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Fail-safe topology optimization is valuable for ensuring that optimized structures remain operable even under damaged conditions. By selectively removing material stiffness in patches with a fixed shape, the complex phenomenon of local failure is modeled in fail-safe topology optimization. In this work, we first conduct a comprehensive study to explore the impact of patch size, shape, and distribution on the robustness of fail-safe designs. The findings suggest that larger sizes and finer distribution of material patches can yield more robust fail-safe structures. However, a finer patch distribution can significantly increase computational costs, particularly for 3D structures. To keep computational efforts tractable, an efficient fail-safe topology optimization approach is established based on the framework of multi-resolution topology optimization (MTOP). Within the MTOP framework, the extended finite element method is introduced to establish a decoupling connection between the analysis mesh and the topology description model. Numerical examples demonstrate that the developed methodology is 2 times faster for 2D problems and over 25 times faster for 3D problems than traditional fail-safe topology optimization while maintaining similar levels of robustness. [ABSTRACT FROM AUTHOR]

Extremophile organisms are known that can metabolize at temperatures down to − 25 °C (psychrophiles) and up to 122 °C (hyperthermophiles). Understanding viability under extreme conditions is relevant for human health, biotechnological applications, and our search for life elsewhere in the universe. Information about the stability and dynamics of proteins under environmental extremes is an important factor in this regard. Here we compare the dynamics of small Fe-S proteins – rubredoxins – from psychrophilic and hyperthermophilic microorganisms, using three different nuclear techniques as well as molecular dynamics calculations to quantify motion at the Fe site. The theory of ‘corresponding states’ posits that homologous proteins from different extremophiles have comparable flexibilities at the optimum growth temperatures of their respective organisms. Although ‘corresponding states’ would predict greater flexibility for rubredoxins that operate at low temperatures, we find that from 4 to 300 K, the dynamics of the Fe sites in these homologous proteins are essentially equivalent. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study is to reveal the influence mechanism of social innovation education (SIE) on sustainability learning outcomes and analyze the roles of intrinsic learning motivation and prosocial motivation. Design/methodology/approach: A sample of 322 undergraduates from one higher education institution in Tianjin was used to test the hypotheses. Findings: This study found that SIE positively affected sustainability learning outcomes, and intrinsic learning motivation mediated the relationship between them. The results showed that prosocial motivation positively moderates the positive effect of SIE on intrinsic learning motivation and the overall mediation model. Practical implications: The findings have important practical implications for higher education institutions to carry out SIE. Higher education institutions should focus on integrating social innovation and sustainability into top-level design. Furthermore, higher education institutions should focus on stimulating students' intrinsic learning motivation and cultivating their prosocial motivation. Originality/value: This study identified the relationship between SIE and sustainability learning outcomes and clarified the influence mechanism of SIE on sustainability learning outcomes. Moreover, this study emphasized the importance of prosocial motivation as a key boundary condition of SIE. [ABSTRACT FROM AUTHOR]

The convenient construction of carbon-based electrochemical immunosensors with high performance is highly desirable for the efficient detection of tumor biomarkers. In this work, an electrochemical immunosensor was fabricated by integrating a biofunctionalized mesoporous silica nanochannel film with a carbon-based electrode, which can enable the sensitive determination of carcinoembryonic antigen (CEA) in serum. The commonly used carbonaceous electrode, glassy carbon electrode (GCE), was employed as the supporting electrode and was pre-treated through electrochemical polarization to achieve the stable binding of a vertically ordered mesoporous silica film with amino groups (NH2-VMSF) without the use of any adhesive layer. To fabricate the immunorecognition interface, antibodies were covalently immobilized after the amino groups on the outer surface of NH2-VMSF was derivatized to aldehyde groups. The presence of amino sites within the high-density nanochannels of NH2-VMSF can facilitate the migration of negatively charged redox probes (Fe(CN)63-/4-) to the supporting electrode through electrostatic adsorption, leading to the generation of electrochemical signals. In the presence of CEA, the formation of immunocomplexes on the recognitive interface can reduce the electrochemical signal of Fe(CN)63-/4- on the supporting electrode. Based on this principle, the sensitive electrochemical detection of CEA was achieved. CEA can be determined to range from 0.01 ng mL−1 to 100 ng mL−1 with a limit of detection of 6.3 pg mL−1. The fabricated immunosensor exhibited high selectivity, and the detection of CEA in fetal bovine serum was achieved. [ABSTRACT FROM AUTHOR]

This study investigated the association of parity with hypertension prevalence in Japanese women while considering a clinical history of hypertensive disorders of pregnancy (HDP) and menopausal status. This cross‐sectional study included 30,530 Japanese women (6700 premenopausal; 23 830 postmenopausal). The association between parity and the prevalence of hypertension was evaluated using a multiple logistic regression model with possible confounders. In premenopausal women, no statistically significant association between parity and hypertension prevalence was found. When not adjusted for current body mass index (BMI), a linear graded association was observed between parity and the prevalence of hypertension in postmenopausal women. However, the association between parity and hypertension prevalence in postmenopausal women was attenuated after adjustment for current BMI. Both current BMI and a clinical history of HDP were significantly associated with a high risk of hypertension in both premenopausal and postmenopausal women. Our results also suggest that continuous surveillance and preventive measures for hypertension should be provided for women with HDP and high parity. [ABSTRACT FROM AUTHOR]

Small moving objects at far distance always occupy only one or a few pixels in image and exhibit extremely limited visual features, which bring great challenges to motion detection. Highly evolved visual systems endow flying insects with remarkable ability to pursue tiny mates and prey, providing a good template to develop image processing method for small target motion detection. The insects’ excellent sensitivity to small moving objects is believed to come from a class of specific neurons called small target motion detectors (STMDs). However, existing STMD-based methods often experience performance degradation when coping with complex natural scenes. In this paper, we propose a bio-inspired visual system with spatio-temporal feedback mechanism (called Spatio-Temporal Feedback STMD) to suppress false positive background movement while enhancing system responses to small targets. Specifically, the proposed visual system is composed of two complementary subnetworks and a feedback loop. The first subnetwork is designed to extract spatial and temporal movement patterns of cluttered background by neuronal ensemble coding. The second subnetwork is developed to capture small target motion information where its output and signal from the first subnetwork are integrated together via the feedback loop to filter out background false positives in a recurrent manner. Experimental results demonstrate that the proposed spatio-temporal feedback visual system is more competitive than existing methods in discriminating small moving targets from complex natural environments. [ABSTRACT FROM AUTHOR]

The response of cells to environmental stimuli, under either physiological or pathological conditions, plays a key role in determining cell fate toward either adaptive survival or controlled death. The efficiency of such a feedback mechanism is closely related to the most challenging human diseases, including cancer. Since cellular responses are implemented through physical forces exerted on intracellular components, more detailed knowledge of force distribution through modern imaging techniques is needed to ensure a mechanistic understanding of these forces. In this work, we mapped these intracellular forces at a whole-cell scale and with submicron resolution to correlate intracellular force distribution to the cytoskeletal structures. Furthermore, we visualized dynamic mechanical responses of the cells adapting to environmental modulations in situ. Such task was achieved by using an informatics-assisted atomic force microscope (AFM) indentation technique where a key step was Markov-chain Monte Carlo optimization to search for both the models used to fit indentation force–displacement curves and probe geometry descriptors. We demonstrated force dynamics within cytoskeleton, as well as nucleoskeleton in living cells which were subjected to mechanical state modulation: myosin motor inhibition, micro-compression stimulation and geometrical confinement manipulation. Our results highlight the alteration in the intracellular prestress to attenuate environmental stimuli; to involve in cellular survival against mechanical signal-initiated death during cancer growth and metastasis; and to initiate cell migration. Quantitative knowledge of internal force distribution in living cells is crucial to understand how cellular machinery responds mechanically to changes in the extracellular environment. Conventional force-sensing methods, which rely on pre-attached sensors, are incapable of providing whole-cell information with high spatial resolution. By machine learning assistance, we could improve AFM indentation's force sensitivity to a level that now enabled force (prestress) to be mapped on whole living cells with submicron resolution. The new capability revealed that cells actively redistribute forces among intracellular components to mitigate negative influence from the environment, and such response mechanisms could be used to understand ailing cellular states like cancer. [ABSTRACT FROM AUTHOR]

A nonlinear rotating piezoelectric energy harvester (N-RPEH) driven by eccentric wheels is proposed to collect rotational energy in the environment. Driven by external rotational motion, an eccentric wheel converts rotational motion into linear motion and realizes electrical energy output through magnetic coupling. To increase the effectiveness of the equipment's energy conversion process, this article aims to transform the rotational motion of an eccentric wheel into a linear motion of a motion board. The effects of the motion board's length L, the cylindrical magnet's height H, and the mass block M at the piezoelectric patch's end on the output performance of N-RPEH are explained by theoretical modeling and simulation. Through theoretical analysis, simulation, and experiment, it is found that when L = 120 mm, H = 6 mm, and M = 5.0 g (medium mass), the output voltage reaches the maximum of 14.16 V. Under this parameter, N-RPEH can produce a maximum power of 7.0688 mW when the external resistance value is 2 kΩ. Application experiments show that N-RPEH can light up 60 light-emitting diodes. Therefore, the proposed N-RPEH can effectively collect rotational energy and has a wide range of potential applications in wireless sensor networks. [ABSTRACT FROM AUTHOR]

This article investigates the application of the pulse voltage method for detecting interturn short-circuit faults in the high-voltage windings of dry-type voltage transformers. We determined the characterization parameters of the high-voltage windings of dry-type voltage transformers and trends in the variation of the characterization parameters with frequency in the presence and absence of faults. The viability of using the pulse voltage method for the detection of interturn short-circuit faults in dry-type voltage transformers was analyzed. A pulse voltage test platform was designed to analyze the response voltage waveforms using pulse-oscillating voltage experiments on transformers with various short-circuit faults. The results demonstrate that during a turn-to-turn short circuit, the equivalent resistance and inductance of a high-voltage winding are significantly lowered. When employing the pulse voltage method to investigate interturn short-circuit faults, tiny inductors are connected in parallel to produce an oscillating voltage waveform that is more uniform. Upon incurring a short circuit between turns, the pulse's oscillating voltage frequency increases. The greater the number of turns in the short-circuit fault is, the more significant the effect of the test. [ABSTRACT FROM AUTHOR]

We have performed and analyzed the first combined 151Eu and 57Fe nuclear resonant vibrational spectroscopy (NRVS) for naturally abundant KEu(III)[Fe(II)(CN)6] and Eu(III)[Fe(III)(CN)6] complexes. Comparison of the observed 151Eu vs.57Fe NRVS spectroscopic features confirms that Eu(III) in both KEu(III)[Fe(II)(CN)6] and Eu(III)[Fe(III)(CN)6] occupies a position outside the [Fe(CN)6] core and coordinates to the N atoms of the CN− ions, whereas Fe(III) or Fe(II) occupies the site inside the [Fe(CN)6]4− core and coordinates to the C atoms of the CN− ions. In addition to the spectroscopic interest, the results from this study provide invaluable insights for the design and evaluation of the nanoparticles of such complexes as potential cellular contrast agents for their use in magnetic resonance imaging. The combined 151Eu and 57Fe NRVS measurements are also among the first few explorations of bi-isotopic NRVS experiments. [ABSTRACT FROM AUTHOR]

Dickkopf‐related protein (DKK) 3, a member of the DKK family, is a secreted glycoprotein that acts as a modulator of Wnt signaling in organogenesis and carcinogenesis. Recent studies have demonstrated that DKK3 has a variety of functions, suggesting that it plays roles not only in tumorigenesis, but also tumor neovascularization, prostatic acinus formation, cardiac vascular remodeling, renal and cardiac fibrosis, and immunological activity. The function of DKK3 is therefore of great interest, but details of the receptors and mechanisms involved have remained unclear. Here, we focused on the extracellular function of DKK3 as a secreted protein, and identified transforming growth factor beta induced protein ig‐h3 (TGFBI) as a secreted protein interacting with DKK3. To investigate the function of these secreted proteins, we employed an in vitro cell model involving human hepatocellular carcinoma cells, human embryonic kidney cells, or non‐neoplastic hepatocyte cells. We showed that DKK3 functions as an extracellular matrix‐like molecule supporting adhesion, motility, and invasion, and that its interaction with TGFBI inhibits the functions of secreted DKK3 in cells expressing both proteins. These results suggest that this extracellular interaction between DKK3 and TGFBI modulates cell adhesion and motility through focal adhesion kinase signaling, and that this might serve as a potential therapeutic target in the context of cancer invasion and metastasis. [ABSTRACT FROM AUTHOR]

Medulloblastoma (MB) is an embryonal tumor of the cerebellum, which commonly occurs in childhood. Herein, we investigated the effects of miR-222-3p on the formation of MB stem-like cells via the Notch2/c-myc pathway. Quantitative real-time PCR (qRT-PCR) or western blotting was performed to determine the expression of miR-222-3p and Notch2, c-myc, proliferating cell nuclear antigen (PCNA), and caspase-3. Luciferase reporter gene, RNA immunoprecipitation (RIP), and RNA pull-down assay were applied to confirm the interaction between miR-222-3p and Notch2. Cell growth was examined by Cell Counting Kit-8. Cell cycle distribution and the number of stem cell marker CD133+ cells were examined using flow cytometry. The sphere formation assay was performed. miR-222-3p expression was decreased and Notch2 expression was increased in human medulloblastoma cells. miR-222-3p overexpression inhibited cell viability and the sphere formation, induced cell cycle arrest, decreased the number of CD133+ cells, and up-regulated caspase-3 expression and down-regulated PCNA, Notch2, and c-myc expression. However, Notch2 overexpression counteracted these effects of miR-222-3p overexpression. Simultaneous overexpression of Notch2 and miR-222-3p increased the c-myc promoter-luciferase activity which was decreased by miR-222-3p overexpression. Luciferase reporter gene, RIP, and RNA pull-down assay revealed that miR-222-3p targeted Notch2. MiR-222-3p suppressed cell viability, altered cell cycle distribution, and inhibited the formation of MB stem-like cells via the Notch2/c-myc pathway. [ABSTRACT FROM AUTHOR]

[Display omitted] • HEA catalysts for electrolysis under acidic conditions summarized. • Differences between PEMWE and alkaline water electrolysis discussed. • HEA catalysts categorized based on presence of precious metals. • The future of HEA catalysts for water electrolysis is envisioned in the manuscript. The gradual deterioration of the energy environment has led to excessive carbon dioxide emissions, making it urgent to seek more environmentally friendly alternative energy sources. In this context, hydrogen as a green energy source has become increasingly important. Currently, water electrolysis is one of the main methods for hydrogen production. The ultimate goal of hydrogen production industry is to produce green hydrogen using renewable energy sources. Compared to the currently widely commercialized alkaline electrolysis (ALK), the initial commercialization of proton exchange membrane (PEM) electrolysis has many advantages, including short start-up time, high current density, high load elasticity, and high operating pressure. Commercial acidic water electrolysis usually relies on precious metal-based catalysts such as Ir/Pt, but high-entropy alloys are expected to reduce the use of precious metals, thereby saving costs, and high-entropy alloys have the characteristic of corrosion resistance. This paper introduces the latest research progress in the field of high-entropy alloy acidic water electrolysis catalysts, briefly outlining the advantages of acidic water electrolysis, and summarizing the progress of high-entropy alloy catalysts in HER and OER, as well as classifying based on the presence of precious metals. Finally, the challenges and opportunities faced by high-entropy alloy catalysts for acidic water electrolysis are discussed. [ABSTRACT FROM AUTHOR]

The design philosophy of fail-safe structures was first proposed in the aerospace industry to provide redundant load paths as back-ups when local damage happens. Most fail-safe topology optimization methods paid more attention to minimizing compliance of the worst failure case. However, the stress concentration due to local failure may lead to secondary damage and further destroy the structure. In the current work, the von Mises stress of damaged structures is considered as the optimization objective, to alleviate the stress concentration caused by possible local failures. Two sorts of topology optimization objectives are investigated: (1) the worst-case formulation; (2) the mean-performance formulation. To avoid the ‘singularity’ problem, the stress is penalized through the RAMP interpolation scheme. The Kreisselmeier-Steinhauser (KS) aggregation function is used to approximate the global stress level. Concerning the highly nonlinear stress behavior, the Method of Moving Asymptotes (MMA) solver is adopted. Finally, the benefits and drawbacks of these two objective functions are systematically compared and discussed through several numerical examples. [ABSTRACT FROM AUTHOR]

In recent years, there is a growing interest in the role of bioactive peptides obtained from natural food resources such as animal muscle proteins. Bioactive peptides/enzymatic protein hydrolysates are biomolecules broken down from proteins due to enzymatic hydrolysis, which usually contain 2–20 amino acids units with significant biological properties including antioxidant, anti-diabetic, and anti-cancer activities. Protein hydrolysates or peptides provide a natural therapeutics for controlling diabetes (type-II) by reducing amylase enzymatic activity and degrade the natural incretin hormone involved in blood glucose regulation. Such biological properties of peptides are highly correlated to sequence of amino acids and size. These bioactive molecules can be isolated, purified, and identified following different approaches such as gel filtration chromatography, Mass spectrometry approaches among others. In general, the animal muscles could be used as sustainable protein sources in the production of bioactive peptide-based functional foods and natural drugs for preventing chronic diseases. This review article aims to summarize the antioxidant, anti-diabetic, and anti-cancer activities of muscle proteins hydrolysates and purified bioactive peptides. [Display omitted] • This review paper discusses on functionality and bioactive characteristics of peptides. • Bioactive peptides can be produced through several enzymatic hydrolysis. • Specific bioactive peptides can be purified through different novel approaches. • Polar and non-polar peptides has anti-cancer and anti-diabetic properties. [ABSTRACT FROM AUTHOR]

Although the anti-inflammatory properties of developmental endothelial locus-1 (DEL-1) are well known, few studies have examined the role of DEL-1 in spinal cord injury (SCI). Here, the protective effect of DEL-1 on SCI was investigated using hypoxia/recovery (H/R) injury of astrocytes and a mouse SCI model. The effects of DEL-1 overexpression/silencing on primary astrocytes were assessed by flow cytometry, immunofluorescence, and western blotting. Female Sprague-Dawley rats were intrathecally injected with recombinant adeno-associated virus (AAV) at T10, and DEL-1 was permanently expressed. Protein levels in the spinal cord, functional testing, and electrophysiology, pathology, and immunofluorescence were all measured after treatment. DEL-1 overexpression significantly increased the expression of SIRT1/SERCA2At the same time, inflammation, endoplasmic reticulum stress, and apoptosis were all significantly inhibited, the motor function of SCI rats was noticeably restored, and the myelin sheath of the injured site was more complete. Furthermore, after DEL-1 silencing SIRT1/SERCA2 expression decreased, while inflammation, endoplasmic reticulum stress, and apoptotic responses increased significantly. DEL-1 treatment, however, did not increase SERCA2 expression after SIRT1 silencing. These findings demonstrate that DEL-1 protects against SCI via SIRT1/SERCA2 signaling, promoting spinal neural recovery. • DEL-1 protects astrocytes from H/R injury through SIRT1/SERCA2 signaling pathway. • DEL-1 protects SCI in mice through SIRT1/SERCA2 signaling pathway. • DEL-1 promoted the recovery of motor function in SCI mice. • DEL-1 provides a new perspective and a potential target for SCI. [ABSTRACT FROM AUTHOR]

Laser cladding CoCrFeNiTiNbB1.25 High entropy alloy coatings on H13 steel was aging treated at 750 °C for 3, 5 and 10 h, respectively. The effect of aging treatment time on the phase constitute, microstructure and wear resistance of the coatings was investigated systematically. The results showed that the phase constitute of the coatings was not changed before and after aging treatment, the volume fraction of TiB phase was gradually increased as aging treatment time increased, and the diffraction peak of fcc phase at 42.98° was gradually shifted to right. The microstructure of the coatings consisted of the typical dendrite, interdendritic structure and dispersed intermetallic compound, the number and size of in-situ TiB dispersed were gradually increased as aging treatment time increased, and the dendrite was not obviously coarsened. The microhardness and wear resistance of the coatings were gradually increased as the aging treatment time increased. Compared with the coatings before aging treatment, the microhardness of the coatings after aging treatment for 10 h was increased by 3.60% and the wear rate was decreased by 3.57%, respectively. The wear mechanism of the coatings before aging treatment was the abrasive wear, and translated into the abrasive wear and adhesive wear after aging treatment. The results of the applied multivariate statistical analysis showed that the aging treatment time had a significant influence on the high entropy alloy coatings. [ABSTRACT FROM AUTHOR]

Hybrid organic framework materials are a class of hierarchical porous crystalline materials that have emerged in recent years, composed of three types of porous crystal materials, namely metal-organic frameworks (MOFs), covalent organic frameworks (COFs), and hydrogen-bonded organic frameworks (HOFs). The combination of various organic framework properties in hybrid organic frameworks generates synergistic effects, which has attracted widespread attention from researchers. The synthesis methods of hybrid organic frameworks are also an intriguing topic, enabling the formation of core-shell heterostructures through epitaxial growth, template conversion, medium growth, or direct combination. These hybrid organic framework materials have demonstrated remarkable performance in the application of photocatalytic wastewater purification and have developed various forms of applications. This article reviews the preparation principles and methods of various hybrid organic frameworks and provides a detailed overview of the research progress of photocatalytic water purification hybrid organic frameworks. Finally, the challenges and development prospects of hybrid organic framework synthesis and their application in water purification are briefly discussed. [Display omitted] [ABSTRACT FROM AUTHOR]

This article develops a multi-resolution topology optimization (MTOP) approach based on the solid isotropic material with penalization (SIMP) method, which is effective in obtaining high-resolution designs at low computational cost. The extended finite element method (XFEM) is employed to decouple the analysis mesh, material description and nodal design variables. By the advantage of XFEM at modelling material discontinuity, detailed geometrical features are generated on a coarse analysis mesh. To obtain a clear interface between material grids, a variation of the traditional sensitivity filter is introduced to produce discrete solutions. The low computational costs make the proposed approach appropriate for dealing with problems requiring a high number of finite element analysis (FEA) processes, typically high-resolution/large-scale models, stress minimization, etc. Accurate von Mises stress is calculated on a high number of Gaussian points, making the approach perform better at stress minimization. Then, several 2D and 3D examples optimized by different solvers are illustrated to demonstrate the effectiveness and excellent generality of the proposed approach. [ABSTRACT FROM AUTHOR]

CoCrFeNiTiNbBx high entropy alloy coatings were prepared on AISI H13 steel using laser cladding. The effect of the boron content on the microstructure and wear resistance of the coatings was systematically investigated. Results showed that a TiB phase was formed in situ after adding boron, which promoted the formation of short rod-like dendrites and equiaxed crystals in the coatings underlying brittle fractures of massive coarse dendrites. The formation of macrocracks was not observed in the coatings after adding boron. The microstructure was more fine and uniform as the boron content increased. The microhardness and wear resistance of the coatings were gradually increased with the increase in the boron content. The microhardness and mass loss of the coatings were 1.25 and 0.61 times that of the coatings without boron, respectively, for a boron content of 1.25. The wear mechanism of the coatings was the adhesive wear and abrasive wear when the boron content was less than 1.0, and the abrasive wear when the boron content was not less than 1.0. [ABSTRACT FROM AUTHOR]

Metal–organic frameworks have been a new type of adsorbent in environmental remediation due to their simple preparation processes and stable chemical properties in water. However, they are limited by their low adsorption capacities to some organic pollutants. Herein, ZIF-67 nanoparticles with a high Brunauer, Emmett and Teller (BET) surface area were designed and successfully synthesized by a time-saving, low cost, and environment liquid phase synthesis method at room temperature. The physicochemical properties of ZIF-67 nanoparticles were well studied by various measurements, such as x-ray diffraction, BET analysis, and scanning transmission microscopy. Meanwhile, the ZIF-67 nanoparticles with the stable structure are introduced as the adsorbent for trapping brilliant green in pollutant water, exhibiting the ultra-high adsorption capacity of 1989 mg g−1 due to their high specific surface area (425 m2 g−1) and the interaction between π–π and the benzene ring. Moreover, the ZIF-67 showed acceptable reusability after regeneration with ethanol. Evidently, the ZIF-67 nanoparticles show excellent adsorption performances for organic dyes. This work can give a new application to zeolite imidazole framework materials in water treatment. [ABSTRACT FROM AUTHOR]

Pulmonary hypertension (PAH) is a cardiopulmonary disease in which pulmonary artery pressure continues to rise, leading to right heart failure and death. Otud6b is a member of the ubiquitin family and is involved in cell proliferation, apoptosis and inflammation. The aim of this study was to understand the role and mechanism of Otud6b in PAH. C57BL/6 and Calpain-1 knockout (KO) mice were exposed to a PAH model induced by 10% oxygen. Human pulmonary artery endothelial cells (HPACEs) and human pulmonary artery smooth muscle cells (HPASMCs) were exposed to 3% oxygen to establish an in vitro model. Proteomics was used to determine the role of Otud6b and its relationship to Calpain-1/HIF-1α signaling. The increased expression of Otud6b is associated with the progression of PAH. ROtud6b activates Otud6b, induces HIF-1α activation, increases the production of ET-1 and VEGF, and further aggravates endothelial injury. Reducing Otud6b expression by tracheal infusion of siOtud6b has the opposite effect, improving hemodynamic and cardiac response to PAH, reducing the release of Calpain-1 and HIF-1α, and eliminating the pro-inflammatory and apoptotic effects of Otud6b. At the same time, we also found that blocking Calpain-1 reduced the effect of Otud6b on HIF-1α, and inhibiting HIF-1α reduced the expression of Calpain-1 and Otud6b. Our study shows that increased Otud6b expression during hypoxia promotes the development of PAH models through a positive feedback loop between HIF-1α and Calpain-1. Therefore, we use Otud6b as a biomarker of PAH severity, and regulating Otud6b expression may be an effective target for the treatment of PAH. [ABSTRACT FROM AUTHOR]

We conducted an in situ study on CFRP fracturing process using atomic-force-microscopy-based stress-sensitive indentation. Tensile stress distribution during fracture initiation and propagation was directly observed quantitatively. It led to a discovery that previously believed catastrophic fracture of individual carbon fiber develops in a controllable manner in the polymer matrix, exhibiting 10 times increase of fracture toughness. Plastic deformation in crack-bridging polymer matrix was accounted for the toughening mechanism. The model was applied to explain low temperature strength weakening of CFRP bulk material when matrix plasticity was intentionally 'shut down' by cryogenic cooling. [ABSTRACT FROM AUTHOR]

This paper presents a computationally efficient multi-resolution topology optimization framework by establishing a novel bi-directional evolutionary structure optimization (BESO) method based on extended finite element method (XFEM). In the proposed framework, the high-resolution designs preserving the topological complexity can be obtained with low degree of freedoms (DOFs). The implementation of the presented multi-resolution optimization framework takes good use of the ability of XFEM at accurately modeling material discontinuities within one element. On the basis of XFEM, a strategy of triangulated partition and a new material interpolation model are introduced to represent the finer material distribution. We employ the coarser finite element (FE) mesh to perform the finite element analysis, the sub-parts partitioned from finite elements to describe material properties and the nodal design variables to perform the optimization. To circumvent artificially stiff patterns, a modified sensitivity filter is applied to regularize the solution. The effectiveness and high efficiency of the presented approach are highlighted by typical 2D and 3D examples. [ABSTRACT FROM AUTHOR]

Surface-enhanced Raman spectroscopy (SERS) is a powerful tool for sensing, which can detect a broad range of chemical and biological analytes at the single-molecule level. In this work, a hybrid structure of Au nanodot array and high-quality graphene monolayer is used as SERS substrate, which integrates the electromagnetic enhancement from Au nanodots and chemical enhancement from monolayer graphene. The fabricated SERS substrates consist of uniform round top shape Au nanodot array with coverage of 36.9% where their diameter and gap distribution ranges from ~ 33 to ~ 42 nm and from ~ 22 to ~ 28 nm. The hybrid Au nanodot array/monolayer Gr SERS substrate exhibited a 4.67 times enhanced Raman signal compared to Au nanodots without Gr at the R6G concentration of 10−6 M. The detection limit of R6G is achieved as low as 4.69 × 10−9 M on the Au nanodot array/Gr SERS substrate. These experiments demonstrate a facile approach to fabricate hybrid metal nanostructure/2D materials SERS substrate for biomedical and environmental sensing and provide a clue for high-performance optoelectronic devices. [ABSTRACT FROM AUTHOR]

Elastic modulus measured through atomic force microscopy (AFM)-based indentation on single carbon fiber (CF) is found with dependence on lateral applied stress. An in situ indentation experiment inside a high-resolution transmission electron microscope was performed to quantitatively understand this phenomenon by observing microstructure change in the indented area. Change of graphitic basal plane misalignment angle during indentation was linked to a continuous change of modulus with the help of finite element simulation. The established relationship between modulus and indentation force was further used to calculate residual stress distribution in CF imbedded in a CF reinforced polymer composite using the AFM indentation technique. The stress-induced formation of nanoscale defects in the CF and their transformation into fracture were directly characterized. [ABSTRACT FROM AUTHOR]

Although bi-directional evolutionary structural optimization (BESO) has the advantages of a simple concept and clear-cut solutions, the edges of the optimal solution are normally non-smooth. This article proposes an approach that directly represents the smooth structure using finite elements. The pseudo-auxiliary line is introduced to make the staggered boundary approach a smooth one, and a rule is presented to make the boundary element deformable to describe the structure's edges. To improve the efficiency, the game of building blocks is incorporated into the classical BESO algorithm. A set of basic blocks is predefined and is positioned in a suitable location to assemble the optimal structure. In this way, the optimal structure has better mechanical performance and smooth edges with acceptable computational cost. The roundness of corners is easily controlled by adjusting the configuration of the basic blocks. Several two- and three-dimensional numerical examples investigate the effects of the parameters of auxiliary lines and the shape of basic blocks on the boundary smoothness and optimization performance. The efficiency of the proposed method is justified through these examples. [ABSTRACT FROM AUTHOR]

Energy, as an indispensable part of human life, has been a hot topic of research among scholars. The water kinetic energy generated by ocean currents, as a kind of clean energy, has high utilization rate, high power generation potential, and a broad prospect of powering microelectronic devices. As a result, the water kinetic piezoelectric energy harvester (WKPEH) has made significant progress in powering ocean sensors by harvesting ocean currents. This paper provides a comprehensive review of technologies that have been used in recent years to harvest energy from marine fluids using WKPEH. Detailed study of the energy harvesting mechanism of WKPEH. WKPEH can use the flutter-induced vibrations, vortex-induced vibrations, and wake oscillation principles to harvest water kinetic energy. The structural characteristics and output performance of each mechanism are also discussed and compared, and finally, a prospect on WKPEH is given. [ABSTRACT FROM AUTHOR]

Detecting small moving targets consisting of one or few pixels is technically demanding due to their limited visual features. Motivated by nature, some bio-inspired models have been developed that simulate the behavior of small target motion detectors (STMDs), a class of specialized neurons found in insects' visual neural systems dominating in detecting small moving targets during activities such as predation or courtship. However, the existing models' high dependence on the sampling frequency of input videos becomes a bottleneck that seriously hinders their real-time applications in the physical world. This is because massive computational power is required to capture and process high-sampling-frequency videos. While model detection performance in low-sampling-frequency videos is plagued by significant spatial errors and weak responses. To address these issues, we propose an STMD-based visual neural model with a fractional-order difference operator for small target motion detection. The fractional-order operator captures instantaneous luminance change and integrates it with memory information, where the instantaneous information dominates the integrated signal. The STMD network further separates the rising and falling luminance components, which are aligned in the time domain and then multiplied to predict the location of moving small targets. Due to the rapid response of instantaneous information and the supplement of memory information, the proposed model locates the small moving targets accurately and robustly in low-sampling-frequencies. Numerical experiments show that the proposed model significantly improves the detection performance for low-sampling-frequency videos. [ABSTRACT FROM AUTHOR]

Motion perception is a critical capability determining a variety of aspects of insects' life, including avoiding predators, foraging, and so forth. A good number of motion detectors have been identified in the insects' visual pathways. Computational modeling of these motion detectors has not only been providing effective solutions to artificial intelligence, but also benefiting the understanding of complicated biological visual systems. These biological mechanisms through millions of years of evolutionary development will have formed solid modules for constructing dynamic vision systems for future intelligent machines. This article reviews the computational motion perception models originating from biological research on insects' visual systems in the literature. These motion perception models or neural networks consist of the looming-sensitive neuronal models of lobula giant movement detectors (LGMDs) in locusts, the translation-sensitive neural systems of direction-selective neurons (DSNs) in fruit flies, bees, and locusts, and the small-target motion detectors (STMDs) in dragonflies and hoverflies. We also review the applications of these models to robots and vehicles. Through these modeling studies, we summarize the methodologies that generate different direction and size selectivity in motion perception. Finally, we discuss multiple systems integration and hardware realization of these bio-inspired motion perception models. [ABSTRACT FROM AUTHOR]

Dendrobium nobile is a medicinal herb in traditional China and Southeast Asian countries. Employing a rat model of ethanol-induced gastric ulcer, we examined the protective effect of polysaccharide (JCP) extracted from Dendrobium nobile and explored the related mechanisms. Oral administration with 100 mg/kg and 300 mg/kg body weight JCP for days can significant prevent the formation of gastric ulcer. Moreover, JCP pretreatment could alleviate ethanol-induced histological damage, antioxidant activities, the level of epidermal growth factor, gastric concentration of prostaglandin E, and regulate the signaling pathways of mitogen-activated protein kinases and matrix metalloproteinases. This study investigated the ethanol-induced gastric ulcer protective effect of JCP for the first time, and elucidated that the protective mechanisms. [ABSTRACT FROM AUTHOR]

• Thousands of heterogenic experimental targets have been analyzed. • Particle swarm optimization algorithm has been applied. • The modeling uncertainties and uncertainty contributions have been evaluated. • The correlation between key reactions has been revealed. In this work, we propose a novel data-driven framework for detailed kinetic mechanisms optimization applying the heuristic algorithm, namely canonic Particle Swarm Optimization (PSO). The PSO is more effective and robust in coping with uncertainties and incomplete information than deterministic and probabilistic optimization algorithms and is more suitable for machine learning applications. In the proposed framework, to avoid trapping in a local minimum, 1000 local optimums have been obtained and statistically handled to select the final feasible model parameter set with reduced uncertainty intervals and parameter correlations. The developed framework was successfully used for the optimization of the joint H 2 and syngas oxidation chemical kinetic model. The data set collected for the model optimization includes 41 reactions and 16 species, and 3000 experimental data targets supplied with uncertainty boundaries measured in shock tubes, jet stirred reactors, plug flow reactors, and premixed laminar flames under wide ranges of temperature, pressure, equivalence ratio, and H 2 /CO ratios. The initially estimated uncertainties of the reaction rate constants for 15 key reactions were significantly constrained. The reaction rate constants for the H 2 oxidation sub-model were re-optimized and their uncertainties were further reduced. [ABSTRACT FROM AUTHOR]

The reaction of protein-bound iron-sulfur (Fe-S) clusters with nitric oxide (NO) plays key roles in NO-mediated toxicity and signaling. Elucidation of the mechanism of the reaction of NO with DNA regulatory proteins that contain Fe-S clusters has been hampered by a lack of information about the nature of the iron-nitrosyl products formed. Herein, we report nuclear resonance vibrational spectroscopy (NRVS) and density functional theory (DFT) calculations that identify NO reaction products in WhiD and NsrR, regulatory proteins that use a [4Fe-4S] cluster to sense NO. This work reveals that nitrosylation yields multiple products structurally related to Roussin's Red Ester (RRE, [Fe2(NO)4(Cys)2]) and Roussin's Black Salt (RBS, [Fe4(NO)7S3]. In the latter case, the absence of 32S/34S shifts in the Fe−S region of the NRVS spectra suggest that a new species, Roussin's Black Ester (RBE), may be formed, in which one or more of the sulfide ligands is replaced by Cys thiolates. [ABSTRACT FROM AUTHOR]

The reaction of protein-bound iron-sulfur (Fe-S) clusters with nitric oxide (NO) plays key roles in NO-mediated toxicity and signaling. Elucidation of the mechanism of the reaction of NO with DNA regulatory proteins that contain Fe-S clusters has been hampered by a lack of information about the nature of the iron-nitrosyl products formed. Herein, we report nuclear resonance vibrational spectroscopy (NRVS) and density functional theory (DFT) calculations that identify NO reaction products in WhiD and NsrR, regulatory proteins that use a [4Fe-4S] cluster to sense NO. This work reveals that nitrosylation yields multiple products structurally related to Roussin's Red Ester (RRE, [Fe2(NO)4(Cys)2]) and Roussin's Black Salt (RBS, [Fe4(NO)7S3]. In the latter case, the absence of 32S/34S shifts in the Fe−S region of the NRVS spectra suggest that a new species, Roussin's Black Ester (RBE), may be formed, in which one or more of the sulfide ligands is replaced by Cys thiolates. [ABSTRACT FROM AUTHOR]

Polyethylene glycol (PEG) as a green solvent was employed to extract polysaccharide. The optimal conditions for PEG-based ultrasonic extraction of Dendrobium nobile Lindl. polysaccharide (JCP) were determined by response surface methodology. Under the optimal conditions: extraction temperature of 58.5 °C; ultrasound power of 193 W, and the concentration of polyethylene glycol-200 (PEG-200) solution of 45%, the highest JCP yield was obtained as 15.23 ± 0.57%, which was close to the predicted yield, 15.57%. UV and FT-IR analysis revealed the general characteristic absorption peaks of both JCP with water extraction (JCP w ) and PEG-200 solvent extraction (JCP p ). Thermal analysis of both JCPs was performed with Thermal Gravimetric Analyzer (TGA) and Differential Scanning Calorimeter (DSC). Antioxidant activities of two polysaccharides were also compared and no significant difference in vitro was obtained. [ABSTRACT FROM AUTHOR]

The composite-structure protective systems in head-on collision with objects are largely subjected to dynamic compression load along the thickness of composite structure. A typical plain weave aramid fabric reinforced polyamide (PA) composite, which is defined as one of single polymer composites (SPCs), is addressed in this paper. Firstly, in the process of sample preparation, processing characteristics of the single polymer composites are skillfully achieved and discussed using differential scanning calorimetry (DSC) and capillary rheometer. Secondly, the out-of-plane compression properties of the composite are studied on Split Hopkinson Pressure Bar (SHPB) apparatus in the strain rate range of 400–1200s −1 . Effects of fiber content and strain rate on dynamic off-plane compression properties are investigated and quasi-static properties are obtained on a universal testing machine as a comparison. Results provide a basis for selecting composite composition and lay-up for designing armor with improved impact resistance. Additionally, penetration of the resin through the fabric is observed by the digital microscope and the internal damage of the laminates is qualitatively predicted by the microstructure of the internal fabric yarns. [ABSTRACT FROM AUTHOR]

Traditional cotton water dyeing has a considerable ecological impact because of the use of water, but the available anhydrous cotton dyeing technologies cannot balance low recyclable energy consumption and excellent dyeing effects. In this study, a recyclable anhydrous cotton dyeing technology was designed and implemented by mixing supercritical carbon dioxide, dimethyl sulfoxide, and ethanol for the first time. Compared to the existing anhydrous cotton dyeing technologies, the novel technology could simultaneously obtain low recyclable energy consumption and excellent dyeing effects, such as dye penetration, washing and crocking fastness, levelness, color depth control and color matching. The dye fixations of reactive dyes in the novel technology are 5.1%–26.4% higher than those in traditional water dyeing. Meanwhile, the energy consumption of the novel technology is only 70% of that of traditional water dyeing, and the comprehensive cost of materials and energy of the novel technology is only 56% of that of traditional water dyeing. It is a new green option with low energy consumption for cotton dyeing. [Display omitted] • No water involves in SC-CO 2 /EtOH/DMSO multi-medium dyeing. • All dyeing media of SC-CO 2 /EtOH/DMSO multi-medium dyeing are recyclable. • SC-CO 2 /EtOH/DMSO multi-medium dyeing is a low-energy process. • SC-CO 2 /EtOH/DMSO multi-medium dyeing has excellent dyeing effects. [ABSTRACT FROM AUTHOR]

Effect of gypenosides on porcine pancreatic lipase (PL) activity was determined in vitro. Gypenosides inhibited the PL activity in a dose-dependent manner at the concentrations of 0-1.0 mg/ml. The Lineweaver-Burk plots for gypenosides indicated that the inhibition on PL by gypenosides was noncompetitive. The conformation of PL was investigated by means of circular dichroism and fluorescence. The result revealed the decrease in α-helix contents, increase in β-sheet and the decrease in fluorescence intensity after gypenosides treatment. The incorporation of cholesterol into micelles was inhibited by gypenosides. A complex was observed by transmission electron microscopy, indicating interaction between cholesterol and gypenosides which led to the decrease in cholesterol micelle solubility. The result revealed the fact that gypenosides played a role in inhibiting PL activity and reducing intestinal cholesterol absorption via inhibition of micelle formation. [ABSTRACT FROM AUTHOR]

This study investigated the hypocholesterolaemic effects of bitter melon aqueous extracts (BMAE) in vitro, the inhibitory effects of BMAE on pancreatic cholesterol esterase (CEase) and incorporation of cholesterol into micelles were investigated. BMAE decreased the in vitro micellar solubility of cholesterol in a dose-dependent manner. The conformation of CEase was investigated by means of circular dichroism (CD) and fluorescence. The result revealed the decrease of α-helix contents, increase of β-sheet and exposure of aromatic amino acid residuals. The incorporation of cholesterol into micelles was inhibited by BMAE. A complex was observed by transmission electron microscopy (TEM), which indicated interaction between cholesterol and BMAE. The result revealed that BMAE can play a role in decreased intestinal cholesterol absorption via inhibition of CEase, and of micelle formation. [ABSTRACT FROM AUTHOR]

Direct spectroscopic evidence for a hydride bridge in the Ni-R form of [NiFe] hydrogenase has been obtained using iron-specific nuclear resonance vibrational spectroscopy (NRVS). The Ni-H-Fe wag mode at 675 cm−1 is the first spectroscopic evidence for a bridging hydride in Ni-R as well as the first iron-hydride-related NRVS feature observed for a biological system. Although density function theory (DFT) calculation assisted the determination of the Ni-R structure, it did not predict the Ni-H-Fe wag mode at ∼675 cm−1 before NRVS. Instead, the observed Ni-H-Fe mode provided a critical reference for the DFT calculations. While the overall science about Ni-R is presented and discussed elsewhere, this article focuses on the long and strenuous experimental journey to search for and experimentally identify the Ni-H-Fe wag mode in a Ni-R sample. As a methodology, the results presented here will go beyond Ni-R and hydrogenase research and will also be of interest to other scientists who use synchrotron radiation for measuring dilute samples or weak spectroscopic features. [ABSTRACT FROM AUTHOR]

This paper proposes a rotating piezoelectric energy harvester for automotive motion (PEH). A mechanical tuning method is used to optimize the output performance of the harvester, including changing the tip mass of the piezoelectric cantilever beam and the base mass. The motion state and natural frequency were analyzed by simulation. An electromechanical coupling model was established through Hamilton's principle and Bernoulli beam theory to theoretically analyze the movement state of the PEH. The power generation performance of PEH under different environmental excitations was tested by experimental methods, and the effect of self-excited vibration on its power generation performance was investigated to test the output variation of the system under different speed changes. Experiments show that when the pulse frequency of the stepper motor is 1700Hz, the tip mass of the piezoelectric cantilever beam is 5.6g, the rotation angle of the support is 0°, the counterweight of the base is 31.6g, and the resistance is 1kΩ, respectively, the harvester output power can reach 6.25 mW. Finally, Finally, the future development of harvester is discussed. [ABSTRACT FROM AUTHOR]

• Hundreds of heterogenic experimental targets have been analyzed. • The Monte Carlo simulation and polynomial regression have been applied. • The modeling uncertainties and uncertainty contributions have been evaluated. • The optimized model demonstrates a good prediction ability. A 19-reactions H 2 oxidation chemical kinetic model has been optimized with uncertainty quantification. The uncertainties of the reaction rate constant (RRC) parameters have been first estimated based on the recommended direct measurements and review works. This deterministic approach was further combined with the probabilistic treatment of RRC to decrease the uncertainty intervals and to extend the temperature validity range for RRCs with the highest uncertainty level, for which two quantities, discrepancy measures and uncertainty contributions, were introduced in the developed framework. Monte Carlo simulations with randomly sampled RRCs and polynomial regression were performed to develop the response surface with high coefficients of determination to be utilized in the model optimization procedure.10 key channels were selected for further optimization, and the probability density functions were calculated on the basis of discrepancy measures for 4 channels to reduce their large uncertainty intervals. The training set was collected from carefully validated measured data following experiments of shock tubes, rapid compression machines, jet stirred reactors, plug flow reactors, and premixed laminar flames. Inconsistent experimental targets were fixed and excluded from considerations. The optimized chemical kinetic model demonstrates good predicting ability for the H 2 combustion experimental data from both the training set and the conditions outside the tested range (blind modeling). [ABSTRACT FROM AUTHOR]

The double layer capacitance per weight of graphene (GN) flakes in aqueous solution at the polarized potential increases with a decrease in the ac-frequency, obeying the inverse of the power law of the frequency. The power law is demonstrated to be equivalent to the constant phase element. The frequency-dependence increases with the thickness of the GN films. Thus, the lower the frequency and the thinner the film is, the larger is the capacitance density per weight. This is confirmed by cyclic voltammetry for several thickness of GN films and several scan rates. Resistance-like voltammograms at thick films are caused by frequency-dispersion. The overall capacitive properties of the GN films are as follows: the thickness of one GN flake is estimated to be 2 nm in average from the comparison of the thickness with the capacitances at the HOPG, which is consistent with values by the STM and AFM images. [ABSTRACT FROM AUTHOR]

A series of Ni dithiolene complexes Ni[S2C2(CF3)]2 n ( n = −2, −1, 0) ( 1, 2, 3) and a 1-hexene adduct Ni[S2C2(CF3)2]2(C6H12) ( 4) have been examined by Ni K-edge X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine-structure (EXAFS) spectroscopies. Ni XANES for 1- 3 reveals clear pre-edge features and approximately +0.7 eV shift in the Ni K-edge position for `one-electron' oxidation. EXAFS simulation shows that the Ni-S bond distances for 1, 2 and 3 (2.11-2.16 Å) are within the typical values for square planar complexes and decrease by ∼0.022 Å for each `one-electron' oxidation. The changes in Ni K-edge energy positions and Ni-S distances are consistent with the `non-innocent' character of the dithiolene ligand. The Ni-C interactions at ∼3.0 Å are analyzed and the multiple-scattering parameters are also determined, leading to a better simulation for the overall EXAFS spectra. The 1-hexene adduct 4 presents no pre-edge feature, and its Ni K-edge position shifts by −0.8 eV in comparison with its starting dithiolene complex 3. Consistently, EXAFS also showed that the Ni-S distances in 4 elongate by ∼0.046 Å in comparison with 3. The evidence confirms that the neutral complex is `reduced' upon addition of olefin, presumably by olefin donating the π-electron density to the LUMO of 3 as suggested by UV/visible spectroscopy in the literature. [ABSTRACT FROM AUTHOR]

In this paper, a piezoelectric electromagnetic composite energy harvester is studied. The device consists of a mechanical spring, upper and lower base, magnet coil, etc. The upper and lower bases are connected by struts and mechanical springs and secured by end caps. The device moves up and down under the vibration of the external environment. As the upper base moves downward, the circular excitation magnet moves downward, and the piezoelectric magnet is deformed under a non-contact magnetic force. Traditional energy harvesters have the problems of a single form of power generation and inefficient energy collection. This paper proposes a piezoelectric electromagnetic composite energy harvester to improve energy efficiency. Through theoretical analysis, the power generation trends of rectangular, circular, and electric coils are obtained. Simulation analysis yields the maximum displacement of the rectangular and circular piezoelectric sheets. The device uses piezoelectric power generation and electromagnetic power generation to achieve compound power generation, improve the output voltage and output power, and can provide power supply to more electronic components. By introducing the nonlinear magnetic action, the mechanical collision and wear of the piezoelectric elements during the work are avoided, so that the service life and service life of the equipment is extended. The experimental results show that the highest output voltage of the device is 13.28 V when the circular magnets mutually repel rectangular mass magnets and the tip magnet of the piezoelectric element is 0.6 mm from the sleeve. The external resistance is 1000 Ω, and the maximum power output of the device is 5.5 mW. [ABSTRACT FROM AUTHOR]

Highlights: [•] Nano-disks of graphite oxide is formed on the HOPG surface by electroxidation. [•] They are 15nm in diameter, an electrical insulator, and surface-bound material. [•] They are different from the conventional view of the intercalation. [ABSTRACT FROM AUTHOR]

Highlights: [•] We set a rat model of cerebral ischemia–reperfusion injury. [•] We have shown the time-dependent expression of NF-κB and TNF-α in this model. [•] Examine the expression of TNF-α mRNA in cytoplasm by in-situ hybridization. [•] Extract nuclear protein and examine the NF-κB P65 protein's expression in nucleus. [•] We demonstrate the ability of vinpocetine to suppress these inflammatory pathways. [ABSTRACT FROM AUTHOR]

The conventional energy calibration for nuclear resonant vibrational spectroscopy (NRVS) is usually long. Meanwhile, taking NRVS samples out of the cryostat increases the chance of sample damage, which makes it impossible to carry out an energy calibration during one NRVS measurement. In this study, by manipulating the 14.4 keV beam through the main measurement chamber without moving out the NRVS sample, two alternative calibration procedures have been proposed and established: (i) an in situ calibration procedure, which measures the main NRVS sample at stage A and the calibration sample at stage B simultaneously, and calibrates the energies for observing extremely small spectral shifts; for example, the 0.3 meV energy shift between the 100%-57Fe-enriched [Fe4S4Cl4]= and 10%-57Fe and 90%-54Fe labeled [Fe4S4Cl4]= has been well resolved; (ii) a quick-switching energy calibration procedure, which reduces each calibration time from 3-4 h to about 30 min. Although the quick-switching calibration is not in situ, it is suitable for normal NRVS measurements. [ABSTRACT FROM AUTHOR]

Abstract: A non-toxigenic strain FS10 was isolated from Chinese fermented soybean to control AFB1 contamination and conformed as Aspergillus niger by 18S rDNA. To elucidate the biocontrol mechanism, the ability of culture filtrate of strain FS10 against growth and AFB1 production by toxigenic Aspergillus flavus was evaluated in vitro. Meanwhile, the influence of filtrate on spore morphology of A. flavus was analyzed by optical microscope and atomic force microscope (AFM). Results demonstrated that the culture filtrate of FS10 significantly suppressed A. flavus growth, sporulation and AFB1 biosynthesis. After 9 days, the inhibition of mycelia growth, sporulation and AFB1 production reached to 37.7%, 100% and 94.5%, respectively. In addition, optical microscopy and AFM showed that the culture filtrate serious damaged spore morphology, accompanying with spore analysis and cell wall collapse, resulted in inhibition of spore germination. The degradation activity of FS10 culture filtrate on AFB1 was also estimated. When AFB1 was incubated with the culture filtrate, 85.8% of AFB1 could be degraded after 5 days. It is concluded that the culture filtrate of strain FS10 has pleiotropic effects on control AFB1 contamination. As a safe, effective and economic biological agent, the filtrate could be applied in fermented food to prevent toxigenic Aspergillus spp. and AFB1 contamination. [Copyright &y& Elsevier]