bluuebunny/crossref_metadata_2025_split huggingface dataset:
High-Throughput Non-Contact Vitrification of Cell-Laden Droplets Based on Cell Printing
Authors: Shi Meng , Ling Kai , Yong Kar Wey , Li Yuhui , Feng Shangsheng , Zhang Xiaohui , Pingguan-Murphy Belinda , Lu Tian Jian , Xu Feng 
Published: December 2015

AbstractCryopreservation is the most promising way for long-term storage of biological samples e.g., single cells and cellular structures. Among various cryopreservation methods, vitrification is advantageous by employing high cooling rate to avoid the formation of harmful ice crystals in cells. Most existing vitrification methods adopt direct contact of cells with liquid nitrogen to obtain high cooling rates, which however causes the potential contamination and difficult cell collection. To address these limitations, we developed a non-contact vitrification device based on an ultra-thin freezing film to achieve high cooling/warming rate and avoid direct contact between cells and liquid nitrogen. A high-throughput cell printer was employed to rapidly generate uniform cell-laden microdroplets into the device, where the microdroplets were hung on one side of the film and then vitrified by pouring the liquid nitrogen onto the other side via boiling heat transfer. Through theoretical and experimental studies on vitrification processes, we demonstrated that our device offers a high cooling/warming rate for vitrification of the NIH 3T3 cells and human adipose-derived stem cells (hASCs) with maintained cell viability and differentiation potential. This non-contact vitrification device provides a novel and effective way to cryopreserve cells at high throughput and avoid the contamination and collection problems.
RNAi mediated inhibition of viroid infection in transgenic plants expressing viroid-specific small RNAs derived from various functional domains
Authors: Adkar-Purushothama Charith Raj , Kasai Atsushi , Sugawara Kohei , Yamamoto Hideki , Yamazaki Yuto , He Ying-Hong , Takada Nobuyuki , Goto Hideki , Shindo Sahori , Harada Takeo , Sano Teruo 
Published: December 2015

AbstractPrevious attempts to develop RNAi-mediated viroid-resistant transgenic plants using nearly full-length Potato spindle tuber viroid (PSTVd) hairpin RNA (hpRNA) were successful; however unusual phenotypes resembling viroid infection occurred. Therefore, in the present work, transgenic Nicotiana benthamiana lines expressing both partial and truncated versions of PSTVd hpRNA were developed. Specifically, seven partial or truncated versions of PSTVd sequences were selected according to the hotspots of both PSTVd-sRNAs and functional domains of the PSTVd. A total of 21 transgenic lines Nicotiana benthamiana were developed under the control of either the CaMV-35S or the CoYMV promoters. All of the transgenic lines established here were monitored for the induction of phenotypic changes, for PSTVd-sRNA expression and for the resistance against PSTVd infection. Additionally, this study demonstrates the use of inverted repeat construct sequences as short as 26- to -49 nucleotides for both the efficient expression of the PSTVd-sRNA and the inhibition of PSTVd infection.
Suspended sediments limit coral sperm availability
Authors: Ricardo Gerard F. , Jones Ross J. , Clode Peta L. , Humanes Adriana , Negri Andrew P. 
Published: December 2015

AbstractSuspended sediment from dredging activities and natural resuspension events represent a risk to the reproductive processes of coral and therefore the ongoing maintenance of reefal populations. To investigate the underlying mechanisms that could reduce the fertilisation success in turbid water, we conducted several experiments exposing gametes of the coralsAcropora tenuisandA. milleporato two sediment types. Sperm limitation was identified in the presence of siliciclastic sediment (230 and ~700 mg L−1), with 2–37 fold more sperm required to achieve maximum fertilisation rates, when compared with sediment-free treatments. This effect was more pronounced at sub-optimum sperm concentrations. Considerable (>45%) decreases in sperm concentration at the water’s surface was recorded in the presence of siliciclastic sediment and a >20% decrease for carbonate sediment. Electron microscopy then confirmed sediment entangled sperm and we propose entrapment and sinking is the primary mechanism reducing sperm available to the egg. Longer exposure to suspended sediments and gamete aging further decreased fertilisation success when compared with a shorter exposure. Collectively, these findings demonstrate that high concentrations of suspended sediments effectively remove sperm from the water’s surface during coral spawning events, reducing the window for fertilisation with potential subsequent flow-on effects for recruitment.
Cardioprotective effects of fatty acid amide hydrolase inhibitor URB694, in a rodent model of trait anxiety
Authors: Carnevali Luca , Vacondio Federica , Rossi Stefano , Macchi Emilio , Spadoni Gilberto , Bedini Annalida , Neumann Inga D. , Rivara Silvia , Mor Marco , Sgoifo Andrea 
Published: December 2015

AbstractIn humans, chronic anxiety represents an independent risk factor for cardiac arrhythmias and sudden death. Here we evaluate in male Wistar rats bred for high (HAB) and low (LAB) anxiety-related behavior, as well as non-selected (NAB) animals, the relationship between trait anxiety and cardiac electrical instability and investigate whether pharmacological augmentation of endocannabinoid anandamide-mediated signaling exerts anxiolytic-like and cardioprotective effects. HAB rats displayed (i) a higher incidence of ventricular tachyarrhythmias induced by isoproterenol and (ii) a larger spatial dispersion of ventricular refractoriness assessed by means of an epicardial mapping protocol. In HAB rats, acute pharmacological inhibition of the anandamide-degrading enzyme, fatty acid amide hydrolase (FAAH), with URB694 (0.3 mg/kg), (i) decreased anxiety-like behavior in the elevated plus maze, (ii) increased anandamide levels in the heart, (iii) reduced isoproterenol-induced occurrence of ventricular tachyarrhythmias and (iv) corrected alterations of ventricular refractoriness. The anti-arrhythmic effect of URB694 was prevented by pharmacological blockade of the cannabinoid type 1 (CB1), but not of the CB2, receptor. These findings suggest that URB694 exerts anxiolytic-like and cardioprotective effects in HAB rats, the latter via anandamide-mediated activation of CB1 receptors. Thus, pharmacological inhibition of FAAH might be a viable pharmacological strategy for the treatment of anxiety-related cardiac dysfunction.
Plant stoichiometric responses to elevated CO2 vary with nitrogen and phosphorus inputs: Evidence from a global-scale meta-analysis
Authors: Huang Wenjuan , Houlton Benjamin Z. , Marklein Alison R. , Liu Juxiu , Zhou Guoyi 
Published: December 2015

AbstractRising levels of atmospheric CO2 have been implicated in changes in the nitrogen (N) and phosphorus (P) content of terrestrial vegetation; however, questions remain over the role of C, N and P interactions in driving plant nutrient stoichiometry, particularly whether N and P additions alter vegetation responses to CO2 enrichment singly. Here we use meta-analysis of 46 published studies to investigate the response of plant N and P to elevated CO2 alone and in combination with nutrient (N and P) additions across temperate vs. tropical biomes. Elevated CO2 reduces plant N concentrations more than plant P concentrations in total biomass pools, resulting in a significant decline in vegetation N/P. However, elevated CO2 treatments in combination with N additions increase plant P concentrations, whereas P additions have no statistical effect on plant N concentrations under CO2 enrichment. These results point to compensatory but asymmetrical interactions between N, P and CO2; that changes in N rapidly alter the availability of P, but not the converse, in response to increased CO2. Our finding implies widespread N limitation with increasing atmospheric CO2 concentrations alone. We also suggest that increased anthropogenic N deposition inputs could enhance plant N and P in a progressively CO2-enriched biosphere.
MicroRNA 19a replacement partially rescues fin and cardiac defects in zebrafish model of Holt Oram syndrome
Authors: Chiavacci Elena , D’Aurizio Romina , Guzzolino Elena , Russo Francesco , Baumgart Mario , Groth Marco , Mariani Laura , D’Onofrio Mara , Arisi Ivan , Pellegrini Marco , Cellerino Alessandro , Cremisi Federico , Pitto Letizia 
Published: December 2015

AbstractHolt-Oram Syndrome (HOS) is an autosomal dominant heart-hand syndrome caused by mutations in the TBX5 gene, a transcription factor capable of regulating hundreds of cardiac-specific genes through complex transcriptional networks. Here we show that, in zebrafish, modulation of a single miRNA is sufficient to rescue the morphogenetic defects generated by HOS. The analysis of miRNA-seq profiling revealed a decreased expression of miR-19a in Tbx5-depleted zebrafish embryos compared to the wild type. We revealed that the transcription of the miR-17-92 cluster, which harbors miR-19a, is induced by Tbx5 and that a defined dosage of miR-19a is essential for the correct development of the heart. Importantly, we highlighted that miR-19a replacement is able to rescue cardiac and pectoral fin defects and to increase the viability of HOS zebrafish embryos. We further observed that miR-19a replacement shifts the global gene expression profile of HOS-like zebrafish embryos towards the wild type condition, confirming the ability of miR-19a to rescue the Tbx5 phenotype. In conclusion our data demonstrate the importance of Tbx5/miR-19a regulatory circuit in heart development and provide a proof of principle that morphogenetic defects associated with HOS can be rescued by transient miRNA modulation.
The interplay of the Notch signaling in hepatic stellate cells and macrophages determines the fate of liver fibrogenesis
Authors: Bansal Ruchi , van Baarlen Joop , Storm Gert , Prakash Jai 
Published: December 2015

AbstractHepatic stellate cells (HSCs) known as “master producers” and macrophages as “master regulators”, are the key cell types that strongly contribute to the progression of liver fibrosis. Since Notch signaling regulates multiple cellular processes, we aimed to study the role of Notch signaling in HSCs differentiation and macrophages polarization and to evaluate its implication in liver fibrogenesis. Notch pathway components were found to be significantly upregulated in TGFβ-activated HSCs, inflammatory M1 macrophages and in mouse and human fibrotic livers. Interestingly, inhibition of Notch using a selective γ-secretase inhibitor, Avagacestat, significantly inhibited TGFβ-induced HSC activation and contractility and suppressed M1 macrophages. Additionally, Avagacestat inhibited M1 driven-fibroblasts activation and fibroblasts-driven M1 polarization (nitric oxide release) in fibroblasts and macrophages co-culture and conditioned medium studies. In vivo, post-disease treatment with Avagacestat significantly attenuated fibrogenesis in CCl4-induced liver fibrosis mouse model. These effects were attributed to the reduction in HSCs activation and inhibition of inflammatory M1 macrophages and upregulation of suppressive M2 macrophages. These findings suggest that Notch signaling plays a crucial role in HSC activation and M1/M2 polarization of macrophages in liver fibrosis. These results provide new insights for the development of novel therapies against liver fibrosis through modulation of Notch signaling.
Comparison of the depolarization response of human mesenchymal stem cells from different donors
Authors: Sundelacruz Sarah , Levin Michael , Kaplan David L. 
Published: December 2015

AbstractBioelectric signaling is currently being explored as a novel regulator of cell processes in non-excitable cells. In particular, stem cells have demonstrated increasing evidence of electrophysiology-mediated regulation of stemness acquisition, proliferation, differentiation and migration. However, in light of many reports of primary stem cell heterogeneity, it is important to characterize the variability of stem cell response to biophysical manipulations in order to assess the utility of bioelectric modulation as a universal strategy for stem cell control. In this work, human mesenchymal stem cells (hMSCs) from five donors were evaluated for their response to membrane potential (Vmem) depolarization. We compared the inter-donor variability of their osteogenic and adipogenic differentiation potential, as well as their ability to maintain a differentiated phenotype after induction. We identified the markers that responded most consistently across donors and found that calcium deposition and gene expression of bone sialoprotein, lipoprotein lipase and fatty acid binding protein 4 are the preferred markers for assessing differentiation response to Vmemdepolarization. We also note that since there exists variability even among some of these markers, these assays should be performed on any newly acquired hMSC population if their bioelectric properties are to be studied further.
Saccade Programming in Strabismic Suppression
Authors: Findlay J M , Walker R , Brown V , Gilchrist I , Clarke M 
Published: December 2015

Individuals with strabismus frequently show a suppression phenomenon in which part of the visual input in one eye is apparently ignored when both eyes are seeing, although the eye may have normal vision when used monocularly. This is often described as an adaptive response to avoid diplopia. We have examined two patients with microstrabismus (angle of squint less than 5 deg) who show strong suppression but with only mild amblyopia. We studied saccade generation in the two eyes using a red — green anaglyph display which allowed us to present stimuli independently to each eye. When single targets were presented in the suppressing eye, saccadic responses usually occurred. However the latencies of these saccades were increased with respect to those elicited from the normal eye (by about 70 ms for one subject and 270 ms for the other). The amplitudes of the saccades were less consistent than those of the normal eye, and saccades were sometimes made in the opposite direction to the target. We also investigated the remote distractor effect. This effect is found consistently in normal subjects and consists of an increase in the latency of a target-elicited saccade when a distractor is simultaneously presented elsewhere in the visual field. When distractors were presented in the suppressing eye, they had no effect on the latency of saccades to a simultaneous target in the other eye. We conclude that visual stimulation in a suppressing eye has no rapid access to the saccadic system.
Saccadic Localisation of Random Dot Targets
Authors: McGowan J W , Kowler E , Sharma A , Chubb C 
Published: December 2015

Saccadic eye movements land at precise places within simple target forms implying that a spatial pooling process operates over attended regions to determine the saccadic endpoint. To study pooling, we used large, unstructured targets and looked for evidence of differential spatial weighting based on local pattern characteristics. Subjects made a saccade to targets composed of 19 dots scattered randomly within a 4 deg diameter region horizontally displaced 3.8 – 4.2 deg to the left or right of initial fixation. Dot intensity was either uniform or variable. Saccadic landing positions were close to the centre-of-gravity (overshooting or under- shooting by 5% – 10% depending on subject, direction and eccentricity). Precision was excellent (SD=10% ecc), although not as good as with single target points (SD=7% ecc). Correlations between the presence of a dot and saccadic landing position showed that all regions of the pattern contributed. Differential weighting of dots according to location (eg near vs far; central vs boundary) did not yield better predictions of the saccadic landing position. However, predictions of the landing position were improved by assigning more weight to higher-intensity dots. Local dot clusters contributed less than would be expected from the contributions of individual dots. Spatial pooling is highly effective over a large region. Saccadic overshoots or undershoots were not due to differential spatial weighting, and may originate after the centre-of-gravity computation. The differential weighting of high-intensity dots and dot clusters demonstrates sensitivity to local characteristics, and implies that the saccadic endpoint may be determined by pooling the activity of units centred on different subregions of the target. The pooling mechanism supports precise saccadic localisation of large, unstructured targets, and accounts for the ease with which we direct saccades to chosen objects in natural scenes.
Colour Constancy, Categories, and Spectral Sensitivity
Authors: Kulikowski J J , Al-Attar Z , Vaitkevicius H 
Published: December 2015

Colour constancy is a multi-stage process whose receptoral and post-receptoral components have been separated by electrophysiological and behavioral studies. A psychophysical study was conducted to determine contributions of the visual processing stage which extracts information about colour categories, and to relate the results to the spectral sensitivity of the chromatic opponent system. Changes in colour appearance with illumination were investigated by using free-viewing and a successive matching method for 40 Munsell hues (saturations: 8 and 4). Subjects were adapted to standard illuminant C and briefly inspected a test chip under a variable illuminant A (tungsten) or g (green). Using criteria similar to those for unique hues, subjects specified ‘typical hues’ under illuminant C: red, yellow, green, blue, and violet (yellow should not contain red or green, green should not contain yellow or blue, etc). For each hue and saturation a dominant wavelength was computed. The degree of colour constancy was then established for all subjects (examined in three series of experiments), all Munsell chips and illuminations, as a one-dimensional Brunswick ratio, BR. The BR was determined by using u‘ v’ coordinates as related to the ratio of perceptual to physical colour changes: BR=1-perceptual/physical. BR was highest for typical (not intermediate) hues and lowest for hues resembling variable illuminants. The BR as a function of dominant wavelength resembles the spectral sensitivity function of chromatic opponency. These findings are interpreted as contributions of high-order opponent interactions to colour constancy.
Cortical Coding of Extended Coloured Figures
Authors: von der Heydt R , Zhou H , Friedman H 
Published: December 2015

We have studied the neural coding of extended coloured objects. Single cells were recorded from parafoveal regions of V1 and V2 in alert, fixating monkeys. In V1 most of our recordings were from the upper layers. A square figure (usually 4 deg × 4 deg, that is, much larger than the response field) of uniform colour on a gray background was placed at various positions relative to the receptive field of the cell. Orientation and colour were optimised for each cell. The vast majority of cells (75/89 in V1, 43/47 in V2) responded only when the receptive field was positioned on or near an edge, but not inside the figure (‘edge-only response’). Of the few cells that did respond with the receptive field inside the figure (‘surface response’), only some were colour selective (V1: 6/14, V2: 2/4); that is, the cell response clearly differentiated colours of similar luminance. This lack of surface responses is surprising, since most LGN cells, namely type I and type II cells respond to large uniform stimuli of some colour. On the other hand, many of the ‘edge-only’ cells were colour selective by the same criterion, some responding exclusively within a small volume of colour space. Most ‘edge-only’ cells were selective for orientation, and also many for edge polarity. V1 and V2 may encode colour of extended figures by edge signals rather than an isomorphic representation. In this case, colour filling-in would result from decay of the colour-specific edge signals rather than spreading of the colour-specific surround activity into the figure.
A Computational Model of the Eye Movement Effects on Motion Perception
Authors: Turano K A , Heidenreich S M 
Published: December 2015

Accurate speed and direction matches can be made between a moving stimulus viewed with a stationary eye and a moving stimulus viewed with an eye moving in the opposite direction to the stimulus. However, when the eye moves in the same direction as the distal stimulus, at a slower speed, subjects match the retinal-image motions of the stimuli rather than their distal motions (Heidenreich and Turano, 1995 Investigative Ophthalmology and Visual Science36 1675). Furthermore, it is only under this latter condition (and when the eye is stationary) that subjects can precisely discriminate distal stimulus speeds (Turano and Heidenreich Vision Research in press). We present a computational model that can account for the results of all three findings. The model assumes that the extraretinal signal mirrors the eye movement. Motion information from the retinal and extraretinal sources is combined in a subtractive manner when the two signals have opposite sign. When the two signals have the same sign, they do not combine, and motion judgments are based solely on information from the retinal source.
The Effect of Temporal Phase on the Perception of Apparent Motion
Authors: Hock H S , Kogan K , Lodes N 
Published: December 2015

In classical apparent motion, a spot of light is presented in alternation such that the waveforms describing the varying luminance at each of two locations are 180° out of phase. However, when the luminance variation at each location is approximately sinusoidal, and the perceiver's task is to discriminate motion direction, the optimum temporal phase is 90° (van Santen and Sperling, 1984 Journal of the Optical Society of America A1 451 – 473). The results reported in this study suggest that the optimality of the 90° temporal phase may be specific to the direction-discrimination task. Our experiments were based on a new procedure for measuring classical apparent motion thresholds (Hock, Kogan, and Espinoza, 1996, paper presented at ARVO). Two horizontally displaced dots are presented simultaneously against a darker background. The luminance ( L1) of one dot is always greater than that of the other ( L2), and the luminance values for the dots are exchanged on successive frames. Whether motion or stationarity is perceived depends on the background-relative luminance contrast (BRLC): ( L1- L2) divided by the difference between the average [( L1+ L2)/2] and background luminance. We found in the current study that motion thresholds depend on the temporal phase of the luminance variation at each location (rather than temporal asynchrony); the greater the phase difference (from 41° to 180°) the less the BRLC required for motion perception. At suprathreshold BRLC values, the perceived speed of apparent motion decreases with increased differences in temporal phase. The results are discussed in terms of Reichardt-type motion detection models.