Co/C Nanocomposites with Tunable Condensed States Induced by Conformation-Mediated Strategy for Electromagnetic Wave Absorption.

The strategic regulation of condensed state structures in multicomponent nanomaterials has emerged as an effective approach for achieving controllable electromagnetic (EM) properties. Herein, a novel conformation-mediated strategy is proposed to manipulate the condensed states of Co and C, as well as their interaction. The conformation of polyvinylpyrrolidone molecules is adjusted using a gradient methanol/water ratio, whereby the coordination dynamic equilibrium effectively governs the deposition of metal-organic framework precursors. This process ultimately influences the combined impact of derived Co and C in the resulting Co/C nanocomposites post-pyrolysis. The experimental results show that the condensed state structure of Co/C nanocomposites transitions from agglomerate state → to biphasic compact state → to loose packing state. Benefiting from the tunable collaboration between interfacial polarization and defects polarization, and the appropriate electrical conductivity, the diphasic compact state of Co/C nanocomposites achieves an effective absorbing bandwidth of 7.12 GHz (2.1 mm) and minimum reflection loss of -32.8 dB. This study highlights the significance of condensed state manipulation in comprehensively regulating the EM wave absorption characteristics of carbon-based magnetic metal nanocomposites, encompassing factors such as conductivity loss, magnetic loss, defect polarization, and interface polarization.

Prevalence and genetic diversity of human rhinovirus among patients with acute respiratory infections in China, 2012-2021.

To understand the prevalence of rhinovirus (RV) among acute respiratory infection (ARI) patients, 10-year ARI surveillance in multiple provinces of China were conducted during 2012-2021. Of 15 645 ARI patients, 1180 (7.54%) were confirmed to have RV infection and 820 (69.49%) were children under 5 years of age. RV typing was performed on the 527 VP1 gene sequences, and species A, B, and C accounted for 73.24%, 4.93%, and 21.82%, respectively. Although no significant difference in the proportions of age groups or disease severity was found between RV species, RV-C was more frequently detected in children under 5 years of age, RV-A was more frequently detected in elderly individuals (≥60), and the proportions of pneumonia in RV-A and RV-C patients were higher than those in RV-B patients. The epidemic peak of RV-A was earlier than that of RV-C. A total of 57 types of RV-A, 13 types of RV-B, and 35 types of RV-C were identified in RV-infected patients, and two uncertain RV types were also detected. The findings showed a few differences in epidemiological and clinical features between RV species in ARI patients, and RV-A and RV-C were more prevalent than RV-B.

Efficacy and safety of anastomotic leak testing in gastric cancer: a randomized controlled trial.

BACKGROUND: Anastomosis-related complications such as bleeding, leakage, and strictures, continue to be serious complications of gastric cancer surgery. Presently, these complications have yet to be reliably prevented. Here we design a comprehensive leak testing procedure which combines gastroscopy, air, and methylene blue (GAM) leak testing. We aimed to evaluated the efficacy and safety of the GAM procedure in patients with gastric cancer. METHODS: Patients aged 18-85 years without an unresectable factor as confirmed via CT were enrolled in a prospective randomized clinical trial at a tertiary referral teaching hospital and were randomly assigned to two groups: intraoperative leak testing group (IOLT) and no intraoperative leak testing group (NIOLT). The primary endpoint was the incidence of postoperative anastomosis-related complications in the two groups. RESULTS: 148 patients were initially randomly assigned to the IOLT group (n = 74) and to the NIOLT group (n = 74) between September 2018 and September 2022. After exclusions, 70 remained in the IOLT group and 68 in the NIOLT group. In the IOLT group, 5 patients (7.1%) were found to have anastomotic defects intraoperatively, which included anastomotic discontinuity, bleeding, and strictures. The NIOLT group had a higher incidence of postoperative anastomotic leakage compared to the IOLT group: 4 patients (5.8%) vs 0 patients (0%), respectively. No GAM-related complications were observed. CONCLUSION: The GAM procedure is an intraoperative leak test that can be performed safely and efficiently after a laparoscopic total gastrectomy. GAM anastomotic leak testing may effectively prevent technical defect-related anastomotic complications in patients with gastric cancer who undergo a gastrectomy. TRIAL REGISTRATION: Clinical Trials.gov Identifier: NCT04292496.

Comparative analysis of the clinical and epidemiological characteristics of human influenza virus versus human respiratory syncytial virus versus human metapneumovirus infection in nine provinces of China during 2009-2021.

A comparative analysis of confirmed cases of human influenza virus (HIFV), human respiratory syncytial virus (HRSV), and human metapneumovirus (HMPV) was conducted to describe their clinical and epidemiological characteristics. During 2009-2021, active surveillance of acute respiratory infections (ARIs) was performed in nine provinces of China. Clinical and epidemiological information and laboratory testing results of HIFV, HRSV, and HMPV were analyzed. Among 11591 ARI patients, the single-infection rates of HIFV, HRSV, and HMPV were 15.00%, 9.59%, and 2.24%, respectively; the coinfection rate of these three viruses was 0.64%. HIFV infection was mainly in adults aged 15-59 years, accounting for 39.10%. HRSV and HMPV infections were mainly in children under 5 years old, accounting for 87.13% and 83.46%, respectively. Patients with HRSV infection were younger than HMPV. HRSV and HMPV had high similarities in clinical manifestations, presenting with lower respiratory symptoms. HIFV mainly presented with an upper respiratory infection. The epidemic peak of HRSV was earlier than that of HIFV, and that of HMPV was later than those of HRSV and HFIV. A total of 85.14% of coinfection cases were children under 5 years old. Coinfection might increase the risk of pneumonia in HIFV cases. During 2020-2021, the positive rates and seasonal patterns of these three viruses changed due to the impact of the COVID-19 pandemic. Certain clinical and epidemiological features were observed in HIFV, HRSV, and HMPV infections, which could be beneficial for guiding clinical diagnosis, treatment, and prevention of these three viruses in China.

Modular Assembly of Drug and Monodisperse SPIONs for Superior Magnetic and T2-Imaging Performance.

Development of superparamagnetic iron oxide nanoparticles (SPIONs) based theranostics has suffered due to its self-contradictory requirements on water dispersity and drug loadings. Generally well-dispersed SPIONs have excellent MRI performance but are insensitive to magnetism mediated delivery. Besides, loading hydrophobic drugs also hampers the stability of SPIONs which is critical for their biomedical applications. Considering these aspects, we employed curcumin as a cross-linking agent to facilitate the modular assembly of drug and monodisperse SPIONs (Cur/ALN-ß-CD-SPIONs). Interestingly, the saturation magnetization of Cur/ALN-ß-CD-SPIONs is higher than that of ALN-ß-CD-SPIONs, and the value of r2 indicating the negative contrast ability increases to 389.96 mM-1 s-1. Furthermore, the Cur/ALN-ß-CD-SPIONs are very stable in PBS buffer over 3 weeks. The mice treated with Cur/ALN-ß-CD-SPIONs by tail vein injection displayed a better tumor inhibition effect than that of free curcumin. This study provides a simple method for modular assembly of drug and monodisperse SPIONs, which is crucial to the design of SPIONs with superior T2-imaging performance and drug delivery.

Influence of Adsorption State and Molecular Interaction on Physical Stability of Confined Amorphous Vortioxetine.

The composites of amorphous vortioxetine (VXT) and ordered mesoporous silica were prepared. Three silica matrixes with different pore sizes were used here: Mobil Composition of Matter No.41 (MCM), Santa Barbara Amorphous No.15 (SBA), and mesostructured cellular foam (MCF). The amorphous composites behaved enhanced physical stability (303.15 K, 56.0 ± 0.4% RH) compared to bulk VXT amorphism. Interestingly, the physical stability of these amorphous composites showed a great difference. Amorphous VXT loaded in MCF crystallized within 1 week, while VXT-SBA composites could be stable over 3 months. The stability of VXT-MCM composites were somewhere in between. In addition, with VXT loading decreasing, the physical stability of confined amorphous VXT became better. Nitrogen adsorption measurements indicated that VXT molecules were adsorbed in SBA in a dispersive state while aggregated in MCM and MCF. VXT-VXT interactions in MCM could be stronger than that in SBA. 1H-13C solid-state nuclear magnetic resonance experiments demonstrated the weaker VXT-VXT interactions in SBA. The dispersive adsorption state and weak VXT-VXT interactions were benefit to the physical stability of amorphous VXT in SBA channels. In addition, dissolution profiles of confined amorphous VXT and bulk crystalline VXT were determined and the dissolution rate of VXT loaded in nanopores was faster than the latter.

Recent Advances in Synthesis and Properties of Nitrated-Pyrazoles Based Energetic Compounds.

Nitrated-pyrazole-based energetic compounds have attracted wide publicity in the field of energetic materials (EMs) due to their high heat of formation, high density, tailored thermal stability, and detonation performance. Many nitrated-pyrazole-based energetic compounds have been developed to meet the increasing demands of high power, low sensitivity, and eco-friendly environment, and they have good applications in explosives, propellants, and pyrotechnics. Continuous and growing efforts have been committed to promote the rapid development of nitrated-pyrazole-based EMs in the last decade, especially through large amounts of Chinese research. Some of the ultimate aims of nitrated-pyrazole-based materials are to develop potential candidates of castable explosives, explore novel insensitive high energy materials, search for low cost synthesis strategies, high efficiency, and green environmental protection, and further widen the applications of EMs. This review article aims to present the recent processes in the synthesis and physical and explosive performances of the nitrated-pyrazole-based Ems, including monopyrazoles with nitro, bispyrazoles with nitro, nitropyrazolo[4,3-c]pyrazoles, and their derivatives, and to comb the development trend of these compounds. This review intends to prompt fresh concepts for designing prominent high-performance nitropyrazole-based EMs.

Survey of Traveler's Diarrhea: Epidemiology and Testing Reveal the Source.

OBJECTIVE: To understand the causes and transmission routes of, as well as risk factors, for a Salmonella outbreak in a tour group. METHOD: A retrospective cohort design was used to conduct an epidemiological field investigation. Real-time fluorescent quantitative PCR, bacterial culture, and serological identification methods were used for pathogen detection and identification. RESULT: There were 7 cases of illness, and the attack rate was 46.67%. The onset date was concentrated on May 9 and 10. All cases were found in the tour group, and no cases occurred in the nontour group. The results of this retrospective cohort study showed that the consumption of boiled eggs for breakfast on May 9 was a common factor (R 2 = 6.67, P=0.023). Salmonella enteritidis was identified from the patients' stool and vomit. CONCLUSION: The food poisoning epidemic was caused by Salmonella enteritidis. In the summer and autumn, attention should be paid to preservation, processing, and cooking of food to avoid bacterial contamination. To prevent sickness, travelers should know the disease prevalence at their destinations in advance.

Coupling effect between the structure and surface characteristics of electrospun carbon nanofibres on the electrochemical activity towards the VO2(+)/VO(2+) redox couple.

In order to investigate the structure-function relationship of electrospun carbon nanofibres (ECNFs), polyacrylonitrile (PAN)-based electrospun carbon webs (ECWs) have been developed, consisting of ECNFs carbonized over the temperature range of 1000-1500 °C in a nitrogen atmosphere. The surface morphology, microstructure, composition, electrical conductivity and hydrophilicity of the ECNFs have been characterized. The electrochemical activity of the ECNFs towards the VO2(+)/VO(2+) redox reaction has been measured by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). It is worth noting that the electrochemical performance of the ECNFs decreases firstly and then rises gradually with the increase in carbonization temperature, and a carbonization temperature of about 1300 °C is the turning point. This unusual phenomenon might be attributed to the coupling effect between the surface and structure characteristics of the ECNFs towards the VO2(+)/VO(2+) redox couple. The surface composition plays a leading role in the electrochemical activity of ECNFs carbonized over the temperature range of 1000-1300 °C; however, the edge planes of graphite crystallites which form during the high temperature range from 1300-1500 °C then become the dominant factor. Therefore, the electrochemical activity decreases with the reduction of functional groups on the surface from carbonization at 1000-1300 °C, and then increases with the addition of the edge planes of graphite crystallites from carbonization at 1300-1500 °C.

Tailoring Built-In Electric Field in a Self-Assembled Zeolitic Imidazolate Framework/MXene Nanocomposites for Microwave Absorption.

Heterointerface engineering, which plays a pivotal role in developing advanced microwave-absorbing materials, is employed to design zeolitic imidazolate framework (ZIF)-MXene nanocomposites. The ZIF-MXene composites are prepared by electrostatic self-assembly of negatively charged titanium carbide MXene flakes and positively charged Co-containing ZIF nanomaterials. This approach effectively creates abundant Mott-Schottky heterointerfaces exhibiting a robust built-in electric field (BIEF) effect, as evidenced by experimental and theoretical analyses, leading to a notable attenuation of electromagnetic energy. Systematic manipulation of the BIEF-exhibiting heterointerface, achieved through topological modulation of the ZIF, proficiently alters charge separation, facilitates electron migration, and ultimately enhances polarization relaxation loss, resulting in exceptional electromagnetic wave absorption performance (reflection loss RLmin = -47.35 dB and effective absorption bandwidth fE = 6.32 GHz). The present study demonstrates an innovative model system for elucidating the interfacial polarization mechanisms and pioneers a novel approach to developing functional materials with electromagnetic characteristics through spatial charge engineering.

Comparison of the postoperative outcome with and without intraoperative leak testing for sleeve gastrectomy: a systematic review and meta-analysis of 469 588 cases.

OBJECTIVE: Postoperative staple line leakage (SLL) after sleeve gastrectomy (SG) is a rare but serious complication. Many surgeons routinely test anastomosis with an intraoperative leak test (IOLT) as part of the SG procedure. This meta-analysis aims to determine whether an IOLT plays a role in reducing the rate of postoperative staple line related complications in patients who underwent SG. METHODS: The authors searched the PubMed, Web of science, the Cochrane Library, and Clinical Trials.gov databases for clinical studies assessing the application of IOLT in SG. The primary endpoint was the development of postoperative SLL. Secondary endpoints included the postoperative bleeding, 30 days mortality rates, and 30 days readmission rates. RESULTS: Six studies totaling 469 588 patients met the inclusion criteria. Our review found that the SLL rate was 0.38% (1221/ 324 264) in the IOLT group and 0.31% (453/ 145 324) in the no intraoperative leak test (NIOLT) group. Postoperative SLL decreased in the NIOLT group compared with the IOLT group (OR=1.27; 95% CI: 1.14-1.42, P =0.000). Postoperative bleeding was fewer in the IOLT group than that in the NIOLT group (OR 0.79; 95% CI: 0.72-0.87, P =0.000). There was no significant difference between the IOLT group and the NIOLT group regarding 30 days mortality rates and 30 days readmission rates ( P >0.05). CONCLUSION: IOLT was correlated with an increase in SLL when included as a part of the SG procedure. However, IOLT was associated with a lower rate of postoperative bleeding. Thus, IOLT should be considered in SG in the situation of suspected postoperative bleeding.

Ultrasound-assisted continuous crystallization of metastable polymorphic pharmaceutical in a slug-flow tubular crystallizer.

Metastable polymorphic pharmaceuticals have garnered significant attention in recent years due to their enhanced physicochemical properties, including solubility, bioavailability, and intellectual property considerations. However, the manufacturing of metastable form pharmaceuticals remains a formidable challenge. The stable preparation of metastable carvedilol (CVD) form Ⅱ crystals during CVD production is elusive, leading to substantial inconsistencies in product quality and regulatory compliance. In this study, we successfully prepared metastable CVD Form Ⅱ crystals using a continuous tubular crystallizer. Our findings demonstrate that the tubular crystallizer exhibits high efficiency and robustness for generating metastable crystal Form Ⅱ. We optimized the crystallization process by incorporating air bubble segments and employing ultrasonic irradiation strategies to overcome blockages and wall sticking issues encountered during operation. Ultimately, we developed an ultrasound-assisted continuous slug-flow tubular crystallization method and evaluated its performance. The results indicate that the CVD crystals produced through this process are resilient, sustainable, and uninterrupted products with promising potential for producing metastable polymorphic pharmaceuticals while effectively addressing encrustation problems associated with continuous tubular crystallization.

Separation performance and agglomeration behavior analysis of solution crystallization in food engineering.

This study employed solution crystallization in food engineering to prepare a high-purity vitamin intermediate, optimize its crystal morphology and regulate its particle size distribution. Model analysis was performed to investigate the quantitative correlations between the process variables and target parameters, indicating the substantial effect of temperature on separation performance. Under optimal conditions, the product purity exceeded 99.5%, which meets the requirement of the subsequent synthesis process. A high crystallization temperature reduced the agglomeration phenomenon and increased particle liquidity. Herein, we also proposed a temperature cycling strategy and a gassing crystallization routine to optimize the particle size. The results illustrated that the synergistic control of temperature and gassing crystallization could substantially improve the separation process. Overall, based on a high separation efficiency, this study combined model analysis and process intensification pathways to explore the process parameters on product properties such as purity, crystal morphology, and particle size distribution.

Preparation of ethyl vanillin spherical particles with functions of sustained release and anti-caking by an organic solvent-free process.

Ethyl vanillin is an important synthetic flavor that occupies a large market share in food additives. However, the shortcomings in terms of too fast aroma release rate and poor powder properties have severely limited its further application. In this work, the intrinsic mechanism of ethyl vanillin oiling-out process is revealed with the help of process analytical technologies. Further, a green and efficient spherical particles preparation technology is developed by constructing the oiling-out phase diagram of ethyl vanillin in the aqueous solution of sodium chloride. The ethyl vanillin spherical product has excellent powder properties with high bulk density (0.74 g/cm3), good sphericity (93.4 %), high flowability (29°), high yield (>95 %) and adjustable particle size distribution. More importantly, the spherical product exhibits 57.9 % lower aroma release rate at 323.15 K and 1400 % higher critical caking cycle compared to irregularly shaped powder, which confirms its sustained release and anti-caking function.

Two Cases of Laparoscopic Resection of Siewert Type II Adenocarcinoma of the Esophagogastric Junction Using a Transhiatal Approach and Complicated by Hemopericardium.

BACKGROUND Siewert type II adenocarcinoma of the esophagogastric junction is located at the boundary of the distal esophagus and gastric cardia, and surgical resection is currently performed using open or laparoscopic methods. This report presents 2 cases of laparoscopic resection of Siewert type II adenocarcinoma of the esophagogastric junction using a transhiatal approach, complicated by hemopericardium. CASE REPORT We present 2 patients diagnosed with Siewert type II esophagogastric junction cancer. A 67-year-old man had intermittent dull pain in the epigastrium without apparent cause for 10 months. A 69-year-old man had persistent dull pain in the middle and upper abdomen for more than 3 months and acid reflux after eating. Gastroscopy with pathological examination confirmed the diagnoses. The patients underwent laparoscopic transhiatal total gastrectomy according to the Japanese Gastric Cancer Treatment Guidelines 2018 (5th edition). Pathological analysis classified the cancers as T3N1M0 and T2N0M0, respectively. The patients' cases were complicated with hemopericardium 18 h and 23 h after surgery, respectively. The shared clinical symptoms of the patients included tachycardia and low blood pressure. Cardiovascular color Doppler ultrasound and computed tomography (CT) were used to identify the hemopericardium. Following emergent ultrasound-guided pericardiocentesis and drainage, the vital signs of the patients improved. Both patients recovered well, and no other complications occurred. CONCLUSIONS Hemopericardium is a life-threatening complication for patients with esophageal-gastric junction cancer who undergo transhiatal laparoscopic surgery. Quick detection and intervention for postoperative hemopericardium following laparoscopic transhiatal total gastrectomy are important. Ultrasound-guided pericardiocentesis and drainage is effective for the treatment of postoperative hemopericardium.

Robotic versus laparoscopic surgery for hiatal hernia repair: a systematic literature review and meta-analysis.

The number of robotic hiatal hernia repairs (RHHR) is increasing. However, the superiority of this minimally invasive approach remains controversial. The aim of this study was to evaluate the available literature reporting on outcomes of RHHR compared with laparoscopic hiatal hernia repair (LHHR) in adult patients. The design of this systematic review was developed using the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Web of Science, PubMed, the Cochrane Library, and ClinicalTrials.gov databases were searched. Identified publications were reviewed independently by two authors. High heterogeneity was further explored through sensitivity analysis. The primary endpoint was the development of postoperative complications. Secondary endpoints included operation time, intraoperative complications, 30 day readmission rates and length of stay. The analysis was performed using Stata 17.0 software. A total of 7 studies totaling 10078 patients met the inclusion criteria. Five studies included postoperative complications. The postoperative complications rate was 4.25% (302/7111) in the LHHR group, and 3.49% (38/1088) in the RHHR group. Postoperative complications significantly decreased after RHHR compared with LHHR (OR 0.52; 95% CI 0.36 to 0.75, P = 0.000). Three studies involving 2176 patients reported length of hospital stay. In the three studies, the mean Length of hospital stay was 3.2 days in the RHHR group, and 4.2 days in the LHHR group. Length of hospital stay was decreased by a mean of 0.68 days for RHHR compared with LHHR (WMD, - 0.68 days; 95% CI - 1.32 to - 0.03, P = 0.02). There was no significant difference between the RHHR group and the LHHR group regarding operative time, intraoperative complications, and 30 day readmission (P > 0.05). Our research shows that RHHR may be the better option, as the approach decreases postoperative complications and length of hospital stay.

A Novel Intraoperative Leak Test Procedure (GAM Procedure) to Prevent Postoperative Anastomotic Leakage in Gastric Cancer Patients Who Underwent Gastrectomy.

BACKGROUND: Anastomotic leakage following a radical gastrectomy is a serious complication of gastric cancer and esophagogastric junction cancer. The benefit of intraoperative leak testing for the prevention of postoperative anastomotic leakage has been controversial. We introduce a new procedure, which combines the techniques of gastroscopy, air, and methylene blue (GAM) for intraoperative leakage testing. Our objective was to evaluate the efficacy and safety of the GAM procedure for intraoperative leak testing and to compare the surgical complications of gastric cancer patients who underwent gastrectomy with and without intraoperative leak testing using the GAM procedure. MATERIALS AND METHODS: A total of 210 patients who underwent radical gastrectomy for gastric cancer were included. Patients were divided into 2 groups: the intraoperative leak testing group using the GAM procedure (IOLT), and the group for which no intraoperative leak testing was done (NIOLT). Clinical and pathologic characteristics, the incidence of postoperative anastomotic leakage, and other surgical complications were compared between the 2 groups. RESULTS: There were 82 patients in the IOLT group and 82 patients in the NIOLT group after propensity score matching. In the IOLT group, 4 (4.9%) patients were found to have anastomotic discontinuity during the operation; we repaired these anastomotic discontinuities intraoperatively. The incidence of postoperative anastomotic leakage was higher in the NIOLT group compared with the IOLT group, 6 (7.3%) versus 0 (0%), respectively ( P =0.01). The average time of the GAM procedure was 4.99±1.75 minutes. The surgical time was prolonged by 30 minutes in the IOLT group compared with the NIOLT group, 302.2±79.9 versus 272.1±85.2, respectively ( P =0.02). The length of hospital stay, 15.80±4.55 versus 17.00±6.20 ( P =0.16) was reduced in the IOLT group compared with the NIOLT group. The logistic regression model suggested that IOLT, sex, age, Eastern Cooperative Oncology Group, cT stage, tumor diameter, pT stage, pN stage, and Lauren classification were not risk factors for postoperative complication. CONCLUSIONS: The GAM procedure of intraoperative leakage testing can effectively reduce the incidence of postoperative anastomotic leakage in gastric cancer patients undergoing gastrectomy.

Effect of Substitutional Oxygen on Properties of Ti3 C2 Tx MXene Produced Using Recycled TiO2 Source.

MXenes are an emerging class of 2D materials with unique properties including metallic conductivity, mechanical flexibility, and surface tunability, which ensure their utility for diverse applications. However, the synthesis of MXenes with high crystallinity and atomic stoichiometry in a low-cost process is still challenging because of the difficulty in controlling the oxygen substitute in the precursors and final products of MXenes, which limits their academic understanding and practical applications. Here, a novel cost-effective method is reported to synthesize a highly crystalline and stoichiometric Ti3 C2 Tx MXene with minimum substitutional oxygen impurities by controlling the amount of excess carbon and time of high-energy milling in carbothermal reduction of recycled TiO2 source. The highest used content (2 wt%) of excess-carbon yields TiC with the highest carbon content and minimal oxygen substitutes, which leads to the Ti3 AlC2 MAX phase with improved crystallinity and atomic stoichiometry, and finally Ti3 C2 Tx MXene with the highest electrical conductivity (11738 S cm-1 ) and superior electromagnetic shielding effectiveness. Additionally, the effects of carbon content and substitutional oxygen on the physical properties of TiC and Ti3 AlC2 are elucidated by density-functional-theory calculations. This inexpensive TiO2 -based method of synthesizing high-quality Ti3 C2 Tx MXene can facilitate large-scale production and thus accelerate global research on MXenes.

A hollow CuS@Mn(OH)2 particle with double-shell structure for Ultra-wide band electromagnetic absorption.

Hollow materials have many advantages when acting as electromagnetic wave (EMW) absorber, such as excellent impedance matching properties, rich micro-interfaces and light weight. In this work, a novel hollow particle with double-shell composed with CuS and Mn(OH)2 is synthesized by coordination etching, precipitation and sulfuration using tetrakaidecahedral Cu2O as template. These hollow particles are expected to be used as improved EMW absorption property at an ultra-wide band. In this hollow particle, tetrakaidecaheral CuS acts as inner shell and Mn(OH)2 acted as outer shell, thus having rich heterogeneous interfaces which induce strong interfacial polarization. Moreover, the lower electrical conductivity and loose structure of the Mn(OH)2 shell facilitates the entry of EMW into the absorbers, and the hollow structure in this particle is beneficial to improve the impedance matching according to Maxwell-Garnett (MG) theory. Therefore, hollow CuS@Mn(OH)2 particles with double-shell exhibit excellent EMW absorption performance. The effective absorption bandwidth (reflection loss (RL) ≤ -10 dB) is 6.88 GHz (from 11.12 GHz to 18 GHz) at 2.3 mm thickness of sample.

Texture Regulation of Metal-Organic Frameworks, Microwave Absorption Mechanism-Oriented Structural Optimization and Design Perspectives.

Texture regulation of metal-organic frameworks (MOFs) is essential for controlling their electromagnetic wave (EMW) absorption properties. This review systematically summarizes the recent advancements in texture regulation strategies for MOFs, including etching and exchange of central ions, etching and exchange of ligands, chemically induced self-assembly, and MOF-on-MOF heterostructure design. Additionally, the EMW absorption mechanisms in approaches based on structure-function dependencies, including nano-micro topological engineering, defect engineering, interface engineering, and hybrid engineering, are comprehensively explored. Finally, current challenges and future research orientation are proposed. This review aims to provide new perspectives for designing MOF-derived EMW-absorption materials to achieve essential breakthroughs in mechanistic investigations in this promising field.