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Lepidium meyenii (Maca) is an annual or biennial herb from South America that is a member of the genus Lepidium L. in the family Cruciferae. This herb has antioxidant, anti-apoptotic, and enhances autophagy functions and can prevent cell death, and protect neurons from ischemic damage. Macamide B, an effective active ingredient of maca, has a neuroprotective role in neonatal hypoxic-ischemic brain damage (HIBD), and the underlying mechanism of its neuroprotective effect is not yet known. The purpose of this study is to explore the impact of macamide B on HIBD-induced autophagy and apoptosis and its potential mechanism for neuroprotection. The modified Rice-Vannucci method was used to induce HIBD on 7-day-old (P7) macamide B and vehicle-pretreated pups. TTC staining was used to evaluate the cerebral infarct volume of pups, brain water content was measured to evaluate the neurological function of pups, neurobehavioral testing was used to assess functional recovery after HIBD, TUNEL and FJC staining was used to detect cell autophagy and apoptosis, and western blot analysis was used to detect the expression levels of the pro-survival signaling pathway phosphatidylinositol-3-kinase/protein kinase B (PI3K/AKT) and autophagy and the apoptosis-related proteins. The results show that macamide B pretreatment can significantly decrease brain damage, improve the recovery of neural function after HIBD. At the same time, macamide B pretreatment can induce the activation of PI3K/AKT signaling pathway after HIBD, enhance autophagy, and reduce hypoxic-ischemic (HI)-induced apoptosis. In addition, 3-methyladenine (3-MA), an inhibitor of PI3K/AKT signaling pathway, significantly inhibits the increase in autophagy levels, aggravates HI-induced apoptosis, and reverses the neuroprotective effect of macamide B on HIBD. Our data indicate that macamide B pretreatment might regulate autophagy through PI3K/AKT signaling pathway, thereby reducing HIBD-induced apoptosis and exerting neuroprotective effects on neonatal HIBD. Macamide B may become a new drug for the prevention and treatment of HIBD.

The thermal stability of collagen has an important effect on its practical applications. Many believe that hydroxyproline (Hyp) improves the structural stability of collagen molecules. In this study, for the first time, a method of building natural collagen molecular models was described. We constructed a collagen model with typical triple-helix structure and calculated the hydrogen bond energy between collagen α chains. The calculated hydrogen bond energy was consistent with the experimental results of differential scanning calorimetry. After the calculation simulation, we verified that the hydrogen bond energy between collagen chains was positively correlated with Hyp content in the models and an increased Hyp content in the model was beneficial in improving the thermal resistance of the structure. In addition, we found that thermal unfolding did not occur simultaneously along the entire molecule but started in the regions with less Hyp content. This study provides a collagen model with a natural collagen amino acid sequence, which will be helpful for further investigation of the physical and chemical properties of natural collagen.

Grape seed proanthocyanidin extract (GSPE), an active component extracted from the grape, has been reported to demonstrate antioxidant, anti-inflammatory, anticancer, and antiapoptosis effects. However, little is known about the role of GSPE on neonatal hypoxic-ischemic (HI) brain injury. The aim of this study was to evaluate the neuroprotective effect of GSPE pretreatment on neonatal HI brain injury in mice. A modified Rice-Vannucci method was performed to induce neonatal HI brain injury in the 7-day-old mouse pups pretreated with GSPE or vehicle. The infarct volumes were determined by TTC staining. TUNEL staining was used to detect cells apoptosis, and the expressions of apoptosis-related proteins: bax, bcl2, and cleaved caspase-3 were assayed by Western blot. Behavioral tests were also conducted to assess the functional recovery after injury. We showed that the brain damage and neurobehavioral outcomes improvement was observed in GSPE pretreated group. GSPE was proved to suppress apoptosis through inhibition of bax and cleaved caspase-3 expression. It demonstrates that GSPE could alleviate brain damage maybe through its antiapoptotic activity in a neonatal HI brain injury model, and GSPE has the potential to be a new drug for effective prevention of this disorder.

Herein, the cost-effective photocatalyst of TiO2/g-C3N4 microspheres/reduced graphene oxide (T-CNS-G) was synthesized through a simplified two-pot hydrothermal procedure and its structure and characteristics were researched by various characterizations. The as-prepared T-CNS-G nanohybirds exhibited obviously enhanced photocatalytic activities (about 90% after 4 h) for Cr(VI) removal and good cycle stability (five cycles), which was irradiated by visible light. The increased photocatalytic activity of T-CNS-G photocatalysts is the result of the positive synergy of TiO2 nanoparticle, g-C3N4 microspheres, and rGO nanosheets. The synergy made the composite catalyst have a larger specific surface area, stronger visible light absorption capacity, lower fluorescence intensity, and higher photocurrent intensity, thereby increasing the active site of the catalysts and the mobility of photoinduced carriers. In addition, the possible photocatalytic reaction mechanism for a high-efficiency removal of Cr(VI) was propo...

Biomass gasification is a promising technology to achieve high-quality syngas in the presence of one or more gasification agents. Nevertheless, operational problems associated with tar formation caused a major obstacle for further progress in biomass gasification. Tar can be minimized in producer gas by catalytic cracking. The purpose of this work was to study the air-steam gasification of pine sawdust with calcined cement as catalyst. The reactivity of calcined cement toward hydrogen production and tar elimination was evaluated. Results showed that catalytic gasification of biomass increased hydrogen concentration and also tar cracking. With cement as an additive in gasification bed, the highest hydrogen concentration (50.3 vol%) and lowest tar yield (0.49 g/Nm3) were achieved. With additional cement loading from 0 to 9 wt%, H2 content increased from 38.1 vol% to 50.3 vol%, while tar yield decreased from 6.92 g/Nm3 to 0.49 g/Nm3.

To figure out how polyphenol compounds with a low molecular weight helped in aluminum tannage, a complex of gallic acid and aluminum as well as its application to the tanning of hide powder was studied in this paper. Precipitation points of aluminum chloride solution with different concentrations of gallic acid were measured to guide the basification in hide powder tannage. UV-Visible spectra showed that gallic acid and aluminum would form soluble complexes in aqueous solution and the complexation reaction was pH reliable. Through stoichiometry studies, generations of the 1:2 complex under pH 4.0 and 2:3 complex under pH 4.5 were discovered. Results of stoichiometry studies and Fourier Transform Infrared Spectroscopy (FTIR) spectra confirmed that aluminum-gallic acid complex played the role of links which connected collagen molecules rather than gallic acid or aluminum forming individual bridges with collagen. According to the results of differential scanning calorimetry (DSC) and thermal gravity analysis (TGA), denaturation temperature (Td) of hide powder tanned with different methods, such as aluminum, gallic acid-aluminum combination or aluminum-gallic acid complex, was 76.1°, 82.8° and 85.5°C respectively, and the initial decomposition temperature for the aluminum-gallic acid complex tannage was 300.7°C, also higher than those for another two methods. Furthermore, the results of inductive coupled plasma emission spectroscopy (ICP) showed that after washing for 12 h, the Al2O3 content in hide powder tanned with complex could be maintained at 93.42% of that in unwashed samples, which was the highest among three tanning methods.

Aero-engine blades are manufactured by electroforming process with electrodes. The blade electrode is usually machined with five-axis micromilling to get required profile roughness. Tool path planning parameters, such as cutting step and tool tilt angle, have a significant effect on the profile roughness of the micro-fillet of blade electrode. In this paper, the scallop height model of blade electrode micro-fillet processed by ball-end milling cutter was proposed. Effects of cutting step and tool tilt angle the machined micro-fillet profile roughness were predicted with the proposed scallop height model. The cutting step and tool tilt angle were then optimised to ensure the contour precision of the micro-fillet shape requirement. Finally, the tool path planning was generated and the machining strategy was validated through milling experiments. It was also found that the profile roughness was deteriorated due to size effect when the cutting step decreased to a certain value.

We consider the problem of estimating volatility for high-frequency data when the observed process is the sum of a continuous Ito semimartingale and a noise process that locally behaves like fractional Brownian motion with Hurst parameter H. The resulting class of processes, which we call mixed semimartingales, generalizes the mixed fractional Brownian motion introduced by Cheridito [Bernoulli 7 (2001) 913–934] to time-dependent and stochastic volatility. Based on central limit theorems for variation functionals, we derive consistent estimators and asymptotic confidence intervals for H and the integrated volatilities of both the semimartingale and the noise part, in all cases where these quantities are identifiable. When applied to recent stock price data, we find strong empirical evidence for the presence of fractional noise, with Hurst parameters H that vary considerably over time and between assets.

The present study systematically investigated the effects of alcohols, including methanol, ethanol, n-butanol, and propanol with different hydroxyl group numbers and locations on the thermal stability and molecular aggregation behavior of collagen. The results of ultra-sensitive differential scanning calorimetry (US-DSC), dynamic light scattering (DLS) and intrinsic fluorescence showed that with the increase of carbon chain length, alcohols can denature collagen, accompanied by transition in triple helical structure, promoted aggregation behavior, and altered molecular interactions. However, with the number of hydroxyl groups in alcohol molecules increased, the thermal stability of collagen increased and the molecules tended to disperse. Furthermore, radial distribution function (RDF) results showed that alcohols can change the structure of the hydration layer around collagen, thus altering the aggregation morphology of collagen molecules in solution. The results of the interaction between components in different alcohol systems demonstrated that with the decrease of alcohol polarity, bridge bond networks were formed between collagen molecules. Specifically, it was found that because the hydroxyl groups in 1,3-propanediol are located at both ends of the carbon chain, the reticular bridge bond structure formed between the collagen molecules changed into chain-like bridge structure. The bridge bonds between collagen molecules were considered to be weak cross-linking, which was an important reason for the destruction of collagen structure. In this study, the mechanism of interaction between different alcohols and collagen was elucidated, which will be helpful for further development of complex alcohol and collagen products.

Objective Our research is designed to explore the function of brain acid soluble protein 1 (BASP1) in the progression of gastric cancer (GC) and its underlying molecular mechanisms. Methods In this study, the expression of BASP1 was detected by quantitative real-time polymerase chain reaction (qRT-PCR) in both GC tissue and GC cells. The cell cloning, proliferation, apoptosis, migration, and invasion potential of AGS and HGC-27 cells were, respectively, determined using colony formation assay, 5-ethynyl-20-deoxyuridine (EDU) assay, flow cytometry, and Transwell assay. The protein expressions of Bax, caspase-3, Bcl-2, matrix metalloproteinases 2 (MMP-2), MMP-9, Wilms tumor 1 (WT1), Wnt, and β-catenin in AGS and HGC-27 cells were measured by western blot. In addition, the mRNA expressions of WT1, Wnt, and β-catenin in AGS and HGC-27 cells were detected by qRT-PCR. Results BASP1 expression was significantly downregulated in both GC tissue and GC cells. BASP1 overexpression markedly repressed proliferation, migration, and invasion and facilitated apoptosis in AGS and HGC-27 cells. In addition, BASP1 overexpression notably promoted the protein expression of Bax and caspase-3 in AGS and HGC-27 cells and inhibited the expression of Bcl-2, MMP-2, and MMP-9. Moreover, BASP1 overexpression significantly inhibited the mRNA and protein expression of WT1, Wnt, and β-catenin in AGS and HGC-27 cells. Conclusion BASP1 could significantly suppress cell proliferation, migration, and invasion and promote apoptosis through inhibiting the activation of the Wnt/β-catenin pathway in GC.

A series of triethanolamine-modified mesoporous SBA-15 catalysts were synthesized by a facile one-pot process, and used as the catalyst for the synthesis of cyclic carbonates through the cycloaddition of CO2 with epoxides. The properties of catalysts were characterized by nitrogen adsorption–desorption, elemental analysis (EA), Fourier transform infrared (FT-IR) spectra, Magic angle spinning nuclear magnetic resonance (MAS NMR), X-ray diffraction (XRD), scanning electron microscope (SEM), and transmission electron microscopy (TEM), and the results suggested that triethanolamine (TEA) had been successfully immobilized on SBA-15. It was highly active in the cycloaddition reaction, in which the maximum yield of PC could achieve 93.47% under the conditions as follow: catalyst amount of 0.20 g, reaction temperature of 110 °C, reaction pressure of 2.0 MPa and reaction time of 4 h. Notably, the catalyst can be easily recovered by filtration, and it can be retained most of its catalytic stability and activity after five recycling times. On the basis of the experimental results, the interactions between the catalysts and the substrates were studied by DFT calculations, and the possible mechanism for the reaction was proposed.

The aggregation behavior of collagen-based materials plays an important role in their processing because it could affect their physicochemical properties. Based on the intrinsic fluorescence characteristic of tyrosine, fluorescence spectrum technology was used to investigate the aggregation state of the acylated collagen molecules in aqueous solution. The results showed that the aggregate degree of the acylated collagen was higher than that of the native collagen due to the hydrophobic interaction. With the increase of concentrations of the acylated collagen or at NaCl higher than 40 mmol/L, the aggregate degree of the acylated collagen molecules increased. When the pH was close to the isoelectric point of the acylated collagen, the hydrophobic interaction and the hydrogen bond helped to increase the aggregation degree. However, with the increase of temperature (10–70 ℃), the aggregation state of the acylated collagen decreased gradually due to the quenching, the molecular collision, and the broken of hydrogen bonds. Furthermore, two-dimensional correlation spectroscopy (2D-COS) showed that the response order was 360 > 305 nm at various acylated collagen and NaCl (>40 mmol/L) concentrations, while the response order was 305 > 360 nm when the pH value was increased from 5.0 to 9.0. Temperature-dependent 2D-COS showed there were four bands that occurred and the response order was listed as follows: 293 > 305 > 360 > 420 nm. In brief, the results might provide an important guide for molding processes of the acylated collagen.

Element Te has significant effect on the intergranular embrittlement of nickel-based alloys. This paper proposes a new alloy infiltration method to investigate the effect of Te infiltration on nickel-based superalloy Inconel 718. Micro-scratch test was performed to quantitatively assess the effect of Te infiltration on the mechanical properties of Inconel 718. Three-dimensional morphology of scratches was analyzed and the deformation behavior of treated samples was investigated. Te infiltration caused to the delamination phenomenon, where the material properties of each layer were different. The new intercrystalline phase (Cr3Te4) formated at the grain boundary was the main reason for weakening the properties of surface material. The stress reduction was larger than 50% in the infiltration zone. The failure mechanism was explained and the destructive effect of Te on Inconel 718 was utilized.

This work focus on evaluating the influence of B site partial substitution on the physicochemical property and the catalytic property of La0.8Ce0.2M0.25Co0.75O3 (M = Cu, Mn, Fe) perovskite catalyst...

Silicon, a trace element found in human body, plays a critical role in the process of collagen self-assembly. In this study, the intermolecular interaction and fibrillogenesis process were investigated to understand the effects of various concentrations of sodium silicate (SS) on collagen self-assembly in vitro. Fourier transform infrared spectroscopy analysis indicated that the triple helical structure of collagen was not significantly affected by SS. Hydrophobic interactions and particle sizes of collagen aggregates, which were measured using pyrene fluorescence and dynamic light scanning, enhanced via adding 2 mM SS whereas decreased with further increasing concentrations (4–8 mM). Kinetic analysis revealed that an increase in hydrophobic interactions boosted collagen self-assembly in the presence of 2 mM SS. The inhibition of self-assembly with the addition of 4–8 mM SS, as illustrated by a reduction in the fibrillogenesis rate and turbidity, was potentially attributed to weak hydrophobic interactions and strong electrostatic repulsion. The observation of microscopy demonstrated that the fibrils exhibited the characteristic D-periodicity at 2 mM SS. The inhibitory effect of 4 mM SS was slight and the fibrils still formed, while the microstructure was consisted of clustered collagen aggregates as SS ≥ 6 mM owing to serious inhibition on collagen self-assembly.

A novel acetic acid/1-ethyl-3-methylimidazolium acetate (AA/[EMIM][Ac]) biphasic solvent system was adopted to alter the aggregation behavior of collagen molecules. Collagen aggregates (0.5 mg/mL) were investigated in the presence of AA/[EMIM][Ac] at various ratios (10:0 to 5:5). Sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) showed that the triple helical structural integrity was maintained integrity across the whole AA/[EMIM][Ac] ratio range. Ultra-sensitive differential scanning calorimetry measurements revealed that the transition temperature varied with the AA/[EMIM][Ac] ratio, indicating a relevant relationship between the aggregated sate of collagen molecules and thermal effects. The surrounding polarity of collagen molecules was examined by fluorescence spectroscopy of pyrene, and disaggregation behavior was enhanced with increasing [EMIM][Ac] ratio, as demonstrated by changes in the size of collagen aggregates determined by dynamic light scattering. Furthermore, the decrease in collagen aggregates was dependent on stronger interactions among collagen molecules. Intrinsic viscosity decreased from 11.526 to 2.607 g/dL, and the Huggins coefficient increased from 0.575 to 4.121 within the AA/[EMIM][Ac] ratio ranging from 10:0 to 5:5. Finally, atomic force microscopy visually confirmed the effect of [EMIM][Ac] on the aggregated state of collagen molecules visually. These findings suggest AA/[EMIM][Ac] could be an efficient solvent system for natural insoluble collagen.

With the development of technology and social demand, rockfill dam are built higher and higher. The Rumei earth core dam to be built in China will be the highest rockfill dam in the world. This stu...

Stable and biocompatible collagen-based hydrogels based on natural extracellular matrix (ECM) with a homogeneous microstructure are ideal scaffolds for tissue engineering; however, lack of structural stability and mechanical property have hindered their application. In this work, Chondroitin Sulfate (CS) was periodate-oxidized to prepare dialdehyde ECM-derived biopolymer with the weight average molecular weight of 3.7 × 104 g/moL to construct the stable collagen-based fibrillar hydrogels. The results of Fourier Transform Infrared (FTIR) analysis and hydroxylamine hydrochloride titration assay confirmed the presence of aldehyde groups in oxidized CS (CSox) with an oxidization degree of 30.67%. Gelation time test and scanning electron microscopy (SEM) observation showed that gel formation and fibrillogenesis process were accelerated by adding CSox, and all hydrogels exhibited a tight fibrillar structure. With an increase in CSox concentration from 0.125 to 2.000 mg/mL, the crosslinking degree increased from 24.95% to 35.05% due to the formation of covalent bonds between the e-amino groups of collagen and aldehyde of CSox. The mechanical strength of collagen/CSox hydrogels reached a maximum value of 11.79 KPa, which was more than triple that of pure collagen hydrogel (3.58 KPa) at 0.125 mg/mL CSox. The swelling ratio, enzymatic resistance, and thermal stability were also improved with the increasing concentration of CSox. When the CSox concentration reached 0.500 mg/mL, the collagen-based hydrogels exhibited the highest thermal denaturation temperature, which was approximately 7.5 °C higher than that of the pure collagen hydrogel. Moreover, the results of the CCK-8 assay and LIVE/DEAD staining demonstrated that all the collagen/CSox hydrogels accelerated cell proliferation and showed acceptable biocompatibility. This work broadens the avenue for the design of natural collagen-based hydrogels for tissue engineering.

The novel HLA-A*68:100 allele differs from HLA-A*68:01:02:01 by one nucleotide substitution in exon 3 at position 371.

Mineralization of collagen is a common combination process mainly involving collagen self-assembly and hydroxyapatite formation. Previous measurement of turbidity showed that collagen self-assembly follows the nucleation–growth model. In the present study, 1.0 M CaCl2 was mixed with 0.6 mg/mL collagen solution in PBS (10 mM phosphate, 80 mM NaCl, pH 7.2, and T = 35 °C) at the beginning of the lag period, at the beginning of the growth period, at t1/2 (the time to reach half of the total turbidity change), and during the plateau period. Four different hydroxyapatite/collagen (HAp/COL) composites were prepared [COL (1), COL (2), COL (3), and COL (4)]. The optical densities increased with CaCl2 addition, and a wave trough appeared in the mineralization kinetic curves because of amorphous/crystalline conversion. HAp formation was confirmed by Fourier transform infrared spectroscopy and X-ray diffraction measurements. Energy-dispersive spectroscopy results showed that the calcium/phosphorus ratio of COL (2) is close to that of human bone. Images obtained by scanning electron microscopy revealed that nanosized plate-like HAp of COL (2) formed and became uniformly embedded in collagen, whereas HAp formed large clusters in COL (1), COL (3), and COL (4). Quantitation analyses of collagen and HAp incorporated into composites showed that mineralization at different time points promote collagen fibril generation and have little impact on the HAp content. These results suggest that the composite fabricated by addition of CaCl2 at the beginning of the growth period is a promising material for bone repair and implantation.

Systematic analysis of the rheological behavior of collagen solution (10 mg/mL) as a function of acetic acid (AA) concentration (0.1–10 M) was performed to achieve a deeper understanding about the interaction between collagen molecules and acidic solvent. Steady shear tests showed that all samples exhibited pseudo-plasticity with shear-thinning behavior. Viscosity decreased from 236.448 to 0.792 Pa·s at 0.1 s−1 suggesting the flow ability of collagen solution improved with increasing AA concentration. Dynamic frequency sweep analysis revealed that the storage modulus, loss modulus, and complex viscosity decreased with the increased AA concentration due to the disentanglement of collagen molecules, while the loss tangent increased. Hysteresis loop areas of collagen solutions were determined by thixotropic measurement, which demonstrated that weaker thixotropic behavior was associated with higher AA concentrations. Furthermore, the ability to resist deformation and elasticity was lower at higher AA concentration. Maximum compliance values increased from 0.042 to 376.407 Pa−1, and the recovery percentage decreased from 97.670% to 0.315%. Finally, corresponding mathematical models were employed to simulate and quantitatively assess the experimental data.

Sulfated polysaccharides (fucoidan) were recovered from Nemacystus decipients using a combination of high pressure homogenization (HPH) and hydrothermal extraction process through employing different homogenization pressure (40–100 MPa) and cycle times (1–3). HPH treatment could result in a high fucoidan yield with preserving sulfate content and the optimal yield was 16.67 ± 0.36%, obtained from 70 MPa for 2 cycles’ extraction. Chemical composition analysis, HPAEC, IR and HPSEC analysis were applied for characterization of extracted polysaccharides. The molecular weight of extracted fucoidan decreased with increasing extraction pressure. All fucoidan exhibited antioxidant activities as determined by DPPH radical scavenging, hydroxyl radical scavenging, and ferrous ion chelating ability as well as reducing power, among which fucoidan extracted at 70 MPa (HN2) possessed excellent antioxidant ability. This study shows that HPH can be used as an efficient means to assist extraction of fucoidan from seaweed and N. decipients could potentially be a raw resource for natural antioxidant.

Because of the complex geological conditions of the seabed, submarine pipelines buried beneath the ocean floor become suspended over the seabed under the long-term scour of waves eroding the surrounding sediment. Further, most oil fields were built in offshore areas while the country was developing. This gives the waves seen in shallow water obvious non-linear features, and the abnormal characteristics of these waves must be considered when calculating their hydrodynamic forces. Particularly under such conditions, these suspended spans of submarine pipelines are prone to damage caused by the action of the external environment load. Such damages and eventual failures may result not only in great property losses, but also pollution of the marine environment. The span length of these areas is a key predictive factor in pipeline damages. Therefore, determining the allowable span length for these submarine pipelines will allow future projects to avoid or prevent damage from excessive suspended span len...

The economic and sustainable use of fish-processing by-products has received considerable attention. Large amounts of fish skin discarded by industry processes can be a source of collagen extraction. This study developed a method to extract collagen with high purity and yield from Southern catfish skins through improved pretreatment methods. Multiple degreasing methods effectively removed fat from fish skins and obtained a maximum degreasing rate (90.24%). The results of electrophoretic, hydroxyproline-content, and extraction-rate analyses revealed that the collagen extracted from defatted skin, which decoloured in 0.5% hydrogen peroxide solution (pH 10), exhibited higher purity and the highest yield (23.14% wet weight and 78.57% dry weight, respectively) as compared with other decolouration conditions. The histological appearance of pretreated fish skin indicated that the non-collagenous substances were removed effectively and the fibres loosened. Amino acid analysis, ultraviolet spectra, Fourier...

Collagen gel is widely used in tissue engineering due to excellent biological properties and swollen three-dimensional network structure. To improve viscoelasticity and thermal stability, collagen gels consisting of fibrils were cross-linked with glutaraldehyde and sequentially dehydrated via ethanol or heating (named as EGC or HGC, respectively). For EGC, ethanol replaced free and loosely bound water and then combined with tightly bound water, inducing the increase in hydrogen bonds and molecular interactions. Therefore, the thermal transition temperature (Tt ) and storage modulus (G') obviously increased from 47.3 ± 0.5°C and 0.1 kPa to 92.7 ± 0.8°C and 7.8 kPa, respectively. Unfortunately, the high deformation (γ > 60%) and low recovery percentage (R < 15%) reflected the poor anti-deformation of gels due to the volatility of ethanol. For HGC, the entanglement and rigidity of fibrils increased owing to the contraction of cross-linked fibrils and cohesive action of denatured collagen. As a result, HGC were more resistant to deformation and exhibited more elasticity than native collagen gel, accompanied by the fact that G' and R increased to 28.8 kPa and 90.0% ± 0.7%. Additionally, HGC exhibited higher Tt (121.4 ± 0.5°C) due to lower water content and higher collagen concentration.

Collagen hydrogels with a three-dimensional network structure were prepared through self-assembly of collagen molecules, and incubated in laccase-catalyzed gallic acid solutions (L-GA) with different concentrations (0.5–10%, w/v, calculated from the L-GA mother solution). UV-visible spectroscopy and Fourier transform infrared spectrometry suggested that quinones and cross-links between the quinones and the collagen molecules had formed. With an increase in L-GA concentration from 0.5 to 5%, the degree of cross-linking increased from 8.78% to 19.13%; when the L-GA concentration exceeded 5%, the degree of cross-linking increased slightly. At L-GA concentrations ≤ 5%, the thermal denaturation temperature (from 67.4to 74.7°C), the storage modulus (from 90 to 251.42 Pa) and the ABTS•+ free radical scavenging activity (from 4.89 to 98.92%) significantly increased, and a distinct decrease was observed in the degree of enzymatic degradation (from 81.48 to 49.34%). At L-GA concentrations >5%, only a slight improvement in these properties was observed. The gel strength of the modified collagen hydrogels reached a maximum value of 1346 g, which was more than twice that of the native collagen hydrogel (656 g) at 5%L-GA. Furthermore, afterthe concentration of L-GA exceeded 1%, the pore sizes observed by scanning electron microscopy began to diminish and showed denser network structures. These data indicated that the properties of collagen hydrogels can be substantially improved by modification with an appropriate concentration of L-GA.

Alloying elements have significant effects on material physical and mechanical properties. The present work studies the effect of element Te on the alterations of microstructure and mechanical property of nickel-based superalloy Inconel 718. Te was diffused into the surface layer of treated samples with a new alloy infiltration method. The microstructure and element distribution within the modified layer were tested and quantitatively characterized with scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). The depth of infiltration layer presented an approximately linear relationship with the treating temperature range from 700 °C to 900 °C. Furthermore, the mechanical property of the modified layer was evaluated through nano-indentation experiments. The results show that the Te infiltration into the surface layer of Inconel 718 presents a gradient distribution from the outmost surface to the matrix, and it results in a substantial weakening of the modified layer. A gradual decrease in nano-hardness was detected from the surface to the matrix, and the nano-hardness value of infiltration layer was weakened by 31% for the Te infiltration treatment at 900 °C. The underlying weakening mechanism of Te on the superalloy Inconel 718 was revealed. Te element penetrates along the grain boundary leading to the formation of new intercrystalline phases. Consequently, the grain boundary is “opened” which causes the embrittlement of grain boundaries and weakening of the treated surface. This study can not only help to understand the influence of alloying elements on the variation of material properties, but also provide guidance for design of material compositions.

A gene encoding a highly thermostable β-mannanase from a thermophilic Bacillus subtilis (TBS2) was successfully expressed in Pichia pastoris. The maximum activity of the recombinant thermostable β-mannanase (ReTMan26) was 5435 U/mL, which was obtained by high-density, fed-batch cultivation after 168-h induction with methanol in a 50-L bioreactor. The protein yield reached 3.29 mg/mL, and the protein had a molecular weight of ~42 kDa. After fermentation, ReTMan26 was purified using a 10-kDa cut-off membrane and Sephadex G-75 column. The pH and temperature optima of purified ReTMan26 were pH 6.0 and 60 °C, respectively, and the enzyme was stable at pH 2.0-8.0 and was active at 20-100 °C. HPLC analysis of the products of locust bean gum hydrolysis showed that the mannan-oligosaccharide content was 62.5%. ReTMan26 retained 58.6% of its maximum activity after treatment at 100 °C for 10 min, which was higher than any other β-mannanase reported up to now, suggesting its potential for industrial applications.

Stochastic resonance (SR) has been widely applied in the field of weak signal detection by virtue of its characteristic of utilizing noise to amplify useful signal instead of eliminating noise in nonlinear dynamical systems. How to quantitatively evaluate the performance of SR, including the enhancement effect and the degree of waveform distortion, and how to accurately extract signal amplitude have become two important issues in the research on SR. In this paper, the signal-to-noise ratio (SNR) of the main component to the residual in the SR output is constructed to quantitatively measure the enhancement effect of the SR method. And two indices are constructed to quantitatively measure the degree of waveform distortion of the SR output, including the correlation coefficient between the main component in the SR output and the original signal, and the zero-crossing ratio. These quantitative indices are combined to provide a comprehensive quantitative index for adaptive parameter selection of the SR method, and eventually the adaptive SR method can be effective in enhancing the weak component hidden in the original signal. Fast Fourier Transform and Fourier Transform (FFT+FT) spectrum correction technology can extract the signal amplitude from the original signal and effectively reduce the difficulty of extracting signal amplitude from the distorted resonance output. The application in vibration analysis for bearing fault diagnosis verifies that the proposed quantitative evaluation method for adaptive SR can effectively detect weak fault feature of the vibration signal during the incipient stage of bearing fault.

Collagen hydrogels, which are comprised of fibrils and possess three-dimensional network structure, were prepared via self-assembly of collagen molecules and sequentially incubated in glutaraldehyde (GTA) solutions with different [CHO]/[NH2] ratios (0–9). The cross-linking degree of outer and inner parts of hydrogels was similar, demonstrating the homogeneous reaction. Based on the results of atomic force microscopy, differential scanning calorimetry and dynamic rheological measurements, it was conjectured that the stability of hydrogels were closely associated with the structural changes of collagen fibrils. When the [CHO]/[NH2] ratios ≤3, cross-linking preferentially occurred between adjacent fibrils; therefore, the fibrils presented in pairs and then densely agglomerated. As a result, the thermal denaturation temperature (from 47.1 to 73.6 °C) and elastic modulus (from 108.32 to 1618.55 Pa) increased drastically, accompanied by a distinct decrease in enzymatic degradation degree (from 93.69 to 26.91%). The effective binding ratio (EB) of aldehyde groups reduced from 72.66 to 43.92%. Moreover, hydrogels turned into yellow and yellowness (Δb*) increased from 0 to 1.68. When the [CHO]/[NH2] ratio reached 3, the arrangement of fibrils became very compact; therefore, although the GTA dosage was multiplicative ([CHO]/[NH2] = 9), there was only a relatively small improvement in thermal stability and anti-enzymolysis. Furthermore, the EB value was only 16.40%, indicating that intensive self-polymerization of GTA molecules caused a large consumption of aldehyde groups, accompanied by a remarkable yellow-stain (Δb* = 2.73). These data on the stability of cross-linked hydrogels could be helpful for the design and fabrication of materials based on collagen hydrogels.

Characteristics, distribution, temporal and spatial configuration, and effectiveness of hydrocarbon migration pathways have been investigated through geochemical and formation pressure analysis etc, to further reveal hydrocarbon accumulation patterns in the Neogene of the Laixi structural belt, southern Bohai Sea of China. Firstly, three factors, faults, carrier rocks (beds) and mud caprocks of the transporting framework in the Neogene were examined to find out its feature and space configuration and made static state evaluation. It is found that besides the Guantao Formation – lower Minghuazhen Formation No. V oil layers, the No. I – III oil layers in the lower Minghuazhen Formation are also the dominant oil and gas carrier beds. Cutted by the adjustment faults and sealed by mudstone capcocks, the two carrier layers are combined into a “layered cake” type hydrocarbon migration framework. Then the hydrocarbon passage pathways were tracked dynamically and described using nitrogen compounds concentration, formation pressure, fluorescence logging and sand bodies description, which shows that the “T03-T02-T01 mudstone cap layers” separate the Neogene hydrocarbon migration pathways into upper and lower units. The massive sandy conglomerate reservoirs in the Guantao Formation – lower Minghuazhen Formation No. V oil layers are the carrier bed of the lower hydrocarbon migration pathway, while the north-south trending overlapped and connected channel sandbodies in lower Minghuazhen Formation No. I – III oil layers are the carrier bed of the upper unit. Hydrocarbon migrated laterally along the two passage ways, accompanying with differential accumulation. Key words: southern Bohai Sea, Laixi structural belt, hydrocarbon passage framework, dominant migration pathway, hydrocarbon migration pattern, accumulation pattern

The senile plaque formed by β-amyloid (Aβ) deposition in the brain is one of the main pathological features of Alzheimer's disease (AD), and the c-Jun N-terminal kinase (JNK) signaling pathway plays an important role in the pathogenesis of AD. This study aimed to investigate that D-serine may ameliorate motor and cognitive impairment in Aβ injected mice by inhibiting JNK signaling pathway. Firstly, Kunming mice were injected intrahippocampally with Aβ1-42 to build AD model. The mice were injected intraperitoneally with saline, D-serine, D-amino acid oxidase (DAAO), and Sodium benzoate (BE) for 10 consecutive days, respectively. Subsequently, the motor and cognitive functions of mice were detected by behavioral tests. The silver staining and immunohistochemical methods were used to detect the distributions of Aβ in the hippocampus of mice. 18F-2-Fluro-D-deoxy-glucose positron emission tomography/computed tomography (18F-FDG PET/CT) scans were performed to detected glucose metabolism of Aβ1-42 induced lesions. The expressions of relative JNK factors were detected by immunohistochemistry and Western blot methods. These results showed that Aβ severely impaired the motor and memory abilities of mice. The expressions of glial fibrillary acidic protein (GFAP), tumor necrosis factor (TNF-α), N-methyl-D-aspartate receptor 1 (NMDAR1), phospho-JNK (p-JNK), p-c-Jun and activating transcription factor 2 (ATF2) increased significantly. After D-serine treatment, the abilities of movement and memory of mice were improved, and the clearance rate of Aβ was accelerated. The expressions of GFAP, TNF-α, NMDAR1, p-JNK, p-c-Jun and ATF2 decreased significantly. DAAO and BE were administered to further validate these results. Therefore, this study showed that D-serine could alleviate the cognitive impairment of Aβ1-42 injected mice by inhibiting JNK signaling pathway. These results provide more evidences for the effect of D-serine on AD and relevant mechanism to treat AD.

The aim of this research is to evaluate the effects of glutamic acid (Glu) on the process of collagen mineralization, the structure and property of mineralized composites. Collagen mineralization was initiated by introducing PBS to blended solutions containing 1 mg/mL collagen, 6 mmol/L calcium and Glu ranged from 0 to 550 mmol/L. The kinetic curves and quantitation analyses showed that Glu could delay the collagen mineralization, and reduce the crystalline size and the amount of hydroxyapatite. With the Glu concentration increased from 50 to 200 mmol/L, the collagen self-assembly was promoted, resulting in the improvement of hardness and thermal stability of mineralized composites. However, further increase in the Glu concentration to 400 mmol/L or above would significantly inhibit the self-assembly of collagen and reduce the hardness and thermal stability of mineralized composites. Scanning electron microscopy revealed that the diameter of collagen became thicker as the Glu concentration increased. Moreover, hydroxyapatite with spherical morphology was uniformly dispersed and well combined with collagen fibril at Glu concentration of 200 mmol/L. These results may provide a broader understanding of the potential mechanism of biomineralization and be critical in the design of biomimetic scaffolds for bone tissue engineering.

In recent years, the extraction fraction of volatile oil from Acorus gramineus has significant effects on anti-dementia and improving the learning and memory of animals. To date, limited studies have determined whether volatile oil from A. gramineus has the protective effect on neuronal damage. The aim of this study was to investigate the protective effects of volatile oil from A. gramineus on Alzheimer's disease (AD) mice, by means of behavior test, immunohistochemistry and western blot methods. In this study, mice were injected with Aβ1-42 in the bilateral hippocampus to establish the AD model. On the seventh day after modeling, the mice with cognitive dysfunction were selected by the novel object recognition task. Subsequently, the volatile oil treatment groups underwent intragastric administration for per 10 g body weight 2.5 or 5 μL volatile oil from A. gramineus for 3 weeks. The control group and the AD group were given the same amount of saline. Our results showed that after treatment of volatile oil from A. gramineus, the number of Doublecortin and Nestin positive cells increased significantly, suggesting that the volatile oil from A. gramineus may induce the regeneration of hippocampal neurons in mice, and promote the growth of hippocampal neurons by upregulation of brain-derived neurotrophic factor, tyrosine protein kinase B, and neurotrophin-3 expression. These results might provide more experimental evidences for underlying mechanism about the neuroprotective effects of volatile oil from A. gramineus against AD relevant symptoms. Anat Rec, 302:2261-2270, 2019. © 2019 American Association for Anatomy.

This research concentrates on evaluating the partially substituted LaM0.5Mn0.5O3 (M = Cu, Co, Fe, Ni, Cr) perovskite oxide catalysts in NOx reduction. This catalytic system performs well in the following aspects, with proper long-term catalytic ability and cyclic catalytic ability, suitable water and sulfur resistance, low cost and high reserves. The partial substitution on B site of LaMnO3 perovskite obviously promotes the catalytic behavior in the following order: LaCu0.5Mn0.5O3 > LaCr0.5Mn0.5O3 > LaNi0.5Mn0.5O3 > LaCo0.5Mn0.5O3 ≈ LaFe0.5Mn0.5O3 > LaMnO3. The greatest catalytic behavior is obtained in LaCu0.5Mn0.5O3 sample at 300 °C, with complete selective conversion for NO and CO, respectively. This sample has great value in practical applications. By the results of in situ DRIFTS, the possible reaction mechanism is tried to propose to evaluate the entire reaction process in NOx reduction.

Alzheimer’s disease (AD) is characterized by a robust inflammatory response elicited by the accumulation and subsequently deposition of amyloid beta (Aβ) within the brain. The immune cells of brain migrate to and invest their processes within Aβ plaques and clear plaques from the brain. Previous studies have shown that treatment of myeloid cell with nuclear factor inhibitor increases expression of phagocytesis-related genes, such as triggering receptor expressed on myeloid cells 2 (TREM2). In myeloid cells, TREM2 has been involved in the regulation of phagocytosis, cell proliferation as well as inflammatory response in vitro. The purpose of this study was to further investigate microglial proliferation, phagocytosis and the expression of brain derived neurotrophic factor (BDNF) induced by up-regulation of TREM2 in Aβ1–42 injected mice. We first singly injected Aβ1–42 into the hippocampus of mice to build the model of AD-like symptoms. Subsequently, ammonium pyrrolidinedithiocarbamate (PDTC) was injected into the lateral ventricle of mice. Various immunohistochemical techniques and Western blot analyses were applied to examine expressions of TREM2, microglia, Aβ, Neuronal migration protein doublecortin (DCX) and BDNF in the hippocampus of mice. In the present study, we found the plaques-associated microglia lowly expressed TREM2 and BDNF in Aβ1–42 intra-hippocampal injected mice. Treatment of the models with a nuclear factor inhibitor, PDTC, further induced the expression of TREM2 and enhanced microglial phagocytosis, coincident with the rapid reduction in plaque burden. The expression of BDNF was up-regulated and the expression of DCX was partly restored. This means that up-regulation of TREM2 might induce the microglia to express the BDNF. These findings further indicate that the level of TREM2 may affect the microglia response to pathological process induced by Aβ.

HLA-A*24:231 has one nucleotide change from HLA-A*24:02:01:01 at position 784 GC.

The effect of hydroxypropyl methylcellulose (HPMC) on the aggregation of collagen molecules with collagen concentrations of 0.25, 0.5 and 1.0mg/mL was studied by fluorescence techniques. On one hand, both the synchronous fluorescence spectra and fluorescence emission spectra showed that there was no change in the fluorescence intensity of collagen intrinsic fluorescence when 30% HPMC was added, while it decreased obviously when HPMC content ≥ 50%. From the two-dimensional fluorescence correlation analysis, it was indicated that collagen molecules in 0.25 and 0.5mg/mL collagen solutions were more sensitive to HPMC than those in 1.0mg/mL collagen solution. On the other hand, the pyrene fluorescence and the fluorescence anisotropy measurements indicated that HPMC inhibited the collagen aggregation for 0.25 and 0.5mg/mL collagen, but promoted it for 1.0mg/mL collagen. The atomic force microscopy images further confirmed the effect of HPMC on collagen with different initial states.