Self‐assembly of a trigonal building subunit with diaminotriazines (DAT) functional groups leads to a unique rod‐packing 3D microporous hydrogen‐bonded organic framework (HOF‐3). This material shows ...permanent porosity and demonstrates highly selective separation of C2H2/CO2 at ambient temperature and pressure.
A 3D microporous rod‐packing hydrogen‐bonded organic framework was constructed from a trigonal building subunit with diaminotriazine functional groups. This framework exhibits highly selective separation of C2H2/CO2 at ambient temperature and pressure.
Bacteria account for nearly one third of the causes of community-acquired central nervous system infections, and traditional diagnostic methods are based on culture results, which are time-consuming ...and have a low detection rate leading to delayed diagnosis and treatment. Since metagenomic next-generation sequencing (mNGS) has the advantages of high timeliness and only detecting microbial trace gene fragments, it has been used more widely in recent years. Based on this, we explored whether the application of cerebrospinal fluid (CSF) mNGS is advantageous in patients with community-acquired purulent meningitis, especially in people who have already used antibiotics. This was a retrospective study of 63 patients with community-acquired purulent meningitis admitted to the Department of Neurology of Shanxi Bethune Hospital from March 2018 to November 2022. Data were systematically collected and classified into CSF culture group, blood culture group and CSF mNGS group according to different detection methods, and the total detection rate of each method was calculated. Each group of patients was divided into two subgroups according to whether antibiotics were used before sampling. The detection rates of the three groups were compared within and between groups to explore whether mNGS has advantages over traditional methods and the influence of antibiotic use on detection rates of the three methods. Among the 63 patients, the cases of CSF culture, blood culture and CSF mNGS were 56, 46, 44, respectively. The total detection rates of the three methods were 17.86%, 36.96%, 81.82%, with statistical differences (p < 0.05),suggesting that the detection rate of mNGS was higher than CSF culture (p < 0.05) and blood culture (p < 0.05),and the detection rate of blood culture higher than CSF culture (p < 0.05). Further grouping found that without antibiotics, the detection rates of CSF culture, blood culture and CSF mNGS were 28.57%, 56.25% and 88.89%, with statistical differences (p < 0.05), and the detection rate of CSF mNGS was higher than that of CSF culture (p < 0.05), but there was no statistical difference between CSF and blood culture (p > 0.05), nor between blood culture and CSF mNGS (p > 0.05). The detection rates of the three groups with antibiotics were 14.29%, 26.67% and 80.00%, with statistical differences (p < 0.05), and the detection rate of CSF mNGS was still higher than CSF culture (p < 0.05) and blood culture (p < 0.05). However, the detection rate of CSF mNGS also decreased after antibiotics were used for more than 3 days. The detection rate of CSF mNGS in patients with purulent meningitis is higher than traditional methods, especially in patients who have been given antibiotics, but the detection rate will decrease with the extension of antibiotic use.
We report a paleomagnetic study of Paleocene marine sediments in the Gamba area of the Tethyan Himalayan terrane, southern Tibet, which aims to accurately locate the position of the northern margin ...of Greater India and further constrain timing of initial contact between India and Asia. Following detailed rock magnetic and paleomagnetic experiments on a total of 675 drill-core samples collected from the Zongpu and Upper Jidula formations, characteristic remanent magnetizations (ChRMs) were successfully isolated from most samples following alternating field (AF) or integrated thermal and AF demagnetization. The ChRMs are of dual polarity and pass fold and reversal tests indicating a pre-folding origin. Together with detailed biostratigraphic investigation of the sampling section, a magnetic polarity sequence is constructed from data at 167 sampled horizons and satisfactorily correlates with polarity chrons C24r to C27r dating the Zongpu Formation between ~
56.2 and 61.8
Ma on the geomagnetic polarity time scale. The ChRM directions from the Zongpu Formation are grouped stratigraphically into 33 sites and yield two paleopoles of 71.6°N, 277.8°E (A
95
=
2.5°) and 67.3°N, 266.3°E (A
95
=
3.5°) for the time intervals comprising 56 to 59
Ma and 59 to 62
Ma, respectively. These new paleopoles imply that the Tethyan Himalayan terrane was sited at low latitudes in the Northern Hemisphere during the interval ~
62–56
Ma, suggesting that initial contact between the Tethyan Himalaya and Lhasa terranes was established before 60.5
±
1.5
Ma, and very likely occurred near the Cretaceous–Tertiary boundary, at least in the central part of the suture zone. The results also indicate that at least 1500
±
480
km of post-collisional crustal shortening occurred within the Himalayas. From the analysis of available paleomagnetic data obtained on both sides of the suture zone, we propose a conceptional collision model for the India–Asia collision.
► The Zongpu Formation in the area of Gamba was dated between ~
56.2 and 61.8
Ma. ► The timing of India–Asia collision was constrained to be 60.5
±
1.5
Ma to 68
±
3
Ma. ► The northern extension of Greater India was constrained to be at least 1500
±
480
km. ► The Main Central Thrust (MCT) was inferred to have initiated as early as ~
35
Ma.
Light absorbing particles（LAP, e.g., black carbon, brown carbon, and dust） influence water and energy budgets of the atmosphere and snowpack in multiple ways. In addition to their effects associated ...with atmospheric heating by absorption of solar radiation and interactions with clouds, LAP in snow on land and ice can reduce the surface reflectance（a.k.a., surface darkening）, which is likely to accelerate the snow aging process and further reduces snow albedo and increases the speed of snowpack melt. LAP in snow and ice（LAPSI） has been identified as one of major forcings affecting climate change, e.g.in the fourth and fifth assessment reports of IPCC. However, the uncertainty level in quantifying this effect remains very high. In this review paper, we document various technical methods of measuring LAPSI and review the progress made in measuring the LAPSI in Arctic, Tibetan Plateau and other mid-latitude regions. We also report the progress in modeling the mass concentrations, albedo reduction, radiative forcing, and climatic and hydrological impact of LAPSI at global and regional scales. Finally we identify some research needs for reducing the uncertainties in the impact of LAPSI on global and regional climate and the hydrological cycle.
Biochar is a carbon-rich solid material derived from the pyrolysis of agricultural and forest residual biomass. Previous studies have shown that biochar is suitable as an adsorbent for soil ...contaminants such as heavy metals and consequently reduces their bioavailability. However, the long-term effect of different biochars on metal extractability or soil health has not been assessed. Therefore, a 1-year incubation experiment was carried out to investigate the effect of biochar produced from bamboo and rice straw (at temperatures ≥500 °C) on the heavy metal (cadmium (Cd), copper (Cu), lead (Pb), and zinc (Zn)) extractability and enzyme activity (urease, catalase, and acid phosphatase) in a contaminated sandy loam paddy soil. Three rates (0, 1, and 5 %) and two mesh sizes (<0.25 and <1 mm) of biochar applications were investigated. After incubation, the physicochemical properties, extractable heavy metals, available phosphorus, and enzyme activity of soil samples were analyzed. The results demonstrated that rice straw biochar significantly (P < 0.05) increased the pH, electrical conductivity, and cation exchange capacity of the soil, especially at the 5 % application rate. Both bamboo and rice straw biochar significantly (P < 0.05) decreased the concentration of CaCl₂-extractable heavy metals as biochar application rate increased. The heavy metal extractability was significantly (P < 0.01) correlated with pH, water-soluble organic carbon, and available phosphorus in soil. The 5 % application rate of fine rice straw biochar resulted in the greatest reductions of extractable Cu and Zn, 97.3 and 62.2 %, respectively. Both bamboo and rice straw biochar were more effective at decreasing extractable Cu and Pb than removing extractable Cd and Zn from the soil. Urease activity increased by 143 and 107 % after the addition of 5 % coarse and fine rice straw biochars, respectively. Both bamboo and rice straw biochars significantly (P < 0.05) increased catalase activity but had no significant impact on acid phosphatase activity. In conclusion, the rice straw biochar had greater potential as an amendment for reducing the bioavailability of heavy metals in soil than that of the bamboo biochar. The impact of biochar treatment on heavy metal extractability and enzyme activity varied with the biochar type, application rate, and particle size.
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The aim of this work was to study the redox-induced mobilization of Ag, Sb, Sn, and Tl in the dissolved, colloidal, and sediment phase of a mining soil treated and untreated with ...biochar as affected by the redox potential (EH) -dependent changes of soil pH, dissolved organic carbon, Fe, Mn and S. The experiment was conducted stepwise at two EH cycles (+200 mV → -30 mV → +333 mV → 0 mV) using biogeochemical microcosm. Silver was abundant in the colloidal fraction in both cycles, indicating that Ag might be associated with colloids under different redox conditions. Antimony, Sn and Tl were abundant in the colloidal fraction in the first cycle and in the dissolved fraction in the second cycle, which indicates that they are retained by colloids under oxic acidic conditions and released under reducing alkaline conditions. Release of dissolved Sb, Sn, and Tl was governed positively by pH, Fe, S, and dissolved aromatic compounds. Biochar mitigated Ag release, but promoted Sb, Sn, and Tl mobilization, which might be due to the wider range of EH (-12 to +333) and pH (4.9–8.1) in the biochar treated soil than the un-treated soil (EH = -30 to +218; pH = 5.9–8.6). Also, the biochar surface functional groups may act as electron donors for the Sb, Sn, and Tl reduction reactions, and thus biochar may play an important role in reducing Tl3+ to Tl+, Sb5+ to Sb3+, and Sn4+ to Sn2+, which increase their solubility under reducing conditions as compared to oxic conditions. Thallium and Sb exhibit higher potential mobility in the solid phase than Sn and Ag. Biochar increased the potential mobility of Sb, Sn, and Tl under oxic acidic conditions. The results improve our understanding of the redox-driven mobilization of these contaminants in soils.
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Antimony (Sb) is introduced into soils, sediments, and aquatic environments from various sources such as weathering of sulfide ores, leaching of mining wastes, and anthropogenic ...activities. High Sb concentrations are toxic to ecosystems and potentially to public health via the accumulation in food chain. Although Sb is poisonous and carcinogenic to humans, the exact mechanisms causing toxicity still remain unclear. Most studies concerning the remediation of soils and aquatic environments contaminated with Sb have evaluated various amendments that reduce Sb bioavailability and toxicity. However, there is no comprehensive review on the biogeochemistry and transformation of Sb related to its remediation. Therefore, the present review summarizes: (1) the sources of Sb and its geochemical distribution and speciation in soils and aquatic environments, (2) the biogeochemical processes that govern Sb mobilization, bioavailability, toxicity in soils and aquatic environments, and possible threats to human and ecosystem health, and (3) the approaches used to remediate Sb-contaminated soils and water and mitigate potential environmental and health risks. Knowledge gaps and future research needs also are discussed. The review presents up-to-date knowledge about the fate of Sb in soils and aquatic environments and contributes to an important insight into the environmental hazards of Sb. The findings from the review should help to develop innovative and appropriate technologies for controlling Sb bioavailability and toxicity and sustainably managing Sb-polluted soils and water, subsequently minimizing its environmental and human health risks.
Highlights
A multifunctional SiC@SiO
2
nanofber aerogel (NFA) was successfully prepared, which exhibits ultra-elastic, fatigue-resistant, high-temperature thermalstability, thermal insulation ...properties, and signifcant strain-dependent piezoresistive sensing behavior.
The SiC@SiO
2
NFA shows excellent electromagnetic wave absorption performance with a minimum refection loss value of −50.36 dB and a maximum effective absorption bandwidth of 8.6 GHz.
Traditional ceramic materials are generally brittle and not flexible with high production costs, which seriously hinders their practical applications. Multifunctional nanofiber ceramic aerogels are highly desirable for applications in extreme environments, however, the integration of multiple functions in their preparation is extremely challenging. To tackle these challenges, we fabricated a multifunctional SiC@SiO
2
nanofiber aerogel (SiC@SiO
2
NFA) with a three-dimensional (3D) porous cross-linked structure through a simple chemical vapor deposition method and subsequent heat-treatment process. The as-prepared SiC@SiO
2
NFA exhibits an ultralow density (~ 11 mg cm
− 3
), ultra-elastic, fatigue-resistant and refractory performance, high temperature thermal stability, thermal insulation properties, and significant strain-dependent piezoresistive sensing behavior. Furthermore, the SiC@SiO
2
NFA shows a superior electromagnetic wave absorption performance with a minimum refection loss (
RL
min
) value of − 50.36 dB and a maximum effective absorption bandwidth (
EAB
max
) of 8.6 GHz. The successful preparation of this multifunctional aerogel material provides a promising prospect for the design and fabrication of the cutting-edge ceramic materials.
Abstract
This is the second of two companion papers on modeling of mesoscale cellular structures and drizzle in marine stratocumulus. In the first, aerosol–cloud–precipitation interactions and ...dynamical feedbacks were investigated to study the formation and evolution of open and closed cellular structures separately. In this paper, coexisting open and closed cells and how they influence one another are examined in a model domain of 180 × 60 × 1.5 km3. Simulations show that gradients in aerosol at the open–closed-cell boundary cause gradients in precipitation that generate a mesoscale circulation. The circulation promotes precipitation in the polluted closed cells but suppresses it in open cells by transporting water vapor to the closed-cell regime and carrying drier air and aerosol back to the open cells. The strength of this circulation depends on the contrast in precipitation under clean and polluted conditions at the boundary. Ship plumes emitted into clean, precipitating regions, simulated as a special case of a clean–polluted boundary, develop a similar circulation. Drizzle in the ship track is first suppressed by the increase in aerosol particles but later recovers and becomes even stronger because the local circulation enhances liquid water path owing to the convergence of water vapor from the region adjacent to the track. This circulation modifies the transport and mixing of ship plumes and enhances their dispersal. Finally, results show that whereas ship emissions do increase cloud albedo in regions of open cells, even the addition of very large aerosol concentrations cannot transform an open cellular structure to a closed one, for the case considered.
Luminescent mechanochromism (e.g., shearing force and hydrostatic pressure) has been intensively studied in recent years. However, there are few reported studies on the difference of the molecular ...configuration changes induced by these stresses. In this study, we chose triphenylamine, C18H6N (TPA), as a model molecule to study different molecular configuration changes under shearing force and hydrostatic pressure. Triphenylamine is an organic optoelectric functional molecule with a propeller-shaped configuration, a large conjugate structure, and a single molecular fluorescence material. Fluorescence and Raman spectra of TPA were recorded in situ under different pressures (0–1.9 GPa) produced by the mechanical grinding or using a diamond anvil cell (DAC). Our results show that the crystal phase of TPA transformed to the amorphous phase by grinding, whereas no obvious phase transition was observed under hydrostatic pressure up to 1.9 GPa, indicating the stability of TPA. Hydrostatic pressure by DAC induces molecular conformation changes, and the pressure-induced emission enhancement phenomenon of TPA is observed. By analyzing the Raman spectra at high pressure, we suggest that the molecular conformation changes under pressure are caused by the twisted dihedral angle between the benzene and the nitrogen atom, which is different from the phase transformation induced by the shearing force of grinding.
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