yt:channel:UC32BboXfQ_tDCV8y1ttx7cg UC32BboXfQ_tDCV8y1ttx7cg KeSimpulan https://www.youtube.com/channel/UC32BboXfQ_tDCV8y1ttx7cg 2011-10-30T22:14:53+00:00 yt:video:kYCFiG41LUM kYCFiG41LUM UC32BboXfQ_tDCV8y1ttx7cg KeSimpulan https://www.youtube.com/channel/UC32BboXfQ_tDCV8y1ttx7cg 2016-08-08T18:28:17+00:00 2017-07-01T03:06:49+00:00 Self-organized centripetal movement of corneal epithelium in the absence of external cues Self-organized centripetal movement of corneal epithelium in the absence of external cues. Erwin P. Lobo et al (2016). Nature Communications http://dx.doi.org/10.1038/ncomms12388 Maintaining the structure of the cornea is essential for high-quality vision. In adult mammals, corneal epithelial cells emanate from stem cells in the limbus, driven by an unknown mechanism towards the centre of the cornea as cohesive clonal groups. Here we use complementary mathematical and biological models to show that corneal epithelial cells can self-organize into a cohesive, centripetal growth pattern in the absence of external physiological cues. Three conditions are required: a circumferential location of stem cells, a limited number of cell divisions and mobility in response to population pressure. We have used these complementary models to provide explanations for the increased rate of centripetal migration caused by wounding and the potential for stem cell leakage to account for stable transplants derived from central corneal tissue, despite the predominantly limbal location of stem cells. yt:video:F8qGf0InoSE F8qGf0InoSE UC32BboXfQ_tDCV8y1ttx7cg KeSimpulan https://www.youtube.com/channel/UC32BboXfQ_tDCV8y1ttx7cg 2016-08-05T19:35:58+00:00 2017-03-15T21:20:44+00:00 Reorganization of hydrogen bond network makes strong polyelectrolyte brushes pH-responsive Reorganization of hydrogen bond network makes strong polyelectrolyte brushes pH-responsive. Bo Wu et al (2016). Science Advances http://dx.doi.org/10.1126/sciadv.1600579 Weak polyelectrolytes have found extensive practical applications owing to their rich pH-responsive properties. In contrast, strong polyelectrolytes have long been regarded as pH-insensitive based on the well-established fact that the average degree of charging of strong polyelectrolyte chains is independent of pH. The possible applications of strong polyelectrolytes in smart materials have, thus, been severely limited. However, we demonstrate that almost all important properties of strong polyelectrolyte brushes (SPBs), such as chain conformation, hydration, stiffness, surface wettability, lubricity, adhesion, and protein adsorption are sensitive to pH. The pH response originates from the reorganization of the interchain hydrogen bond network between the grafted chains, triggered by the pH-mediated adsorption-desorption equilibrium of hydronium or hydroxide with the brushes. The reorganization process is firmly identified by advanced sum-frequency generation vibrational spectroscopy. Our findings not only provide a new understanding of the fundamental properties of SPBs but also uncover an extensive family of building blocks for constructing pH-responsive materials. yt:video:9RqIr37Fixc 9RqIr37Fixc UC32BboXfQ_tDCV8y1ttx7cg KeSimpulan https://www.youtube.com/channel/UC32BboXfQ_tDCV8y1ttx7cg 2016-08-05T19:20:22+00:00 2017-03-15T21:20:53+00:00 Battery-free, stretchable optoelectronic systems for wireless optical characterization of the skin Battery-free, stretchable optoelectronic systems for wireless optical characterization of the skin. Jeonghyun Kim et al (2016). Science Advances http://dx.doi.org/10.1126/sciadv.1600418 Recent advances in materials, mechanics, and electronic device design are rapidly establishing the foundations for health monitoring technologies that have “skin-like” properties, with options in chronic (weeks) integration with the epidermis. The resulting capabilities in physiological sensing greatly exceed those possible with conventional hard electronic systems, such as those found in wrist-mounted wearables, because of the intimate skin interface. However, most examples of such emerging classes of devices require batteries and/or hard-wired connections to enable operation. The work reported here introduces active optoelectronic systems that function without batteries and in an entirely wireless mode, with examples in thin, stretchable platforms designed for multiwavelength optical characterization of the skin. Magnetic inductive coupling and near-field communication (NFC) schemes deliver power to multicolored light-emitting diodes and extract digital data from integrated photodetectors in ways that are compatible with standard NFC-enabled platforms, such as smartphones and tablet computers. Examples in the monitoring of heart rate and temporal dynamics of arterial blood flow, in quantifying tissue oxygenation and ultraviolet dosimetry, and in performing four-color spectroscopic evaluation of the skin demonstrate the versatility of these concepts. The results have potential relevance in both hospital care and at-home diagnostics. yt:video:nxqW1BNiMLI nxqW1BNiMLI UC32BboXfQ_tDCV8y1ttx7cg KeSimpulan https://www.youtube.com/channel/UC32BboXfQ_tDCV8y1ttx7cg 2016-08-05T18:55:56+00:00 2017-03-15T21:20:59+00:00 Magnetic Particle Imaging for High Temporal Resolution Assessment of Aneurysm Hemodynamics Magnetic Particle Imaging for High Temporal Resolution Assessment of Aneurysm Hemodynamics. Jan Sedlacik et al (2016). PLoS ONE http://dx.doi.org/10.1371/journal.pone.0160097 Purpose The purpose of this work was to demonstrate the capability of magnetic particle imaging (MPI) to assess the hemodynamics in a realistic 3D aneurysm model obtained by additive manufacturing. MPI was compared with magnetic resonance imaging (MRI) and dynamic digital subtraction angiography (DSA). Materials and Methods The aneurysm model was of saccular morphology (7 mm dome height, 5 mm cross-section, 3–4 mm neck, 3.5 mm parent artery diameter) and connected to a peristaltic pump delivering a physiological flow (250 mL/min) and pulsation rate (70/min). High-resolution (4 h long) 4D phase contrast flow quantification (4D pc-fq) MRI was used to directly assess the hemodynamics of the model. Dynamic MPI, MRI, and DSA were performed with contrast agent injections (3 mL volume in 3 s) through a proximally placed catheter. Results and Discussion 4D pc-fq measurements showed distinct pulsatile flow velocities (20–80 cm/s) as well as lower flow velocities and a vortex inside the aneurysm. All three dynamic methods (MPI, MRI, and DSA) also showed a clear pulsation pattern as well as delayed contrast agent dynamics within the aneurysm, which is most likely caused by the vortex within the aneurysm. Due to the high temporal resolution of MPI and DSA, it was possible to track the contrast agent bolus through the model and to estimate the average flow velocity (about 60 cm/s), which is in accordance with the 4D pc-fq measurements. Conclusions The ionizing radiation free, 4D high resolution MPI method is a very promising tool for imaging and characterization of hemodynamics in human. It carries the possibility of overcoming certain disadvantages of other modalities like considerably lower temporal resolution of dynamic MRI and limited 2D characteristics of DSA. Furthermore, additive manufacturing is the key for translating powerful pre-clinical techniques into the clinic. yt:video:5LhLd3Pn7tg 5LhLd3Pn7tg UC32BboXfQ_tDCV8y1ttx7cg KeSimpulan https://www.youtube.com/channel/UC32BboXfQ_tDCV8y1ttx7cg 2016-08-05T18:40:24+00:00 2016-08-05T18:42:39+00:00 Seabird acoustic communication at sea: a new perspective using bio-logging devices Seabird acoustic communication at sea: a new perspective using bio-logging devices. Andréa Thiebault et al (2016). Scientific Reports http://dx.doi.org/10.1038/srep30972 Most seabirds are very noisy at their breeding colonies, when aggregated in high densities. Calls are used for individual recognition and also emitted during agonistic interactions. When at sea, many seabirds aggregate over patchily distributed resources and may benefit from foraging in groups. Because these aggregations are so common, it raises the question of whether seabirds use acoustic communication when foraging at sea? We deployed video-cameras with built in microphones on 36 Cape gannets (Morus capensis) during the breeding season of 2010–2011 at Bird Island (Algoa Bay, South Africa) to study their foraging behaviour and vocal activity at sea. Group formation was derived from the camera footage. During ~42 h, calls were recorded on 72 occasions from 16 birds. Vocalization exclusively took place in the presence of conspecifics, and mostly in feeding aggregations (81% of the vocalizations). From the observation of the behaviours of birds associated with the emission of calls, we suggest that the calls were emitted to avoid collisions between birds. Our observations show that at least some seabirds use acoustic communication when foraging at sea. These findings open up new perspectives for research on seabirds foraging ecology and their interactions at sea. yt:video:hd7jvQB5At8 hd7jvQB5At8 UC32BboXfQ_tDCV8y1ttx7cg KeSimpulan https://www.youtube.com/channel/UC32BboXfQ_tDCV8y1ttx7cg 2016-08-05T18:15:47+00:00 2017-04-15T14:38:21+00:00 HIV-1 Tat exacerbates lipopolysaccharide-induced cytokine release via TLR4 signaling HIV-1 Tat exacerbates lipopolysaccharide-induced cytokine release via TLR4 signaling in the enteric nervous system. Joy Guedia et al (2016). Scientific Reports http://dx.doi.org/10.1038/srep31203 The loss of gut epithelium integrity leads to translocation of microbes and microbial products resulting in immune activation and drives systemic inflammation in acquired immunodeficiency syndrome (AIDS) patients. Although viral loads in HIV patients are significantly reduced in the post-cART era, inflammation and immune activation persist and can lead to morbidity. Here, we determined the interactive effects of the viral protein HIV-1 Tat and lipopolysaccharide (LPS) on enteric neurons and glia. Bacterial translocation was significantly enhanced in Tat-expressing (Tat+) mice. Exposure to HIV-1 Tat in combination with LPS enhanced the expression and release of the pro-inflammatory cytokines IL-6, IL-1β and TNF-α in the ilea of Tat+ mice and by enteric glia. This coincided with enhanced NF-κB activation in enteric glia that was abrogated in glia from TLR4 knockout mice and by knockdown (siRNA) of MyD88 siRNA in wild type glia. The synergistic effects of Tat and LPS resulted in a reduced rate of colonic propulsion in Tat+ mice treated with LPS. These results show that HIV-1 Tat interacts with the TLR4 receptor to enhance the pro-inflammatory effects of LPS leading to gastrointestinal dysmotility and enhanced immune activation. yt:video:2dfn9aRLZ8Q 2dfn9aRLZ8Q UC32BboXfQ_tDCV8y1ttx7cg KeSimpulan https://www.youtube.com/channel/UC32BboXfQ_tDCV8y1ttx7cg 2016-08-05T17:47:37+00:00 2017-01-28T07:32:10+00:00 Simulated Microgravity and 3D Culture Enhance Induction, Viability, Proliferation Simulated Microgravity and 3D Culture Enhance Induction, Viability, Proliferation and Differentiation of Cardiac Progenitors from Human Pluripotent Stem Cells. Rajneesh Jha et al (2016). Scientific Reports http://dx.doi.org/10.1038/srep30956 Efficient generation of cardiomyocytes from human pluripotent stem cells is critical for their regenerative applications. Microgravity and 3D culture can profoundly modulate cell proliferation and survival. Here, we engineered microscale progenitor cardiac spheres from human pluripotent stem cells and exposed the spheres to simulated microgravity using a random positioning machine for 3 days during their differentiation to cardiomyocytes. This process resulted in the production of highly enriched cardiomyocytes (99% purity) with high viability (90%) and expected functional properties, with a 1.5 to 4-fold higher yield of cardiomyocytes from each undifferentiated stem cell as compared with 3D-standard gravity culture. Increased induction, proliferation and viability of cardiac progenitors as well as up-regulation of genes associated with proliferation and survival at the early stage of differentiation were observed in the 3D culture under simulated microgravity. Therefore, a combination of 3D culture and simulated microgravity can be used to efficiently generate highly enriched cardiomyocytes. yt:video:ZBPZNtsDLNA ZBPZNtsDLNA UC32BboXfQ_tDCV8y1ttx7cg KeSimpulan https://www.youtube.com/channel/UC32BboXfQ_tDCV8y1ttx7cg 2016-08-04T18:48:29+00:00 2016-08-04T18:51:40+00:00 Distinct roles of visual, parietal, and frontal motor cortices in memory-guided sensorimotor Distinct roles of visual, parietal, and frontal motor cortices in memory-guided sensorimotor decisions. Michael J Goard et al (2016). eLIFE http://dx.doi.org/10.7554/eLife.13764 Mapping specific sensory features to future motor actions is a crucial capability of mammalian nervous systems. We investigated the role of visual (V1), posterior parietal (PPC), and frontal motor (fMC) cortices for sensorimotor mapping in mice during performance of a memory-guided visual discrimination task. Large-scale calcium imaging revealed that V1, PPC, and fMC neurons exhibited heterogeneous responses spanning all task epochs (stimulus, delay, response). Population analyses demonstrated unique encoding of stimulus identity and behavioral choice information across regions, with V1 encoding stimulus, fMC encoding choice even early in the trial, and PPC multiplexing the two variables. Optogenetic inhibition during behavior revealed that all regions were necessary during the stimulus epoch, but only fMC was required during the delay and response epochs. Stimulus identity can thus be rapidly transformed into behavioral choice, requiring V1, PPC, and fMC during the transformation period, but only fMC for maintaining the choice in memory prior to execution. yt:video:9-r3lsKTESk 9-r3lsKTESk UC32BboXfQ_tDCV8y1ttx7cg KeSimpulan https://www.youtube.com/channel/UC32BboXfQ_tDCV8y1ttx7cg 2016-08-04T18:32:18+00:00 2016-08-04T18:37:53+00:00 A mitochondrial DNA hypomorph of cytochrome oxidase specifically impairs male fertility A mitochondrial DNA hypomorph of cytochrome oxidase specifically impairs male fertility in Drosophila melanogaster. Maulik R Patel et al (2016). eLIFE http://dx.doi.org/10.7554/eLife.16923 Due to their strict maternal inheritance in most animals and plants, mitochondrial genomes are predicted to accumulate mutations that are beneficial or neutral in females but harmful in males. Although a few male-harming mtDNA mutations have been identified, consistent with this ‘Mother’s Curse’, their effect on females has been largely unexplored. Here, we identify COIIG177S, a mtDNA hypomorph of cytochrome oxidase II, which specifically impairs male fertility due to defects in sperm development and function without impairing other male or female functions. COIIG177S represents one of the clearest examples of a ‘male-harming’ mtDNA mutation in animals and suggest that the hypomorphic mtDNA mutations like COIIG177S might specifically impair male gametogenesis. Intriguingly, some D. melanogaster nuclear genetic backgrounds can fully rescue COIIG177S -associated sterility, consistent with previously proposed models that nuclear genomes can regulate the phenotypic manifestation of mtDNA mutations. yt:video:MrsJRDC8gPs MrsJRDC8gPs UC32BboXfQ_tDCV8y1ttx7cg KeSimpulan https://www.youtube.com/channel/UC32BboXfQ_tDCV8y1ttx7cg 2016-08-04T18:10:59+00:00 2016-10-21T23:00:50+00:00 Chromatin remodelling and antisense-mediated up-regulation of the developmental switch gene Chromatin remodelling and antisense-mediated up-regulation of the developmental switch gene eud-1 control predatory feeding plasticity. Vahan Serobyan et al (2016). Nature Communications http://dx.doi.org/10.1038/ncomms12337 Phenotypic plasticity has been suggested to act through developmental switches, but little is known about associated molecular mechanisms. In the nematode Pristionchus pacificus, the sulfatase eud-1 was identified as part of a developmental switch controlling mouth-form plasticity governing a predatory versus bacteriovorous mouth-form decision. Here we show that mutations in the conserved histone-acetyltransferase Ppa-lsy-12 and the methyl-binding-protein Ppa-mbd-2 mimic the eud-1 phenotype, resulting in the absence of one mouth-form. Mutations in both genes cause histone modification defects and reduced eud-1 expression. Surprisingly, Ppa-lsy-12 mutants also result in the down-regulation of an antisense-eud-1 RNA. eud-1 and antisense-eud-1 are co-expressed and further experiments suggest that antisense-eud-1 acts through eud-1 itself. Indeed, overexpression of the antisense-eud-1 RNA increases the eud-1-sensitive mouth-form and extends eud-1 expression. In contrast, this effect is absent in eud-1 mutants indicating that antisense-eud-1 positively regulates eud-1. Thus, chromatin remodelling and antisense-mediated up-regulation of eud-1 control feeding plasticity in Pristionchus. yt:video:m6_7y35jS90 m6_7y35jS90 UC32BboXfQ_tDCV8y1ttx7cg KeSimpulan https://www.youtube.com/channel/UC32BboXfQ_tDCV8y1ttx7cg 2016-08-04T17:45:41+00:00 2016-10-05T19:01:41+00:00 Inkjet Printing Based Mono-layered Photonic Crystal Patterning for Anti-counterfeiting Structural Inkjet Printing Based Mono-layered Photonic Crystal Patterning for Anti-counterfeiting Structural Colors. Hyunmoon Nam et al (2016). Scientific Reports http://dx.doi.org/10.1038/srep30885 Photonic crystal structures can be created to manipulate electromagnetic waves so that many studies have focused on designing photonic band-gaps for various applications including sensors, LEDs, lasers, and optical fibers. Here, we show that mono-layered, self-assembled photonic crystals (SAPCs) fabricated by using an inkjet printer exhibit extremely weak structural colors and multiple colorful holograms so that they can be utilized in anti-counterfeit measures. We demonstrate that SAPC patterns on a white background are covert under daylight, such that pattern detection can be avoided, but they become overt in a simple manner under strong illumination with smartphone flash light and/or on a black background, showing remarkable potential for anti-counterfeit techniques. Besides, we demonstrate that SAPCs yield different RGB histograms that depend on viewing angles and pattern densities, thus enhancing their cryptographic capabilities. Hence, the structural colorations designed by inkjet printers would not only produce optical holograms for the simple authentication of many items and products but also enable a high-secure anti-counterfeit technique. yt:video:chqsprw-CGk chqsprw-CGk UC32BboXfQ_tDCV8y1ttx7cg KeSimpulan https://www.youtube.com/channel/UC32BboXfQ_tDCV8y1ttx7cg 2016-08-03T18:46:14+00:00 2016-08-04T02:58:13+00:00 Evidence for Ventilation through Collective Respiratory Movements in Giant Honeybee (Apis dorsata) Evidence for Ventilation through Collective Respiratory Movements in Giant Honeybee (Apis dorsata) Nests. Gerald Kastberger et al (2016). PLoS ONE http://dx.doi.org/10.1371/journal.pone.0157882 The Asian giant honeybees (Apis dorsata) build single-comb nests in the open, which makes this species particularly susceptible to environmental strains. Long-term infrared (IR) records documented cool nest regions (CNR) at the bee curtain (nCNR = 207, nnests ~ 20) distinguished by marked negative gradients (ΔTCNR/d ~ -3°C / 5 cm) at their margins. CNRs develop and recede within minutes, predominantly at higher ambient temperatures in the early afternoon. The differential size (ΔACNR) and temperature (ΔTCNR) values per time unit correlated mostly positively (RAT ~ 0) displaying the Venturi effect, which evidences funnel properties of CNRs. The air flows inwards through CNRs, which is verified by the negative spatial gradient ΔTCNR/d, by the positive grading of TCNR with Tamb and lastly by fanners which have directed their abdomens towards CNRs. Rare cases of RAT ~ 0 (~ 3%) document closing processes (for ΔACNR/Δt ~ -0.4 cm2/s) but also suggest ventilation of the bee curtain (for ΔACNR/Δt ~ +0.4 cm2/s) displaying “inhalation” and “exhalation” cycling. “Inhalation” could be boosted by bees at the inner curtain layers, which stretch their extremities against the comb enlarging the inner nest lumen and thus causing a pressure fall which drives ambient air inwards through CNR funnels. The relaxing of the formerly “activated” bees could then trigger the “exhalation” process, which brings the bee curtain, passively by gravity, close to the comb again. That way, warm, CO2-enriched nest-borne air is pressed outwards through the leaking mesh of the bee curtain. This ventilation hypothesis is supported by IR imaging and laser vibrometry depicting CNRs in at least four aspects as low-resistance convection funnels for maintaining thermoregulation and restoring fresh air in the nest. yt:video:641IjYVbmWI 641IjYVbmWI UC32BboXfQ_tDCV8y1ttx7cg KeSimpulan https://www.youtube.com/channel/UC32BboXfQ_tDCV8y1ttx7cg 2016-08-03T18:28:35+00:00 2016-12-06T16:55:12+00:00 The sense of body ownership relaxes temporal constraints for multisensory integration The sense of body ownership relaxes temporal constraints for multisensory integration. Antonella Maselli et al (2016). Scientific Reports http://dx.doi.org/10.1038/srep30628 Experimental work on body ownership illusions showed how simple multisensory manipulation can generate the illusory experience of an artificial limb as being part of the own-body. This work highlighted how own-body perception relies on a plastic brain representation emerging from multisensory integration. The flexibility of this representation is reflected in the short-term modulations of physiological states and perceptual processing observed during these illusions. Here, we explore the impact of ownership illusions on the temporal dimension of multisensory integration. We show that, during the illusion, the temporal window for integrating touch on the physical body with touch seen on a virtual body representation, increases with respect to integration with visual events seen close but separated from the virtual body. We show that this effect is mediated by the ownership illusion. Crucially, the temporal window for visuotactile integration was positively correlated with participants’ scores rating the illusory experience of owning the virtual body and touching the object seen in contact with it. Our results corroborate the recently proposed causal inference mechanism for illusory body ownership. As a novelty, they show that the ensuing illusory causal binding between stimuli from the real and fake body relaxes constraints for the integration of bodily signals. yt:video:w6j8xTZufUc w6j8xTZufUc UC32BboXfQ_tDCV8y1ttx7cg KeSimpulan https://www.youtube.com/channel/UC32BboXfQ_tDCV8y1ttx7cg 2016-08-03T18:04:46+00:00 2017-06-17T23:18:31+00:00 Evidence that birds sleep in mid-flight Evidence that birds sleep in mid-flight. Niels C Rattenborg et al (2016). Nature Communications http://dx.doi.org/10.1038/ncomms12468 Many birds fly non-stop for days or longer, but do they sleep in flight and if so, how? It is commonly assumed that flying birds maintain environmental awareness and aerodynamic control by sleeping with only one eye closed and one cerebral hemisphere at a time. However, sleep has never been demonstrated in flying birds. Here, using electroencephalogram recordings of great frigatebirds (Fregata minor) flying over the ocean for up to 10 days, we show that they can sleep with either one hemisphere at a time or both hemispheres simultaneously. Also unexpectedly, frigatebirds sleep for only 0.69 h d−1 (7.4% of the time spent sleeping on land), indicating that ecological demands for attention usually exceed the attention afforded by sleeping unihemispherically. In addition to establishing that birds can sleep in flight, our results challenge the view that they sustain prolonged flights by obtaining normal amounts of sleep on the wing. yt:video:i2Q-E6qJRCc i2Q-E6qJRCc UC32BboXfQ_tDCV8y1ttx7cg KeSimpulan https://www.youtube.com/channel/UC32BboXfQ_tDCV8y1ttx7cg 2016-08-03T17:31:19+00:00 2016-12-06T17:04:08+00:00 High-brightness organic light-emitting diodes for optogenetic control of Drosophila locomotor High-brightness organic light-emitting diodes for optogenetic control of Drosophila locomotor behaviour. Andrew Morton et al (2016). Scientific Reports http://dx.doi.org/10.1038/srep31117 Organic light emitting diodes (OLEDs) are in widespread use in today’s mobile phones and are likely to drive the next generation of large area displays and solid-state lighting. Here we show steps towards their utility as a platform technology for biophotonics, by demonstrating devices capable of optically controlling behaviour in live animals. Using devices with a pin OLED architecture, sufficient illumination intensity (0.3 mW.mm−2) to activate channelrhodopsins (ChRs) in vivo was reliably achieved at low operating voltages (5 V). In Drosophila melanogaster third instar larvae expressing ChR2(H134R) in motor neurons, we found that pulsed illumination from blue and green OLEDs triggered robust and reversible contractions in animals. This response was temporally coupled to the timing of OLED illumination. With blue OLED illumination, the initial rate and overall size of the behavioural response was strongest. Green OLEDs achieved roughly 70% of the response observed with blue OLEDs. Orange OLEDs did not produce contractions in larvae, in agreement with the spectral response of ChR2(H134R). The device configuration presented here could be modified to accommodate other small model organisms, cell cultures or tissue slices and the ability of OLEDs to provide patterned illumination and spectral tuning can further broaden their utility in optogenetics experiments.