ChatGPT and Environmental Research

ChatGPT and Environmental Researc

MXene/CNTs/Aramid Aerogels for Electromagnetic Interference Shielding and Joule Heating

It is a considerable challenge to develop a composite material with ultra-light and high electromagnetic interference (EMI) shielding efficiency for the next generation of electronic equipment. MXenes have received extensive attention in composite aerogel EMI shielding due to their abundant surface groups and ultra-high conductivity. However, the poor mechanical properties make them difficult to apply on a large scale. Here, we demonstrate a simple method to construct ultra-light conductive Ti3C2Tx MXene/aramid nanofibers (ANFs)/carbon nanotubes (CNTs) aerogels with a “sandwich” structure. CNTs and MXene absorb and reflect electromagnetic waves, while ANF aerogel provides good mechanical strength. Our composite aerogels with an extra-high EMI shielding efficiency of up to 69.0 dB at the X-band, despite their thickness and density being only 2 mm and 0.0428 g/cm3, respectively. At the same time, the composite aerogel with a low 0.0488 W/(m·K) thermal conductivity shows extraordinary flame resistance, heat preservation, and insulation ability. Besides, MXene/ANFs/CNTs aerogel can reach 104 °C in 3 s under an 8 V voltage and shows long-term Joule heating stability. This work provides a forward-looking idea for building multifunctional EMI shielding materials. The obtained aerogels have potential applications in aerospace, portable electronic devices, and defense industries

DNA methylation marker identification and poly-methylation risk score in prediction of healthspan termination

Supplementary figures 1-3Supplementary tables 1-9Supplementary materials and methods</p

Qualitative and quantitative analysis of chemical constituents of <i>Ptychopetalum olacoides</i> Benth

<p><i>Ptychopetalum olacoides</i> is a folk medicinal plant for health care in market, especially in Brazil. Fourteen known compounds were isolated from <i>P. olacoides</i> and their chemical structures were elucidated by extensive spectroscopic data, including 1D NMR, 2D NMR, UV, IR and HR-ESI-MS. The 14 known compounds were identified as N-trans-feruloyl-3,5-dihydroxyindolin-2-one (<b>1</b>), magnoflorine (<b>2</b>), menisperine (<b>3</b>), 4-coumaroylserotonin (<b>4</b>), moschamine (<b>5)</b>, luteolin (<b>6</b>), 4′-methoxyluteolin (<b>7</b>), 3-methoxyluteolin (<b>8</b>), 3, 7-dimethoxyluteolin (<b>9</b>), caffeic acid (<b>10</b>), ferulic acid (<b>11</b>), vanillic acid (<b>12)</b>, syringic acid (<b>13</b>) and ginsenoside Re (<b>14</b>). To our knowledge, compounds (<b>1</b>–<b>6</b>, <b>13</b>–<b>14</b>) were isolated from the plant for the first time. Additionally, quantitative analysis results indicated that calibration equations of compounds (<b>1</b>–<b>3</b>, <b>6</b>, <b>9</b>, <b>11</b>–<b>13</b>) exhibited good linear regressions within the test ranges (<i>R</i>² ≥ 0.9990) and magnoflorine and menisperine were the major constituents in the barks of <i>P. olacoides</i>. The contents of magnoflorine and menisperine accounted for 75.96% of all analytes. However, the content of phenolic components was smaller and the highest content was no more than 1.04 mg/g. Collectively, these results suggested that alkaloids are the dominant substances in <i>P. olacoides</i>, which can make a difference for the quality control and further use of <i>P. olacoides.</i></p