Ceramic foams with multi‐scale pores and large specific surface area have received extensive attention due to their unique structure and superior properties. Considering that there are still ...challenges to synthesize porous ceramics with large specific surface area, a novel ceramic foam material with ultra‐large specific surface area has been prepared using hollow silica mesoporous spheres (HMSSs) as building block in this work. These building blocks were made weakly hydrophobic in order to produce HMSS particle stabilized foams. The foams exhibit a uniform primary macropore structure, which is composed of a three dimensional HMSS‐assembled network, via HMSS‐stabilized foams. The influence of sintering temperature on the microstructure and properties of HMSS foams is investigated. The HMSS foams exhibit highest specific surface area of 1733 m2/g, attributed to the radial mesopores in HMSS shell, when sintered at between 500°C and 800°C. This specific surface area is much higher than that of existing ceramic materials. The uniform pore structure and ultra‐large specific surface area make it a promising lightweight material in potential application fields, including catalyst, adsorption, fire‐resistant thermal insulation, and load and control release system.
Hollow mesoporous silica spheres assembled foam material with uniform macro‐pore structure and ultra‐high specific surface area, prepared from HMSSs stabilized colloidal foams
Abstract
BACKGROUND
The differentiation between intracranial atherosclerotic stenosis (ICAS) and intracranial embolism as the immediate cause of acute ischemic stroke requiring endovascular therapy ...is important but challenging. In cases of ICAS, we often observe a phenomenon we call the microcatheter “first-pass effect,” which is temporary blood flow through the occluded intracranial artery when the angiographic microcatheter is initially advanced through the site of total occlusion and immediately retrieved proximally.
OBJECTIVE
To evaluate whether this microcatheter first-pass effect can be used to differentiate ICAS from intracranial embolism.
METHODS
A total of 61 patients with acute ischemic stroke resulting from large intracranial artery occlusion and in whom recanalization was achieved by endovascular treatment were included in the study. The microcatheter first-pass effect was tested in these patients. The sensitivity, specificity, positive predictive values (PPV), and accuracy of the microcatheter first-pass effect for prediction of ICAS were assessed.
RESULTS
The microcatheter first-pass effect was more frequently observed in patients with ICAS than in those with intracranial embolism (90.9% vs 12.8%, P < .001). For identifying ICAS, sensitivity, specificity, PPV, and accuracy of the microcatheter first-pass effect were 90.9%, 87.2%, 80.0%, 88.5%, respectively.
CONCLUSION
The sensitivity and PPV of the microcatheter first-pass effect are high for prediction of ICAS in patients with acute symptoms.
Summary
We aimed to identify the efficacy of haploidentical related donor (HID) haematopoietic stem cell transplantation (HSCT) in adolescent and young adults (AYAs) with acute myeloid leukaemia ...(AML) in a large cohort. Consecutive AML AYAs (15–39 years old, n = 599) receiving HID HSCT in complete remission (CR) were included. The 3‐year cumulative incidence of measurable residual disease occurrence, relapse and non‐relapse mortality after HID HSCT was 28.6% (95% CI: 25.0–32.2), 11.6% (95% CI: 9.0–14.2) and 6.7% (95% CI: 4.7–8.7) respectively. The 3‐year probability of event‐free survival, leukaemia‐free survival (LFS) and overall survival (OS) after HID HSCT was 60.7% (95% CI: 56.9–64.8), 81.7% (95% CI: 78.7–84.9) and 85.6% (95% CI: 82.8–88.4) respectively. In multivariable analysis, AML risk category at diagnosis and comorbidity burdens before HID HSCT were independently associated with LFS and OS. Compared to the older adults (≥ 40 years, n = 355) with AML receiving HID HSCT in CR during the same time period, AYAs have a lower incidence of non‐relapse mortality and higher probabilities of LFS and OS. Thus, we firstly confirmed the safety and efficacy of HID HSCT in AYAs with AML‐CR.
The 3‐year probabolities of overall survival after haploidentical related donor haematopoitic stem cell transplantation according to (A) favourable‐, intermidiate‐ and poor‐risk acute myeloid leukaemia category at diagnosis and (B) low‐ intermidiate‐ and high‐risk haematopoietic stem cell transplantation‐specific comorbidity index scores before allo‐ haematopoietic stem cell transplantation.
Zirconia ceramic foams with ultra‐high porosity of 96%–98% have been fabricated using sodium dodecyl sulfate (SDS) as the particle stabilizer of zirconia particles for the first time. The wet foams ...stabilized by zirconia particles are ultra‐stable due to partially hydrophobic zirconia particles modified by SDS. Zirconia foams exhibit close cells with thin cell wall and small grain size. Increasing SDS concentration favors the foamability of the suspension, and further increases the porosity of ceramic foams. Zirconia ceramic foams with porosity of 98.1% have compressive strength of 0.26 ± 0.05 MPa. Decreasing solid loading leads to the porosity of ceramic foams. The compressive strength could be improved significantly by increasing the sintering temperature. Zirconia ceramic foams with porosity of 97.9% has low thermal conductivity of 0.027 ± 0.004 W·(m·K)−1, which could be used as thermal insulation and refractory material.
Decarbonization in operational residential buildings worldwide has become critical in achieving the carbon neutral target due to the growing household energy demand. To accelerate the pace of global ...carbon neutrality, this study explores the operational carbon change in global residential buildings through the generalized Divisia index method and decoupling analysis, considering the decarbonization levels of residential buildings at different scales. The results show that (1) most of the samples showed a decrease in the total emissions from 2000 to 2019. Except for China and the United States (US), the carbon emissions in global residential building operations decreased by 7.95 million tons of carbon dioxide (MtCO2) per year over the study period. Emissions per gross domestic product (GDP) was the most positive driver causing the decarbonization of residential buildings, while GDP was the most negative driver. (2) Carbon intensity was essential to achieving a strong decoupling of economic development and carbon emissions. The US almost consistently presented strong decoupling, while China showed weak decoupling over the last two decades. (3) The pace of decarbonization in global residential building operations is gradually slowing down. From 2000 to 2019, decarbonization from residential buildings across 30 countries was 2094.3 MtCO2, with a decarbonization efficiency of 3.4%. Overall, this study addresses gaps in evaluating global decarbonization from operational residential buildings and provides a reference for evaluating building decarbonization by other emitters.
•Global carbon emissions from residential building operations declined 0.9% yr−1 from 2000 to 2019.•Emissions per GDP were the key cause of the decarbonization of residential building operations.•The U.S. showed strong decoupling, while China showed weak decoupling over the study period.•By 2019, global decarbonization was 2094.3 MtCO2 with a decarbonization efficiency of 3.4%.•Decarbonization in electricity is the key to hit carbon neutrality in residential building operations.
Thermal electron transfer through hydrogen bonds remains largely unexplored. Here we report the study of electron transfer through amide-amide hydrogen bonded interfaces in mixed-valence complexes ...with covalently bonded Mo
units as the electron donor and acceptor. The rate constants for electron transfer through the dual hydrogen bonds across a distance of 12.5 Å are on the order of ∼ 10
s
, as determined by optical analysis based on Marcus-Hush theory and simulation of ν(NH) vibrational band broadening, with the electron transfer efficiencies comparable to that of π conjugated bridges. This work demonstrates that electron transfer across a hydrogen bond may proceed via the known proton-coupled pathway, as well as an overlooked proton-uncoupled pathway that does not involve proton transfer. A mechanistic switch between the two pathways can be achieved by manipulation of the strengths of electronic coupling and hydrogen bonding. The knowledge of the non-proton coupled pathway has shed light on charge and energy transport in biological systems.
The objective of this study was to investigate the effect of lactic acid bacteria (LAB) inoculums on fermentation quality and in vitro digestibility of corn stover silage. Corn stover was ensiled ...without (control) or with Lactobacillus plantarum (LP), Enterococcus faecalis (EF), and Enterococcus mundtii (EM) for 45 days. The fermentation characteristics were assessed, and subsequent in vitro dry matter digestibility (DM-D), neutral detergent fiber digestibility (NDF-D), volatile fatty acids (VFA), methane (CH4) production, cellulolytic bacteria proportions and their activities per corn stover silage were also determined. There was no significant difference (P>0.05) among the silage pH, lactic acid, crude protein (CP), water soluble carbohydrates (WSC) and lignocelluloses contents of different treatments. The relative proportions of Ruminococcus flavefaciens and Fibrobacter succinogenes, carboxymethyl-ocellulose and β-glycosidase activities, DM-D, NDF-D, and VFA production of in vitro incubation was higher (P<0.05) for silages inoculated with LP and EF than those of the control silage. Silage inoculated with LP showed the lowest (P<0.05) CH4 production per unit yield of VFA, which was positively corresponded to the lowest (P<0.05) ratio of acetate to propionate. In summary, the ensiling fermentation quality and subsequent utilization of corn stover silage were efficiently improved by inoculated with L. plantarum.
To study the force and deformation characteristics of a full-section immersed tube with post-pouring belt under the action of hydration reaction, the numerical model of full-section immersed tube ...with post-pouring belt was established by using MIDAS FEA (V2013) finite element analysis software, and the stress, cracking and deformation of the segment of the post-pouring belt were analyzed. The results show that under the action of hydration reaction, the concrete reaches the highest temperature at about 36 h, which appears at the roof of the tube gallery in the immersed tube, and the bottom steel plate expands rapidly initially, and subsequently shrinks gradually. The outer surface of the post-pouring segment concrete is stretched, and the internal region is under pressure, and as the internal temperature of the concrete cools down, the bottom plate starts to contract. The steel bar connection between the post-pouring belt and the surrounding immersed tube segment will increase the risk of cracking in the bottom plate of the full-section immersed tube. When only the steel bars in the bottom plate are connected, the maximum tensile stress of the immersed tube bottom plate will increase by 16.0% compared to the no connection case. If the steel bars of the immersed tube’s web and roof are also connected, the maximum tensile stress will increase by over 20%. By connecting the steel bars, the peripheral tube section plays a certain role in limiting the transverse deformation of the post-pouring belt and constraining the reinforcement of the bottom plate and web (and roof) can reduce the transverse deformation of the immersed tube to a great extent, reducing the proportion by over 10%.
Flawless porous fibrous alumina ceramics with high performance were fabricated via a novel approach involving direct coagulation casting and lost‐mold method. Stable alumina suspensions were prepared ...by adding sodium tri‐polyphosphate as dispersant using alumina fibers as raw material and K2SO4 as sintering aid. Resin‐coated sand molds with designed shapes for suspension casting were fabricated through 3D printing with subsequent post‐treatments. Alumina green bodies were obtained by in situ coagulation of the suspension after treating at 90°C within 40 minutes. Porous alumina ceramics were obtained after direct furnace sintering of green bodies without demolding, in which the molds would collapse automatically at around 650°C with less exhaust emission. The effect of various K2SO4 contents and sintering temperatures on mechanical properties of porous ceramics was investigated. The SEM results showed that the fibers interconnected with obvious interfacial bondings on junctions when sintered at 1450°C. The XRD patterns showed that the sample sintered with various K2SO4 additions consisted of different phases, mainly including aluminosilicates. Porosity of ceramic samples increased slightly whereas the compressive strength enhanced significantly with increasing K2SO4 addition. The density of sintered samples with different K2SO4 contents was in accord with the porosity variation tendency. The ceramic samples had uniform pore size distribution with average size from 3.18 to 7.24 μm as increasing K2SO4 addition to 40 wt%. This approach may provide a convenient and general route to fabricate various dense and porous advanced ceramics with complex shapes and good composition homogeneity.
A series of three Mo2 dimers bridged by a meta‐phenylene group has been studied in terms of electronic coupling (EC) and electron transfer (ET) in comparison with the para isomers. Optical analyses ...on the mixed‐valence complexes indicate that by replacing a para‐phenylene bridge with a meta one, the EC between the two Mo2 centers is dramatically weakened; consequently, the ET rates (ket) are lowered by two to three orders of magnitude. In the para series, the EC parameters (Hab) and ET rates (ket) are greatly affected by O/S atomic alternation of the bridging ligand. However, for the meta analogues, similar EC and ET parameters are obtained, that is, Hab=300–400 cm−1 and ket≈109 s−1. These results suggest that through‐σ‐bond and/or through‐space coupling channels become operative as the π conjugation is disabled. DFT calculations reveal that destructive quantum interference features seen for the meta series arise from the cancellation of two π‐conjugated coupling pathways.
Quantum constructive vs. destructive effects: Optical analysis of Mo2 mixed‐valence donor‐bridge‐acceptor systems indicates that a meta phenylene bridge lowers the electron‐transfer rate by two to three orders of magnitude with respect to the para analogues. DFT calculations reveal that the destructive quantum interference features arise from the cancellation of two coupling pathways.
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