect soil from prescribed depth intervals. The researchers found significant correlations between change in elevation and soil surface carbonate, illustrating the indirect relationship between crop management techniques and changes in land sustainability. You've just had a sneak peek of the September 2017 issue of JoVE. Visit the website to see the full-length articles, plus many more, in JoVE: The World's Premier Video Journal.

JoVE Monthly Highlights: May 2017

Here's a look at what's coming up in the May 2017 issue of JoVE: The World's Premier Video Journal Mindfulness is at the heart of our first featured article this month, from JoVE Behavior. Here, our Authors use a combination of electroencephalography*(EEG) and electrocardiography*(ECG) to investigate traditional spiritual stress-reduction techniques. Examining the EEG and ECG's of participants before and after an 8-week Mindfulness-based Stress Reduction course, the authors recorded changes in the wavelet entropy of these data based on the training level or meditation type used. This provides a quantifiable methodology for the study of the effects of mindfulness training on the links between the brain and the heart. This slides nicely into our next highlighted article on another heart- and brain- healthy subject - fish oils. In JoVE Chemistry, our Authors present a protocol for the rapid evaluation of the lipid profiles in fish oil supplements. Using high resolution Nuclear Magnetic Resonance spectroscopy, individual fatty acids can be identified, as well as their positional distribution on the glycerol backbone. This method is a powerful analytical tool for the screening encapsulated supplements, and can help protect consumers from any fishy products... From wellness and fish oils to well-oiled fish, our next article in JoVE Biology looks at the effects of alcohol exposure on zebrafish. To investigate Alcoholic Liver Disease (ALD)*, our Authors exposed zebrafish larvae to acute ethanol treatment, and then visualized their livers using a specifically optimized Hematoxylin and Eosin (H&E)* staining protocol. The authors show that steatosis and swelling of the hepatic blood vessels is apparent after just 24 hours of exposure to high ethanol levels. This versatile protocol can also be applied to other models of toxin- and virus-induced injury in the increasingly used zebrafish liver model. Finally this month, let's chill out with a novel freezing method from JoVE Biology. Here, our Authors present time-resolved electron microscopy, dubbed flash-and-freeze, which gives a snapshot of membrane dynamics on the order of milliseconds and nanometers. The flash is an optogenetic stimulation of neuronal activity, and induces neurotransmitter release. A high-pressure freeze then swiftly preserves the cells at the resultant stages, allowing researchers to follow morphological changes after synaptic transmission. That's super cool! You've just had a sneak peek of the May 2017 issue of JoVE. Visit the website to see the full-length articles, plus many more, in JoVE: The World's Premier Video Journal.

JoVE Monthly Highlights: April 2017

Here's a look at what's coming up in the April 2017 issue of JoVE: The World's Premier Video Journal The plight of the honeybee holds our first spotlight this month. Pesticides brought back to colonies by workers foraging on contaminated flowers can be spread throughout honeybee colonies, severely impacting health of larvae and adults, and potentially causing colony collapse. In JoVE Environment, our Authors describe feeding methods in which an insect growth regulator and commonly used pesticide - PPN - is fed both to individual honeybees and an entire colony, in a manner that can be applied to any potentially harmful chemicals or pathogens. A technique enabling a better understanding of the challenges facing these critical pollinators leaves us buzzing. From food-producing pollinators to clean water...in JoVE Bioengineering this month, our Authors present methods to prepare low-cost, efficient membranes for water purification. Here, zwitterionic hydrogels are produced using SBMA* crosslinked to polyethylene glycol diacrylate to improve mechanical strength. When impregnated into a highly porous hydrophobic support, the resultant tightly bound layers prevent antifouling of the membranes by physically preventing attachment to the surface. These properties combined allow for production of energy efficient and long lasting filters to meet increasing demand for clean water. Something we can all toast to, cheers! In JoVE Behavior, our Authors demonstrate a procedure of exposure manipulation involving sorting novel and familiar objects paired with an acoustic signal, to reveal the powerful shaping role of experience in recognizing human language. At 3-4 months infants broadly recognize both human and nonhuman primate vocalizations as cues to support object categorization, but by 6-to 7-months only human vocalizations are utilized. This method shows that merely exposing infants to nonhuman primate vocalizations can preserve this early-established link, whereas the same effect is not observed when the child is exposed to backwards speech. Finally, as the first buds of spring emerge, our last video highlight this month gives a fascinating glimpse into the private life of plants. In JoVE Developmental Biology, our Author uses confocal microscopy to show how the intricate inflorescences of the Arabidopsis plant develop in real time. Moreover, the demonstrated procedure allows expression of multiple genes to be visualized at once, aiding in the elucidation of the complex genetic networks, which unravel simultaneously to specify the identities of the different floral organs. Blooming marvelous! You've just had a sneak peek of the April 2017 issue of JoVE. Visit the website to see the full-length articles, plus many more, in JoVE: The World's Premier Video Journal.

March 2017: This Month in JoVE: Human Embryo Vitrification, Paper Microfluidic Devices, Virtual Hand/Face Illusions, and Quantification of Amyloid-Beta for Alzheimer's Diagnosis

Here's a look at what's coming up in the March 2017 issue of JoVE: The Journal of Visualized Experiments. As the start of spring brings new life, we begin the month investigating exciting new developments in embryo storage for in-vitro fertility treatment. In JoVE Developmental Biology, our authors present a modified technique for vitrification and preservation of human embryos. This aseptic technique uses all FDA-compliant materials including ionomeric resin embryo straws and sterile flexipettes, and allows fast, safe, and repeatable embryo storage independent of operator variation. In addition, with a greater than 95% embryo survival-rate the method contributes to excellent pregnancy outcomes. Paper cards...printers, it's all so 1990's, right? Well, our next video highlight might make you reconsider. In JoVE Bioengineering this month, our authors reveal 3-dimensional paper microfluidic devices for immunoassays. By patterning paper with hydrophobic barriers, the transfer of fluids can be controlled and directed. Stacking multiple layers of patterned paper creates sophisticated 3-D microfluidic networks that can be utilized in cheap and simple bioanalytical assays, such as the detection of Human Chorionic Gonadotriphin, or hCG - the pregnancy hormone. So don't throw out those old Valentine's Day cards yet - upcycle! In JoVE Medicine this month, our authors reveal an accurate procedure for quantifying the plaque-forming amyloid-beta protein in cerebral spinal fluid to provide diagnoses in suspected Alzheimer's cases. Current diagnosis is mostly based on mental state and cognitive testing, with some studies beginning to examine amyloid-beta levels, but this is hampered by variability and reproducibility issues. Here, our authors use a combination of solid-phase extraction and liquid chromatography tandem mass spectrometry to quantify amyloid-beta levels to a high degree of accuracy, quantifying the deposition of the protein in plaques in the brain and enhancing the power for accurate diagnoses. Our final video highlight this month comes from JoVE Behavior, and showcases a new technique to create human body illusions. Here, our authors demonstrate a computer-based virtual hand and face that move in synchrony with the operator's action, creating an illusion that the model is an extension of the participant's own body. This is a useful tool in the study of self-representation, and is an advance over traditional studies requiring demonstrators to mimic actions on participants in time with actions performed on a physical model body part. Ah, just one small step until I realize my dream of becoming a super-fast blue hedgehog. You've just had a sneak peek of the March 2017 issue of JoVE. Visit the website to see the full-length articles, plus many more, in JoVE: The Journal of Visualized Experiments.

JoVE Monthly Highlights: February 2017

Here's a look at what's coming up in the February 2017 issue of JoVE: The Journal of Visualized Experiments. After a long day at the bench, who doesn't love to let their hair down and listen to a little music? In JoVE Behavior this month our Authors reveal methods for quantifying the effect of music listening on levels of psychobiological stress. Using assessment of subjective stress levels as well as salivary cortisol and salivary alpha-amylase levels to measure HPA* and ANS* function, the authors show how the effect of music on stress can be tested in a daily-life setting, outside the conventional laboratory. So relax...no need to feel guilty about that Backstreet boys album you've been dancing to in the lab...it's for science! Keeping the momentum going into our second spotlight article this month, in JoVE Biology our Authors investigate the link between aerobic exercise and autophagy. Autophagy is the essential pathway that targets unused or damaged cellular components for degradation and nutrient recycling, and is critical to maintaining healthy cells. By encouraging mice to undertake treadmill exercise or wheel running, our authors demonstrate that autophagy can be stimulated in vivo and quantified in various tissues including muscle, liver, heart and brain. So running to that faculty meeting was for exercise, not because you were late...right? Next up, we switch gears from self-recycling to self-assembly as we showcase the amazing nanostructures of helical polycarbodiiamides. In JoVE Chemistry this month, our Authors constructed protein-like macromolecules that self-assemble into unique architectures such as donuts, ribbons, spheres, or helices. Characterized by atomic force microscopy and scanning electron microscopy, the polycarbodiiamides form predictable secondary structures based on their molecular structure, concentration, and solvent...making them ideal candidates for biosensors or drug carriers. I wonder if they come in strawberry or banana flavor, too? In the month of Valentines and love, our final February highlight turns to...mating drive in Drosophila. In JoVE Neuroscience, our Authors describe a behavioral assay that uses male mating drive to investigate the genetic, cellular and molecular mechanisms of motivation. Using studies of male fruit flies mated over several days, small neuronal populations associated with specific motivational functions can be identified. These clusters can then be manipulated to alter courtship drive via the stimulation of dopaminergic neurons. Or they can just bring you a tiny box of chocolates, your call. You've just had a sneak peek of the February 2017 issue of JoVE. Visit the website to see the full-length articles, plus many more, in JoVE: The Journal of Visualized Experiments.

2016: This Year in JoVE

Welcome to JoVE's Year in Review, where we highlight some of the most interesting video protocols of the past year. In January 2016 JoVE started out with a bang...or rather, it didn't need to...as JoVE Engineering gave us a protocol for the production of synthetic nuclear melt glass. This is a valuable tool for forensic study of post-detonation, without the boom. February was a treasure of a month for JoVE - not only did we publish our 6000th article, but in JoVE Chemistry we showcased research on gold nanoparticles from the laboratory of a Nobel Prize winner. In March, JoVE Biology described RNA interference in the malaria vector Mosquito Anopheles gambiae, through direct pupal injection. This promising research may pave the way for the next generation of mosquito-borne disease control. April heralded the launch of a new Science Education collection - Chemistry. Here, we unveiled protocols covering the fundamentals of general, organic, and Inorganic chemistry - giving students the chance to explore lab techniques, common equipment, and core theories of Chemistry. Shhh! In May, JoVE Environment profiled a novel technique for tracking and identifying individual cheetahs from just their footprints...allowing researchers to better monitor and protect Africa's most endangered large Felid. June gave us the new Science Education Clinical Skills collections, providing a foundation for performing physical examinations of patients including the assessment of vital signs, and basic external and internal evaluations. In July, JoVE Neuroscience was buzzing with cool science. We showcased research into the taste perception of honeybees to different nutrients and toxins and how this influences the feeding behavior of these critical pollinators. JoVE Medicine got to the heart of the matter in August...profiling a new method to help investigate angina and identify constrictions in coronary arteries. September launched three new JoVE Journal sections covering Genetics, Cancer Research, and Biochemistry.These new collections include groundbreaking research into topics as diverse as genetic engineering of unconventional yeast strains for biofuels...mass spectrometry for meat authentication...and mixed cell culture models to mimic tumor microenvironments. In October, JoVE Immunology and Infection took us behind the scenes in a Biosafety Level 4 facility. In a four article series, we showed how researchers operate aerobiology chambers...use safety suits and biosafety cabinets...and perform medical imaging in an environment containing life threatening diseases like the Ebola virus. November's JoVE Behavior explored...um...oh yes...memory.Our authors showed that turtles actively use memory and recall to find their seasonal habitats, and not simply environmental cues. Finally, in December, JoVE Bioengineering helped us to see things more clearly, with a new technique for performing 3D super-resolution microscopy of individual cell structures and components. This Year in Review was just a sampling of more than 1100 video-articles that JoVE published in 2016. 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

October 2016: This Month in JoVE

Here's a look at what's coming up in the October 2016 issue of JoVE: The Journal of Visualized Experiments. In Immunology and Infection, we showcase a series of four videos detailing safety and logistical procedures for working in an Animal Biosafety Level 4, or (A)BSL-4, laboratory. The first of this group, filmed at the NIH Integrated Research Facility at Fort Detrick, demonstrates the safe entry and exit procedures for work inside an (A)BSL-4 suit laboratory suite. Inhalation studies of high-consequence pathogens can simulate natural aerosol transmission, or allow researchers to investigate outcomes of intentional pathogenic aerosol releases. In the second of this series, the authors walk through the safe operation of aerobiology chambers for maximum containment level pathogens, such as the Ebola virus. The challenge of carrying out medical imaging in a high biosafety environment is the focus of the third of these releases. Here, our Authors detail how to prepare animals infected with high-consequence pathogens for noninvasive medical imaging, whilst ensuring that the equipment remains easily accessed and free from contamination. In the final video of this miniseries, we take an in-depth look at the extra precautions and procedures involved in performing viral assays in a Class II biosafety cabinet in a BSL-4 environment. As a whole, these four releases are a valuable library for researchers handling challenging and potentially harmful biological materials. Woody plants and secondary tree stems are key habitats, as well as being of great cultural and commercial importance. Understanding stem growth and wood formation is therefore an important topic for tree production, conservation, and preservation. In JoVE Genetics this month, Spokevicius et al (our Authors) describe a method to create transgenic somatic tissue sectors directly in the living secondary stem of woody plants. This versatile method can facilitate rapid functional characterization of genes of interest, be utilized in a range of tree species, and test multiple genes and promoters at a high throughput level. Arguably one of the most recognizable paintings of all time, the Mona Lisa is famous for the subject's elusive and indefinable expression. In JoVE Behavior, Soranzo and Newbury (our Authors) demonstrate how a similar visual illusion-dubbed the uncatchable smile because of it's tendency to disappear as the observer tries to catch it-was discovered in La Bella Principessa, also by Da Vinci. Using a combination of methods including interobservation, psychophysical experiments, and structured interviews, the authors reveal that the ambiguity in La Bella Principessa's expression is attributed to a visual illusion at the mouth of the subject similar to that observed in the Mona Lisa. You've just had a sneak peek of the October 2016 issue of JoVE. Visit the website to see the full-length articles, plus many more, in JoVE: The Journal of Visualized Experiments.

August 2016 - This Month in JoVE: Sampling in Suspension Feeders, Staining Three-Dimensional Skin, Spasms in the Heart Vasculature, and Emotional Reponses to Beverages

Here's a look at what's coming up in the August 2016 issue of JoVE: The Journal of Visualized Experiments. In JoVE Environment, we take a look at aquatic organisms that feed on particles floating in the water around them, aptly named suspension feeders. Most studies involving these animals require their housing in laboratory settings, which can disrupt behavior. So Morganti et al.present a method to build an apparatus-modified for scuba diving-that can be used to collect water inhaled or exhaled by suspension feeders in their natural environments. Samples gathered with this method can then be analyzed, helping us better understand the roles these organisms play within their ecosystems, for example in nutrient cycling. Researchers are also exploring the roles different cells perform in their environments-such as the organs they might help comprise. As a result, tissue samples are being processed in new ways that maintain their three-dimensional structure. This month, JoVE Biology highlights one such staining protocol developed by Liang et al., which allows for the visualization of proteins within individual cells present in full-thickness mouse skin. Due to its use of whole mount samples, this effective procedure can help elucidate interactions between the different layers of this important regenerative organ, including those that may contribute to skin cancer. Disease diagnosis can rely on analyses of protein expression, as well as direct observations of a patient and their physiological responses. For example, angina-or chest pain-is a topic of interest in JoVE Medicine, and may be a symptom of vasomotor disorders, which include spasms of the vasculature supplying blood to the heart. Here, Ong et al. describe a method to diagnose such disorders that relies on the sequential administration of increasing concentrations of a neurotransmitter, assessing a patient's electrocardiograms, and looking for any constrictions in the coronary arteries. This method provides a convenient protocol that can be implemented in clinical settings, with limited risk to a patient. Finally, we switch gears in JoVE Behavior, where an analysis of individuals' emotional responses to different types of beverages is featured. How a person reacts to a drink can be distinguished-in part-by facial muscle movements, which can be recorded using video. In this study, Crist et al.present a standardized protocol to collect such data, and interpret it using Automated Facial Expression Analysis software. Importantly, this method can be extended to other applications, like interpreting how an individual responds to product packaging. You've just had a sneak peek of the Aug 2016 issue of JoVE. Visit the website to see the full-length articles, plus many more, in JoVE: The Journal of Visualized Experiments.

July 2016: This Month in JoVE

Here's a look at what's coming up in the July 2016 issue of JoVE: The Journal of Visualized Experiments. In JoVE Neuroscience, gustatory perception - or taste - is an important factor for pollinating insects and the flowers that they feed from. Most studies have used restrained honeybees to study gustatory responses towards nutrients and toxins. This month, Ma et al. present a new behavioral assay that uses freely moving bumblebees to measure how different compounds influence their feeding behavior. This assay will be useful to pollination biologists, toxicologists, and neuroethologists studying the bumblebee's taste system. In JoVE Environment, trace metal measurements in natural waters are often inaccurate due to inadequate sampling and analytical techniques. In fact, using improved techniques, researchers are finding that true concentrations of dissolved trace metals may be orders of magnitude lower than previously thought. So Jiann et al. present a protocol for clean sampling and trace metal analysis of river and estuary waters. They present techniques for reducing contamination throughout all phases of trace metal analysis. The improved data quality allows accurate assessment of trace metals and their relationships to environmental parameters. In JoVE Engineering, Janus colloids are special nanoparticles that have multiple chemical, physical, and structural properties - making them attractive tools for biomedical applications. Campbell et al. present a method to prepare catalytically active Janus colloids that swim in fluids, and determine their 3D motion using fluorescence microscopy. With this method, 3D trajectories are obtained for the swimming colloid, which allows accurate measurement of swimming velocity and other physical phenomena. In JoVE Behavior, vision problems can have a major impact on development. But in young children or those with intellectual disabilities, it is often difficult quantitatively assess visual problems, which limits accurate diagnostics. To overcome these problems, Kooiker et al. describe a method for quantifying visual information processing. A remote eye tracker measures eye movements in response to different visual stimuli - providing valuable information for vision assessment and rehabilitation. You've just had a sneak peek of the July 2016 issue of JoVE. Visit the website to see the full-length articles, plus many more, in JoVE: The Journal of Visualized Experiments.

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 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 Giger et al. 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 JoVE Immunology & Infection, 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, Shi and Lin 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 JoVE Behavior, 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, Gao et al. 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 JoVE Bioengineering, 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 Phan et al. 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 April 2016 issue of JoVE. Visit the website to see the full-length articles, plus many more, in JoVE: The Journal of Visualized Experiments.

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 JoVE's 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 patient's 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. November's 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.

December 2015 - This Month in JoVE: Flu Surveillance in Swine, DNA Nanorobots, Analyzing Crude Oil, and a Translational Model of Depression

Here's a look at what's coming up in the December 2015 issue of JoVE: The Journal of Visualized Experiments. In JoVE Immunology & Infection, we know that the peak of flu season is on its way-and because pigs are important hosts for the influenza A virus, it is critical to monitor virus evolution in swine populations to get a snapshot of current circulating strains. Nasal swabs are a gold-standard technique for taking diagnostic samples from live pigs, but it requires restraining the pigs. Nolting et al. present an alternative sampling method using nasal wipes, which involves rubbing a piece of fabric across the snout of the pig with minimal to no restraint of the animal. The nasal wipe procedure is simple to perform, and virus detection and isolation rates are adequate to make it a viable and low-stress sampling method for flu in pigs. In JoVE Chemistry, DNA nanorobots are hollow hexagonal nanodevices that open in response to specific stimuli to present the cargo sequestered inside. This month, Amir et al. describe a nanorobot fabrication protocol that uses the DNA origami technique. This involves mixing short single-stranded DNA staples with long, circular, single-stranded DNA scaffolds. In a standard thermocycler, the staples anneal to the scaffolds, thus driving the folding of the nanorobot. After the folding reaction is complete, agarose gel electrophoresis (AGE) is used to visualize and estimate the purity of the DNA nanorobots. Finally, nanorobot fabrication is verified by transmission electron microscopy (TEM). This procedure allows for the construction of complex 2D/3D nano-architecture. In JoVE Environment, crude oil is one of the most valuable natural resources because it is the raw material for many fuels and chemical products. Accurate analysis of crude oil, especially the content of highly toxic hydrogen sulfide (H2S), is essential for developing and implementing safety measures in the event of a release or spill. Heshka and Hager present a multidimensional gas chromatography method for analyzing dissolved hydrogen sulfide in crude oil samples. As far as we know, this is the only method that can accurately measure dissolved hydrogen sulfide in heavy crudes, without the use of sub-ambient cooling. In JoVE Behavior, Frisbee et al. present one of the most useful models for studying the pathophysiology of depression in rodents. This protocol uses a variety of mild stressors, and after a period of exposure to unpredictable chronic mild stress, rodents develop behaviors and cardiovascular alterations that are comparable to the symptoms of clinical depression. This approach allows for detailed studies of the pathological mechanisms of chronic stress, and can be used to test new therapies and interventions for chronic stress-induced depression. You've just had a sneak peek of the December 2015 issue of JoVE. Visit the website to see the full-length articles, plus many more, in JoVE: The Journal of Visualized Experiments.

November 2015 - This Month in JoVE: Drosophila Social Space, Structured Rehabilitation for Multifunctional Prosthetics, and Thermal Imaging in Wild Birds

Here's a look at what's coming up in the November 2015 issue of JoVE: The Journal of Visualized Experiments. In JoVE Neuroscience, we know that fruit flies (Drosophila melanogaster)are a lot like humans in many ways-especially because they like their personal space. And in fruit flies, this preferred social distance can be measured using the social space assay. McNiel et al. demonstrate this straightforward protocol, which requires only simple equipment and experimental setups. Flies are blown into a social chamber and forced to form a tight group. Then they're allowed to take their preferred distance from one another. These distances are measured and processed with free online software (ImageJ). This social space assay provides a simple yet powerful paradigm for analyzing the underlying neurogenetics and environmental factors of social behavior. In JoVE Behavior, humans have a natural ability to acquire new motor skills, and this ability is crucial for upper limb amputees as they learn the complex control schemes for advanced multifunctional prosthetics. This month, Roche et al. present a case study of a structured rehabilitation method, which aims to improve multifunctional prosthetic control. Their subject underwent a structured protocol of imitation, repetition, and reinforcement learning. The subject demonstrated improvement in a widely used hand function test. This study suggests that a structured rehabilitation method may facilitate proficiency for multifunctional prosthetic control, and provides basis for larger clinical studies. Stress is a major concept in JoVE Behavior, and comprises various physiological responses to challenges. Among other responses, stress increases body temperature, which provides a quantitative measure of this response. However, the very act of measuring body temperature can be stressful to subjects, especially if they're wild animals. So Jerem et al. present a protocol for noninvasively measuring temperature in wild birds using infrared thermography. Their set-up is equipped with bird food and an infrared camera. This takes a thermal video of the bird before and after the researcher remotely closes the box, which acts as a mild acute stressor. The skin around the bird's eye is the warmest area in the image, and this protocol provides a time series of eye-region temperature with fine temporal resolution. With further validation, this method may prove valuable for studying the dynamics of the stress response for a wide range of researchers from environmental science to medicine. You've just had a sneak peek of the November 2015 issue of JoVE. Visit the website to see the full-length articles, plus many more, in JoVE: The Journal of Visualized Experiments.

September 2015 - This Month in JoVE: Measuring Greenhouse Gases and Herbicide Resistance, Bioengineering Bone, and Analyzing Neuromuscular Control with Virtual Reality

Here's a look at what's coming up in the September 2015 issue of JoVE: The Journal of Visualized Experiments. In JoVE Environment, we've had a pretty warm summer in the northern hemisphere, so we can't help but think about all the greenhouse gases in our atmosphere that keep our planet nice and warm. These days, livestock are a major source of greenhouse gas emissions, especially methane. Livestock contribute anywhere from 7 to 18% of global emissions-depending on who you ask. Naturally, climate scientists are interested in controlling enteric methane from livestock. This requires accurate and precise measurement techniques, so Hristov et al. present a method using the Automated Head-Chamber System (AHCS), which monitors methane (CH4) and carbon dioxide (CO2) mass fluxes from the breath of ruminant animals (e.g., cattle). This system produces repeatable and accurate emission results, and can help efforts to curb greenhouse gas emissions. In JoVE Environment, we're also concerned about herbicide resistance in weeds, which poses a serious threat to food and fiber production. Plants can gain resistance to herbicides through genetic mutations or through enhanced activity of enzymes that metabolize and detoxify chemicals. In order to determine rates of herbicide metabolism in certain weeds, Ma et al. developed an excised leaf assay, which allows them to take experiments from the greenhouse into the lab so they can perform radiolabeled herbicide experiments more efficiently. As more and more plants become resistant to herbicides, this method will be useful for investigating the metabolic basis of herbicide resistance. In JoVE Bioengineering, one of the ultimate goals of tissue engineering is to regenerate large bone defects using synthetic scaffolds or templates. Most available scaffolds don't allow appreciable cell infiltration or distribution to achieve significant bone regeneration, so Oh et al. have developed a highly porous bone-like template with micro-channels and nanopores. Cells can be seeded into the biogenic templates through capillary action, and grow to confluence within days. This concept can help advance the repair of large bone defects. In JoVE Behavior, the human neuromuscular junction can be studied using a variety of noninvasive techniques, including electromyography (EMG), 3D motion capture, and transcranial magnetic stimulation. This month, Talkington et al. add the unique aspect of virtual reality to this test battery, and describe a customizable circuit that synchronizes data sampled from all of these techniques. You've just had a sneak peek of the September 2015 issue of JoVE. Visit the website to see the full-length articles, plus many more, in JoVE: The Journal of Visualized Experiments.

July 2015 - This Month in JoVE: Treating Canine Halitosis, Minimizing Workplace Stress, and Assessing Electrical Activity and Herbicide Resistance in Plants

Here's a look at what's coming up in the July 2015 issue of JoVE: The Journal of Visualized Experiments. In JoVE Medicine, we feature an approach for diagnosing halitosis, commonly known as bad breath, in man's best friend: the dog. The approach is much more advanced than simply smelling the dog's breath-it involves taking breath samples and using a gas chromatograph to quantify stinky compounds found in bad breath, such as hydrogen sulfide, methyl mercaptan, and dimethyl sulfide. Di Cerbo et al. use this assay in a randomized, placebo-controlled trial of dog food specially formulated to fight halitosis. The results of their study suggest that certain dietary supplements might reduce embarrassing bad breath in our beloved canine companions. In JoVE Behavior, we know all too well that working in a chronically stressful environment can have deleterious effects-so we feature a stress reduction intervention that might retrain the brain to change its usual responses to stressful situations. Klatt et al. present a structured group program that incorporates mindful meditation, yoga, and relaxing music. This intervention can be delivered onsite, at the workplace, so it's a potentially viable method of stress reduction for busy working adults. In JoVE Environment, we have two articles that explore how plants interact with certain environmental factors. Like animals, plants can transmit electrical signals over long distances, which is an advantageous trait because it allows quick responses to external stimuli. But plants have no nerves, so Salvador-Recatala and Tjallingii examine the plant vasculature, namely the sieve elements of the phloem, as a possible conduit of stimulus-induced electrical signals. They wire up aphids to record signals transmitted from another part of the plant that is sustaining damage, such as a leaf getting cut by scissors or eaten by a caterpillar. The resulting data may reveal how phloem sieve elements integrate information from different environmental stimuli. Another article in JoVE Environment demonstrates methods for testing herbicide resistance in weeds. Overuse of herbicides, combined with natural genetic variability in plants, has selected for resistance in hundreds of weed species reported to date. This is a major concern for ecosystem management and for agriculture. Panozzo et al. present protocols for testing herbicide resistance, inferring the tolerance level by using multiple herbicide doses in the experiments. Besides being highly robust and reliable, these protocols can easily be adapted to a wide range of weeds. The data obtained from these experiments can inform further research and optimize the management of herbicide use. You've just had a sneak peek of the July 2015 issue of JoVE. Visit the website to see the full-length articles, plus many more, in JoVE: The Journal of Visualized Experiments.

June 2015: This Month in JoVE - Celebrating JoVE's 100th Issue

Here's a look at what's coming up in the June 2015 issue of JoVE: The Journal of Visualized Experiments. This month marks the release of JoVE's 100th issue, and we now have 10 scientific sections: Biology, Neuroscience, Immunology & Infection, Medicine, Bioengineering, Engineering, Chemistry, Behavior, Environment, and Developmental Biology. In the field of Developmental Biology, sometimes you'll come across the term coat-which might sound like a pet's coat color, or maybe a manicure, or maybe the leather under-armor worn by 17th Century cavalry. But a buffy coat is a product of centrifuging whole blood, and refers to the cloudy layer containing white blood cells, which forms between the red blood cells and the plasma. Meraviglia et al. collect the buffy coats and turn peripheral blood mononuclear cells (PBMNCs) into induced pluripotent stem cells (iPSCs). Instead of inducing pluripotency as usual with viral vectors, our authors reprogram the cells using non-integrating plasmids. The resulting iPSC colonies show normal morphology, stable karyotypes, and significant expression of pluripotency markers. As far as we know, this is the first report of deriving virus-free iPSCs from frozen buffy coats, which are commonly stored in biobanks, and could become a valuable source of iPSCs for regenerative medicine. In JoVE Bioengineering, we know that cells can behave differently depending on the stiffness of the extracellular matrix, which is measured in kiloPascals (kPA). Metastatic cancer cells, in particular, show higher traction stress than non-metastatic cells, so scientists examine tumor cell invasion and metastasis using traction force assays. However, traction data are lacking for primary tumor cells. Therefore, Yakut Ali et al. extract primary cells from human tumors and culture them on hydrogel substrates for traction cytometry. This technique may lead to the use of biophysical parameters, such as tumor cell stiffness and traction, in cancer prognostics. In JoVE Behavior, we feature protocols that deal with cognition and learning in children. In the experimental paradigm by Sargent et al., a mobile hangs above an infant, and a light-emitting diode (LED) is secured to the infant's leg. When it reaches a certain height, the LED activates the mobile. The infants discover that the mobile will spin and play music if they kick their legs up. A motion capture system records these movements so the learning process can be quantified. Also in JoVE Behavior, children with speech impairments may benefit from a speech-generating device (SGD), which produces an electronic voice using a synthesizer. Some devices have dynamic interfaces, so users can access new words by changing levels. Cognitive factors can affect the ability to navigate through these levels, so Robillard et al. present a detailed protocol for assessing how cognitive factors contribute to navigational abilities. This could, in turn, guide clinicians to select the appropriate speech-generating device for a patient. You've just had a sneak peek of the June 2015 issue of JoVE. Visit the website to see the full-length articles, plus many more, in JoVE: The Journal of Visualized Experiments.

This Month in JoVE - Assessing Freezing Tolerance in Plants, Patterning 2D Shapes with DNA, Studying Ischemia In Vitro, Studying Social Cognition in Monkeys

Here's a look at what's coming up in the May 2015 issue of JoVE: The Journal of Visualized Experiments. In JoVE Environment, it's the middle of spring in the earth's Northern Hemisphere, so seeds are sprouting and buds are blooming. But for actively growing plants, especially those with no freezing tolerance, a cold snap can be deadly. A hard frost can dramatically alter natural ecosystems and devastate agriculture. Even more concerning, erratic weather patterns related to climate change can cause cold-susceptible plants to bud and bloom too early, then fall victim to a subsequent freeze. To protect plants from freezing, we need a better understanding of the freezing process. Wisniewski et al. describe a protocol to visualize this process using high-resolution infrared thermography (HRIT). Using this technology, scientists can determine how ice forms and propagates, and test various compounds that might alter the freezing process or increase freezing tolerance. In JoVE Chemistry, the principles of self-assembly have been used to engineer a variety of complex structures from biological and non-biological building blocks. This month, Wei et al. present detailed protocols for the self-assembly of single-stranded DNA tiles into complex 2D shapes with the tiles acting as molecular pixels on molecular canvases. These are visualized by atomic force microscopy. The modular nature of this approach allows it to be scalable, and the tiles can self-assemble into tubes and rectangles of varying sizes. This technique is also highly versatile-enabling the construction virtually any 2D shape. In JoVE Clinical & Translational Medicine, ischemic stroke happens when a blockage in an artery restricts blood flow to the brain, depriving it of oxygen and nutrients. When the blood returns, reperfusion can cause further damage by disrupting the blood-brain barrier and triggering inflammation and oxidative stress. There are many in vivo models of ischemia-reperfusion injury, and while all disease models have drawbacks, in vivo models tend to be technically challenging, with limited applicability for mechanistic studies. To help overcome some of these limitations, Alluri et al. present an in vitro model of ischemia-reperfusion, which can be used to study the molecular mechanisms of blood-brain barrier dysfunction and signs of oxidative stress. In JoVE Behavior, Fagot et al. study social cognition in monkeys. In this protocol, monkeys living in social groups have free access to multiple test units. When a monkey enters a testing chamber, and reaches through the hand port, a computer recognizes the monkey through its radio frequency ID (RFID) chip and starts the experiment A touch screen displays the stimulus and a food dispenser delivers the reward. Over several years, this procedure has been shown enhance motivation in the subjects and favor complex learning-particularly the social aspects. You've just had a sneak peek of the May 2015 issue of JoVE. Visit the website to see the full-length articles, plus many more, in JoVE: The Journal of Visualized Experiments.