Passivation process and the mechanism of packing particles in the Fe⁰/GAC system during the treatment of ABS resin wastewater

<div><p>This study provides mechanistic insights into the passivation of the packing particles during the treatment of acrylonitrile–butadiene–styrene (ABS) resin wastewater by the Fe⁰/GAC system. The granular-activated carbon (GAC) and iron chippings (Fe⁰) were mixed together with a volumetric ratio of 1:1. GAC has a mean particle size of approximately 3–5 mm, a specific surface of 748 m² g⁻¹, a total pore volume of 0.48 mL g⁻¹ and a bulk density of 0.49 g cm⁻³. The iron chippings have a compact and non-porous surface morphology. The results show that the packing particles in the Fe⁰/GAC system would lose their activity because the removal of TOC and for ABS resin wastewater could not carried out by the Fe⁰/GAC system after 40 days continuous running. Meanwhile, the availability of O₂ and intrinsic reactivity of Fe⁰ play a key role on the form of passive film with different iron oxidation states. The passive film on the surface of iron chippings was formed by two phases: (a) local corrosion phase (0–20 d) and (b) co-precipitation phase (20–40 d), while that of GAC was mainly formed by the co-precipitation of corrosion products with and because and would not easily reach the Fe⁰ surface. Therefore, in order to avoid the occurrence of filler passivation, high concentrations of and in wastewater should be removed before the treatment process of the Fe/GAC system.</p></div

Ultrasensitive Mg²⁺-Modulated Carbon Nanotube/Tannic Acid Aerogels for High-Performance Wearable Pressure Sensors

Three-dimensional (3D) carbon nanotube-based porous networks have received considerable attention as active nanomaterials for flexible/wearable sensor applications due to their excellent conductivity and mechanical flexibility. Herein, ultralight, biocompatible, and conductive SWCNT/tannic acid (TA) and Mg2+/SWCNT/TA aerogels have been facilely fabricated using TA as a dispersion reagent and crosslinker and Mg2+ to introduce a metal–phenolic network. The construction of a SWCNT@TA core–shell structure and the low CNT concentration of SWCNT/TA3:3 contribute to a high linear sensitivity of 432 kPa–1 in a wide pressure range (0.014–28 kPa), while Mg2+ modulation endows Mg2+/SWCNT/TA1:1 with an ultrahigh linear sensitivity of 13662 kPa–1 in a pressure range of 0.014–1.05 kPa. The superior sensing performance of as-prepared aerogels, including high sensitivity, wide working range, low detection limit (14 Pa), and fast stimuli-response (200–300 ms), enables them to detect tiny changes in human biosignals and imperceptible vibration, which show great potential in applications of health monitoring, human–machine interfaces, and various flexible electronics

Ultrasensitive Mg²⁺-Modulated Carbon Nanotube/Tannic Acid Aerogels for High-Performance Wearable Pressure Sensors

Three-dimensional (3D) carbon nanotube-based porous networks have received considerable attention as active nanomaterials for flexible/wearable sensor applications due to their excellent conductivity and mechanical flexibility. Herein, ultralight, biocompatible, and conductive SWCNT/tannic acid (TA) and Mg2+/SWCNT/TA aerogels have been facilely fabricated using TA as a dispersion reagent and crosslinker and Mg2+ to introduce a metal–phenolic network. The construction of a SWCNT@TA core–shell structure and the low CNT concentration of SWCNT/TA3:3 contribute to a high linear sensitivity of 432 kPa–1 in a wide pressure range (0.014–28 kPa), while Mg2+ modulation endows Mg2+/SWCNT/TA1:1 with an ultrahigh linear sensitivity of 13662 kPa–1 in a pressure range of 0.014–1.05 kPa. The superior sensing performance of as-prepared aerogels, including high sensitivity, wide working range, low detection limit (14 Pa), and fast stimuli-response (200–300 ms), enables them to detect tiny changes in human biosignals and imperceptible vibration, which show great potential in applications of health monitoring, human–machine interfaces, and various flexible electronics

Ultrasensitive Mg²⁺-Modulated Carbon Nanotube/Tannic Acid Aerogels for High-Performance Wearable Pressure Sensors

Three-dimensional (3D) carbon nanotube-based porous networks have received considerable attention as active nanomaterials for flexible/wearable sensor applications due to their excellent conductivity and mechanical flexibility. Herein, ultralight, biocompatible, and conductive SWCNT/tannic acid (TA) and Mg2+/SWCNT/TA aerogels have been facilely fabricated using TA as a dispersion reagent and crosslinker and Mg2+ to introduce a metal–phenolic network. The construction of a SWCNT@TA core–shell structure and the low CNT concentration of SWCNT/TA3:3 contribute to a high linear sensitivity of 432 kPa–1 in a wide pressure range (0.014–28 kPa), while Mg2+ modulation endows Mg2+/SWCNT/TA1:1 with an ultrahigh linear sensitivity of 13662 kPa–1 in a pressure range of 0.014–1.05 kPa. The superior sensing performance of as-prepared aerogels, including high sensitivity, wide working range, low detection limit (14 Pa), and fast stimuli-response (200–300 ms), enables them to detect tiny changes in human biosignals and imperceptible vibration, which show great potential in applications of health monitoring, human–machine interfaces, and various flexible electronics

Ultrasensitive Mg²⁺-Modulated Carbon Nanotube/Tannic Acid Aerogels for High-Performance Wearable Pressure Sensors

Three-dimensional (3D) carbon nanotube-based porous networks have received considerable attention as active nanomaterials for flexible/wearable sensor applications due to their excellent conductivity and mechanical flexibility. Herein, ultralight, biocompatible, and conductive SWCNT/tannic acid (TA) and Mg2+/SWCNT/TA aerogels have been facilely fabricated using TA as a dispersion reagent and crosslinker and Mg2+ to introduce a metal–phenolic network. The construction of a SWCNT@TA core–shell structure and the low CNT concentration of SWCNT/TA3:3 contribute to a high linear sensitivity of 432 kPa–1 in a wide pressure range (0.014–28 kPa), while Mg2+ modulation endows Mg2+/SWCNT/TA1:1 with an ultrahigh linear sensitivity of 13662 kPa–1 in a pressure range of 0.014–1.05 kPa. The superior sensing performance of as-prepared aerogels, including high sensitivity, wide working range, low detection limit (14 Pa), and fast stimuli-response (200–300 ms), enables them to detect tiny changes in human biosignals and imperceptible vibration, which show great potential in applications of health monitoring, human–machine interfaces, and various flexible electronics

Temperature-Dependent Henry’s Law Constants of Atmospheric Organics of Biogenic Origin

There have been growing interests in modeling studies to understand oxidation of volatile organic compounds in the gas phase and their mass transfer to the aqueous phase for their potential roles in cloud chemistry, formation of secondary organic aerosols, and fate of atmospheric organics. Temperature-dependent Henry’s law constants, key parameters in the atmospheric models to account for mass transfer, are often unavailable. In the present work, we investigated gas–liquid equilibriums of isoprene, limonene, α-pinene, and linalool using a bubble column technique. These compounds, originating from biogenic sources, were selected for their implications in atmospheric cloud chemistry and secondary organic aerosol formation. We reported Henry’s law constants (<i>K</i>_H), first order loss rates (<i>k</i>), and gas phase diffusion coefficients over a range of temperatures relevant to the lower atmosphere (278–298 K) for the first time. The measurement results of <i>K</i>_H values for isoprene, limonene, α-pinene, and linalool at 298 K were 0.036 ± 0.003; 0.048 ± 0.004; 0.029 ± 0.004; and 21.20 ± 0.30 mol L^–1 atm^–1, respectively. The fraction for these compounds in stratocumulus and cumulonimbus clouds at 278 K were also estimated in this work (isoprene, 1.0 × 10^–6, 6.8 × 10^–6; limonene, 1.5 × 10^–6, 1.0 × 10^–5; α-pinene, 4.5 × 10^–7, 3.1 × 10^–6; and linalool, 6.2 × 10^–4, 4.2 × 10^–3). Our measurements in combination with literature results indicated that noncyclic alkenes could have smaller <i>K</i>_H values than those of cyclic terpenes and that <i>K</i>_H values may increase with an increasing number of double bonds. It was also shown that estimated Henry’s law constants and their temperature dependence based on model prediction can differ from experimental results considerably and that direct measurements of temperature-dependent Henry’s law constants of atmospheric organics are necessary for future work

Transgenerational Inheritance of Modified DNA Methylation Patterns and Enhanced Tolerance Induced by Heavy Metal Stress in Rice (<em>Oryza sativa</em> L.)

<div><h3>Background</h3><p>DNA methylation is sensitive and responsive to stressful environmental conditions. Nonetheless, the extent to which condition-induced somatic methylation modifications can impose transgenerational effects remains to be fully understood. Even less is known about the biological relevance of the induced epigenetic changes for potentially altered well-being of the organismal progenies regarding adaptation to the specific condition their progenitors experienced.</p> <h3>Methodology/Principal Findings</h3><p>We analyzed DNA methylation pattern by gel-blotting at genomic loci representing transposable elements and protein-coding genes in leaf-tissue of heavy metal-treated rice (<em>Oryza sativa</em>) plants (S0), and its three successive organismal generations. We assessed expression of putative genes involved in establishing and/or maintaining DNA methylation patterns by reverse transcription (RT)-PCR. We measured growth of the stressed plants and their unstressed progenies <em>vs.</em> the control plants. We found (1) relative to control, DNA methylation patterns were modified in leaf-tissue of the immediately treated plants, and the modifications were exclusively confined to CHG hypomethylation; (2) the CHG-demethylated states were heritable via both maternal and paternal germline, albeit often accompanying further hypomethylation; (3) altered expression of genes encoding for DNA methyltransferases, DNA glycosylase and <em>SWI/SNF</em> chromatin remodeling factor (<em>DDM1</em>) were induced by the stress; (4) progenies of the stressed plants exhibited enhanced tolerance to the same stress their progenitor experienced, and this transgenerational inheritance of the effect of condition accompanying heritability of modified methylation patterns.</p> <h3>Conclusions/Significance</h3><p>Our findings suggest that stressful environmental condition can produce transgenerational epigenetic modifications. Progenies of stressed plants may develop enhanced adaptability to the condition, and this acquired trait is inheritable and accord with transmission of the epigenetic modifications. We suggest that environmental induction of heritable modifications in DNA methylation provides a plausible molecular underpinning for the still contentious paradigm of inheritance of acquired traits originally put forward by Jean-Baptiste Lamarck more than 200 years ago.</p> </div

Alteration in DNA methylation patterns in the heavy metal-stressed plant seedlings (S0 generation) relative to the mock control (Mock) of rice ssp. <i>japonica</i>, cv. Matsumae.

<p>Gel-blotting patterns were generated by hybridizing the selected probes to DNA samples digested with a pair of methylation-sensitive isoschizomers, <i>Hpa</i>II and <i>Msp</i>I. Patterns of three of the 18 studied sequences (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0041143#s4" target="_blank">Materials and methods</a>) are shown. Evidently, all alterations represent exclusive CHG hypomethylation (occurred only in <i>Msp</i>I digest). <b>A</b>, <i>Tos17</i>, which showed CHG hypomethylation in four of the eight treatments; <b>B</b>, <i>Hombox gene</i>, which showed CHG hypomethylation in five of the eight treatments; <b>C</b>, <i>CAL-11</i>, which showed CHG hypomethylation in six of the 8 treatments; <b>D</b>, <i>Hombox gene</i>, which showed complete stability in the methylation patterns in all 18 randomly chosen mock control plants (Mock S0). Arrowheads denote methylation alterations as a significant reduction in band signal intensity or complete band loss relative to the mock control.</p

Alteration in the steady-state transcript abundance of a set of nine chromatin-related genes encoding for putative DNA methyltransferases (six), 5-methylcytosine DNA glycosylase (one) and the <i>SWI/SNF</i> chromatin remodeler (<i>DDM1</i>) (two) in the heavy-metal treated rice plants at the S0, S1 and S2 generations determined by semi-quantitative RT-PCR analysis.

<p>(<b>A</b>) Transcript abundance of the nine genes in the Mock S0 and each of the four kinds of heavy-metal treatments at the indicated concentration labeled as stressed S0. (<b>B</b>) Transmission of the altered transcript abundance as well as further alteration of each of the nine genes by heavy-metal Hg²⁺ (50 µm) treatment from S0 to its eight S1 progenies. (<b>C</b>) Transmission of the altered transcript abundance of six genes in one S1 individual (S1#4) to its 14 S2 progenies. (<b>D</b>) Two examples showing lack of fluctuation for the chromatin-related genes in the untreated mock control plants across generations. For all analysis, three batches of independent RNAs were isolated from seedling-leaf tissue at the same stage, and RT-PCR was performed with each of them. The results were highly reproducible among the three independent RNA batches, and hence, only one experiment was presented. Gene name and amplification cycles are labeled. The rice <i>Actin</i> gene (Genbank accession number:X79378 ) was used as an internal control in all cases. Lack of genomic DNA was validated by the <i>Actin</i> gene on template without RT.</p

Phenotypes and quantitative measurements of traits from mock control and progenies of heavy metal (Hg²⁺ at 100 µm) stressed plants under normal and heavy metal stress conditions (Hg²⁺ at 100, 300 and 500 µm, respectively).

<p>(<b>A</b>) The overall seedling phenotypes of plants (two individuals are shown) under normal (left-most) and three heavy metal (from left to right: 100, 300 and 500 µm) Hg²⁺ stress conditions, Bars = 5 cm. (<b>B</b>) Phenotypic analysis of mock control plants (Mock) and two successive selfed-pollinated progenies, S1 and S2, derived from S0-Hg²⁺ (50 µm). Seeds were germinated and seedlings grown for 10 days on Hoagland nutrient solution with or without the indicated concentrations of Hg²⁺. Plant height, fresh weight and chlorophyll content were measured. For all measurements, data are from three independent experiments each containing 10 individual plants. Error bars represent standard error (SE). * and ** denote statistical significance at 0.05 and 0.01 levels respectively in student's test.</p