Efficient Production of Graphene through a Partially Frozen Suspension Exfoliation Process: An Insight into the Enhanced Interaction Based on Solid-Solid Interfaces.

Liquid phase exfoliation (LPE) offers a promising path for scalable graphene production, but struggles with high energy consumption and low yield, with over 99.99% of the input energy wasted. Here, we present an energy-efficient approach for producing graphene via partially frozen-suspension exfoliation (PFE). As opposed to traditional liquid-solid interfaces, the solid-solid interface enhances shear strength between the frozen solvent and graphite from about 40 N m-2 to 105 N m-2. Additionally, the suspension flow transitions from turbulent to laminar, aligning graphite parallel to the flow direction and conducive to the effective utilization of shear force. Compared to conventional liquid-phase exfoliation (LPE), PFE improves energy efficiency by 102∼103 times. Furthermore, a production rate of 5 g h-1 has been achieved in a 10 L tank at an ultralow shear rate of 3 × 102 s-1.

Predictive value of thromboelastography for postoperative lower extremity deep venous thrombosis in gastric cancer complicated with portal hypertension patients.

BACKGROUND: To explore the predictive value of thromboelastography (TEG) for the occurrence of lower extremity deep venous thrombosis (LDVT) in gastric cancer combined with portal hypertension patients after operation. METHODS: 172 gastric cancer patients combined with portal hypertension were randomly divided into laparoscopic surgery or laparotomy groups. All patients were taken venous blood on an empty stomach 1 day before operation, 1 day, 3 days, and 5 days after operation. RESULTS: There was no significant difference in R value, K value, α angle, and MA before and after operation (P > .05). Compared with the same group before operation, the R value and K value were decreased at 1, 3, and 5 days after operation, while the α angle and MA were increased (P < .05). Compared with the non-LDVT group, the postoperative R value and K value in the LDVT group were significantly lower, while the α angle and MA were significantly higher (P < .05). The AUC of R value, K value, α angle, and MA levels at 3 days after surgery to identify patients with LDVT was 0.778, 0.718, 0.881, and 0.781, respectively. The estimated probability of the final model for LDVT was 0.622. Compared with the estimated probability ≥0.622 group, the LDVT rate in the estimated probability <0.622 group was significantly increased (χ2 = 60.128, P < .001). CONCLUSIONS: The combination of R value, K value, α angle, and MA at 3 days after surgery has a moderately effective predictive effect for the occurrence of LDVT in gastric cancer patients combined with portal hypertension.

Ultralight reduced graphene oxide aerogels prepared by cation-assisted strategy for excellent electromagnetic wave absorption.

In this work, to maximize the unique attributes of reduced graphene oxide (RGO) for excellent microwave absorption, the ultralight RGO aerogels with improved dispersion and interface polarization performance were fabricated via a facile cation-assisted hydrothermal treatment process. The prepared RGO/paraffin composite exhibits excellent microwave absorption (MA) performance in a wideband frequency range of 8.0 ∼ 18.0 GHz with an ultralow absorbent content of 0.5 wt.%. Such performance is comparable with most previously reported results on RGO-based composites but required much higher absorbent content. The mechanisms for the enhancement of polarization relaxation loss and conductive loss were investigated in detail. This study provides a promising and facile method for preparing RGO-based excellent microwave absorption materials with ultra-low filler content, which is significant for designing efficient MA absorbers.

Heterogeneous iron-nickel compound/RGO composites with tunable microwave absorption frequency and ultralow filler loading.

We fabricated heterogeneous iron-nickel compound/reduced graphene oxide (RGO) composites to obtain lightweight and high-efficiency microwave absorption materials with tunable absorption frequency. Using a facile hydrothermal route in combination with calcination at varying temperatures of 500-700 °C, the magnetic components Fe0.64Ni0.36, Fe0.64Ni0.36@Fe2Ni2N, and Fe2Ni2N were obtained. Due to strong interfacial polarization and dipole polarization as well as the conductive network formed by the substantial number of interfaces, all the magnetic RGO hybrids presented remarkable electromagnetic wave attenuation ability even when the filler content was only 5.2 wt%. More importantly, the optimization of reflection loss and tunable absorption frequency could be successfully realized by tuning the hybrid architecture and electromagnetic properties. This work reveals the mechanism of polarization-related dielectric relaxation of RGO, which provides new opportunities for designing lightweight and highly efficient microwave-absorbing materials by fully utilizing the hetero-interfacial effects.

Preparation of Cellulose/Graphene Oxide Composite Membranes and Their Application in Removing Organic Contaminants in Wastewater.

Cellulose/graphene oxide composite membranes (CGCMs) were prepared using a vacuum-filtration method. The CGCMs were then used as filters to remove organic pollutants from wastewater. It was found that the CGCM filters could efficiently and simultaneously achieve wastewater treatment and adsorbent separation. Their adsorption of Rhodamine B (RhB, an organic dye) varied with varying cellulose/graphene oxide mass ratios. The CGCM obtained at a cellulose/graphene oxide mass ratio of 8:1 exhibited the maximum removal efficiency for RhB. The maximum adsorption capacity of the CGCMs for RhB was found to be 86.4 mg/g. In addition, the CGCMs were easily regenerated and the regenerated CGCMs retained good abilities to remove contaminants, which could be significant for their application in wastewater treatment.

Interface Engineering of Titanium Nitride Nanotube Composites for Excellent Microwave Absorption at Elevated Temperature.

Currently, the microwave absorbers usually suffer dreadful electromagnetic wave absorption (EMWA) performance damping at elevated temperature due to impedance mismatching induced by increased conduction loss. Consequently, the development of high-performance EMWA materials with good impedance matching and strong loss ability in wide temperature spectrum has emerged as a top priority. Herein, due to the high melting point, good electrical conductivity, excellent environmental stability, EM coupling effect, and abundant interfaces of titanium nitride (TiN) nanotubes, they were designed based on the controlling kinetic diffusion procedure and Ostwald ripening process. Benefiting from boosted heterogeneous interfaces between TiN nanotubes and polydimethylsiloxane (PDMS), enhanced polarization loss relaxations were created, which could not only improve the depletion efficiency of EMWA, but also contribute to the optimized impedance matching at elevated temperature. Therefore, the TiN nanotubes/PDMS composite showed excellent EMWA performances at varied temperature (298-573 K), while achieved an effective absorption bandwidth (EAB) value of 3.23 GHz and a minimum reflection loss (RLmin) value of - 44.15 dB at 423 K. This study not only clarifies the relationship between dielectric loss capacity (conduction loss and polarization loss) and temperature, but also breaks new ground for EM absorbers in wide temperature spectrum based on interface engineering.

Effects of Adipose Plasma Transfusion Compared with Normal Plasma Transfusion on Adverse Transfusion Reactions, Important Functional Indicators, and Clinical Safety in Patients with Parenteral Nutrition: Based on a Retrospective Cohort Study.

Objective: Based on a retrospective cohort study, the study aims to investigate the effects of adipose plasma transfusion compared with normal plasma transfusion on adverse transfusion reactions, important functional indicators, and clinical safety in patients with parenteral nutrition (PN). Methods: One hundred and twenty inpatients who needed PN and plasma transfusion in Xianning Central Hospital from September 1, 2021, to March 31, 2022, were enrolled as the actual application verification cases. All the patients in the group noticed the informed consent form, and the normal plasma transfusion was set as the control group (n = 40), and the fat plasma transfusion was set as the study group. Mild adipose plasma transfusion was adopted in study group ① and moderate adipose plasma transfusion was used in study group ②, 40 cases in each group. The blood routine tests, blood lipids, blood coagulation, liver function tests, and the incidence of adverse reactions of blood transfusion were compared. Results: The comparison results of platelet count, red blood cell count, hemoglobin, and hematocrit among the three groups are as follows: study group ②> study group ①> control group (P < 0.05).The levels of blood lipids in the three groups, triglyceride, total cholesterol, high density lipoprotein, and low density lipoprotein were compared in group ②>group ①>control group (P < 0.05).The liver function tests indexes of the three groups were compared: ALT, AST, LDH: study ②study ①>control group. Regarding the incidence of adverse transfusion reactions, the incidence of adverse transfusion reactions in the study group was lower than in the control group (P < 0.05). Conclusion: Compared with normal plasma transfusion, the inpatients who need PN and plasma transfusion can effectively use the scrapped mild and moderate fatty plasma and reduce the plasma scrap rate. In the meantime, it has little effect on the function of the important indexes of the patients, and the incidence of adverse reactions of blood transfusion is low and the safety is high. Infusion of adipose plasma can also improve the effective individual and rational utilization of blood products. Trial registration: This trial is registered with chiCTR220005918.

Efficient and scalable high-quality graphene nanodot fabrication through confined lattice plane electrochemical exfoliation.

Reported is a confined lattice plane electrochemical exfoliation method that exploits the electrochemical reaction of face (basal) or side (edge) planes of highly oriented pyrolytic graphite (HOPG) while other planes are blocked using wax, based on the anisotropy of HOPG for efficient and effective fabrication of graphene nanodots with uniform size distribution.

Preparation of Graphene Sheets by Electrochemical Exfoliation of Graphite in Confined Space and Their Application in Transparent Conductive Films.

A novel electrochemical exfoliation mode was established to prepare graphene sheets efficiently with potential applications in transparent conductive films. The graphite electrode was coated with paraffin to keep the electrochemical exfoliation in confined space in the presence of concentrated sodium hydroxide as the electrolyte, yielding ∼100% low-defect (the D band to G band intensity ratio, ID/IG = 0.26) graphene sheets. Furthermore, ozone was first detected with ozone test strips, and the effect of ozone on the exfoliation of graphite foil and the microstructure of the as-prepared graphene sheets was investigated. Findings indicate that upon applying a low voltage (3 V) on the graphite foil partially coated with paraffin wax that the coating can prevent the insufficiently intercalated graphite sheets from prematurely peeling off from the graphite electrode thereby affording few-layer (<5 layers) holey graphene sheets in a yield of as much as 60%. Besides, the ozone generated during the electrochemical exfoliation process plays a crucial role in the exfoliation of graphite, and the amount of defect in the as-prepared graphene sheets is dependent on electrolytic potential and electrode distance. Moreover, the graphene-based transparent conductive films prepared by simple modified vacuum filtration exhibit an excellent transparency and a low sheet resistance after being treated with NH4NO3 and annealing (∼1.21 kΩ/□ at ∼72.4% transmittance).

Efficient and Lightweight Electromagnetic Wave Absorber Derived from Metal Organic Framework-Encapsulated Cobalt Nanoparticles.

Porous-carbon-based nanocomposites are gaining tremendous interest because of good compatibility, lightweight, and strong electromagnetic wave absorption. However, it is still a great challenge to design and synthesize porous-carbon-based composites with strong absorption capability and broad frequency bandwidth. Herein, a facile and effective method was developed to synthesize Co magnetic nanoparticles/metal organic framework (MOF) (Co NPs/ZIF-67) nanocomposites. Co NPs/porous C composites were subsequently obtained by annealing Co NPs/ZIF-67 nanocomposites at different temperatures under an inert atmosphere. The carbonized nanocomposites showed highly efficient electromagnetic wave absorption capability. Specifically, the optimal composite (i.e., Co/C-700) possessed a maximum reflection loss (RL) value of -30.31 dB at 11.03 GHz with an effective absorption bandwidth (RL ≤ -10 dB) of 4.93 GHz. The electromagnetic parameters and the absorption performance of the composites are readily tunable by adjusting the carbonization temperature and the concentration of Co NPs in the composites. Because of the combination of good impedance matching, dual-loss mechanism, and the synergistic effect between Co NPs and porous carbon composites, these Co NPs/MOF-derived composites are attractive candidates for electromagnetic wave absorbers.

Unique Static Magnetic and Dynamic Electromagnetic Behaviors in Titanium Nitride/Carbon Composites Driven by Defect Engineering.

Recently, the defect-induced static magnetic behaviours of nanomaterials have been a cutting-edge issue in diluted magnetic semiconductor materials. However, the dynamic magnetic properties of nanomaterials are commonly ignored if their bulk counterparts are non-magnetic. In the present research, titanium nitride-carbon (TiN/C) nanocomposites were found to exhibit both static and dynamic magnetic properties that vary in the opposite trend. Moreover, novel unconventional electromagnetic resonance behaviour was demonstrated in TiN/C systems, and their permeability and permittivity show similar trend. This is challenging for the traditional understanding of electromagnetism and makes it possible to achieve an appropriate balance between the permeability and permittivity simultaneously in a simple system. Hopefully, the results could provide some valuable clues to revealing the magnetism and electromagnetism of nanostructures.

Integrated analysis reveals that STAT3 is central to the crosstalk between HER/ErbB receptor signaling pathways in human mammary epithelial cells.

Human epidermal growth factor receptors (HER, also known as ErbB) drive cellular proliferation, pro-survival and stress responses by activating several downstream kinases, in particular ERK, p38 MAPK, JNK (SAPK), the PI3K/AKT, as well as various transcriptional regulators such as STAT3. When co-expressed, the first three members of HER family (HER1-3) can form homo- and hetero-dimers, and there is considerable evidence suggesting that the receptor dimers differentially activate intracellular signaling pathways. To better understand the interactions in this system, we pursued multi-factorial experiments where HER dimerization patterns and signaling pathways were rationally perturbed. We measured the activation of HER1-3 receptors and of the sentinel signaling proteins ERK, AKT, p38 MAPK, JNK, STAT3 as a function of time in a panel of human mammary epithelial (HME) cells expressing different levels of HER1-3 stimulated with various ligand combinations. We hypothesized that the HER dimerization pattern is a better predictor of downstream signaling than the total receptor activation levels. We validated this hypothesis using a combination of model-based analysis to quantify the HER dimerization patterns, and by clustering the activation data in multiple ways to confirm that the HER receptor dimer is a better predictor of the signaling through p38 MAPK, ERK and AKT pathways than the total HER receptor expression and activation levels. We then pursued combinatorial inhibition studies to identify the causal regulatory interactions between sentinel signaling proteins. Quantitative analysis of the collected data using the modular response analysis (MRA) and its Bayesian Variable Selection Algorithm (BVSA) version allowed us to obtain a consensus regulatory interaction model, which revealed that STAT3 occupies a central role in the crosstalk between the studied pathways in HME cells. Results of the BVSA/MRA and cluster analysis were in agreement with each other.

VEGF treatment induces signaling pathways that regulate both actin polymerization and depolymerization.

The angiogenic growth factor vascular endothelial growth factor (VEGF) enhances endothelial cell migration through the activation of multiple signaling transduction pathways. Actin reorganization is an important component in VEGF-induced migration, yet the signaling pathways mediating this process remain unclear. Actin reorganization involves both actin polymerization and depolymerization, and in this study we demonstrate that VEGF-treatment regulates both of these activities. With respect to actin polymerization, our results indicate that the actin nucleation promoting factors (NPF) neural Wiskott-Aldrich syndrome protein (N-WASP) binds the SH2- plus SH3-domain containing adaptor protein Nck in both control and VEGF-treated cells. We had previously showed that VEGF treatment leads to the recruitment of Nck to activated receptor, and our current results indicate a VEGF-dependent redistribution of N-WASP to the cell surface. A Nck dominant-negative blocked Nck recruitment to receptor, blocked N-WASP cellular redistribution and attenuated actin stress fiber formation. With respect to actin depolymerization, VEGF-treatment led to the rapid phosphorylation of the actin depolymerization factor cofilin, and its upstream regulator, LIM-kinase (LIMK). Unlike what is observed in certain other cell types, the p21-activated kinase (PAK), a Nck binding protein, does not mediate VEGF-induced LIMK phosphorylation, as a PAK dominant-negative had no effect on this activity. The PAK dominant-negative also did not affect VEGF-induced actin reorganization. Pharmacological inhibitors of phosphoinositide-3 kinase (PI3-K) and the rho-activated kinase (ROCK) attenuated VEGF-induced LIMK phosphorylation, indicating a role for (PI3-K) and ROCK in the signaling pathways leading to regulation of LIMK activity.

Nck and Crk mediate distinct VEGF-induced signaling pathways that serve overlapping functions in focal adhesion turnover and integrin activation.

We have asked whether the Nck and Crk adaptor proteins play important roles in the vascular endothelial growth factor (VEGF)-induced signaling pathways that lead to an enhancement in cell migration. The introduction into human umbilical vein endothelial cells of a dominant-negative inhibitor for either Nck or Crk blocked the recruitment of both endogenous proteins to the KDR VEGF receptor subtype indicating that both proteins are recruited to the same docking site. The Nck and Crk dominant-negatives led to the formation of abnormally large focal adhesion, blocked VEGF-induced integrin activation, and blocked VEGF-induced actin dynamics. The dominant-negatives had no effects on these properties in cells expressing constitutively active Rac1 or RhoA. Since a DN to either Nck or Crk blocks the cellular responses mediated by both proteins, we performed experiments directed at clarifying signaling pathways specifically mediated by each protein. Inhibition of the interaction between Nck with its downstream effector PAK led to abnormally large focal adhesions, but had no effect on integrin activation or cell adhesiveness. Evidence is presented that Crk complexes with C3G in control cells, and VEGF treatment leads to the recruitment of the complex to the cell surface. Inhibition of the C3G downstream effector Rap1 leads to enlarged focal adhesions and blocks VEGF-induced integrin activation. We conclude that Nck and Crk mediate distinct VEGF-induced signaling pathways that serve overlapping functions in cell migration.