Determining the Geometric Surface Area of Mesoporous Materials

Specific surface area is an important property of porous materials and a crucial index in multiple disciplines, which is mainly measured using nitrogen isotherms and the Brunauer–Emmett-Teller (BET) equation. The BET surface area is remarkably higher than the geometric surface area, which is defined as the surface area of the crystal geometry structure. However, many studies directly use the BET surface area as the geometric surface area. We proposed a simple, general, and accurate method that only needs the nitrogen adsorption isotherm as the input to calculate the geometric surface area of mesoporous materials. The proposed method considers the adsorptive potential influences and the physical state of adsorbed nitrogen in estimating the surface area. We utilized 18 isotherms generated by molecular simulations and actual experiments to cover a wide range of materials, including minerals, catalysts, and carbon-based tubes, and validate the effectiveness of the proposed method. Our results showed that the surface area determined by the proposed method is almost identical to the referenced geometric area. The surface area obtained by the proposed method can be typically considered a geometric surface area

Precision Replication of Hierarchical Biological Structures by Metal Oxides Using a Sonochemical Method

A novel method for duplicating the hierarchical structures of biological substances at nanometer resolution in manganese oxides has been developed. This innovation uses natural biomorphic specimens, such as butterfly wing, cotton, and wood as templates. The biotemplates were first treated with either HCl/NaOH or HCl/H2O2/NaOH and then mixed with an aqueous solution of KMnO4. The treated biological materials were then ultrasonically irradiated, and finally, the biological templates were removed by calcination in air at temperatures between 500 and 800 °C. The structures of the resulting manganese oxides were characterized by a combination of XRD, FE-SEM, TEM and EDS. It was found that the fine hierarchical structures of the biological templates down to the nanometer scale were faithfully duplicated, and the duplication was positive. A mechanism for the positive replication is proposed and discussed in terms of the effects of the sonochemical reaction as well as the surface modification prior to the sonochemical reaction. The same sonochemical method can be extended to the duplication of intricate hierarchical structures of other biological forms in a large range of metal oxides

High intrinsic thermal conductivity in cellulose nanocrystal films through pitch regulation

Polymers are widely used in thermal management systems for modern electronics due to their light weight, electrical insulation abilities, and low cost. However, the low intrinsic thermal conductivity (TC) of polymers restricts their applications. This low intrinsic TC is due to the entanglement of the polymer chains and defects such as voids, which act as phonon scattering sites. Regulating the structure of polymers is an effective way to improve their intrinsic TC. Generally, traditional approaches can achieve only a partially ordered structure, while the construction of an ordered structure on both the microscale and macroscale is beneficial to phonon transportation. Inspired by the excellent crystalline properties of biopolymers of CNCs (cellulose nanocrystals), herein, we develop an approach for the fabrication of a CNC composite film that has a highly ordered structure on both the microscale (crystalline chains of cellulose) and macroscale (highly compacted lamella structure). CNCs combined with Fe3O4/CNC (CNCs loaded with Fe3O4nanoparticles) can self-assemble into a chiral nematic structure, and the pitch of the ordered structure can be adjusted under an external magnetic field. With an increase in the magnetic field from 0 mT to 32 mT, the pitch decreases from 363 ± 35 nm to 210 ± 11 nm, and the TC improves significantly because Fe3O4/CNC compresses the structure uniformly and reduces voids and cracks. At the optimized concentration of 1.10 wt%, the CNC composite film shows a TC of up to 0.798 W m−1K−1, which is 2-3 times that reported for a typical polymer. The film has good transparency and is suitable for the application requirements of mobile devices and windows. This work paves an avenue for the design and fabrication of polymer matrices with extremely high intrinsic TC, and it is expected to contribute to theoretical studies

Graphene-Based Nanomaterials for Solar-Driven Overall Water Splitting

Water splitting through photocatalysis and photoelectrochemical methods is a promising strategy for solar energy utilization. Graphene is widely used in solar-driven overall water splitting because of its versatile properties. This review summarizes the preparation of graphene-based photocatalysts and photoelectrodes and the functions of graphene, and highlights the challenges and prospects of the future applications of graphene in solar-driven water splitting

Facile Synthesis of Hierarchical Networks Composed of Highly Interconnected V₂O₅ Nanosheets Assembled on Carbon Nanotubes and Their Superior Lithium Storage Properties

Hierarchical networks with highly interconnected V₂O₅ nanosheets (NSs) anchored on skeletons of carbon nanotubes (CNTs) are prepared by a facile hydrothermal treatment and a following calcination for the first time. Benefiting from these unique structural features, the as-prepared CNT@V₂O₅ material shows dramatically excellent electrochemical performance with remarkable long cyclability (137–116 mA h g^–1 after 400 cycles) at various high rates (20 C to 30 C) and very good rate capability for highly reversible lithium storage. The excellent electrochemical performance suggests its promising use as a cathode material for future lithium-ion batteries

Image_4_Association of bevacizumab and stroke in ovarian cancer: a systematic review and meta-analysis.TIF

BackgroundThe prognosis for patients with ovarian cancer is bleak. Clinical trials have shown the efficacy of bevacizumab in ovarian cancer treatment. However, life-threatening strokes may limit the usage of bevacizumab and require specific follow-up strategies. This study aims to systematically evaluate the risk of stroke of bevacizumab treatment in ovarian cancer.MethodsWe retrieved all relevant articles published up to December 4th, 2022, from Embase, PubMed, Web of Science, and the Cochrane Library. The risk of stroke in patients with ovarian cancer treated with bevacizumab combined with chemotherapy was analyzed. Meta-analysis was performed using the Stata 17 software and R 4.2.1 program.ResultsSix randomized controlled trials (RCTs) of bevacizumab combined with chemotherapy or chemotherapy for ovarian cancer and six single-experimental-arm trials were included in this study. The meta-analysis showed a pooled risk ratio (RR) of 2.14 [95% confidence interval (CI): 0.88–7.99] for patients with ovarian cancer treated with bevacizumab combined with chemotherapy. Subgroup analyses showed that the incidence of stroke-related adverse events in the carboplatin + paclitaxel + bevacizumab group was 0.01% (95% CI: 0.00–0.01, p ConclusionsThis meta-analysis indicates that chemotherapy combined with bevacizumab may not increase the incidence of stroke in patients with ovarian cancer. However, stroke-related adverse events may be higher in older patients. Cerebral hemorrhage might cause the incidence of stroke more than cerebral ischemia.Systematic review registrationPROSPERO (CRD42022381003).</p

Image_2_Association of bevacizumab and stroke in ovarian cancer: a systematic review and meta-analysis.TIF

BackgroundThe prognosis for patients with ovarian cancer is bleak. Clinical trials have shown the efficacy of bevacizumab in ovarian cancer treatment. However, life-threatening strokes may limit the usage of bevacizumab and require specific follow-up strategies. This study aims to systematically evaluate the risk of stroke of bevacizumab treatment in ovarian cancer.MethodsWe retrieved all relevant articles published up to December 4th, 2022, from Embase, PubMed, Web of Science, and the Cochrane Library. The risk of stroke in patients with ovarian cancer treated with bevacizumab combined with chemotherapy was analyzed. Meta-analysis was performed using the Stata 17 software and R 4.2.1 program.ResultsSix randomized controlled trials (RCTs) of bevacizumab combined with chemotherapy or chemotherapy for ovarian cancer and six single-experimental-arm trials were included in this study. The meta-analysis showed a pooled risk ratio (RR) of 2.14 [95% confidence interval (CI): 0.88–7.99] for patients with ovarian cancer treated with bevacizumab combined with chemotherapy. Subgroup analyses showed that the incidence of stroke-related adverse events in the carboplatin + paclitaxel + bevacizumab group was 0.01% (95% CI: 0.00–0.01, p ConclusionsThis meta-analysis indicates that chemotherapy combined with bevacizumab may not increase the incidence of stroke in patients with ovarian cancer. However, stroke-related adverse events may be higher in older patients. Cerebral hemorrhage might cause the incidence of stroke more than cerebral ischemia.Systematic review registrationPROSPERO (CRD42022381003).</p

A New Route for Degradation of Volatile Organic Compounds under Visible Light: Using the Bifunctional Photocatalyst Pt/TiO_2−<i>x</i>N_<i>x</i> in H₂−O₂ Atmosphere

The bifunctional photocatalyst Pt/TiO2−xNx has been successfully prepared by wet impregnation. The properties of Pt/TiO2−xNx have been investigated by diffuse reflectance spectra, X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, a photoluminescence technique with terephthalic acid, and electric field induced surface photovoltage spectra. The photocatalytic activity of the sample was evaluated by the decomposition of volatile organic pollutants (VOCs) in a H2−O2 atmosphere under visible light irradiation. The results demonstrated that nitrogen-doped and platinum-modified TiO2 in a H2−O2 atmosphere could enormously increase the quantum efficiency of the photocatalytic system with excellent photocatalytic activity and high catalytic stability. The increased quantum efficiency can be explained by enhanced separation efficiency of photogenerated electron–hole pairs, higher interface electron transfer rate, and an increased number of surface hydroxyl radicals in the photocatalytic process. A mechanism was proposed to elucidate the degradation of VOCs over Pt/TiO2−xNx in a H2−O2 atmosphere under visible light irradiation

Image_1_Association of bevacizumab and stroke in ovarian cancer: a systematic review and meta-analysis.TIF

BackgroundThe prognosis for patients with ovarian cancer is bleak. Clinical trials have shown the efficacy of bevacizumab in ovarian cancer treatment. However, life-threatening strokes may limit the usage of bevacizumab and require specific follow-up strategies. This study aims to systematically evaluate the risk of stroke of bevacizumab treatment in ovarian cancer.MethodsWe retrieved all relevant articles published up to December 4th, 2022, from Embase, PubMed, Web of Science, and the Cochrane Library. The risk of stroke in patients with ovarian cancer treated with bevacizumab combined with chemotherapy was analyzed. Meta-analysis was performed using the Stata 17 software and R 4.2.1 program.ResultsSix randomized controlled trials (RCTs) of bevacizumab combined with chemotherapy or chemotherapy for ovarian cancer and six single-experimental-arm trials were included in this study. The meta-analysis showed a pooled risk ratio (RR) of 2.14 [95% confidence interval (CI): 0.88–7.99] for patients with ovarian cancer treated with bevacizumab combined with chemotherapy. Subgroup analyses showed that the incidence of stroke-related adverse events in the carboplatin + paclitaxel + bevacizumab group was 0.01% (95% CI: 0.00–0.01, p ConclusionsThis meta-analysis indicates that chemotherapy combined with bevacizumab may not increase the incidence of stroke in patients with ovarian cancer. However, stroke-related adverse events may be higher in older patients. Cerebral hemorrhage might cause the incidence of stroke more than cerebral ischemia.Systematic review registrationPROSPERO (CRD42022381003).</p

In Situ Formation of Al3Ti and Its Effects on the Microstructure, Hardness and Tribological Properties of Al Matrix Composites with Various Ti Contents

At present, Al matrix composites (AMCs) have drawn much attention owing to their light weight, high specific strength, high thermal conductivity, and superior excellent wear resistance, which endows them with great potential in the aerospace, automobile and military industries. In this study, AMCs with different Ti contents (0, 5 and 10 vol.%) were prepared by powder metallurgy. During the sintering, Al3Ti particles were in situ formed in the Al matrix. It was found that the Ti completely reacted with the Al matrix and formed fine in situ Al3Ti particles in Al-10Ti, while some large Ti-Al3Ti core-shell formed in Al-5Ti due to the incomplete reaction between the Ti and the Al matrix. Furthermore, the hardness of the composites was significantly improved by the in situ formed Al3Ti particles, reaching 143.3 HV in Al-5Ti and the highest value at 331.2 HV in Al-10Ti, respectively. The wear resistance of the composites is remarkably enhanced by Al3Ti particles compared to the unreinforced Al. Al-5Ti has the highest wear resistance among the samples. The wear resistance of the Al-10Ti composite becomes slightly deteriorated compared to Al-5Ti due to the brittle nature of Al3Ti, which leads to a three-body abrasive wear