Effect of Paste Fluidity and Paste-to-Aggregate Ratio on the Strength and Permeability of Porous Mortar from Manufactured Sand.

Many places in the world suffer from a shortage of river sand because of population growth and environmental protection, and people have to replace river sand with manufactured sand (M-sand). In this study, M-sand was adopted as aggregate and the effect of the mix design (paste fluidity (PF) and paste-to-aggregate ratio (P/A)) on the properties of porous mortar was investigated through a combined experimental, statistical and response surface method (RSM). By including variations in both P/A (0.16-0.26) and PF (160-200 mm), the method was utilized to develop ANOVA models and construct response surface and contour lines. The experimental results revealed that the compressive strength of the porous mortar increased by 62.3% to a value of 34.1 MPa while the PF increased to 190 mm from 160 mm at a P/A of 0.20, and the water permeability coefficient was 7.2 mm/s under the same conditions. In addition, the ANOVA analysis of the measured properties revealed a strong interactive effect of the paste-to-aggregate ratio and paste fluidity on the porous mortar properties, and the developed relationship models between the variables and responses were accurate. A porous mortar with a compressive strength over 30 MPa and a permeability coefficient over 7 mm/s could be conveniently designed by RSM. Additionally, the compressive strength of the porous concrete reached more than 40 MPa at a P/A of 0.26.

Characteristic analysis of three-ecofriendly reduced graphene oxides (rGOs) and their application in water-ethanol-based fluids with different volume ratios.

In this paper, three-ecofriendly reduced graphene oxides (rGOs) were obtained by using three green reducing agents (beer, wine and cocoa) to reduce the graphene oxide (GO), and were labeled as B-rGO, W-rGO and C-rGO. Meanwhile, rGO nanofluids with different water-ethanol volume ratios (25 : 75, 50 : 50, 75 : 25) were prepared based on three-ecofriendly rGOs. The structure properties of the three-ecofriendly rGOs were investigated by XRD, FR-IT, Raman spectroscopy and XPS analysis. Meanwhile, the thermophysical properties of rGO nanofluids were analyzed. Experimental results indicated that the stability and thermophysical properties of rGO nanofluids were slightly different, indicating that the properties of the nanofluids are dependent on the type of base fluids and nanoparticles. When the water-ethanol volume ratio was maintained at 25 : 75, the stability experiment results showed that W-rGO nanofluids presented excellent stability, which indirectly confirmed their excellent thermal conductivity. Furthermore, the contact angle experiment indicated that the contact angles of rGO nanofluids decreased with the increase of temperature. In a word, these three rGOs and their nanofluids exhibited preferable properties that make them promising in the field of heat transfer.

Excellent Energy Storage Performance in Bi(Fe0.93Mn0.05Ti0.02)O3 Modified CaBi4Ti4O15 Thin Film by Adjusting Annealing Temperature.

Dielectric capacitors with ultrahigh power density are highly desired in modern electrical and electronic systems. However, their comprehensive performances still need to be further improved for application, such as recoverable energy storage density, efficiency and temperature stability. In this work, new lead-free bismuth layer-structured ferroelectric thin films of CaBi4Ti4O15-Bi(Fe0.93Mn0.05Ti0.02)O3 (CBTi-BFO) were prepared via chemical solution deposition. The CBTi-BFO film has a small crystallization temperature window and exhibits a polycrystalline bismuth layered structure with no secondary phases at annealing temperatures of 500-550 °C. The effects of annealing temperature on the energy storage performances of a series of thin films were investigated. The lower the annealing temperature of CBTi-BFO, the smaller the carrier concentration and the fewer defects, resulting in a higher intrinsic breakdown field strength of the corresponding film. Especially, the CBTi-BFO film annealed at 500 °C shows a high recoverable energy density of 82.8 J·cm-3 and efficiency of 78.3%, which can be attributed to the very slim hysteresis loop and a relatively high electric breakdown strength. Meanwhile, the optimized CBTi-BFO film capacitor exhibits superior fatigue endurance after 107 charge-discharge cycles, a preeminent thermal stability up to 200 °C, and an outstanding frequency stability in the range of 500 Hz-20 kHz. All these excellent performances indicate that the CBTi-BFO film can be used in high energy density storage applications.

Polyvinyl-Alcohol-Modified Calcium Sulphoaluminate Cement Repair Mortar: Hydration and Properties.

Polyvinyl alcohol (PVA) and calcium sulphoaluminate (CSA) cement were used to prepare repair mortar for the restoration of the walls of a building built with bricks. The preparation, hydration, and properties of the PVA-modified CSA cement repair mortar were studied. Besides this, the mechanism by which PVA improves the bonding strength is also discussed. The results demonstrate that PVA prolongs the setting time of CSA cement, which is ascribed to PVA inhibiting the dissolution of C4A3$ (4CaO·3Al2O3·SO3) and the precipitation of AFt (3CaO·Al2O3·3CaSO4·26H2O) within the hydration age of 0~60 min. PVA lowers the mechanical strength of CSA cement repair mortar at the hydration age of 6 h. After 6 h, the mechanical strength is improved. PVA could also improve the bonding strength between CSA repair mortar and bricks. This is mainly ascribed to the Al ions in both the hydration products of CSA cement and the clay bricks reacting with the hydroxyl group of PVA and forming the chemical bond C-O-Al. Therefore, a tighter combination between CSA cement repair mortar and the clay bricks forms, thereby improving the bonding strength.

Flexible Lead-Free Ba0.5Sr0.5TiO3/0.4BiFeO3-0.6SrTiO3 Dielectric Film Capacitor with High Energy Storage Performance.

Ferroelectric thin film capacitors have triggered great interest in pulsed power systems because of their high-power density and ultrafast charge-discharge speed, but less attention has been paid to the realization of flexible capacitors for wearable electronics and power systems. In this work, a flexible Ba0.5Sr0.5TiO3/0.4BiFeO3-0.6SrTiO3 thin film capacitor is synthesized on mica substrate. It possesses an energy storage density of Wrec ~ 62 J cm-3, combined with an efficiency of η ~ 74% due to the moderate breakdown strength (3000 kV cm-1) and the strong relaxor behavior. The energy storage performances for the film capacitor are also very stable over a broad temperature range (-50-200 °C) and frequency range (500 Hz-20 kHz). Moreover, the Wrec and η are stabilized after 108 fatigue cycles. Additionally, the superior energy storage capability can be well maintained under a small bending radius (r = 2 mm), or after 104 mechanical bending cycles. These results reveal that the Ba0.5Sr0.5TiO3/0.4BiFeO3-0.6SrTiO3 film capacitors in this work have great potential for use in flexible microenergy storage systems.

Pyomelanin produced by Streptomyces sp. ZL-24 and its protective effects against SH-SY5Y cells injury induced by hydrogen peroxide.

A soluble melanin pigment produced by Streptomyces sp. ZL-24 was purified and named StrSM. The elemental analysis of StrSM showed it consists of carbon, hydrogen, and oxygen. The spectrum analysis, including ultraviolet-visible absorption spectrum, Fourier-transform infrared spectrum, and pyrolysis-gas chromatography-mass spectrometry, indicated that StrSM might be pyomelanin. High performance liquid chromatography and liquid chromatography-mass spectra analysis of intermediate metabolite showed the presence of homogentisic acid (HGA). Moreover, the enzyme 4-hydroxyphenylpyruvate dioxygenase, involved in HGA biosynthesis, showed high activity during melanin production. Subsequently, a tyrosinase gene (melC2) and hydroxyphenylpyruvate dioxygenase gene double mutant demonstrated StrSM is pyomelanin. In vitro bioactivity assay showed that StrSM had excellent protective capability against SH-SY5Y cell oxidative injury. To our knowledge, the results firstly provide comprehensive data on Streptomyces pyomelanin identification and a promising candidate compound to treat oxidative injury of neurocytes.

DAPT suppresses proliferation and migration of hepatocellular carcinoma by regulating the extracellular matrix and inhibiting the Hes1/PTEN/AKT/mTOR signaling pathway.

BACKGROUND: The aim of the present study was to investigate the antitumor properties of N-(N-[3,5-difluorophenacetyl]-1-alanyl)-S-phenylglycine t-butyl ester (DAPT) against hepatocellular carcinoma (HCC), as well as the underlying mechanism. METHODS: Immunohistochemistry and quantitative reverse transcription polymerase chain reaction (qRT-PCR) assay were used to determine the expression of Notch1 in HCC tissues. The expression of Notch1 in 3 HCC cell lines was evaluated by qRT-PCR and Western blot. The proliferation ability of cells was detected by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and colony formation assays. Flow cytometry and Transwell assay were used to check the apoptosis and migration of HepG2 cells, respectively. Western blot was used to determine the expression level of Notch1, Hes1, Phosphatase and tensin homolog (PTEN), protein kinase B1 (AKT1), phosphorylated AKT1, mammalian target of rapamycin (mTOR), phosphorylated mTOR, intracellular adhesion molecule-1, vascular cell adhesion protein 1, matrix metalloproteinase (MMP)-2, MMP-9, and focal adhesion kinase in cells and tumor tissues. A HepG2 xenograft experiment was conducted to evaluate the in vivo antitumor properties of DAPT. RESULTS: Notch1 was found to be significantly upregulated in both HCC tissues and cell lines. DAPT significantly inhibited the proliferation and migration of HepG2 cells in a dose-dependent manner, accompanied by the suppression of Notch1/Hes1 signaling, inactivation of AKT/mTOR signaling, downregulation of MMPs, and decreased expression of adhesion molecules. The activation of Notch1/Hes1 or AKT/mTOR signaling removed the inhibitory effect of DAPT on the proliferation and migration of HepG2 cells, as well as the inhibitory properties of DAPT on the expression of MMPs and adhesion molecules. The antitumor properties and regulatory effect of DAPT against the extracellular matrix (ECM) and Hes1/PTEN/AKT/mTOR signaling were verified by the HepG2 xenograft experiments. CONCLUSIONS: DAPT could suppress the proliferation and migration of HCC by regulating the ECM and inhibiting the Hes1/PTEN/AKT/mTOR signaling pathway.

Enhancement of angucycline production by combined UV mutagenesis and ribosome engineering and fermentation optimization in Streptomyces dengpaensis XZHG99T.

Strain improvement of Streptomyces dengpaensis XZHG99T was performed by combined UV mutagenesis and ribosome engineering, as well as fermentation optimization for enhanced angucycline production (rabelomycin and saquayamycin B1). First, four streptomycin-resistant mutants were obtained after screening of UV mutagenesis and ribosome engineering. Then a rpsL mutant (HTT7) with higher productivity of rabelomycin and saquayamycin B1 was selected according to genetic screening and HPLC/LC-MS analyses, whose maximum titers of rabelomycin and saquayamycin B1 were 3.6 ± 0.02 mg/L and 7.5 ± 0.04 mg/L, respectively, about fourfold higher than those produced by XZHG99T. Next, fermentation optimization of HTT7 was successively carried out by single-factor experiments in shake flasks. The titers of rabelomycin and saquayamycin B1 were increased to 11.2 ± 0.04 mg/L and 20.5 ± 0.02 mg/L after optimization of shake flask fermentation conditions, respectively, which was increased about sixfold compared with those produced by XZHG99T. Finally, the titers of rabelomycin and saquayamycin B1 reached 15.7 ± 0.05 mg/L and 39.9 ± 0.05 mg/L after the scaled-up fermentation, which was 7.8-fold and 11.4-fold higher than those produced by XZHG99T, respectively. These data demonstrate that the combined empirical strain-breeding approaches are still an effective and convenient pathway to improve strain production ability.

Streptomyces tibetensis sp. nov., an actinomycete isolated from the Tibetan Plateau.

A novel actinomycete, designated strain XZ 46T, was isolated from acid sandy soil collected from the Tibetan Plateau, China. Its taxonomic position was determined using a polyphasic approach. Strain XZ 46T shows the typical morphological and chemotaxonomic features of members of the genus Streptomyces: slightly yellow to brown substrate mycelia and grayish white to slightly yellow aerial hyphae forming cylindrical and spiny spores; meso-diaminopimelic acid in the cell wall peptidoglycan; MK-9(H8), MK-9(H4) and MK-9(H2) as predominant menaquinones; diphosphatidylglycerol, phospatidylethanolamine, phosphatidylglycerol and phosphatidylinositol as main polar lipids; and iso-C15:0, iso-C16:0 and anteiso-C15:0 as major cellular fatty acids. The G+C content of the draft genome sequence, consisting of 8,995,813 bp, is 71.23%. The16S rRNA gene sequence analysis indicated that strain XZ 46T shows high sequence similarity to Streptomyces luteogriseus NBRC 13402T as well as forming an independent lineage clade with it in phylogenetic trees. Multilocus sequence analysis (MLSA) of five housekeeping genes (atpD, gyrB, recA, rpoB and trpB) illustrated that Streptomyces hawaiiensis is also a very closely related taxon. However, DNA-DNA hybridization, MLSA evolutionary distance and phenotypic properties demonstrate that strain XZ 46T can be distinguished from these phylogenetically related Streptomyces species. Therefore, it is concluded that strain XZ 46T represents a novel species of the genus Streptomyces, for which the name Streptomyces tibetensis is sp. nov. proposed. The type strain is XZ 46T (= CGMCC 4.7579T = KCTC 49221T).

Effect of Tartaric Acid on the Printable, Rheological and Mechanical Properties of 3D Printing Sulphoaluminate Cement Paste.

Rapid setting and low viscosity of sulphoaluminate cement (SAC) make it difficult to be extruded by 3D printing (3DP) technique. In this study, the effect of tartaric acid (TA) on printability, rheology and mechanical property of 3DP SAC paste is investigated. The experimental results indicate that the setting time, hydration evolution and apparent viscosity of SAC paste can be well controlled by adding a proper amount of TA to satisfy the requirements of 3DP. An excellent structure of SAC paste with the ultimate deformation rate less than 10% can be printed without compromising mechanical strength.

Di-n-butyl phthalate exposure negatively influences structural and functional neuroplasticity via Rho-GTPase signaling pathways.

Di-n-butyl phthalate (DBP) has been reported to cause disruptions in hippocampal plasticity, but its specific mechanism has not yet been ascertained. In this research, a mouse model of chronic DBP exposure was generated by intragastric administration of DBP (10, 50, or 250°mg/kg/d) for 5 weeks. Chronic exposure to high concentrations of DBP (250°mg/kg/d) induced a spatial learning deficit in the Morris water maze in male mice. By determining the activity of Rho-GTPase signaling pathways in the hippocampal tissues, we found that DBP exposure inhibited the activity of Rac1/PAK1/LIMK1 but activated RhoA/ROCK/LIMK2 signaling and eventually suppressed cofilin activity by phosphorylation. Consistent with this, the differential activation was also observed in the acute exposure model of neuronal cells generated by incubation with DBP (100°ng/ml, 1, 10, or 100°µg/ml) for 72 hours. Moreover, acute exposure to high concentrations of DBP (100°µg/ml) altered cell morphology by inhibiting neurite outgrowth. A ROCK inhibitor, but not inhibitors of Rac1 or PAK1, reversed the inhibition of DBP to the activity of cofilin and neurite outgrowth in cells. These findings provide the first evidence that DBP exposure results in impairment of neuroplasticity by differential regulation of Rho-GTPase signaling pathways.

Inhibition of Nischarin Expression Promotes Neurite Outgrowth through Regulation of PAK Activity.

Nischarin is a cytoplasmic protein expressed in various organs that plays an inhibitory role in cell migration and invasion and the carcinogenesis of breast cancer cells. We previously reported that Nischarin is highly expressed in neuronal cell lines and is differentially expressed in the brain tissue of adult rats. However, the physiological function of Nischarin in neural cells remains unknown. Here, we show that Nischarin is expressed in rat primary cortical neurons but not in astrocytes. Nischarin is localized around the nucleus and dendrites. Using shRNA to knockdown the expression of endogenous Nischarin significantly increases the percentage of neurite-bearing cells, remarkably increases neurite length, and accelerates neurite extension in neuronal cells. Silencing Nischarin expression also promotes dendrite elongation in rat cortical neurons where Nischarin interacts with p21-activated kinase 1/2 (PAK1/2) and negatively regulates phosphorylation of both PAK1 and PAK2. The stimulation of neurite growth observed in cells with decreased levels of Nischarin is partially abolished by IPA3-mediated inhibition of PAK1 activity. Our findings indicate that endogenous Nischarin inhibits neurite outgrowth by blocking PAK1 activation in neurons.