Search

Realizing high-efficiency solar-driven CO2 reduction to chemicals and fuels requires high-performance photocatalysts with high utilization efficiency of solar light, efficient charge separation and transfer, and robust adsorption capacity for CO2. In this work, a tubular In2O3-C/CdIn2S4 (IOC/CIS) ternary heterojunction with an intimate interfacial contact was fabricated by pyrolysis of In-MIL-68 and subsequent solvothermal synthesis of CdIn2S4. The construction of a heterojunction promotes the separation and transfer efficiency of photogenerated carriers. The introduction of carbon not only accelerates the interfacial charge migration but also enhances light absorption and CO2 adsorption. The resulting 5IOC/CIS sample presents a remarkably improved photocatalytic CO2 reduction activity with a CO generation rate of 2432 μmol g-1 h-1, much higher than that of the In2O3/CdIn2S4 (IO/CIS) heterojunction (1906 μmol g-1 h-1). Furthermore, the type II charge transfer mechanism of the heterojunction was confirmed by the electron paramagnetic resonance characterization. This work provides new insight into the design and preparation of a highly efficient hollow heterojunction for photocatalytic applications.

The homogeneous dispersion of graphene oxide (GO) in cementitious materials is critical to achieve its unique properties. In this study, based on the formation kinetic of GO aggregation and the pro...

BACKGROUND: Graphene oxide (GO) has abundant oxygen‐containing functionalities such as hydroxyl groups and carboxyl groups with distinct acidities. This feature makes GO a potential solid acid catalyst for the acid‐catalyzed reactions such as the production of ethyl levulinate (EL), a platform chemical, from the acid‐treatment of furfuryl alcohol (FA). The structure and functionalities of GO are closely related to its catalytic performance, and thus it is necessary to establish the relationship between the chemical structure and the catalytic properties of GO. To achieve this aim, in this work, the GO catalysts were designed by a facile one‐pot synthetic route with no subsequent modification. By controlling the parameters of oxidation process in preparation, multiple functional groups were immobilized onto graphitic substrate, significantly impacting the catalytic activity of GO in the conversion of FA to EL in an ethanol (EtOH) medium. RESULTS: The results showed that, the oxidation process significantly influenced the distribution of oxygen‐containing functionalities on the surface of GO. The amount of the oxygen‐containing functionalities can be adjusted by the oxidation parameters such as oxidizing agent equivalent, reaction time and temperature, while the organosulfate can only be remained at a moderate oxidation temperature. The existence of the synergistic effect between the oxygen‐containing functionalities and the organosulfate functionalities promoted the catalytic activity of GO for the acid‐catalyzed conversion of FA to EL. CONCLUSIONS: This work provides a new strategy of design and development of functional graphene‐based catalysts for the acid‐catalyzed reactions, and lays foundation of the practicability of GO in biomass conversion. © 2019 Society of Chemical Industry

The research on the cement hydration with graphene oxide (GO) can provide a guidance for designing GO-modified cement-based materials. Ye’elimite is the dominant mineralogical phase in calcium sulfoaluminate cement. However, an in-depth understanding of GO on the hydration behavior of ye’elimite is still lacking. Here, we demonstrate the influences of GO on the hydration process and products of ye’elimite. Firstly, GO was successfully coated on the surface of ye’elimite and then the hydration development of ye’elimite was investigated by iso-thermal calorimetry and X-ray diffraction. The results revealed that the hydration time of ye’elimite moved up at first and delayed later with the increasing amounts of GO. The addition of GO could enhance the hydration degree of ye’elimite and promote the formation of monosulfate. The complexation effect of Ca2+ and –COOH group played a negative role in the formation of ettringite. This study provides a promising way for employing GO to regulate the hydration of ye’elimite.

The primary objective of this study is to predict the short-term demand of free-floating bike sharing (FFBS) using deep learning approach. The FFBS trip data in Shanghai city are collected from the Mobike Company. Other datasets such as weather data and air quality data are also collected. The spatiotemporal patterns of FFBS demand indicates that the weekday rides exhibit an obvious commuting pattern while the weekend rides are usually involved with various trip purposes. Then, a hybrid deep learning neural network (HDL-net) is developed to predict the short-term FFBS demand for different time intervals including 15, 20 and 30 min. The proposed HDL-net exhibits better performance on morning peak than the evening peak and non-peak hours for all the three time intervals. Moreover, five benchmark methods are also used to compare with the proposed HDL-net. The results suggest that the proposed hybrid deep learning framework outperform the benchmarks in the prediction performance for all three time intervals. The results of this study could provide insightful suggestions for transportation authorities to develop effective rebalancing strategies and bike lanes planning schemes to promote the service level of cycling in an urban city.

Iron (Fe)- and nitrogen (N)-codoped carbon materials hold broad application prospects in the oxygen reduction reaction (ORR) because of their abundant reserves, low cost, and excellent catalytic activity. In this study, a N-doped carbon nanotube (CNT)–graphene framework with encapsulated Fe/Fe3N nanoparticles (Fe–N–CNT@RGO) is designed and synthesized by annealing a mixture of iron acetylacetonate, dicyandiamide, and graphene oxide via a one-step calcination strategy. Fe–N–CNT@RGO has a better ORR catalytic activity than reduced graphene oxide (RGO), N-doped graphene, and N-doped CNTs with encapsulated Fe/Fe3N nanoparticles with respect to the onset potential, limiting current density, and kinetic current density. Fe–N–CNT@RGO also has high stability and a high discharging cell voltage, which approaches those of platinum/carbon in zinc–air batteries. The relationship between the structure and activity of Fe–N–CNT@RGO demonstrates that the high density of Fe–N and pyridinic N sites, moderate wettability, a...

The trajectory of tethered underwater robot is usually controlled by actuating the rotating speeds of control propellers attached to the robot and/or adjusting the length of umbilical cable. When the trajectory control problem of a tethered underwater robot is studied, it is necessary to couple the main body of underwater robot, umbilical cable and control propellers together forming an integrated hydrodynamic model so that the robot is in a comprehensive dynamic equilibrium condition, suitable control algorithms are then jointed into the hydrodynamic model constructing a hydrodynamic and control model for the tethered underwater robot system. Only in this way the hydrodynamic and control nature of a tethered underwater robot during different kinds of control manipulations can be numerically revealed objectively. In this paper, a hydrodynamic and control model to simulate the trajectory following control of a tethered underwater robot system is proposed, and the hydrodynamic performances of the robot and the umbilical cable are observed. To achieve this goal, three-dimensional hydrodynamic model of tethered underwater robot system is first introduced, feed-forward control technique for adjusting the length of umbilical cable and incremental PID algorithm for regulating the rotating speeds of propellers are then incorporated into the hydrodynamic model forming the hydrodynamic and control model. Based on the established hydrodynamic and control mode, relationships between the thrusts from the propellers and the rotating speeds of the propellers, and those among the trajectory following of the underwater robot and the control actions of adjusting the length of umbilical cable and governing the rotating speeds of the propellers are analyzed, and also the hydrodynamic performances of the tethered underwater robot system under the control manipulation are observed. In the research, the amplitude limit filtering method is applied in solving the governing equations of the umbilical cable, this technique is applied to avoid the chattering effect in the cable tension computation, so that a successive and stable computation process is maintained. The main factors affecting the singular nature of coefficient matrices during the numerical solutions of the proposed model are also investigated in the paper.

Objective. Systematically evaluate the efficacy of physical ablation combined with TKI in the treatment of advanced non-small cell lung cancer (NSCLC). Methods. We performed a comprehensive search of databases including OVID, PubMed, EMBASE, the Cochrane Library, and three Chinese databases (China National Knowledge Infrastructure, Wanfang Database, and Chongqing Weipu Database). The aim was to identify randomized controlled trials (RCT) investigating physical ablation as the treatment for advanced NSCLC. We also evaluated the methodological quality of the included studies and summarized the data extracted for meta-analysis with Review Manager 5.3. Results. A total of 9 studies, including 752 patients, were evaluable. The meta-analysis results show that the complete response rate (CRR) (RR: 2.23, 95% CI: 1. 46 to 3.40, P 0.01), partial response rate (PRR) (RR: −2.25, 95% CI: 1.41 to 3.59, P 0.01), and disease control rate (DCR) (RR: −2.80, 95% CI: 1.64 to 4.80, P < 0.01) of patients with advanced NSCLC who received physical ablation combined with TKI therapy were higher than those who did not receive physical ablation therapy. The control groups from seven of the studies had a total of 606 patients with targeted therapies and chemotherapy. The complete response rate was (CRR) (RR: 2.48, 2.4895% CI: 1.55 to 2.47, P 0.01), partial response rate (PRR) (RR: −1.66, 95% CI: 1.20 to 2.31, P < 0.01), and disease control rate (DCR) (RR: −2.68, 95% CI: 1.41 to 5.06, P < 0.01) for patients with advanced NSCLC who had received physical ablation combined with targeted therapies and chemotherapy, compared to patients who had not received physical ablation therapy. This difference was statistically significant. Above all, these results showed that the clinical efficacy of physical ablation combined EGFR-TKIs therapy (regardless of whether it was combined with chemotherapy) was better than that of EGFR-TKIs therapy alone. Conclusion. Physical ablation combined with TKI treatment in patients with advanced NSCLC can improve efficacy.

With unique 2D nanostructures and excellent properties, graphene and its derivatives are a class of advanced nanosized reinforcements for cementitious materials. Sulfonated graphene (SG), one of the most important modified graphene materials, possesses sulfonate groups on the surface and significantly improves the mechanical and thermal properties of cement-based composites. It is important to investigate the influence of SG on cement-based materials as it is a prerequisite for practical applications. Herein, SG was prepared and introduced into cement paste to investigate its influence on the rheological properties of cement paste. With the increased addition of SG, a stable slurry was gradually obtained with low fluidity and high rheological parameters. The mechanism of the SG effect on the rheological properties of cement paste was also illustrated. Because of the high specific surface area and sulfonate groups of SG nanosheets, a large amount of flocculated structure was created by the complexing effect, chemical interaction, physical interaction and mechanical interlocking between SG and hydrated/unhydrated cement particles. Furthermore, polycarboxylate ether (PCE) superplasticizer was introduced to ensure fluidity and transportability in the practical application of SG. The results in this work lay a foundation for the practical application of modified graphene in cementitious materials.

Recently, carbon dots (CDs) have received much attention in light-emitting applications owing to their low cost, non-toxicity and favorable fluorescence. In view of the aggregation-induced quenching effect and poor thermal stability of CDs, the development of a simple and high-efficiency strategy for solving these tough issues and improving the practicality of CDs is urgently necessary. Herein, a CD doped boehmite composite (CDs@AlOOH) is directly achieved through a facile one-step decomposition route. The uniform dispersion of CDs in AlOOH effectively alleviates the adverse self-quenching effect of CDs and gives rise to a tunable fluorescence feature of the composite. The N doping and energy transfer between CDs and AlOOH are beneficial for the photoluminescence (PL) enhancement of CDs@AlOOH. Meanwhile, CDs@AlOOH has outstanding long-term thermal stability, and maintains 98%, 90% and 80% of the initial PL performance after air heating treatment at 150 °C for 100 h, 250 h and 500 h, respectively. Moreover, the white lighting application is also demonstrated by combining CDs@AlOOH samples and commercial UV/blue light-emitting diodes (LEDs) without other phosphors. What is discussed in this study might offer some inspiration for dealing with the bottleneck problems of CDs in practical lighting and display fields.

Venous thromboembolism (VTE) is a relatively frequent complication in hospitalized patients, especially in those with risk factors. The benefit of using direct oral anticoagulants (DOACs) for prevention is controversial. This systematic review was performed as part of the American Society of Hematology (ASH) guidelines on VTE, developed in partnership with McMaster University. MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, and Epistemonikos were used as data sources from date of inception to November 2019. We included randomized trials in patients hospitalized for an acute medical disease, evaluating any DOACs vs other pharmacological prophylaxis, and included 3 trials with low risk of bias. We analyzed the effects of DOACs vs low-molecular-weight heparins (LMWHs) at 2 different time points: at the end of the short-term treatment phase (both drugs given for the same period of time) and at the end of the extended prophylaxis period (extended DOACs vs a shorter course of LMWHs). We observed that the use of DOACs did not reduce the risk of pulmonary embolism or symptomatic deep venous thrombosis (DVT) in comparison with LMWHs. However, the risk of major bleeding was slightly increased. Additionally, we observed that the benefit of DOACs previously reported was largely based on the reduction of asymptomatic DVT and was not apparent when only symptomatic events were considered. The use of DOACs in hospitalized medical patients slightly increases the risk of major bleeding with no appreciable benefit over LMWHs.

Thrombolytic therapy might reduce venous thromboembolism-related mortality and morbidity, but it could also increase the risk of major bleeding. We systematically reviewed the literature to evaluate the effectiveness and safety of thrombolytics in patients with pulmonary embolism (PE) and/or deep venous thrombosis (DVT). We searched Medline, Embase, and Cochrane databases for relevant randomized controlled trials up to February 2019. Multiple investigators independently screened and collected data. We included 45 studies (4740 participants). Pooled estimates of PE studies indicate probable reduction in mortality with thrombolysis (risk ratio [RR], 0.61; 95% confidence interval [CI], 0.40-0.94) (moderate certainty) and possible reduction in nonfatal PE recurrence (RR, 0.56; 95% CI, 0.35-0.89) (low certainty). Pooled estimates of DVT studies indicate the possible absence of effects on mortality (RR, 0.77; 95% CI, 0.26-2.28) (low certainty) and recurrent DVT (RR, 0.99; 95% CI, 0.56-1.76) (low certainty), but possible reduction in postthrombotic syndrome (PTS) with thrombolytics (RR, 0.70; 95% CI, 0.59-0.83) (low certainty). Pooled estimates of the complete body of evidence indicate increases in major bleeding (RR, 1.89; 95% CI, 1.46-2.46) (high certainty) and a probable increase in intracranial bleeding (RR, 3.17; 95% CI 1.19-8.41) (moderate certainty) with thrombolytics. Our findings indicate that thrombolytics probably reduce mortality in patients with submassive- or intermediate-risk PE and may reduce PTS in patients with proximal DVT at the expense of a significant increase in major bleeding. Because the balance between benefits and harms is profoundly influenced by the baseline risks of critical outcomes, stakeholders involved in decision making would need to weigh these effects to define which clinical scenarios merit the use of thrombolytics. ispartof: BLOOD ADVANCES vol:4 issue:7 pages:1539-1553 ispartof: location:United States status: published

This paper presents a "cooperative vehicle sorting" strategy that seeks to optimally sort connected and automated vehicles (CAVs) in a multi-lane platoon to reach an ideally organized platoon. In the proposed method, a CAV platoon is firstly discretized into a grid system, where a CAV moves from one cell to another in the discrete time-space domain. Then, the cooperative sorting problem is modeled as a path-finding problem in the graphic domain. The problem is solved by the deterministic Astar algorithm with a stepwise strategy, where only one vehicle can move within a movement step. The resultant shortest path is further optimized with an integer linear programming algorithm to minimize the sorting time by allowing multiple movements within a step. To improve the algorithm running time and address multiple shortest paths, a distributed stochastic Astar algorithm (DSA) is developed by introducing random disturbances to the edge costs to break uniform paths (with equal path cost). Numerical experiments are conducted to demonstrate the effectiveness of the proposed DSA method. The results report shorter sorting time and significantly improved algorithm running time due to the use of DSA. In addition, we find that the optimization performance can be further improved by increasing the number of processes in the distributed computing system., 56 pages, 19 figures

MicroRNAs (miRNAs) have been demonstrated to be essential regulators in the development and progression of various cancers. The role of miR-188-5p in gastric cancer (GC) has not been determined. In this study, we found that the expression of miR-188-5p was downregulated in GC tissues compared with adjacent normal tissues. The lowly expressed miR-188-5p was significantly associated with lymph node metastasis and advanced TNM stage. Moreover, overexpression of miR-188-5p significantly inhibited GC cell proliferation, migration, and invasion but promoted cellular apoptosis. Mechanistically, we identified transcription factor ZFP91 as a target gene of miR-188-5p in GC. We found that miR-188-5p overexpression significantly inhibited the expression of ZFP91 in GC cell lines. There was an inverse correlation between the expression of miR-188-5p and ZFP91 in GC tissues. We found that restoration of ZFP91 in miR-188-5p-overexpressed MGC-803 and SGC-7901 cells promoted cell proliferation, migration, and invasion. Finally, we also showed that overexpression of miR-188-5p inhibited tumor growth in vivo. Taken together, our findings indicated that miR-188-5p serves as a tumor suppressor in human GC by targeting ZFP91, suggesting that miR-188-5p might be a promising therapeutic target for GC treatment.

RGO (reduced graphene oxide)-Fe3O4 nanohybrids were successfully synthesized by a solvothermal reduction method. Fe3O4 nanoparticles, RGO and the nanohybrids were characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Raman spectroscopy and vibrating sample magnetometer (VSM). The electromagnetic interference (EMI) shielding effectiveness (SE) of RGO-Fe3O4/SF/PP composite was much higher than that of Fe3O4/SF/PP composite at 8-12 GHz, which was attributed to synergistic effect between RGO and Fe3O4 nanoparticles. The EMI SE (%) improved with the increase of RGO-Fe3O4 content and the maximum value of 80.44% was obtained for the RGO-Fe3O4/SF/PP composite. Furthermore, the dominant shielding mechanism of RGO-Fe3O4/SF/PP was absorption.

Ideal electromagnetic absorbing materials with lightweight and high efficiency have broad application outlook in military and civil fields. In this work, a 3D nanostructure material by hybridizing Fe 3 O 4 nanocrystals and reduced graphene oxide (Fe 3 O 4 /rGO) were synthesized through an environmental-friendly one-pot solvothermal method. The effect of GO loading on electromagnetic (EM) wave absorption characteristic of Fe 3 O 4 /rGO was investigated. The introduction of rGO sheets not only prevented Fe 3 O 4 from agglomerating, also improved the absorption performance of Fe 3 O 4 /rGO hybrids. With an appropriate addition, Fe 3 O 4 /rGO obtained a minimum reflection loss (RL) of −22.7 dB and the absorption bandwidth was 3.13 GHz (90% absorption).

Objectives: This study evaluates the efficacy of Chinese herbal medicines after percutaneous coronary intervention (PCI). Background: PCI is the primary treatment for coronary atherosclero...

Background. Whether traditional Chinese medicine preparation combined therapy can improve the efficacy of chemotherapy is controversial. This meta-analysis evaluates the efficacy of traditional Chinese medicine preparation combined with chemotherapy. Method. Three databases were searched from inception through August 2018. Eligible randomized controlled trials (RCTs) involving the combined treatment of chemotherapy and traditional Chinese medicine preparation compared to chemotherapy alone for treating cancer were retrieved. The methodological quality of the included RCTs was assessed with Cochrane Collaboration’s risk of bias assessment tool. Meta-analysis was adopted to make comprehensive comparisons between the experimental and control groups. Results. Four RCTs were included in this review, comprising 256 subjects. The majority of the RCTs were judged as being of poor methodological quality. Meta-analysis showed that the combination of traditional Chinese medicine preparation and chemotherapy appeared to be more effective than chemotherapy alone, for the treatment of cancer, as assessed by the disease control rate (RR: 1.41, 95% CI: 1.11 to 1.79) and the objective response rate (RR: 2.71, 95% CI: 1.28 to 5.77). There were no statistically significant differences between the groups in terms of bone marrow suppression (RR: 0.88, 95% CI: 0.57 to 1.37) or gastrointestinal reaction (RR: 1.12, 95% CI 0.75 to 1.69). Conclusions. Traditional Chinese medicine preparation combined with chemotherapy may improve objective response rates and disease control rates more than chemotherapy alone. The evidence that combined traditional Chinese medicine preparation can reduce the side effects of chemotherapy is insufficient. More rigorous randomized controlled trials are needed to confirm these conclusions.

Exercise may effectively reduce side effects caused by chemotherapy. However, no meta-analyses of exercise during or postchemotherapy for cancer patients have been definitely performed to guide clinical practice.To evaluate and summarize available scientific evidence to provide recommendations of an exercise intervention for cancer patients undergo chemotherapy.A systematic review and meta-analysis were performed with databases searching of MEDLINE, Cochrane Library, and Embase from their inception to October 15, 2017. Literature was selected to identify randomized controlled trials of exercise during or postchemotherapy for cancer patients. Risk-of-bias assessment was performed by two reviewers independently. Data were analyzed using the Cochrane Collaboration's RevMan 5.3 (Review Man, Copenhagen, Denmark).A total of 10 trials with 838 participants were included in our study. Exercise could have a beneficial effect in cancer patients undergo chemotherapy in the outcome of physical fitness (MD: 0.16, 95% CI: 0.08-0.25, p .01 and MD: 2.46, 95% CI: 1.44-3.47, p .01) and depression (MD: -1.36, 95% CI: -2.68 to -0.04, p = .04), but not in FACT-G, FACT-B, anxiety, weight, and BMI (all p .05). Exercise sequence (during or postchemotherapy) did not influence the effect of exercise for cancer patients undergo chemotherapy. In total, six studies were assessed as an overall low risk of bias. Subgroup analyses and sensitivity analyses reached results similar to those of the meta-analyses, which reflected our results were reliable and robust.Exercise seems to have a beneficial effect on physical fitness and depression, but not on quality of life, anxiety, weight, and BMI. More specific and detailed description of the implementation of exercise programs should be proposed in the future.

Nd:YAG crystal is one of the major gain media used in high-power solid-state laser systems. In this work, the single-line waveguides with Type Ⅰ modification have been fabricated in Nd:YAG crystal by femtosecond laser writing. The waveguides show good guiding properties in both TE and TM polarizations, which is different from the well-developed Type II structures. The high-resolution confocal micro-photoluminescence and micro-Raman spectra images obtained by scanning the cross-section of the track region certify a positive refractive-index change induced in femtosecond laser irradiated region. The fluorescence properties remain 82% in the waveguide region, which shows the potential for active photonic devices.

The direct femtosecond laser writing has been proved to be one of the most efficient techniques for micro-structuring of transparent materials, which can induce refractive index modifications to construct waveguide structures. In this work, laser-induced tracks with single-line configuration are formed inside the BK7 glass by using inscription of femtosecond laser pulses with 1 MHz repetition rate at wavelength of 1030 nm and 515 nm, respectively. The high-resolution confocal Raman spectra are obtained in the track regions to investigate the physical mechanisms of the modification. The results indicate that the specified regions inside the tracks induced by 1030-nm femtosecond laser expand and squeeze the adjacent area under certain writing conditions, leading to a refractive index increase in the core region. The 515-nm femtosecond laser brings out relatively more severe damage in comparison to the 1030-nm laser irradiation. A directional coupler structure has been fabricated by using the optimized writing parameters, showing a nearly balanced output with a ratio of 49.7:50.3 and an insertion loss of 1.36 dB for the single-line waveguide at 1064 nm.

Reduced graphene oxide modified carbon fiber (rGO-CF) was synthesized by electrophoretic deposition and chemical reduction. The GO concentration, electrophoretic time and voltage were taken as variables. Epoxy based composites (rGO-CF/EP) were prepared through molding process and the effects of electrophoretic condition on electromagnetic interference (EMI) shielding performance of rGO-CF/EP were studied. Scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy showed that rGO nanosheets were successfully immobilized on CF. The shielding effectiveness (SE) of composites was tested, and the electrophoretic time and voltage have positive impact on SE value. When the voltage increased to 21 V for 60 min, the rGO-CF/EP composite obtained maximum EMI SE of 37.6 dB, which had a 47.6% improvement than that of CF/EP. Furthermore, a high calculated electrical conductivity of 7.20 S/m was achieved at the same condition. Therefore, controlling the electrophoretic condition is available to achieve lightweight high EMI shielding rGO-CF/EP.

Reduced graphene oxide deposited carbon fiber (rGO-CF) was prepared by introducing GO onto CF surface through electrophoretic deposition method, following by reducing the GO sheets on CF with NaBH 4 solution. The rGO-CF was found to be more effective than CF to improve the electromagnetic interference (EMI) shielding property of unsaturated polyester (UP) based composites. With 0.75% mass fraction of rGO-CF, the shielding effectiveness of the composite reached 37.8 dB at the frequency range of 8.2–12.4 GHz (x-band), which had 16.3% increase than that of CF/UP composite (32.5 dB) in the same fiber mass fraction. The results suggest that rGO-CF is a good candidate for the use as a light-weight EMI shielding material.

Graphene oxide (GO) has been extensively employed to improve the mechanical strength, hydration and durability of cement composites. Recently, an interesting phenomenon can be found that the variation of cement performances is inconsistent with identical GO dosage. However, the related mechanisms remain unclear. Herein, we elucidate the relationship between the spatial dispersion of GO and inconsistent properties of cement composites. Firstly, X-ray computed tomography is developed to observe the distribution of GO. Moreover, the morphology and pore structure of hardened cement paste are studied. Finally, the scattered degree of mechanical strength is evaluated. Obtained results show GO forms many agglomerations with irregular flat shape. Polycarboxylate-ether could reduce the amount of GO aggregations, but not completely eliminate the agglomerations. Aggregated GO induces uncertain pores and sequentially increases the total porosity. The spatial distribution of GO aggregations is non-uniform. These factors lead to the larger scattered strength of specimens with GO. The discrepancies in dispersion degree of GO are mainly responsible for the inconsistent properties of cement composites. This study could provide a deeper understanding of the conflicting properties of GO reinforced cement-based materials.

Despite amazing recent progress on graphene oxide (GO) modified cement composites, the effects of oxygen-containing functional groups of GO on cement properties have not been explored. This study presents the measurements of hydration process, microstructure and compressive strength of cement composites coated by original and reduced GO. Reduced GO is obtained by carrying out the annealing treatment at 300 °C for 60 min. Results show the incorporation of pristine and reduced GO could accelerate cement hydration and promote the formation of crystals due to the nucleation sites effect. The hardened cement paste with original 0.6 wt% GO increases approximately 23.66% hydration degree, while the corresponding increase percentage of cement after annealing is 4.92%. The increments in compressive strength are 8.19 & 15.07% at 3 days and 0.85 & 1.30% at 28 days, which are much higher than that with reduced GO (the increased rates are 2.91 & 7.42% at 3 days and 0.08 & 0.54% at 28 days). The amounts of oxygen-containing groups play a critical role in formulating GO-cement composites. The outcomes of this research develop a new avenue to deeply understand the role of oxygen groups of GO in cement composites.

For modern concrete technology, how to control the generation and propagation of thermal cracks is still a challenge. The large temperature gradient between the internal and external surface is primarily responsible for the cracks. The present study successfully develops a new avenue to minimize the temperature difference of cement composites by introducing reduced graphene oxide (rGO). The effective dispersion of rGO in cement matrix is achieved by applying the polycarboxylate dispersant. The incorporation of rGO enhances the thermal properties of mortar, resulting in a lower temperature difference. The uniformity of calculated heat flux and early-age shrinkage of cement composites are improved by adding rGO. Moreover, the mechanical strength slightly increases at 3 days up to doping 0.6 wt % rGO and does not display significant enhancement after 28 days. Obtained results demonstrate doping rGO is a promising approach to reduce the thermal stress and restrain the development of thermal cracks.

Background/Aims An updated systematic review and meta-analysis was conducted to assess the effect of prophylactic dexamethasone for tracheal intubation of general anesthesia on postoperative sore throat (POST). Methods Comprehensive literature search of databases for randomized controlled trials (RCTs), including Embase, PubMed, and Cochrane Library, which evaluate the effect of prophylactic dexamethasone on POST was conducted. RevMan 5.0 and STATA 12.0 software were used to perform meta-analyses. Results Fourteen RCTs totaling 1,837 patients were included for analysis. Compared with placebo, a significant reduction in the incidence of POST (OR 0.44, 95% CI 0.33-0.58, P

The dispersion behavior of graphene oxide in cement matrix is one important factor in enhancing cement performance. In this work, we investigated the dispersion of graphene oxide in cement by simulating alkaline environment with a solution of calcium hydroxide and studied the corresponding strategy of improving dispersion. The obtained results showed that graphene oxide would flocculate even if calcium hydroxide concentration was very low, which might be the main reason of the unstable properties of the graphene oxide-doped cement. In addition, we discovered that, compared to -OH group, the -COOH group and the long chain of polycarboxylate-based superplasticizer were more effective in delaying the flocculation of graphene oxide. Finally, we proposed a dispersion mechanism of polycarboxylate-based superplasticizer. The study provides inspiration for the design of graphene oxide-doped cement materials. La posible dispersión que el óxido de grafeno pueda inducir en matrices de cemento es un factor importante a considerar para mejorar el rendimiento del cemento. En este trabajo, se ha investigado la dispersión de óxido de grafeno en cemento simulando el ambiente alcalino con una solución del hidróxido de calcio, estudiando las estrategias correspondientes para mejorar el grado de dispersión. Los resultados obtenidos mostraron que el óxido de grafeno flocula incluso cuando la concentración de hidróxido de calcio es muy baja, lo que podría ser la razón principal de las características inestables del cemento dopado con óxido de grafeno. Además, se ha determinado que, en contraste con los grupos OH, los grupos COOH y las largas cadenas de los aditivos superplastificantes basados en policarboxilatos retrasan dicha floculación. Finalmente, se propone un mecanismo de dispersión de dichos aditivos superplastificantes basados en policarboxilatos. Este estudio proporciona una base para el diseño de materiales de cemento dopados con óxido de grafeno.

The study on electromagnetic interference (EMI) shielding materials is a long-standing project in civil and military areas. In this work, a novel kind of shielding material was fabricated and the shielding effectiveness (SE) over broad frequency was investigated. The epoxy (EP) resin was reinforced by reduced graphene oxide coated carbon fiber (rGO-CF, GCF) and Fe 3 O 4 nanoparticles deposited rGO nanohybrids (magnetic graphene, MG). With only 0.5 wt% of GCF and 9 wt% of MG, the GCF/MG 3 /EP exhibited excellent SE (>30 dB over 8.2–26.5 GHz) and a maximum value of 51.1 dB at 26.5 GHz, which had a 31.7% increase than that of GCF/EP. The 3-aminopropyltriethoxysilane (APTES) modified MG (NMG) gained better dispersion in resin and could further increased absorbing property of composites. The synergistic effect between GCF and MG raised by 3D interpenetration structure of the ternary nanocomposite was favorable for high efficient shielding in wide frequency range. This composites show promise in lightweight and high-efficiency EMI shielding field.