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In this paper, five kinds of typical improvement methods for the performance of SC cycle are compared and analyzed using the developed thermodynamic model based on the first and second laws of thermodynamics. The results shows that SCE cycle has a most positive effect. The COP of SCSLHX cycle only has an increase of 15% in high temperature conditions, conversely TCFGB cycle can improve by 15% and 28% in common and low temperature conditions. TCIGc cycle has a middle but stable increase of 14%~21%, and margin improvement of TCIC cycle is less than 10% in research conditions. The exergy analysis reveals that SCE, SCSLHX, TCFGB and TCIGc cycles improve the COP mainly by reducing throttling losses, while the improvement of COP for TCIC cycle is mainly achieved by reducing the loss of gas coolers. Furthermore, the exergy loss of each component in each cycle is also quantified. [ABSTRACT FROM AUTHOR]

Graphene has emerged as a novel green broad-spectrum antibacterial material, with little bacterial resistance and tolerable cytotoxic effect on mammalian cells. It exerts its antibacterial action via physical damages such as direct contact of its sharp edges with bacterial membranes and destructive extraction of lipid molecules. These damages also include wrapping and photothermal ablation mechanisms. Alternatively, chemical damage of bacteria is caused by oxidative stress with the generation of reactive oxygen species and charge transfer. Furthermore, graphene has been used as a support to disperse and stabilize various nanomaterials, such as metals, metal oxides, and polymers, with high antibacterial efficiency due to the synergistic effect. In addition, graphene-based antibiotic drug delivery platforms have been constructed. Due to the superior antibacterial properties and good biocompatibility, graphene-based nanocomposites have a wide range of applications, such as antibacterial packaging, wound dressing, and water disinfection. In this review, we highlight the antibacterial mechanism of graphene and summarize recent advances related to the antibacterial activity of graphene-based materials. Many of the recent application examples are further discussed. We hope that this review provides valuable insight, stimulates broader concerns, and spurs further developments in this promising field. [ABSTRACT FROM AUTHOR]

The use of Formic acid as an alternative to fossil fuels is promising, both from economical and ecological standpoints, and has received great of attention owing to its inherently superiority in recent decades. Nevertheless, efficient and low-cost solid catalyst for formic acid dehydrogenation at room temperature still constitutes a biggish challenge. Moreover, comparing to increase the catalytic performance of catalysts, very little attention payed to the kinetic mechanism of dehydrogenation reaction because of the lack of effective characterization artifice. Here, the as-prepared Ni@Pd nanoparticles by a sequential reduction process can be useful catalyst for formic acid decomposition at room temperature without a promoter. Thanks to the effective catalyst and isotope distribution technique, preliminary mechanistic results firstly reveal that hydrogen is obtained via a H-atom recombination on isolated sites after the proton exchange randomly between activated H and solvent. • The catalyst shows the enhanced formic acid dehydrogenation performance (645 h−1). • The Ni-core helps to increase the activity and CO resistance of Pd a lot. • Compare to pure Pd NCs, the cost of catalyst is greatly reduced. • Activated H exchange with water was firstly revealed by isotope substitution design. [ABSTRACT FROM AUTHOR]

The experimental study on heat transfer and pressure drop for R417A flow boiling in horizontal smooth and internally grooved tubes was conducted. Based on the experimental results, heat transfer and pressure drop performance for R417A in different tubes were compared, and the influences of vapor quality and mass flux on heat transfer enhancement and pressure drop performance were analyzed and discussed. The result indicates: enhancement factors of R417A in Tube II and Tube III focus on a range of 1.26–2.0 and 1.5–2.8 respectively, and enhancement factors vary with vapor qualities and mass fluxes. The total pressure drops for R417A in Tube II and Tube III are 1.8–2.6 times and 1.67–2.3 times of R417A in smooth tube respectively. Both enhancement factor and penalty factor increase with increasing mass flux, while enhancement parameters show different situations in different internally grooved tubes. Compared with Tube II, Tube III possesses a better heat transfer enhancement efficiency. [ABSTRACT FROM AUTHOR]

Abstract: The enzyme 1-hydroxy-2-methyl-2-(E)-butenyl-4-diphosphate reductase (HDR) is a terminal-acting enzyme in the plastid MEP pathway, which produce isoprenoid precursors. The full-length cDNA of HDR, designated SmHDR1 (Genbank Accession No. JX516088), was isolated for the first time from Salvia miltiorrhiza Bge. f. alba. SmHDR1 contains a 1389-bp open reading frame encoding 463 amino acids. The deduced SmHDR1 protein, which shows high identity to HDRs of other plant species, is predicted to possess a chloroplast transit peptide at the N-terminus and four conserved cysteine residues. Transcription pattern analysis revealed that SmHDR1 has high levels of transcription in leaves and low levels of transcription in roots and stems. The expression of SmHDR1 was induced by 0.1 mM methyl-jasmonate (MeJA) and salicylic acid (SA), but not by 0.1 mM abscisic acid (ABA), in the hairy roots of S. miltiorrhiza Bge. f. alba. Complementation of SmHDR1 in the Escherichia coli HDR mutant MG1655 ara < > ispH demonstrated the function of this enzyme. A functional color assay in E. coli showed that SmHDR1 accelerates the biosynthesis of β-carotene, indicating that SmHDR1 encodes a functional protein. Overexpression of SmHDR1 enhanced the production of tanshinones in cultured hairy roots of S. miltiorrhiza Bge. f. alba. These results indicate that SmHDR1 is a novel and important enzyme involved in the biosynthesis of diterpenoid tanshinones in S. miltiorrhiza Bge. f. alba. [Copyright &y& Elsevier]

[Display omitted] • A multifunctional nanoplatform (g-CPFD) based on g-C 3 N 4 quantum dots is synthesized. • The g-CPFD achieves chemo-photodynamic combination therapy in one system. • The g-CPFD exhibits folate receptor-mediated targeting ability. • The g-CPFD is traceable and exhibits pH-responsive release property. Graphitic carbon nitride quantum dots (g-CNQDs) have shown great potential in imaging, drug delivery and photodynamic therapy (PDT). However, relevant research on g-CNQDs for PDT or drug delivery has been conducted separately. Herein, we develop a g-CNQDs-based nanoplatform (g-CPFD) to achieve simultaneously imaging and chemo-photodynamic combination therapy in one system. A g-CNQDs-based nanocarrier (g-CPF) is first prepared by successively introducing carboxyamino-terminated oligomeric polyethylene glycol and folic acid onto the surface of g-CNQDs via two-step amidation. The resultant g-CPF possesses good physiological stability, strong blue fluorescence, desirable biocompatibility, and visible light-stimulated reactive oxygen species generating ability. Further non-covalently loaded doxorubicin enables the system with chemotherapy function. Compared with free doxorubicin, g-CPFD expresses more efficient chemotherapy to HeLa cells due to improved folate receptor-mediated cellular uptake and intracellular pH-triggered drug release. Furthermore, g-CPFD under visible light irradiation shows enhanced inhibition on the growth of cancer cells compared to sole chemotherapy or PDT. Thus, g-CPFD exhibits exceptional anti-tumor efficiency due to folate receptor-mediated targeting ability, intracellular pH-triggered drug release and a combined treatment effect arising from PDT and chemotherapy. Moreover, this nanoplatform benefits imaging-guided drug delivery because of inherent fluorescent properties of doxorubicin and g-CPF, hence achieving the goal of imaging-guided chemo-photodynamic combination treatments. [ABSTRACT FROM AUTHOR]

• A drug delivery system based on fluorescent MoS 2 QDs is synthesized. • PEGylated MoS 2 QDs has good physiological stability and is suitable for carrier. • The drug delivery system is traceable and exhibits pH-responsive release property. Since low pH value is widely observed in most of solid tumors, pH-responsive drug delivery system (DDS) can provide a general strategy for tumor-targeting therapy. In this work, a traceable and pH-responsive DDS (MoS 2 -PEG-DOX) based on MoS 2 quantum dots (MoS 2 QDs) is successfully developed by covalently grafting MoS 2 QDs with diamine-terminated oligomeric polyethylene glycol (PEG) and then loading with a fluorescent antineoplastic anthracycline drug, doxorubicin (DOX). The functionalization of MoS 2 QDs with PEG imparts the nanocomposite with strong blue photoluminescence, low cytotoxicity, and excellent physiological stability. The MoS 2 -PEG-DOX nano-assembly can be effectively taken up by U251 cells, and an accelerated DOX release is then triggered by intracellular acid condition, which in turn diminishing unwanted side effects derived by the incorporation of DOX into healthy cells. Meanwhile, the cellular uptake of the MoS 2 -PEG-DOX nano-assembly, consequent DOX release and the localization of nanocarrier can be real-time monitored due to the inherent stable fluorescence of MoS 2 -PEG and DOX. These findings demonstrate that MoS 2 -PEG-DOX will be promising for high treatment efficacy with minimal side effects in future therapy. [ABSTRACT FROM AUTHOR]