•A timely review based on the dealloying-enabled hierarchical porous metals.•A comprehensive summary of principles for hierarchical porous metals by dealloying.•We emphasise the integration of other ...manufacturing methods with dealloying.•The outstanding performances of dealloying-enabled hierarchical porous metals.
Hierarchical porous materials exist widely in nature as a result of the survival rules of nature. Inspired by the unique properties of these native hierarchical porous materials, researchers have long endeavoured to develop hierarchical porous metal materials for specific industrial needs. This review discusses the developments to date in hierarchical porous metallic materials by focusing on dealloying-enabled hierarchical porous structures, with or without the combination of other manufacturing processes, and their distinctive properties and industrial applications. It is shown that the dealloying method opens up new avenues in the creation of functional hierarchical porous metals for a wide variety of promising applications.
In the context of classical molecular simulations, the accuracy of a force field is highly influenced by the values of the relevant simulation parameters. In this work, a parameter-space mapping ...(PSM) workflow is proposed to aid in the calibration of force-field parameters, based mainly on the following features: (i) regular-grid discretization of the search space; (ii) partial sampling of the search-space grid; (iii) training of surrogate models to predict the estimates of the target properties for nonsampled parameter sets; (iv) post hoc interpretation of the results in terms of multiobjective optimization concepts; (v) attenuation of statistical errors achieved via empiric extension of the duration of the simulations; (vi) iterative search-space translation according to a user-defined scalar objective function that measures the accuracy of the force field (e.g., the weighted root-mean-square deviation of the target properties relative to the reference data). This combination of features results in a hybrid of a single- and a multiobjective optimization strategy, allowing for the approximate determination of both a local minimum of the chosen objective function and its neighboring Pareto efficient points. The PSM workflow is implemented in the extensible Python program gmak, which is made available in the Git repository at http://github.com/mssm-labmmol/gmak. Using this implementation, the PSM workflow was tested in a proof-of-concept fashion in the recalibration of the Lennard-Jones parameters of the 3-point Optimal Point Charge (OPC3) water model for compatibility with the GROMOS treatment of nonbonded interactions. The recalibrated model reproduces typical pure-liquid properties with an accuracy similar to the original OPC3 model and represents a significant improvement relative to the Simple Point Charge (SPC) model, which is the official recommendation for simulations using GROMOS force fields.
A type of light absorber made of continuous layers of metal and dielectric films is studied. The metal films can have thicknesses close to their skin depths in the wavelength range concerned, which ...allows for both light transmission and reflection. Resonances induced by multiple reflections in the structure, when combined with the inherent lossy nature of metals, result in strong absorption spectral features. An eigen-mode analysis is carried out for the plasmonic multilayer nanostructures which provides a generic understanding of the absorption features. Experimentally, the calculation is verified by a reflection measurement with a representative structure. Such an absorber is simple to fabricate. The highly efficient absorption characteristics can be potentially deployed for optical filter designs, sensors, accurate photothermal temperature control in a micro-environment and even for backscattering reduction of small particles, etc.
Integrated Enzyme-Based Biofuel Cells-A Review Willner, I.; Yan, Y.-M.; Willner, B. ...
Fuel cells (Weinheim an der Bergstrasse, Germany),
February, 2009, Letnik:
9, Številka:
1
Journal Article
Recenzirano
Enzyme‐based biofuel cells provide versatile means to generate electrical power from biomass or biofuel substrates, and to use biological fluids as fuel‐sources for the electrical activation of ...implantable electronic medical devices, or prosthetic aids. This review addresses recent advances for assembling biofuel cells based on integrated, electrically contacted thin film‐modified enzyme electrodes. Different methods to electrically communicate the enzymes associated with the anodes/cathodes of the biofuel cell elements are presented. These include: (i) The reconstitution of apo‐enzymes on relay‐cofactor monolayers assembled on electrodes, or the crosslinking of cofactor‐enzyme affinity complexes assembled on electrodes. (ii) The immobilisation of enzymes in redox‐active hydrogels associated with electrodes. (iii) The use of nano‐elements, such as carbon nanotubes, for the electrical contacting of the enzyme electrodes comprising the biofuel cells. All three methods are implemented for the electrical contacting of oxidases and dehydrogenases with electrodes acting as anodes of biofuel cells, and for the electrical wiring of bilirubin oxidase, cytochrome oxidase, and laccase with electrodes, that yield the cathode units of the biofuel cells. Different methods to control the biofuel cells, operation by external stimuli are discussed, including the application of external magnetic fields, and the electrochemical switching of the biofuel cell operation.
Obesity presents a serious threat to human health and broiler performance. The expansion of adipose tissue is mainly regulated by the differentiation of preadipocytes. The differentiation of ...preadipocytes is a complex biological process regulated by a variety of transcription factors and signaling pathways. Previous studies have shown that the transcription factor HMG-box protein 1 (HBP1) can regulate the differentiation of mouse 3T3-L1 preadipocytes by activating the Wnt/β-catenin signaling pathway. However, it is unclear whether HBP1 involved in chicken preadipocyte differentiation and which signaling pathways it regulates. The aim of the current study was to explore the biological function and molecular regulatory mechanism of HBP1 in the differentiation of chicken preadipocytes. The expression patterns of chicken HBP1 in abdominal adipose tissue and during preadipocyte differentiation were analyzed by RT-qPCR and Western blot. The preadipocyte stably overexpressing HBP1 or knockout HBP1 and their control cell line were used to analyze the effect of HBP1 on preadipocyte differentiation by oil red O staining, RT-qPCR and Western blot. Cignal 45-Pathway Reporter Array was used to screen the signal pathways that HBP1 regulates in the differentiation of chicken preadipocytes. Chemical inhibitor and siRNA for signal transducer and activator of transcription 3 (STAT3) were used to analyze the effect of STAT3 on preadipocyte differentiation. The preadipocyte stably overexpressing HBP1 was transfected by the siRNA of STAT3 or treated with a chemical inhibitor of STAT3 for the rescue experiment. The results of gene expression analysis showed that the expression of HBP1 was related to abdominal fat deposition and preadipocyte differentiation in chickens. The results of function gain and loss experiments indicated that overexpression/knockout of HBP1 in chicken preadipocytes could inhibit/promote (P<0.05) lipid droplet deposition and the expression of adipogenesis-related genes. Mechanismlly, HBP1 activates (P<0.05) the signal transducer and activator of transcription 3 (STAT3) signaling pathway by targeting janus kinase 2 (JAK2) transcription. The results of functional rescue experiments indicated that STAT3 signaling mediated the regulation of HBP1 on chicken preadipocyte differentiation. In conclusion, HBP1 inhibits chicken preadipocyte differentiation by activating the STAT3 signaling pathway via directly enhancing JAK2 expression. Our findings provided new insights for further analysis of the molecular genetic basis of chicken adipose tissue growth and development.
Breast cancer is the most common cause of cancer among women in most countries (WHO). Ovarian hormone disorder is thought to be associated with breast tumorigenesis. The present study investigated ...the effects of estrogen and progesterone administration on cell proliferation and underlying mechanisms in breast cancer MCF-7 cells. It was found that a single administration of estradiol (E2) or progesterone increased MCF-7 cell viability in a dose-dependent manner and promoted cell cycle progression by increasing the percentage of cells in the G2/M phase. A combination of E2 and progesterone led to a stronger effect than single treatment. Moreover, cyclin G1 was up-regulated by E2 and/or progesterone in MCF-7 cells. After knockdown of cyclin G1 in MCF-7 cells using a specific shRNA, estradiol- and progesterone-mediated cell viability and clonogenic ability were significantly limited. Additionally, estradiol- and progesterone-promoted cell accumulation in the G2/M phase was reversed after knockdown of cyclin G1. These data indicated that estrogen and progesterone promoted breast cancer cell proliferation by inducing the expression of cyclin G1. Our data indicated that novel therapeutics against cyclin G1 are promising for the treatment of estrogen- and progesterone-mediated breast cancer progression.
The occurrence of the β (bcc) to αm (hcp) massive transformation in Ti–6Al–4V (wt.%) during additive manufacturing (AM) by selective electron beam melting (SEBM) has been identified. A variety of ...patch-shaped massive grains including both grain boundary (GB)-crossing and non-GB-crossing instances were characterised and their formation temperature and growth rate were estimated. In contrast to conventional Ti–6Al–4V, the massive grains in SEBM-fabricated Ti–6Al–4V consist of ultrafine lamellar α and β phases (100 nm wide β strips) due to in-situ decomposition of the massive grains during AM. The resulting ultrafine α-β lamellae obey the typical Burgers orientation relationship established for the lamellar α-β structure in conventional Ti–6Al–4V. These findings show that the β (bcc) to αm (hcp) massive transformation significantly contributes to development of the Ti–6Al–4V microstructure during AM by SEBM, providing an alternative microstructural design strategy for AM of Ti–6Al–4V and other titanium alloys.
(a) EBSD colour inverse pole figure (IPF) showing both non-GB-crossing (i.e.③) and GB-crossing (i.e. ④ and ⑤) massive phase grains. (b) Multiple-spot TEM BF image showing the ultra-fine α-β microstructures within the massive phase grain. The inset in (a) is an EBSD band-contrast map showing the original prior-β GB. The side arrow in (a) represents the SEBM building direction. Display omitted
The metastatic cascade is a complex and multistep process with many potential barriers. Recent evidence has shown that microRNAs (miRNAs) are involved in carcinogenesis and tumor progression in ...non-small-cell lung cancer (NSCLC). In this study, by comparing the miRNA expression profiles of SPC-A-1sci (high metastatic) and SPC-A-1 (weakly metastatic) cells, we demonstrated that the downregulation and function of miR-193a-3p and miR-193a-5p in NSCLC metastasis and the expression of these miRNAs was suppressed in NSCLC compared with corresponding non-tumorous tissues. Decreased miR-193a-3p/5p expression was significantly associated with tumor node metastasis (TNM) and lymph node metastasis. Furthermore, functional assays showed that the overexpression of miR-193a-3p/5p inhibited NSCLC cell migration, invasion and epithelial-mesenchymal transition (EMT) in vitro and lung metastasis formation in vivo. In addition, we discovered that ERBB4 and S6K2 were the direct targets of miR-193a-3p and that PIK3R3 and mTOR were the direct targets of miR-193a-5p in NSCLC. We also observed that miR-193a-3p/5p could inactivate the AKT/mTOR signaling pathway. Thus, miR-193a-3p/5p functions as a tumor suppressor and has an important role in NSCLC metastasis through ERBB signaling pathway.
In this research, samples of the H13 steel, a commonly used hot work tool steel in the die/mould manufacturing industry, were additively manufactured using selective laser melting (SLM). Their ...as-built microstructures were characterised in detail using transmission electron microscopy (TEM) and compared with that of the conventionally manufactured H13 (as-supplied). SLM resulted in the formation of martensite and also its partial decomposition into fine α-Fe and Fe
3
C precipitates along with retained austenite. TEM analyses further revealed that the lattice of the resulting α-Fe phase is slightly distorted due to enhanced Cr, Mo and V contents. Substantially high residual stresses in the range of 940–1420 MPa were detected in the as-built H13 samples compared with its yield strength of ~1650 MPa. In addition, it was identified that the high residual stress existed from just about two additive layers (100 µm) above the substrate along the build direction. The high residual stresses were mainly attributed to the martensitic transformation that occurred during SLM. The research findings of this study suggest that the substantially high residual stresses can be easily problematic in the AM of intricate H13 dies or moulds by SLM.
A damage detection method is proposed for structural health monitoring under varying environmental and operational conditions. The method is based on principal component analysis (PCA) applied to ...vibration features identified during the monitoring of the structure. The advantage of the method is that it does not require to measure environmental parameters because they are taken into account as embedded variables. The number of principal components of the vibration features is implicitly assumed to correspond to the number of independent environmental factors. Since the environmental effects may be effectively eliminated by the proposed procedure, the residual error of the PCA prediction model remains small if the structure is healthy, and it increases significantly when structural damage occurs. Novelty analysis on the residual errors provides a statistical indication of damage. In the present paper, the environmental conditions are assumed to have a linear (or weakly non-linear) effect on the vibration features, and the PCA-based damage detection method is illustrated using computer-simulated and laboratory testing data. The extension of the proposed method to non-linear cases is addressed in a companion paper where the efficiency of the method is verified using data obtained from a 1-year in situ monitoring of a bridge.
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