Active removal of waste dye pollutants using Ta[sub]3N[sub]5/W[sub]18O[sub]49 nanocomposite fibres

A scalable solvothermal technique is reported for the synthesis of a photocatalytic composite material consisting of orthorhombic Ta3N5 nanoparticles and WOx≤3 nanowires. Through X-ray diffraction and X-ray photoelectron spectroscopy, the as-grown tungsten(VI) sub-oxide was identified as monoclinic W18O49. The composite material catalysed the degradation of Rhodamine B at over double the rate of the Ta3N5 nanoparticles alone under illumination by white light, and continued to exhibit superior catalytic properties following recycling of the catalysts. Moreover, strong molecular adsorption of the dye to the W18O49 component of the composite resulted in near-complete decolourisation of the solution prior to light exposure. The radical species involved within the photocatalytic mechanisms were also explored through use of scavenger reagents. Our research demonstrates the exciting potential of this novel photocatalyst for the degradation of organic contaminants, and to the authors’ knowledge the material has not been investigated previously. In addition, the simplicity of the synthesis process indicates that the material is a viable candidate for the scale-up and removal of dye pollutants on a wider scale

Effects of Anacetrapib in Patients with Atherosclerotic Vascular Disease

BACKGROUND: Patients with atherosclerotic vascular disease remain at high risk for cardiovascular events despite effective statin-based treatment of low-density lipoprotein (LDL) cholesterol levels. The inhibition of cholesteryl ester transfer protein (CETP) by anacetrapib reduces LDL cholesterol levels and increases high-density lipoprotein (HDL) cholesterol levels. However, trials of other CETP inhibitors have shown neutral or adverse effects on cardiovascular outcomes. METHODS: We conducted a randomized, double-blind, placebo-controlled trial involving 30,449 adults with atherosclerotic vascular disease who were receiving intensive atorvastatin therapy and who had a mean LDL cholesterol level of 61 mg per deciliter (1.58 mmol per liter), a mean non-HDL cholesterol level of 92 mg per deciliter (2.38 mmol per liter), and a mean HDL cholesterol level of 40 mg per deciliter (1.03 mmol per liter). The patients were assigned to receive either 100 mg of anacetrapib once daily (15,225 patients) or matching placebo (15,224 patients). The primary outcome was the first major coronary event, a composite of coronary death, myocardial infarction, or coronary revascularization. RESULTS: During the median follow-up period of 4.1 years, the primary outcome occurred in significantly fewer patients in the anacetrapib group than in the placebo group (1640 of 15,225 patients [10.8%] vs. 1803 of 15,224 patients [11.8%]; rate ratio, 0.91; 95% confidence interval, 0.85 to 0.97; P=0.004). The relative difference in risk was similar across multiple prespecified subgroups. At the trial midpoint, the mean level of HDL cholesterol was higher by 43 mg per deciliter (1.12 mmol per liter) in the anacetrapib group than in the placebo group (a relative difference of 104%), and the mean level of non-HDL cholesterol was lower by 17 mg per deciliter (0.44 mmol per liter), a relative difference of -18%. There were no significant between-group differences in the risk of death, cancer, or other serious adverse events. CONCLUSIONS: Among patients with atherosclerotic vascular disease who were receiving intensive statin therapy, the use of anacetrapib resulted in a lower incidence of major coronary events than the use of placebo. (Funded by Merck and others; Current Controlled Trials number, ISRCTN48678192 ; ClinicalTrials.gov number, NCT01252953 ; and EudraCT number, 2010-023467-18 .)

Descending pathways generate perception of and neural responses to weak sensory input

<div><p>Natural sensory stimuli frequently consist of a fast time-varying waveform whose amplitude or contrast varies more slowly. While changes in contrast carry behaviorally relevant information necessary for sensory perception, their processing by the brain remains poorly understood to this day. Here, we investigated the mechanisms that enable neural responses to and perception of low-contrast stimuli in the electrosensory system of the weakly electric fish <i>Apteronotus leptorhynchus</i>. We found that fish reliably detected such stimuli via robust behavioral responses. Recordings from peripheral electrosensory neurons revealed stimulus-induced changes in firing activity (i.e., phase locking) but not in their overall firing rate. However, central electrosensory neurons receiving input from the periphery responded robustly via both phase locking and increases in firing rate. Pharmacological inactivation of feedback input onto central electrosensory neurons eliminated increases in firing rate but did not affect phase locking for central electrosensory neurons in response to low-contrast stimuli. As feedback inactivation eliminated behavioral responses to these stimuli as well, our results show that it is changes in central electrosensory neuron firing rate that are relevant for behavior, rather than phase locking. Finally, recordings from neurons projecting directly via feedback to central electrosensory neurons revealed that they provide the necessary input to cause increases in firing rate. Our results thus provide the first experimental evidence that feedback generates both neural and behavioral responses to low-contrast stimuli that are commonly found in the natural environment.</p></div

Feedback inactivation strongly increases behavioral detection thresholds.

<p>(a) Relevant anatomy diagram showing the main brain areas considered. Behavioral responses were recorded before and after lidocaine, a sodium channel antagonist, was injected bilaterally into the nPs (top left inset), which will inactivate feedback input onto ELL PCells (red cross). (b) Top: Stimulus waveform (blue) and its envelope (red) showing contrast as a function of time. Bottom: EOD frequency from a representative example individual fish before (dark brown) and after (light brown) feedback inactivation. The behavioral detection threshold strongly increased after feedback inactivation (compare the position of the leftmost and rightmost black circles). (c) Whisker-box plots comparing population-averaged detection thresholds computed from behavior before (dark brown) and after (light brown) feedback inactivation to those obtained from PCells after feedback inactivation computed using firing rate (green, left) and phase locking (green, right) and to those computed from firing rate in EAs (blue). Overall, PCell firing rate was a much better predictor of behavior than phase locking. The similarity of detection thresholds obtained from EA and PCell firing rate to that of behavior after feedback inactivation strongly suggests that, for low contrasts (<15%), phase locking in EAs is detected by PCells but is not decoded by downstream brain areas to give rise to behavior. “*” indicates significance at the <i>p</i> = 0.05 level using a Wilcoxon sign rank or Kruskal-Wallis test (behavior). The data can be downloaded at <a href="https://figshare.com/s/93707200732db87bb80f" target="_blank">https://figshare.com/s/93707200732db87bb80f</a>. EA, electrosensory afferent; ELL, electrosensory lateral line lobe; EOD, electric organ discharge; nP, nucleus praeeminentialis; n.s., not significant; PCell, pyramidal cell; Ts, torus semicircularis; VS, vector strength.</p

EAs reliably detect low-contrast stimuli through phase locking but not through overall changes in firing rate.

<p>(a) Relevant anatomy diagram showing the main brain areas considered. Recordings were made from individual EAs. (b) Top: Stimulus waveform (blue) and its envelope (red) showing contrast as a function of time. Middle: Spiking activity (black) from a representative example EA. The insets show magnification at two time points. In both cases, the spiking response is modulated. Bottom: Double y-axis plot showing the mean firing rate (solid blue) and VS (dashed blue) of this EA as a function of time. The bands delimit the upper range of values determined from this EA activity in the absence of stimulation for VS (dark blue) and firing rate (light blue). The detection threshold obtained from VS (leftmost black circle) was much lower than that obtained from the mean firing rate (rightmost black circle). Inset: The population-averaged detection thresholds obtained from firing rate (left) was significantly higher than those obtained from VS (middle) and behavior (right) (Kruskal-Wallis, df = 2, Firing Rate–VS: <i>p</i> = 2.6 × 10⁻⁹; firing rate–Behavior: <i>p</i> = 8.9 × 10⁻⁵). The population-averaged detection threshold obtained from VS was not significantly different than that obtained from behavior (Kruskal-Wallis, df = 2, <i>p</i> = 1). “*” indicates significance at the <i>p</i> = 0.05 level. The data can be downloaded at <a href="https://figshare.com/s/93707200732db87bb80f" target="_blank">https://figshare.com/s/93707200732db87bb80f</a>. EA, electrosensory afferent; ELL, electrosensory lateral line lobe; nP, nucleus praeeminentialis; TS, torus semicircularis; VS, vector strength.</p

Feedback inactivation strongly increases PCell detection thresholds computed from firing rate but does not affect those computed from phase locking.

<p>(a) Relevant anatomy diagram showing the main brain areas considered. Recordings were made from individual PCells while lidocaine, a sodium channel antagonist, was injected bilaterally into nP (top left inset), which will inactivate feedback input (red cross). (b) Top: Spiking activity of a representative PCell before (dark green) and after (light green) feedback inactivation, in response to the stimulus (blue) and its time-varying envelope (red) as a function of time. The insets show magnification at two time points. PCell activity was strongly phase locked to the stimulus before and after feedback inactivation, indicating a strong response to feedforward input from EAs even for low-stimulus contrasts. Middle: Mean firing rates before (solid green) and after (light green) feedback inactivation. The detection threshold of this cell strongly increased after feedback inactivation (compare the position of the leftmost and rightmost black circles). Inset: The population-averaged firing rate detection thresholds were significantly increased after feedback inactivation (Wilcoxon sign rank test, <i>p</i> = 0.0039). Bottom: Vector strength curves as a function of time before (solid green) and after (light green) feedback inactivation for this same cell. The phase locking detection thresholds (black circles) before and after feedback inactivation were similar to one another. Inset: The population-averaged phase locking detection threshold was not significantly altered by feedback inactivation (Wilcoxon sign rank test, <i>p</i> = 0.92). The data can be downloaded at <a href="https://figshare.com/s/93707200732db87bb80f" target="_blank">https://figshare.com/s/93707200732db87bb80f</a>. EA, electrosensory afferent; ELL, electrosensory lateral line lobe; nP, nucleus praeeminentialis; n.s., not significant; PCell, pyramidal cell; TS, torus semicircularis.</p

ELL PCell responses display low firing rate and phase locking detection threshold values that are comparable to behavior.

<p>(a) Relevant anatomy diagram showing the main brain areas considered. Recordings were made from individual PCells. (b) Top: Stimulus waveform (blue) and its envelope (red) showing contrast as a function of time. Middle: Spiking activity (black) from a representative example PCell. The insets show magnification at two time points. In both cases, the PCell activity strongly phase locked to the stimulus, but the average number of spikes per stimulus cycle increased with contrast. Bottom: Double y-axis plot showing the mean firing rate (solid green) and VS (dashed green) of this PCell as a function of time. The bands delimit the upper range of values determined from this PCell’s activity in the absence of stimulation. The detection threshold obtained from firing rate (rightmost black circle) was similar to that obtained from VS rate (leftmost black circle). Inset: The population-averaged detection thresholds obtained from firing rate (left) were not significantly different from behavior (Kruskal-Wallis, df = 2, <i>p</i> = 0.23). The population-averaged detection thresholds obtained from VS (middle) were significantly lower compared to those obtained from firing rate or behavior (right) (Kruskal-Wallis, df = 2, Firing Rate–VS: <i>p</i> = 0.0054; VS-behavior: <i>p</i> = 1.1 × 10⁻⁵). The data can be downloaded at <a href="https://figshare.com/s/93707200732db87bb80f" target="_blank">https://figshare.com/s/93707200732db87bb80f</a>. EA, electrosensory afferent; ELL, electrosensory lateral line lobe; EODf, electric organ discharge frequency; nP, nucleus praeeminentialis; PCell, pyramidal cell; TS, torus semicircularis; VS, vector strength.</p

STCells within nP display low detection thresholds that are comparable to behavior.

<p>(a) Relevant anatomy diagram showing the main brain areas considered. Recordings were made from individual STCells. (b) Top: Stimulus waveform (blue) and its envelope (red) showing contrast as a function of time. Middle: Spiking activity from a representative STCell. The insets show magnification at two time points. In both cases, the STCell activity strongly phase locked to the stimulus, but the average number of spikes per stimulus cycle increased with contrast, similar to that observed for PCells under control conditions. Bottom: Double y-axis plot showing the mean firing rate (solid orange) and VS (dashed orange) of this STCell as a function of time. The band delimits the upper range of values determined from this STCell’s firing rate in the absence of stimulation. Because STCells tended to not fire action potentials in the absence of stimulation, it was not possible to compute a threshold level for the VS. The VS detection threshold (upper black circle) was thus set to the lowest contrast for which the STCell reliably fired action potentials for at least 5 consecutive stimulus cycles (see <a href="http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.2005239#sec015" target="_blank">Materials and methods</a>). Inset: The population-averaged detection thresholds obtained from firing rate (left) and VS (middle) were not significantly different from one another or from behavior (Kruskal-Wallis, df = 2; Firing Rate–VS: <i>p</i> = 0.51; Firing Rate–Behavior: <i>p</i> = 0.06; VS-Behavior: <i>p</i> = 0.99). The data can be downloaded at <a href="https://figshare.com/s/93707200732db87bb80f" target="_blank">https://figshare.com/s/93707200732db87bb80f</a>. EA, electrosensory afferent; ELL, electrosensory lateral line lobe; EODf, electric organ discharge frequency; nP, nucleus praeeminentialis; PCell, pyramidal cell; STCell, stellate cell; VS, vector strength.</p

Weakly electric fish display low behavioral contrast detection thresholds.

<p>(a) Relevant anatomy diagram showing the main brain areas considered. (b) Top: EOD spectrogram (i.e., time-varying power spectrum showing frequency as a function of time) obtained under baseline conditions (i.e., in the absence of stimulation but in the presence of the animal’s unmodulated EOD). We found that the frequency at which there is maximum power (i.e., the EOD frequency) fluctuated as a function of time, which was used to compute the range of values that contains 95% of the probability distribution (white dashed lines) to determine whether behavioral responses obtained under stimulation were significantly different from those obtained in the absence of stimulation. Middle: Stimulus waveform (blue) and its envelope (red) showing contrast as a function of time. Bottom: EOD spectrogram in response to the stimulus. It is seen that the EOD frequency (“EODf”) increases after stimulus onset. The detection threshold is the contrast corresponding to the earliest time after stimulus onset for which the EOD frequency was outside the range of values determined in the absence of stimulation (black circle and white dashed line). Inset: Population-averaged detection threshold values for behavior (<i>n</i> = 35, brown). The data can be downloaded at <a href="https://figshare.com/s/93707200732db87bb80f" target="_blank">https://figshare.com/s/93707200732db87bb80f</a>. EA, electroreceptor afferent; ELL, electrosensory lateral line lobe; EOD, electric organ discharge; nP, nucleus praeeminentialis; TS, torus semicircularis.</p