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Find video protocols related to scientific articles indexed in Pubmed.
Determining the Electronic Performance Limitations in Top-Down-Fabricated Si Nanowires with Mean Widths Down to 4 nm.
Nano Lett.
PUBLISHED: 10-13-2014
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Silicon nanowires have been patterned with mean widths down to 4 nm using top-down lithography and dry etching. Performance-limiting scattering processes have been measured directly which provide new insight into the electronic conduction mechanisms within the nanowires. Results demonstrate a transition from 3-dimensional (3D) to 2D and then 1D as the nanowire mean widths are reduced from 12 to 4 nm. The importance of high quality surface passivation is demonstrated by a lack of significant donor deactivation, resulting in neutral impurity scattering ultimately limiting the electronic performance. The results indicate the important parameters requiring optimization when fabricating nanowires with atomic dimensions.
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Design and fabrication of memory devices based on nanoscale polyoxometalate clusters.
Nature
PUBLISHED: 06-26-2014
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Flash memory devices-that is, non-volatile computer storage media that can be electrically erased and reprogrammed-are vital for portable electronics, but the scaling down of metal-oxide-semiconductor (MOS) flash memory to sizes of below ten nanometres per data cell presents challenges. Molecules have been proposed to replace MOS flash memory, but they suffer from low electrical conductivity, high resistance, low device yield, and finite thermal stability, limiting their integration into current MOS technologies. Although great advances have been made in the pursuit of molecule-based flash memory, there are a number of significant barriers to the realization of devices using conventional MOS technologies. Here we show that core-shell polyoxometalate (POM) molecules can act as candidate storage nodes for MOS flash memory. Realistic, industry-standard device simulations validate our approach at the nanometre scale, where the device performance is determined mainly by the number of molecules in the storage media and not by their position. To exploit the nature of the core-shell POM clusters, we show, at both the molecular and device level, that embedding [(Se(iv)O3)2](4-) as an oxidizable dopant in the cluster core allows the oxidation of the molecule to a [Se(v)2O6](2-) moiety containing a {Se(v)-Se(v)} bond (where curly brackets indicate a moiety, not a molecule) and reveals a new 5+ oxidation state for selenium. This new oxidation state can be observed at the device level, resulting in a new type of memory, which we call 'write-once-erase'. Taken together, these results show that POMs have the potential to be used as a realistic nanoscale flash memory. Also, the configuration of the doped POM core may lead to new types of electrical behaviour. This work suggests a route to the practical integration of configurable molecules in MOS technologies as the lithographic scales approach the molecular limit.
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Further studies on sex pheromones of female Lygus and related bugs: development of effective lures and investigation of species-specificity.
J. Chem. Ecol.
PUBLISHED: 01-04-2014
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Mirid bugs (Heteroptera: Miridae) are important pests of many crops worldwide. In previous work by others and ourselves, several species of Lygus bugs were shown to produce blends of three compounds, hexyl butyrate, (E)-2-hexenyl butyrate, and (E)-4-oxo-2-hexenal. These have been proposed as components of the female-produced sex pheromones, but attraction of males to synthetic lures has been difficult to demonstrate. We studied the volatiles released by females of four species: Lygus rugulipennis, Lygus pratensis, Lygocoris pabulinus, and Liocoris tripustulatus. Analyses of volatiles from individual, undisturbed insects showed that the three compounds were produced in species-specific blends, by females only, or in greater quantities by females than by males. The three compounds were loaded into pipette tips, which released the defined blends over at least 30 days. Traps baited with the blend for L. rugulipennis caught more males than traps baited with virgin females, with all three compounds required for maximum attractiveness. Traps baited with the specific blends for each of the four species caught males of three of the species, indicating considerable cross-attraction. There is evidence that other, non-chemical factors, such as time-of-day of production of pheromone, contribute to species-specificity of attraction. This is the first report of consistent attraction of Lygus bugs to synthetic lures in the field.
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Synthesis and characterization of potential dimers of gatifloxacin - an antibacterial drug.
Sci Pharm
PUBLISHED: 09-01-2013
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Gatifloxacin is an antibacterial agent belonging to the fourth-generation fluoroquinolone family. Four piperazine-linked fluoroquinolone dimers of Gatifloxacin were observed during the laboratory process for Gatifloxacin and they were identified. The present work describes the origin, synthesis, characterization, and control of these dimers along with the synthesis of Despropylene Gatifloxacin (metabolite).
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Pneumatosis Intestinalis Predictive Evaluation Study (PIPES): a multicenter epidemiologic study of the Eastern Association for the Surgery of Trauma.
J Trauma Acute Care Surg
PUBLISHED: 06-20-2013
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Pneumatosis intestinalis (PI) is associated with numerous adult conditions, ranging from benign to life threatening. To date, series of PI outcomes consist of case reports and small retrospective series.
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Rural residency and the risk of mortality while waiting for liver transplantation.
Clin Transplant
PUBLISHED: 12-28-2011
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Our liver transplant program services a region that has a prominent rural demographic. The influence of rural residency on liver transplant wait-list mortality has not been previously studied. We hypothesized that residence in a rural setting, by imposing challenges to medical care access, might be associated with inferior survival while waiting for liver transplantation. To test this hypothesis, multivariable time-to-event analysis was performed using Cox proportional hazards and competing risks regression on data from a consecutive five-yr cohort of 159 primary liver transplant candidates, to derive covariate adjusted effect measures for the association between residence in a rural area and wait-list mortality. For the primary analysis, a standardized, census-based, definition was used to assign rural residency status. The Kaplan-Meier estimated 90-d and one-yr wait-list mortality for the cohort was 7.6% (95% CI: 4.2-13.8) and 15.6% (95% CI: 9.4-25.2). The covariate adjusted hazard ratio for the relationship between Rural and Small Town residency status and wait-list mortality was 0.497 (95% CI: 0.171-1.438, p = 0.197) for the Cox regression model and 0.628 (95% CI: 0.224-1.757, p = 0.376) for the competing risk regression model. As defined in this study, candidate residence in a rural setting was not found to be associated with inferior survival while awaiting liver transplantation.
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The Model for End-stage Liver Disease accurately predicts 90-day liver transplant wait-list mortality in Atlantic Canada.
Can. J. Gastroenterol.
PUBLISHED: 08-31-2011
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To determine the generalizability of the predictions for 90-day mortality generated by Model for End-stage Liver Disease (MELD) and the serum sodium augmented MELD (MELDNa) to Atlantic Canadian adults with end-stage liver disease awaiting liver transplantation (LT).
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[Food and Nutritional Surveillance System (SISVAN) in children from Rio Grande do Sul State, Brazil: coverage, nutritional status, and data reliability].
Cad Saude Publica
PUBLISHED: 08-08-2011
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This study aimed to evaluate: the coverage of the Food and Nutritional Surveillance System (SISVAN) in the State of Rio Grande do Sul, Brazil, and it Regional Health Offices in 2006; the nutritional status of children 0-10 years of age; and the reliability of data on nutritional status recorded in the system. A cross-sectional descriptive study was conducted with secondary data on 63,320 children. Coverage was defined as the proportion of children younger than 10 years covered by the Family Health Strategy in the States various municipalities (counties). Height-for-age (H/A) and body mass index for age (BMI/A) were classified according to World Health Organization (WHO) criteria. Agreement between the nutritional classifications recorded in the system and those calculated in this study was evaluated with the weighted kappa coefficient (at 5%). The systems coverage in the State of Rio Grande do Sul was 10.5%. Low height-for-age was found in 7.1% of children and overweight in 8.4%. Agreement between the classifications showed a kappa coefficient of 0.43. The systems coverage and agreement between classifications were both low, and the study showed the coexistence of high overweight and stunting rates in this age group.
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Is premigration health screening for tuberculosis worthwhile?
Med. J. Aust.
PUBLISHED: 08-04-2011
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To determine whether premigration screening for tuberculosis is worth undertaking in visa applicants, and whether screening resources are being appropriately directed towards intending migrants at highest risk of tuberculosis.
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Use of health information systems in small municipalities in Southern Brazil.
Rev Saude Publica
PUBLISHED: 05-11-2011
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To describe the use of health information systems in towns with fewer than 10,000 inhabitants.
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A comparative examination of tuberculosis immigration medical screening programs from selected countries with high immigration and low tuberculosis incidence rates.
BMC Infect. Dis.
PUBLISHED: 01-04-2011
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Tuberculosis (TB) in migrants is an ongoing challenge in several low TB incidence countries since a large proportion of TB in these countries occurs in migrants from high incidence countries. To meet these challenges, several countries utilize TB screening programs. The programs attempt to identify and treat those with active and/or infectious stages of the disease. In addition, screening is used to identify and manage those with latent or inactive disease after arrival. Between nations, considerable variation exists in the methods used in migration-associated TB screening. The present study aimed to compare the TB immigration medical examination requirements in selected countries of high immigration and low TB incidence rates.
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RPE-secreted factors: influence differentiation in human retinal cell line in dose- and density-dependent manner.
J Ocul Biol Dis Infor
PUBLISHED: 12-01-2010
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Retinal pigment epithelial (RPE) cells play an important role in normal functioning of retina and photoreceptors, and some retinal degenerations arise due to malfunctioning RPE. Retinal pigment epithelium transplantation is being explored as a strategy to rescue degenerating photoreceptors in diseases such as age-related macular degeneration (AMD) and retinitis pigmentosa (RP). Additionally, RPE-secreted factors could rescue degenerating photoreceptors by prolonging survival or by their ability to differentiate and give rise to photoreceptors by transdifferentiation. In this study, we have explored what role cell density could play in differentiation induced in a human retinal progenitor cell line, in response to RPE-secreted growth factors. Retinal progenitors plated at low (1?×?10(4) cells/cm(2)), medium (2-4?×?10(4) cells/cm(2)), and high (1?×?10(5) cells/cm(2)) cell density were exposed to various dilutions of RPE-conditioned medium (secreted factors) under conditions of defined medium culture. Progenitor cell differentiation was monitored phenotypically (morphological, biochemical analysis, and immunophenotyping, and western blot analysis were performed). Our data show that differentiation in response to RPE-secreted factors is modulated by cell density and dilutions of conditioned medium. We conclude that before embarking on RPE transplantation as a modality for treatment of RP and AMD, one will have to determine the role that cell density and inhibitory and stimulatory neurotrophins secreted by RPE could play in the efficacy of survival of transplants. We report that RPE-conditioned medium enhances neuronal phenotype (photoreceptors, bipolars) at the lowest cell density in the absence of cell-cell contact. Eighty percent to 90% of progenitor cells differentiate into photoreceptors and bipolars at 50% concentration of conditioned medium, while exposure to 100% conditioned medium might increase multipolar neurons (ganglionic and amacrine phenotypes) to a small degree. However, no clear-cut pattern of differentiation in response to RPE-secreted factors is noted at higher cell densities.
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The effect of presleep video-game playing on adolescent sleep.
J Clin Sleep Med
PUBLISHED: 04-24-2010
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Video-game use before bedtime has been linked with poor sleep outcomes for adolescents; however, experimental evidence to support this link is sparse. The present study investigated the capacity of presleep video-game playing to extend sleep latency and reduce subjective feelings of sleepiness in adolescents. The arousing psychophysiologic mechanisms involved and the impact of presleep video-game playing on sleep architecture were also explored.
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Product inhibition in the radical S-adenosylmethionine family.
FEBS Lett.
PUBLISHED: 03-13-2009
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Members of the radical S-adenosylmethionine (AdoMet) superfamily reductively cleave AdoMet to generate the highly reactive 5-deoxyadenosyl radical (DOA()) which initiates biological transformations by abstraction of a hydrogen atom. We demonstrate that three members of the family: biotin synthase (BioB), lipoyl synthase (LipA) and tyrosine lyase (ThiH) are inhibited in vitro by a combination of the products 5-deoxyadenosine (DOA) and methionine. These results suggest the observed inhibition is a common feature of the radical AdoMet proteins that form DOA and methionine as products. Addition of 5-methylthioadenosine/S-adenosylhomocysteine nucleosidase (MTAN) to BioB, LipA or ThiH activity assays removed the product inhibition by catalysing the hydrolysis of DOA and gave an increase in activity.
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The impact of prolonged violent video-gaming on adolescent sleep: an experimental study.
J Sleep Res
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Video-gaming is an increasingly prevalent activity among children and adolescents that is known to influence several areas of emotional, cognitive and behavioural functioning. Currently there is insufficient experimental evidence about how extended video-game play may affect adolescents sleep. The aim of this study was to investigate the short-term impact of adolescents prolonged exposure to violent video-gaming on sleep. Seventeen male adolescents (mean age = 16 ± 1 years) with no current sleep difficulties played a novel, fast-paced, violent video-game (50 or 150 min) before their usual bedtime on two different testing nights in a sleep laboratory. Objective (polysomnography-measured sleep and heart rate) and subjective (single-night sleep diary) measures were obtained to assess the arousing effects of prolonged gaming. Compared with regular gaming, prolonged gaming produced decreases in objective sleep efficiency (by 7 ± 2%, falling below 85%) and total sleep time (by 27 ± 12 min) that was contributed by a near-moderate reduction in rapid eye movement sleep (Cohens d = 0.48). Subjective sleep-onset latency significantly increased by 17 ± 8 min, and there was a moderate reduction in self-reported sleep quality after prolonged gaming (Cohens d = 0.53). Heart rate did not differ significantly between video-gaming conditions during pre-sleep game-play or the sleep-onset phase. Results provide evidence that prolonged video-gaming may cause clinically significant disruption to adolescent sleep, even when sleep after video-gaming is initiated at normal bedtime. However, physiological arousal may not necessarily be the mechanism by which technology use affects sleep.
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Are there geographical disparities in access to liver transplantation in Atlantic Canada?
Can. J. Gastroenterol.
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To characterize the patient population served by Atlantic Canadas Multi-Organ Transplant Program liver transplant service over the first five years of activity in its current iteration.
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Synthesis of compounds related to the anti-migraine drug eletriptan hydrobromide.
Beilstein J Org Chem
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Eletriptan hydrobromide (1) is a selective serotonin (5-HT(1)) agonist, used for the acute treatment of the headache phase of migraine attacks. During the manufacture of eletriptan hydrobromide the formation of various impurities were observed and identified by LC-MS. To control the formation of these impurities during the preparation of active pharmaceutical ingredients, the structure of the impurities must be known. Major impurities of the eletriptan hydrobromide synthesis were prepared and characterized by using various spectroscopic techniques, i.e., mass spectroscopy, FTIR , (1)H NMR, (13)C NMR/DEPT, and further confirmed by co-injection in HPLC. The present study will be of great help in the synthesis of highly pure eletriptan hydrobromide related compounds.
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What is Visualize?

JoVE Visualize is a tool created to match the last 5 years of PubMed publications to methods in JoVE's video library.

How does it work?

We use abstracts found on PubMed and match them to JoVE videos to create a list of 10 to 30 related methods videos.

Video X seems to be unrelated to Abstract Y...

In developing our video relationships, we compare around 5 million PubMed articles to our library of over 4,500 methods videos. In some cases the language used in the PubMed abstracts makes matching that content to a JoVE video difficult. In other cases, there happens not to be any content in our video library that is relevant to the topic of a given abstract. In these cases, our algorithms are trying their best to display videos with relevant content, which can sometimes result in matched videos with only a slight relation.