Commonly Neglected Ester Groups Enhanced Microwave Absorption.

Oxygen-containing functional groups have high potential to excite polarization loss. The nature and mechanism of the polarization loss brought on by oxygen-containing functional groups, however, remain unclear. In this study, metal-organic framework precursors are in situ pyrolyzed to produce ultrathin carbon nanosheets (UCS) that are abundant in oxygen functional groups. By altering the pyrolysis temperature, the type and concentration of functional groups are altered to produce good microwave absorption capabilities. It is demonstrated that the main processes of electromagnetic loss are polarization caused by "field effects and induced effects" brought on by strongly polar ester functional groups. Moreover, links between various oxygen functional groups and structural flaws are established, and their respective contributions to polarization are sharply separated. The sample with the highest ester group content ultimately achieves an effective absorption bandwidth of 6.47 GHz at a pyrolysis temperature of 800°C. This research fills a theoretical hole in the frequently overlooked polarization mechanism in the microwave band by defining the key polarization parameters in chaotic multiple dipole systems and, in particular, redefining the significance of ester groups.

Toxicity of Nanoscale Zero-Valent Iron to Soil Microorganisms and Related Defense Mechanisms: A Review.

Soil pollution is a global environmental problem. Nanoscale zero-valent iron (nZVI) as a kind of emerging remedial material is used for contaminated soil, which can quickly and effectively degrade and remove pollutants such as organic halides, nitrates and heavy metals in soil, respectively. However, nZVI and its composites can enter the soil environment in the application process, affect the physical and chemical properties of the soil, be absorbed by microorganisms and affect the growth and metabolism of microorganisms, thus affecting the ecological environment of the entire soil. Because of the potential risks of nZVI to the environment and ecosystems, this paper summarizes the current application of nZVI in the remediation of contaminated soil environments, summarizes the various factors affecting the toxic effects of nZVI particles and comprehensively analyzes the toxic effects of nZVI on microorganisms, toxic mechanisms and cell defense behaviors to provide a theoretical reference for subsequent biosafety research on nZVI.

Adsorption of Heavy Metal Ions Copper, Cadmium and Nickel by Microcystis aeruginosa.

To investigate the treatment effect of algae biosorbent on heavy metal wastewater, in this paper, the adsorption effect of M. aeruginosa powder on heavy metal ions copper, cadmium and nickel was investigated using the uniform experimental method, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and TG-DSC comprehensive thermal analysis. The experimental results showed that the initial concentration of copper ion solution was 25 mg/L, the temperature was 30 °C, the pH value was 8 and the adsorption time was 5 h, which was the best condition for the removal of copper ions by algae powder adsorption, and the removal rate was 83.24%. The initial concentration of cadmium ion solution was 5 mg/L, the temperature was 35 °C, the pH value was 8 and the adsorption time was 4 h, which was the best condition for the adsorption of cadmium ion by algae powder, and the removal rate was 92.00%. The initial nickel ion solution concentration of 15 mg/L, temperature of 35 °C, pH value of 7 and adsorption time of 1 h were the best conditions for the adsorption of nickel ions by algae powder, and the removal rate was 88.67%. The spatial structure of algae powder changed obviously before and after adsorbing heavy metals. The functional groups such as amino and phosphate groups on the cell wall of M. aeruginosa enhanced the adsorption effect of heavy metal ions copper, cadmium and nickel. Additionally, M. aeruginosa adsorption of heavy metal ions copper, cadmium, nickel is an exothermic process. The above experiments show that M. aeruginosa can be used as a biological adsorbent to remove heavy metals, which lays a theoretical foundation for the subsequent treatment of heavy metal pollution by algae.

Novel Cellulose Nanocrystals-Based Polyurethane: Synthesis, Characterization and Antibacterial Activity.

As a new type of polymer, water-driven polyurethane (PU) has attracted increasing attention of researchers; however, with the popularization of its application, the following infection problems limit their applications, especially in the biomedical field. Herein, a series of novel cellulose nanocrystals (CNCs)-based PUs were first synthesized by chemical cross-linking CNCs with triblock copolymer polylactide-poly (ethylene glycol)-polylactide (CNC-PU). After covalent binding with tannic acid (TA-CNC-PU), the silver nanoparticles (Ag NPs) were further introduced into the material by a reduction reaction (Ag/TA-CNC-PU). Finally, the prepared serial CNCs-based PU nanocomposites were fully characterized, including the microstructure, water contact angle, water uptake, thermal properties as well as antibacterial activity. Compared with CNC-PU, the obtained TA-CNC-PU and Ag/TA-CNC-PU were capable of lower glass transition temperatures and improved thermal stability. In addition, we found that the introduction of tannic acid and Ag NPs clearly increased the material hydrophobicity and antibacterial activity. In particular, the Ag/TA-CNC-PU had a better antibacterial effect on E. coli, while TA-CNC-PU had better inhibitory effect on S. aureus over a 24 h time period. Therefore, these novel CNCs-based PUs may be more beneficial for thermal processing and could potentially be developed into a new class of smart biomaterial material with good antibacterial properties by adjusting the ratio of TA or Ag NPs in their structures.

Are the measurement structures of the Traditional Chinese Dispositional Flow Scale-2 equivalent between schizophrenic patients and healthy subjects?

BACKGROUND: The Dispositional Flow Scale-2 (DFS-2) is an instrument for measuring the flow experiences of the general population while participating in daily activities. This study aimed to examine the equivalence in the measurement structure of Traditional Chinese DFS-2 (TCDFS-2) between the schizophrenic patients and healthy subjects. METHODS: We recruited 100 adults with schizophrenia or schizoaffective disorder from the psychiatric clinics or the centers for daycare or rehabilitation and 104 healthy adults. Each participant finished the TCDFS-2 by recalling the most important and meaningful daily activity. RESULTS: We conducted two two-group confirmatory factor analyses (CFA) with the healthy subjects and schizophrenic patients as the reference group respectively in LISREL. When the healthy subjects as the reference standard, 43 items of the TCDFS-2 were added to this constrained two-group CFA model for the schizophrenic patients, but the cross-group equivalence was still unsatisfactory. By contrast, when the schizophrenic patients as the reference standard, only 6 items were added for the healthy subjects, and the cross-group equivalence was barely acceptable. CONCLUSION: Thus, the measurement structures of the TCDFS-2 were quite different between the schizophrenic patients and healthy subjects. The flow states experienced by the schizophrenic patients might not entirely be the same as those of the healthy subjects.

Traditional-Chinese Dispositional Flow Scale-2 and Flow State Scale-2 in Taiwanese subjects with schizophrenia or schizoaffective disorder.

INTRODUCTION: The 36-item Dispositional Flow Scale-2 (DFS-2) and Flow State Scale-2 (FSS-2) were developed to assess flow experience in daily and specific activities. Although their validity and reliability had been examined in general populations and different cultures, little is known for schizophrenic subjects. Thus, this study aimed to validate Traditional-Chinese DFS-2 (TCDFS-2) and FSS-2 (TCFSS-2) in Taiwanese subjects with schizophrenia or schizoaffective disorder. METHODS: We recruited 229 adult participants from outpatient clinics, day care centers, and psychiatric rehabilitation centers in Taipei. They filled out 36-item TCDFS-2 and TCFSS-2 under guidance. The LISREL 9.30 software was used to conduct exploratory factor analysis for exploring measurement structures, and then confirmatory factor analysis for identifying factor models. RESULTS: The six first-order factor and one second-order factor measurement models were obtained for both 36-item TCDFS-2 (Chi-square statistic = 999.1, df = 545, p < 0.0001, Root Mean Square Error of Approximation [RMSEA] = 0.0603, and Comparative Fit Index [CFI] = 0.9213) and TCFSS-2 (Chi-square statistic = 987.9, df = 539, p < 0.0001, RMSEA = 0.0603, and CFI = 0.9213). CONCLUSION: Our factor models differed remarkably from those of 36-item DFS-2 and FSS-2. Yet, they were barely acceptable to be used to measure flow experiences in schizophrenic subjects in clinical applications. Since the factor scores, measurement structures, or even definitions of flow experiences could differ substantially between healthy people and patients with mental illness, disease-specific instruments of flow experiences should be considered in the future.