适用于锂氧电池的高容量碳基电极

以碳酸钠为催化剂，将间苯二酚与甲醛进行缩聚，所生成的气凝胶在800℃的惰性气氛中进行碳化以制备多孔的碳气凝胶。碳的多孔质地由改变凝胶前体中间苯二酚与催化剂的摩尔比来调节，摩尔比的范围为100~500。气凝胶和碳气凝胶的多孔结构以在绝对温度77K下进行的氮气的吸附–解吸附测量结果表征。已经发现，总孔隙度和碳的平均孔径随着凝胶前体的摩尔比的增加而增大。作为一种活性材料，碳气凝胶用于制造合成碳电极。合成碳电极的电化学性能以将其用作锂/氧电池的负极来进行测试。由静电充放电测量发现，随着摩尔比的增加，由碳气凝胶制造的锂/氧电池的比容量由716 mAhg1增加到2077 mAhg1。所得到的最初10次充/放电循环的电压分布图表明，这些碳样品具有出色的循环稳定性。     

Omnidirectional broadband absorption enhancement in laterally assembled quadrangle silicon nanowire solar cells

In this paper, effects of geometry and spatial placement of quadrangle silicon nanowires (NWs) on the performance of laterally assembled NW solar cells are investigated. Two different approaches are proposed to reach the broadband absorption enhancement in these types of solar cells. In the first method, a semi-periodic array is used to have a better utilization of the optical antenna effect. The current density can be enhanced as a result of a compromise between the diffraction and optical antenna effects. In the second approach, multiple NWs with different geometries are employed to use the cavity modes of the various NWs. The best current density is achieved for the combination of both of these methods. The different parameters in each structure are selected using the optimization algorithm. Finally, a multilayer structure with the optimized dimensions is proposed to obtain the maximum achievable current density in ultrathin solar cells. The broadband absorption enhancement in the proposed structure is preserved for a wide range of incident angles. Using the multilayer NW arrays, it is possible to improve the absorption enhancement of solar cells without introducing more absorbing material.     

Additive manufacturing management: a review and future research agenda

Based on the phenomenal changes that additive manufacturing (AM) has brought to industries and markets, managerial approaches should be re-examined and developed to take advantage of emerging opportunities. This revolutionary technology is dramatically changing business and innovation models, shrinking supply chains and altering the global economy. For example, 3D printing shifts production locations closer to customers and leads to free-form product design as well as sustainable manufacturing. Several studies have been conducted on AM technology, but the research stream on AM management is still developing, with studies dispersed in journals across different research areas. Our study presents both systematic and quantitative analyses of the literature, including co-citation analysis, factor analysis and multidimensional scaling, to explore the structure of the AM research domains in the scope of management, business and economics. We found eight main research streams: AM technology selection, supply chain, product design and production cost models, environmental aspects, strategic challenges, manufacturing systems, open-source innovation and business models and economics. Finally, based on the results of our in-depth analysis of the literature, we found nine promising future research directions.     

Characterization of $${\hbox {BaTiO}_{3}}$$ piezoelectric perovskite material for multilayer actuators

In this study, we present the results of the manufacturing of \(\hbox {BaTiO}_{3}\) powder, which is meant for use in stacked-disk multilayer actuator production. The solid-state technique was used for powder preparation. The properties of barium titanate material, at each stage of its fabrication (powder, granulate, sintered material), influencing on its application for the stacked-disk multilayer actuator were determined. Particularly, the four parameters of \(\hbox {BaTiO}_{3}\) sinter affecting on the usability properties of actuators, not found before in the literature, were estimated. Parameters characterizing the extent of material sintering, SEM microstructures and electric properties of the fabricated pellets are presented and discussed. The dilatometric curve was executed using the high temperature dilatometer to determine at which temperature barium titanate pellets and beams should be sintered to receive full dense sinters. Parameters characterizing the extent of material sintering: the apparent density, the apparent porosity and the water absorbability were estimated. Finally, the problem of metal layer deposition on barium titanate ceramics during actuator fabrication is considered.     

Factorial design analysis and optimisation of chitosan‐based nanogels as controlled release system for gentamicin

The aim of this study was preparation and optimisation of a controlled‐release delivery system to decrease the dose‐dependent side effects of gentamicin. Hydrogel nanoparticles composed of a polycationic polymer (chitosan) and an inorganic polyanion (sodium tripolyphosphate) were fabricated in the presence of gentamicin. An experimental design was drawn upon to determine the optimum condition of nanoparticle preparation. Various features of the nanoparticles including drug loading parameters, particle size distribution, zeta potential and in vitro drug release profile were evaluated. Ultimately, the antimicrobial activity of the gentamicin‐loaded nanoparticles was analysed by determination of the minimum inhibitory concentration (MIC) and the potency test. As a result, the nanocarriers with an average size of about 250 nm (unloaded) and 493 nm (gentamicin‐loaded) were obtained with unimodal distribution and a notable polydispersity index (≤0.3). The drug loading efficiency was between 28 and 32%. The gradual and sustained releases (∼90%) of gentamicin were achieved in 24 h. The MIC and potency test showed no significant decrease in the antibacterial activity of gentamicin‐loaded nanoparticles. The outcomes demonstrated that the optimised chitosan nanogels prepared in this study can be considered as a suitable carrier for a controlled release system.Inspec keywords: hydrogels, nanoparticles, drug delivery systems, particle size, electrokinetic effects, antibacterial activity, nanomedicineOther keywords: factorial design analysis, chitosan‐based nanogels, gentamicin, controlled‐release delivery system, hydrogel nanoparticles, polycationic polymer, inorganic polyanion, sodium tripolyphosphate, particle size distribution, drug loading parameters, zeta potential, in vitro drug release profile, antimicrobial activity, minimum inhibitory concentration, polydispersity index, drug loading efficiency, antibacterial activity     

Extracellular synthesis of silver nanoparticles using four fungal species isolated from lichens

Extracellular biosynthesis of silver nanoparticles using five fungal species including Fusarium oxysporum and four others isolated from native lichens (Kerman, Iran) was investigated in this study. These fungal species were identified as Arctoparmelia incurva, Penicillium chrysogenum, Uncultured root‐associated fungus, and Caloplaca arnoldii by using ITS rRNA sequence analysis. These species were then cultivated in four common industrial wastes, namely a combination of yeast and malt extract, sugar beet molasses, whey, and wastewater of beverage industry, prior to their use for biosynthesis. The synthesis of the nanoparticles was monitored by UV–visible spectroscopy. It was found to be significantly affected by both fungal species and their cultivation media. C. arnoldii cultivated in the yeast and malt extract resulted in the best performance regarding reaction kinetics, particle mean diameter and size distribution. The mean diameter and variance of the nanoparticles were determined to be about 11 nm and 24 by using transmission electron microscopy and powder X‐ray diffraction techniques, respectively. The zeta potential of the nanoparticles was measured to be −21.5 mV confirming their long‐term stability. These findings suggest a new biosynthetic route towards eco‐friendly and inexpensive production of the nanoparticles in bulk.Inspec keywords: silver, nanoparticles, nanofabrication, microorganisms, ultraviolet spectra, visible spectra, X‐ray diffractionOther keywords: silver nanoparticles, fungal species, extracellular biosynthesis, Fusarium oxysporum, native lichens, Arctoparmelia incurva, Penicillium chrysogenum, uncultured root‐associated fungus, Caloplaca arnoldii, ITS rRNA sequence analysis, industrial wastes, yeast, malt extract, sugar beet molasses, whey, wastewater, beverage industry, UV–visible spectroscopy, Ag     

Cytotoxicity of biologically synthesised bismuth nanoparticles against HT‐29 cell line

This study was purposed to examine the cytotoxicity and functions of biologically synthesised bismuth nanoparticles (Bi NPs) produced by Delftia sp. SFG on human colon adenocarcinoma cell line of HT‐29. The structural properties of Bi NPs were investigated using transmission electron microscopy, energy dispersive X‐ray, and X‐ray diffraction techniques. The cytotoxic effects of Bi NPs were analysed using flow cytometry cell apoptosis while western blot analyses were applied to analyse the cleaved caspase‐3 expression. Oxidative stress (OS) damage was determined using the measurement of the glutathione (GSH) and malondialdehyde (MDA) levels and antioxidant activity of superoxide dismutase (SOD) and catalase (CAT) levels. The half maximal inhibitory concentration (IC₅₀) value of Bi NPs was measured to be 28.7 ± 1.4 µg/ml on HT‐29 cell line. The viability of HT‐29 represented a concentration‐dependent pattern (5–80 µg/ml). The mode of Bi NPs induced apoptosis was found to be mainly related to late apoptosis or necrosis at IC₅₀ concentration, without the effect on caspase‐3 activities. Furthermore, Bi NPs reduced the GSH and increased the MDA levels and decreased the SOD and CAT activities. Taken together, biogenic Bi NPs induced cytotoxicity on HT‐29 cell line through the activation of late apoptosis independent of caspase pathway and may enhance the OS biomarkers.Inspec keywords: bismuth, nanoparticles, cellular biophysics, toxicology, nanomedicine, cancer, transmission electron microscopy, X‐ray chemical analysis, X‐ray diffraction, enzymes, biochemistryOther keywords: cytotoxicity, biologically synthesised bismuth nanoparticles, HT‐29 cell line, Delftia sp. SFG, human colon adenocarcinoma cell line, structural properties, transmission electron microscopy, energy dispersive X‐ray techniques, X‐ray diffraction, cytotoxic effects, flow cytometry cell apoptosis, western blot analyses, cleaved caspase‐3 expression, oxidative stress damage, glutathione, malondialdehyde, antioxidant activity, superoxide dismutase, catalase level, half maximal inhibitory concentration, cell viability, concentration‐dependent pattern, apoptosis, MDA levels, caspase pathway, Bi     

Synthesis and characterisation of liposomal doxorubicin with loaded gold nanoparticles

Developing nanostructures for cancer treatment is growing significantly. Liposomal doxorubicin is a drug that is used in the clinic and represents a lot of benefits over doxorubicin. The development of multifunctional liposomes with different cancer treatment capability enables broader applications of doxorubicin chemotherapy. Many efforts were carried to prepare more effective liposomal formulation through loading gold nanoparticles (GNPs) in the formulation. Here, GNPs with an average size of 6 nm were loaded in liposomal formulation alongside doxorubicin. The hydrodynamic diameter of final formulation was 177.3 ± 33.9 nm that in comparison with liposomes without GNPs (112.5 ± 10.3 nm), GNPs‐loaded liposomes showed the bigger hydrodynamic diameter. GNPs‐loaded liposomes are slightly positively charged (4.4 ± 1.1 mV), while liposomes without loading the GNPs were negatively charged (−18.5 ± 1.6 mV). Doxorubicin was loaded in this formulation through active loading technique. Doxorubicin loading efficiency in gold‐loaded liposomes is slightly lesser than liposomes without GNPs, but still considerably high in comparison to passive loading techniques.Inspec keywords: nanofabrication, drugs, nanomedicine, gold, cancer, lipid bilayers, drug delivery systems, nanoparticles, crystal growth from solutionOther keywords: liposomal doxorubicin, multifunctional liposomes, doxorubicin chemotherapy, active loading technique, doxorubicin loading efficiency, gold‐loaded liposomes, passive loading techniques, gold nanoparticles, cancer treatment, liposomal formulation, GNP‐loaded liposomes, hydrodynamic diameter     

Synthesis,characterisation and potential biomedical applications of magnetic core–shell structures: carbon‐, dextran‐, SiO2 ‐ and ZnO‐coated Fe3 O4 nanoparticles

Due to the strong effect of nanoparticles'' size and surface properties on cellular uptake and bio‐distribution, the selection of coating material for magnetic core–shell nanoparticles (CSNPs) is very important. In this study, the effects of four different biocompatible coating materials on the physical properties of Fe₃ O₄ (magnetite) nanoparticles (NPs) for different biomedical applications are investigated and compared. In this regard, magnetite NPs are prepared by a simple co‐precipitation method. Then, CSNPs including Fe₃ O₄ as a core and carbon, dextran, ZnO (zincite) and SiO₂ (silica) as different shells are synthesised using simple one‐ or two‐step methods. A comprehensive study is carried out on the prepared samples using X‐ray diffraction, vibrating sample magnetometry, transmission electron microscopy and Fourier transform infrared spectroscopy analyses. According to the authors'' findings, it is suggested that carbon‐ and dextran‐coated magnetite NPs with high M _s have great potential in the application of magnetic resonance imaging contrast agents. Moreover, silica‐coated magnetite NPs with high coercivity are potentially suitable candidates for hyperthermia and ZnO‐coated Fe₃ O₄ is potentially suitable for photothermal therapy.Inspec keywords: iron compounds, carbon, silicon compounds, zinc compounds, nanomedicine, biomedical materials, nanofabrication, nanoparticles, magnetic particles, coatings, X‐ray diffraction, magnetometry, transmission electron microscopy, Fourier transform spectra, infrared spectra, biomedical MRI, hyperthermia, radiation therapyOther keywords: biomedical applications, magnetic core‐shell nanoparticles, CSNP, cellular uptake, biodistribution, coating material, biocompatible coating materials, co‐precipitation, dextran, zincite, silica, X‐ray diffraction, vibrating sample magnetometry, transmission electron microscopy, Fourier transform infrared spectroscopy, magnetic resonance imaging contrast agents, hyperthermia, photothermal therapy, SiO₂ ‐Fe₃ O₄ , ZnO‐Fe₃ O₄      

Gentamicin‐gold nanoparticles conjugate: a contrast agent for X‐ray imaging of infectious foci due to Staphylococcus aureus

There is no optimal imaging method for the detection of unknown infectious foci in some diseases. This study introduces a novel method in X‐ray imaging of infection foci due to Staphylococcus aureus by developing a contrast agent based on gold nanoparticles (GNPs). GNPs in spherical shape were synthesised by the reduction of tetrachloroauric acid with sodium citrate. Then gentamicin was bound directly to citrate functionalised GNPs and the complex was stabilised by polyethylene glycol. The interaction of gentamicin with GNPs was confirmed by ultraviolet–visible and Fourier transform infrared spectroscopies. The stability of complex was studied in human blood up to 6 h. The stability of conjugate was found to be high in human blood with no aggregation. The biodistribution study showed localisation of gentamicin–GNPs conjugate at the site of Staphylococcal infection. The infection site was properly visualised in X‐ray images in mouse model using the gentamicin–GNPs conjugate as a contrast agent. The results demonstrated that one may consider the potential of new nanodrug as a contrast agent for X‐ray imaging of infection foci in human beings which needs more investigations.Inspec keywords: drugs, nanomedicine, nanoparticles, nanofabrication, diagnostic radiography, microorganisms, diseases, polymers, ultraviolet spectra, visible spectra, Fourier transform infrared spectra, goldOther keywords: gentamicin‐gold nanoparticle conjugate, contrast agent, X‐ray imaging, Staphylococcus aureus, disease, tetrachloroauric acid reduction, sodium citrate, polyethylene glycol, ultraviolet‐visible spectroscopy, Fourier transform infrared spectroscopy, human blood, Staphylococcal infection, X‐ray images, murine model, nanodrug