Multi-point STM: Effects of Drawing Speed and Number of Focal Points on Users’ Responses using Ultrasonic Mid-Air Haptics

Spatiotemporal modulation (STM) is used to render tactile patterns with ultrasound arrays. Previous research only explored the effects of single-point STM parameters, such as drawing speed (Vd). Here we explore the effects of multi-point STM on both perceptual (intensity) and emotional (valence/arousal) responses. This introduces a new control parameter for STM - the number of focal points (Nfp) – on top of conventional STM parameter (Vd). Our results from a study with 30 participants showed a negative effect of Nfp on perceived intensity and arousal, but no significant effects on valence. We also found the effects of Vd still aligned with prior results for single-point, even when different Nfp were used, suggesting that effects observed from single-point also apply to multi-point STM. We finally derive recommendations, such as using single-point STM to produce stimuli with higher intensity and/or arousal, or using multi-point STM for milder and more relaxing (less arousing) experience

Characterization of organic matter in sauce-aroma Chinese liquors by GC-MS and high resolution mass spectrometry

In this study, a total of 25 main compounds of three sauce-aroma Chinese liquors were identified by GC-MS and high-resolution mass spectrometry, and 6 of them (methyl palmitate, ethyl palmitate, methyl linoleate, ethyl linoleate, methyl oleate, and ethyl oleate) were speculated to be characteristic substances of the Maotai series with sauce-aroma type. This study aims to find out the characteristic fingerprint of Chinese liquor and provide a new way for the rapid identification of liquor type and quality. Further experiments are needed to verify the suppose

Probing the Drug Dynamics of Chemotherapeutics Using Metasurface-Enhanced Infrared Reflection Spectroscopy of Live Cells.

Infrared spectroscopy has drawn considerable interest in biological applications, but the measurement of live cells is impeded by the attenuation of infrared light in water. Metasurface-enhanced infrared reflection spectroscopy (MEIRS) had been shown to mitigate the problem, enhance the cellular infrared signal through surface-enhanced infrared absorption, and encode the cellular vibrational signatures in the reflectance spectrum at the same time. In this study, we used MEIRS to study the dynamic response of live cancer cells to a newly developed chemotherapeutic metal complex with distinct modes of action (MoAs): tricarbonyl rhenium isonitrile polypyridyl (TRIP). MEIRS measurements demonstrated that administering TRIP resulted in long-term (several hours) reduction in protein, lipid, and overall refractive index signals, and in short-term (tens of minutes) increase in these signals, consistent with the induction of endoplasmic reticulum stress. The unique tricarbonyl IR signature of TRIP in the bioorthogonal spectral window was monitored in real time, and was used as an infrared tag to detect the precise drug delivery time that was shown to be closely correlated with the onset of the phenotypic response. These results demonstrate that MEIRS is an effective label-free real-time cellular assay capable of detecting and interpreting the early phenotypic responses of cells to IR-tagged chemotherapeutics

Probing the Drug Dynamics of Chemotherapeutics Using Metasurface-Enhanced Infrared Reflection Spectroscopy of Live Cells

Infrared spectroscopy has drawn considerable interest in biological applications, but the measurement of live cells is impeded by the attenuation of infrared light in water. Metasurface-enhanced infrared reflection spectroscopy (MEIRS) had been shown to mitigate the problem, enhance the cellular infrared signal through surface-enhanced infrared absorption, and encode the cellular vibrational signatures in the reflectance spectrum at the same time. In this study, we used MEIRS to study the dynamic response of live cancer cells to a newly developed chemotherapeutic metal complex with distinct modes of action (MoAs): tricarbonyl rhenium isonitrile polypyridyl (TRIP). MEIRS measurements demonstrated that administering TRIP resulted in long-term (several hours) reduction in protein, lipid, and overall refractive index signals, and in short-term (tens of minutes) increase in these signals, consistent with the induction of endoplasmic reticulum stress. The unique tricarbonyl IR signature of TRIP in the bioorthogonal spectral window was monitored in real time, and was used as an infrared tag to detect the precise drug delivery time that was shown to be closely correlated with the onset of the phenotypic response. These results demonstrate that MEIRS is an effective label-free real-time cellular assay capable of detecting and interpreting the early phenotypic responses of cells to IR-tagged chemotherapeutics

Insulin- and warts-dependent regulation of tracheal plasticity modulates systemic larval growth during hypoxia in Drosophila melanogaster.

Adaptation to dynamic environmental cues during organismal development requires coordination of tissue growth with available resources. More specifically, the effects of oxygen availability on body size have been well-documented, but the mechanisms through which hypoxia restricts systemic growth have not been fully elucidated. Here, we characterize the larval growth and metabolic defects in Drosophila that result from hypoxia. Hypoxic conditions reduced fat body opacity and increased lipid droplet accumulation in this tissue, without eliciting lipid aggregation in hepatocyte-like cells called oenocytes. Additionally, hypoxia increased the retention of Dilp2 in the insulin-producing cells of the larval brain, associated with a reduction of insulin signaling in peripheral tissues. Overexpression of the wildtype form of the insulin receptor ubiquitously and in the larval trachea rendered larvae resistant to hypoxia-induced growth restriction. Furthermore, Warts downregulation in the trachea was similar to increased insulin receptor signaling during oxygen deprivation, which both rescued hypoxia-induced growth restriction, inhibition of tracheal molting, and developmental delay. Insulin signaling and loss of Warts function increased tracheal growth and augmented tracheal plasticity under hypoxic conditions, enhancing oxygen delivery during periods of oxygen deprivation. Our findings demonstrate a mechanism that coordinates oxygen availability with systemic growth in which hypoxia-induced reduction of insulin receptor signaling decreases plasticity of the larval trachea that is required for the maintenance of systemic growth during times of limiting oxygen availability

Hypoxia-induced molting defects are rescued by trachea-specific overexpression of the insulin receptor and Warts downregulation.

<p>Under normoxic conditions, overexpression of the wildtype InR (B–B″′) and downregulation of Warts (C–C″′) in the larval trachea did not inhibit molting of the larval trachea or progression through the larval instars, as demonstrated by the presence of third instar serrations in the mouth hooks. Normoxic wildtype controls are represented in A–A″′. Under hypoxic conditions, tracheal molting was inhibited (D–D″), and larvae did not reach the third instar developmental stage, as demonstrated by the presence of younger instar serrations in the mouth hooks (D″′). Inhibition of tracheal molting and developmental progression were rescued by tracheal-specific overexpression of the wildtype InR (E–E″′) and downregulation of Warts (F–F″′). Scale bar in A applies to A–F″′, excluding panels labeled as triple-primed (″′): 20 µm. Scale bar in A″′ applies to all triple-primed (″′) panels: 10 µm. Inset in D highlights persistence of early tracheal cuticles that had not been shed. The upper dashed line denotes the edge of the tracheal lumen that was inflated. The middle dotted line and bottom dashed line highlight the tracheal cuticles that had not been shed.</p

Warts downregulation in the larval trachea rescues growth restriction and enhances oxygen delivery.

<p>[A–B] Downregulation of Warts in the larval trachea led to a statistically significant increase in larval size under hypoxic conditions (n = 24), as compared to the hypoxic wildtype control (<i>btl></i>) (n = 30). Downregulation of Warts in the trachea did not affect larval size under normoxic conditions (n = 30), as compared to the normoxic wildtype control (n = 17) (N.S denotes “no significance”). [C–E″] During normoxia, Sima (green) levels in the larval fat body were hardly detected (C–C″) compared to the significant increase in cytoplasmic and nuclear Sima under hypoxic conditions (D–D″). Upon downregulation of Warts in the larval trachea, Sima levels decrease in the fat body (E–E″), similar to those observed in the normoxic wildtype control (C–C″). TOPRO staining (red) marks cell nuclei. Scale bar in B represents 0.50 mm. Scale bar in C applies to C–E″: 20 µm.</p

Hypoxia restricts larval growth and induces lipid metabolic changes distinct from starvation.

<p>[<b>A–B</b>] Rearing wildtype larvae under hypoxic conditions resulted in a significant reduction in larval size (<b>B</b>), compared to those reared under normoxic conditions (<b>A</b>). [<b>C–D</b>] Hypoxia decreased fat body opacity (<b>D</b>), as compared to that observed in normoxia (<b>C</b>). White arrows point to the larval fat body. [<b>E–G′</b>] Control larvae reared under hypoxic (<i>promE(800)>2xEGFP</i>) and starvation (<i>w¹¹¹⁸</i>) conditions exhibited increased lipid droplet accumulation in the larval fat body (<b>F, G</b>), compared to the control (<b>E</b>). Lipids did not aggregate in the larval oenocytes during hypoxia (<b>F′</b>), compared to the control (<b>E′</b>), unlike what was observed during starvation (<b>G′</b>). Oenocytes in <b>E′</b> and <b>F′</b> are outlined with a dashed line, and their corresponding cellular structure can be appreciated in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0115297#pone.0115297.s001" target="_blank"><b>S1A–B Fig</b></a>. Scale bar in <b>A</b> applies to <b>A–B</b>: 0.50 mm. Scale bar in C represents 0.50 mm, and scale bar in D represents 0.25 mm. Scale bar in E applies to E–G′: 20 µm.</p

Lipid and insulin signaling changes in hypoxic larvae.

<p>[A] Under normoxic conditions, Sima is degraded and remains at low levels in the larval fat body. Increased lipid droplet aggregation does not occur, and lipids are not mobilized from the fat body into the hemolymph, eliminating the need for lipids to be taken up by the oenocytes. Under normal conditions, a fat-body derived signal is secreted and relayed to the larval brain in order to promote Dilp secretion from the insulin-producing cells <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0115297#pone.0115297-Geminard1" target="_blank">[20]</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0115297#pone.0115297-Rajan1" target="_blank">[22]</a>. These secreted Dilps can go on to bind to the insulin receptor in target tissues to initiate insulin signaling. Activation of insulin signaling specifically in the larval trachea promotes tracheal growth, perhaps through an insulin-dependent inhibition of Warts. Under normoxic conditions, this feed-forward circuit involving fat body-mediated control of Dilp secretion and insulin- and Warts-dependent regulation of tracheal growth functions to modulate systemic growth during periods of adequate oxygen availability. [B] Under hypoxic conditions, degradation of Sima is reduced, and Sima accumulates in the larval fat body. Hypoxia-induced Sima accumulation in the fat body triggers increased lipid droplet aggregation in this tissue and lipid mobilization from the fat body into the hemolymph. Mobilization of lipids from the fat body is normally coupled with lipid uptake by the oenocytes. However, aggregation of lipid droplets is not observed under hypoxic conditions, suggesting a potential defect in lipid uptake by the oenocytes. Sima accumulation in the fat body results in increased Dilp2 retention, possibly through a reduction in the normal fat body-derived signal that promotes Dilp secretion from the IPCs. Increased Dilp2 retention in hypoxia is associated with the reduction of insulin signaling in peripheral tissues. As a consequence of systemic reduction of insulin receptor signaling to enable adaptation to hypoxia, the larval tracheal system is limited in its growth and plasticity, perhaps through increased Warts function.</p

Insulin signaling under hypoxic conditions.

<p>[A–C] Dilp2 antibody staining (white) of the larval brain was hardly detected in the IPCs of wildtype larvae reared in normoxia (A) but accumulated in those of wildtype larvae reared in hypoxia (B). The increased Dilp2 retention under hypoxic conditions phenocopied that observed during starvation (C). IPCs in B were reared in 2.5% O₂ from 48–72 hAH. [D] Under hypoxic conditions, ubiquitous overexpression of the wildtype form of the <i>Drosophila</i> insulin receptor (InR-WT), using the driver da-GAL4, led to a statistically significant rescue in larval size (n = 52), as compared to the hypoxic wildtype control (da>) (n = 49). Ubiquitous overexpression of the InR-WT led to a minor reduction in larval size under normoxic conditions (n = 37), as compared to the normoxic wildtype control (n = 33), most likely due to an increased growth rate and shortened duration of growth due to insulin-stimulated ecdysone production in the prothoracic gland <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0115297#pone.0115297-Colombani2" target="_blank">[19]</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0115297#pone.0115297-Mirth1" target="_blank">[24]</a>–<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0115297#pone.0115297-Boulan1" target="_blank">[26]</a>. [E-F] InR-WT overexpression in the larval trachea, using the trachea-specific driver btl-GAL4, led to a statistically significant rescue of larval size during hypoxia (n = 20), as compared to the hypoxic wildtype control (btl>) (n = 30) (F; quantified in E). Under normoxic conditions, tracheal-specific overexpression (n = 20) of the insulin receptor leads to a statistically significant mild decrease in larval growth, as compared to the normoxic wildtype control (<i>btl></i>) (n = 20). Tracheal-specific downregulation of the insulin receptor (n = 46) with its respective control (n = 54) was carried out at 29°C to enhance InR knockdown and leads to a statistically significant mild reduction in larval length. [G] Overexpression of Dilp2 in the larval trachea (btl>dilp2) under hypoxic conditions (n = 35) did not rescue growth restriction, as compared to the hypoxic wildtype control (btl>) (n = 20). Volumetric analysis also demonstrated no statistical significance (data not shown). Scale bar in A applies to A–C: 10 µm. Scale bar in F represents 0.50 mm. Statistical significance was determined using a Student's t-test.</p