On-device phase engineering.

In situ tailoring of two-dimensional materials' phases under external stimulus facilitates the manipulation of their properties for electronic, quantum and energy applications. However, current methods are mainly limited to the transitions among phases with unchanged chemical stoichiometry. Here we propose on-device phase engineering that allows us to realize various lattice phases with distinct chemical stoichiometries. Using palladium and selenide as a model system, we show that a PdSe2 channel with prepatterned Pd electrodes can be transformed into Pd17Se15 and Pd4Se by thermally tailoring the chemical composition ratio of the channel. Different phase configurations can be obtained by precisely controlling the thickness and spacing of the electrodes. The device can be thus engineered to implement versatile functions in situ, such as exhibiting superconducting behaviour and achieving ultralow-contact resistance, as well as customizing the synthesis of electrocatalysts. The proposed on-device phase engineering approach exhibits a universal mechanism and can be expanded to 29 element combinations between a metal and chalcogen. Our work highlights on-device phase engineering as a promising research approach through which to exploit fundamental properties as well as their applications.

[Structural characterization of PCP-â from Poria as vaccine adjuvant and its hydrolytic oligosaccharide].

Poria is an important medical herb in clinic. The authors isolated a polysaccharide(PCP-Ⅰ) from Poria in previous studies, which is composed of galactose, mannose, fucose and glucose. PCP-Ⅰ exhibited significant adjuvant effects on H1N1 influenza vaccine, hepatitis B surface antigen and anthrax protective antigen, and its adjuvant activity was stronger than aluminium adjuvant. However, little is known about the chemical structure of PCP-Ⅰ at present. In this study, weak acid hydrolysis was used to obtain the backbone oligosaccharide of PCP-Ⅰ. Then periodate oxidation, Smith degradation, methylation analysis, Fourier transform infrared spectroscopy(FT-IR), nuclear magnetic resonance(NMR) and gas chromatography-mass spectrometry(GC-MS) were performed to investigate the chemical structural features of PCP-Ⅰ and its hydrolytic oligosaccharide(PCP-Ⅰ-hy-1). These results suggested that the backbone of PCP-Ⅰ was composed of galactose with α anomeric carbon and ß anomeric carbon. The linking residues of galactan are(1→),(l→6) and(1→2,6).

Longibramides A-E, Peptaibols Isolated from a Mushroom Derived Fungus Trichoderma longibrachiatum Rifai DMG-3-1-1.

Five new peptaibols, longibramides A-E (1-5) with 11 amino acid residues, were isolated from a fungus Trichoderma longibrachiatum Rifai DMG-3-1-1, which was isolated from a mushroom Clitocybe nebularis (Batsch) P. Kumm collected from coniferous forest in the subboreal area of northeast China. The structures of longibramides A-E were determined by their spectroscopic data (NMR and MS-MS spectra), their absolute configurations were determined by X-ray diffractions and Marfey's analyses. The X-ray diffractions of longibramides A, B, and the similar CD spectra of A-E showed that they all had α-helix conformations. Longibramides B and E showed moderate cytotoxicities against BV2 and MCF-7 cells and also showed some inhibitory effects against methicillin-resistant Staphylococcus aureus MRSA T144. L-trans-Hyp was not commonly found in natural peptaibols, which was the 6th or 10th amino acid residue in longibramides C-E. The X-ray diffractions of longibramides A and B afforded the accuracy conformations of their secondary structures, which maybe help to interpret the structure-activity relationships of the family of peptaibols in the future.

Enhancing the Heat-Dissipation Efficiency in Ultrasonic Transducers via Embedding Vertically Oriented Graphene-Based Porcelain Radiators.

Ultrasonic transducers with large output power have attracted extensive attentions due to their widespread applications in sonar, acoustic levitation, ultrasonic focusing, and so forth. However, the traditional transducer has almost no heat-dissipation capability itself, strictly relying on the assistant coolant system. Introducing high-performance heat-dissipation component is thus highly necessary. Herein, an embedded porcelain radiator component was designed by combining the excellent thermal conductivity of vertically oriented graphene (VG) with the outstanding heat-dissipation characteristics of thermosensitive ceramics, and a new-type transducer with an embedded VG/ceramic-hybrid radiator was constructed to show high heat-dissipation efficiency (up to ∼5 °C/min). Remarkably, prominent heat-dissipation effectiveness (temperature decline of ∼12 °C), enhanced amplitude and vibration uniformity were also achieved for the new-type transducer along with stabilized operating states. This research should pave ways for extending the applications of VG/ceramic hybrids to heat-dissipation scenarios and provide newfangled thoughts for the performance upgrade of multitudinous high-power devices.

Marburg virus-like particles by co-expression of glycoprotein and matrix protein in insect cells induces immune responses in mice.

BACKGROUND: Marburg virus (MARV) causes severe haemorrhagic fever in humans and nonhuman primates and has a high mortality rate. However, effective drugs or licensed vaccines are not currently available to control the outbreak and spread of this disease. METHODS: In this study, we generated MARV virus-like particles (VLPs) by co-expressing the glycoprotein (GP) and matrix protein (VP40) using the baculovirus expression system. MARV VLPs and three adjuvants, Poria cocos polysaccharide (PCP-II), poly(I:C) and aluminium hydroxide, were evaluated after intramuscular vaccination in mice. RESULTS: Murine studies demonstrated that vaccination with the MARV VLPs induce neutralizing antibodies and cellar immune responses. MARV VLPs and the PCP-II adjuvant group resulted in high titres of MARV-specific antibodies, activated relatively higher numbers of B cells and T cells in peripheral blood mononuclear cells (PBMCs), and induced greater cytokine secretion from splenocytes than the other adjuvants. CONCLUSION: MARV VLPs with the PCP-II adjuvant may constitute an effective vaccination and PCP-II should be further investigated as a novel adjuvant.

A polysaccharide from the stems of Rubus amabilis Focke and its immunological enhancement activity.

A water-soluble polysaccharide (named RAP) was newly isolated from the stems of Rubus amabilis. Structural confirmation of the polysaccharide was provided by hydrolysis, periodate oxidation, Smith degradation, and methylation analysis, combined with nuclear magnetic resonance (NMR), capillary electrophoresis (CE), infrared spectroscopy (IR), and gas chromatography-mass spectra (GC-MS). In vitro immunological enhancement activity was characterized using the proliferative activity of spleen lymphocytes and phagocytic activity of peritoneal macrophages in mice. The polysaccharide was mainly composed of xylose, arabinose, glucose, rhamnose, galactose, mannose, glucuronic acid, and galactocuronic acid in the molar ratio of 1.0:6.9:0.8:1.1:6.9:0.3:0.5:3.3, with the average molecular weight of 26.2 kDa. The linkage types of netural monosaccharides were as follows: the arabinose was →2) Ara (1→ and galactose were Gal (1→, →3) Gal (1→, →3,6) Gal (1→, →2,3,6) Gal (1→ and →2,3,6) Galf (1→. Xyl (1→, →6) Glc (1→, →2) Glc (1→, →3) Rha (1→, Rha (1→ and Man (1→ were also found in the structure. RAP-B-2 could improve the proliferative activity of spleen T cells and B cells and boost phagocytic activity of peritoneal macrophages at the concentration of 50 µg/ml (p < 0.05, p < 0.01).

An α-glucan isolated from root of Isatis Indigotica, its structure and adjuvant activity.

The root of Isatis indigotica is a traditional Chinese herbal medicine. An α-glucan (IIP-A-1) was firstly isolated from the roots. In this study we elucidated the chemical structure of IIP-A-1 and determined its adjuvant activity by co-immunizing mice with H1N1 influenza virus split and recombinant hepatitis B surface antigen (HBsAg), respectively. The polysaccharide was pretreated with periodate oxidation, Smith degradation and methylation in order to analyze its structure using GC, HPGPC, FT-IR, NMR and GC-MS. The adjuvant effect was evaluated by determining the antibody titers of serum against H1N1 influenza and HBsAg using ELISA. The proliferation and TNF-α secretion of macrophages administrated with different dose of IIP-A-1 were measured in vitro. The results of this study revealed that IIP-A-1 was an α-glucan with the molecular weight of 3,600 Da. The backbone was α-(1 → 4)-D-glucan with (1 → 6) branch chain. The α-glucan could significantly enhance the immune response of mice immunized with H1N1 influenza or HBsAg in vivo and exert good dose-dependent effects on the proliferation and the TNF-α secretion of macrophages in vitro. These results supported that IIP-A-1 was expected to be an efficacious adjuvant candidate for prophylactic and therapeutic vaccines.

Characterization of an Ebosin derivative produced by heterologous gene replacement in Streptomyces sp. 139.

BACKGROUND: Ebosin is a novel exopolysaccharide (EPS) produced by Streptomyces sp. 139 and evidenced to possess an anti-rheumatic arthritis activity in vivo. The Ebosin biosynthesis gene cluster (ste) consists of 27 ORFs and ste7 has previously been demonstrated to code for a fucosyltransferase, which plays an essential role in the formation of repeating sugar units during Ebosin production. Aiming to generate derivatives of Ebosin for better activity, we replaced ste7 with a gene encoding for a glucosyltransferase (gtf) from Streptococcus thermophilus. RESULTS: This alteration resulted in a novel Ebosin derivative (EPS-7 g) with its monosaccharide composition dramatically changed, especially in the proportion of glucose which increased from 1.1% (Ebosin) to 84.01% (EPS-7 g). In an ELISA analysis, EPS-7 g exhibited a higher binding activity for IL-1R, as a competitor of interleukin-1, than that of Ebosin. It also exhibited a higher inhibitory effect on the activity of IL-1ß-converting enzyme and production of IL-1ß in fibroblast-like synoviocytes (FLS). In addition, experiments with acute inflamed mice induced by croton oil showed a significantly higher anti-inflammatory activity of EPS-7 g compared with Ebosin. CONCLUSIONS: The new Ebosin derivative EPS-7 g is more bioactive than Ebosin evaluated by a series of experiments. This is the first report demonstrating a modification of EPS structure via heterologous gene replacement in Streptomyces.

Absorption, distribution and pathological injury in mice due to ricin poisoning via the alimentary pathway.

The aim of this work was to investigate the potential interactions between intestinal absorbance and ricin poisoning. The Caco-2 cell monolayer and everted intestinal sac (VEIS) models were used. The distribution of ricin in CD-1 mice intoxicated with 0.1 mg/kg of ricin intragastrically was determined by immunohistochemistry. The results showed that ricin could not transfer across the healthy Caco-2 cell monolayer within three hours after poisoning. However, it could pass through the everted rat intestinal wall after 0.5 h of incubation. The toxin in the liver, spleen, lungs and kidneys of mice could be detected as early as 1 h after intoxication. The pathological results were in accordance with the cytotoxicities of ricin in Caco-2, HepG 2, H1299 and MDCK cells, indicating that though no significant symptom in mice could be observed within 3 h after ricin intoxication, important tissues, especially the kidneys, were being injured by the toxin and that the injuries were progressing.

Characterization of and functional evidence for Ste27 of Streptomyces sp. 139 as a novel spermine/spermidine acetyltransferase.

Ebosin, a novel exopolysaccharide produced by Streptomyces sp. 139, has remarkable anti-rheumatoid arthritis activity in vivo and its biosynthesis gene cluster (ste) consists of 27 ORFs (open reading frames). The present paper reports our study of the protein product encoded by ste27. Database searching reveals the homology of Ste27 with some spermidine/spermine acetyltransferases. To confirm the prediction, the ste27 gene was cloned and expressed in Escherichia coli BL21(DE3) cells and recombinant Ste27 was purified. The following enzymatic analysis revealed its ability of transferring the acetyl group from acetyl-CoA to spermidine and spermine, with spermidine being the preferred substrate. Ste27 can acetylate the N1, N4 and N8 positions on spermidine. The Km values of Ste27 were determined for spermidine and spermine, as well as for acetyl-CoA, poly-L-lysine and glucosamine 6-phosphate. Upon gene knockout, the exopolysaccharide-27m produced by the mutant strain Streptomyces sp. 139 (ste27-), compared with Ebosin, exhibited a significantly reduced binding activity to the interleukin-1 receptor. After gene complementation, the binding activity was partially restored. This demonstrated that the ste27 gene is involved in the biosynthesis of Ebosin. Molecular modelling was also carried out to predict the binding mode of Ste27 with acetyl-CoA, spermidine or spermine.

Rapid isolation of new furostanol saponins from fenugreek seeds based on ultra-performance liquid chromatography coupled with a hybrid quadrupole time-of-flight tandem mass spectrometry.

An ultra-performance liquid chromatography coupled with a hybrid quadrupole time-of-flight tandem mass spectrometry method was established to rapidly identify and guide the isolation of target saponins from fenugreek seeds. Based on the online screening performance, totally forty-six furostanol saponins were detected and elucidated. Among them, twenty compounds were predicted to be new. To rapidly obtain new furostanol saponins from these seeds, a further phytochemical study was carried out under the guidance of the ultra-performance liquid chromatography coupled with a hybrid quadrupole time-of-flight tandem mass spectrometry. Finally, six new furostanol saponins, named as trigoneosides XIV (1), XV (2), XVI (3), XVIIa (4), XVIIb (5), and XIV (6), together with one known furostanol saponin, parvifloside (7), were rapidly obtained, and their definitive structures were determined by NMR and chemical evidence.

Radial vibration analysis for functionally graded ring piezoelectric transducers based on electromechanical equivalent circuit method.

Ring piezoelectric transducers (rPETs) have attracted multitudinous attentions due to their widespread applications in hydro-acoustic engineering, structural health monitoring, and energy harvesting. However, cracks are inevitably occurred by the concentrated stress at the interface between metal and piezoelectric ceramics, which will seriously affect the performance and service life of the devices. Hence, a novel functionally graded ring piezoelectric transducer (FG-rPET) has been designed and an accurate analytical system is constructed mainly including a three-port electromechanical equivalent circuit model (EECM) which can acquire exact solutions in radial vibration. In addition, the proposed three-port EECM has excellent generalizability, which is also applicable to conventional rPETs. The validity of the EECM is verified by experiments and the finite element method. The vibration characteristics (resonance/anti-resonance frequencies and effective electromechanical coupling coefficient (keff)) with fundamental and second modes for the FG-rPETs can be regulated via the inhomogeneity index and wall thickness. Markedly enhanced keff at second modes can be obtained for the FG-rPETs with specific wall thicknesses. The proposed analytical system has important guiding significance for structure optimization design of piezoelectric devices, and the designed FG-rPET is expected to break the bottleneck of mechanical properties for the conventional rPETs.

Surfactin isoforms isolated from a mushroom derived Bacillus halotolerans DMG-7-2.

A new iso-C14 [Val2, Val7] surfactin isoform (1) together with eight known ones (2-9), was isolated from the culture of a mushroom derived bacterium, Bacillus halotolerans DMG-7-2. The structures of them were mainly elucidated by NMR and MS data, and the NMR data of 5 also was reported for the first time. The absolute configuration of 1 was determined by Marfey's analysis (for amino acid residues) and the 13C NMR calculation of the two plausible epimers of 1 (for fatty acid). Compounds 1-9 showed moderate cytotoxicity against two human cancer cell lines (A549, MCF-7) and mice microglial BV2 cells, the IC50 values ranged from 8.91 to 33.00 µM, and the IC50 values of the positive control 5-FU were 99.94, 71.49 and 0.12 µM, respectively.[Formula: see text].

Designing New-Generation Piezoelectric Transducers by Embedding Superior Graphene-Based Thermal Regulators.

Cascaded-piezoelectric-transducers (CPETs) is a key component in modern energy-conversion fields, possessing versatile applications in ultrasonic scalpels, acoustic levitation, and sonar. However, serious self-heating inevitably occurs inside high-power CPETs, severely limiting their practical applications in broader fields. To tackle this, multidirectional heat-escape channels of multidimensional (multi-D, 3D/2D) graphene films are introduced in designing new-type thermal regulators. A porous AlN-ceramic thermal-sink is creatively selected as a template for directly synthesizing graphene via a two-step chemical vapor deposition strategy. This perfect combination of 3D/2D-graphene and the AlN ceramic can integrate their complementary advantages in uniformizing, transmitting, and releasing heat. Amazingly, in the new-generation CPETs embedded with these graphene-based thermal regulators, the self-heating-induced temperature rise can be substantially reduced by ≈60% (far exceeding actual demand standard). As another kernel parameter, electroacoustic-energy-conversion efficiency is dramatically improved in the new-generation CPETs. Briefly, this research realizes the first synthesis of a novel multi-D-graphene/AlN-ceramic hybrid, and propels its brand-new application directions in new-generation energy-conversion- and thermal-management-related territories.

Adhesion-Enhanced Vertically Oriented Graphene on Titanium-Covered Quartz Glass toward High-Stability Light-Dimming-Related Applications.

Improving the adhesion property of graphene directly grown on an insulating substrate is essential for promoting the reliability and durability of the related applications. However, effective approaches have rarely been reported, especially for vertically oriented graphene (VG) films grown on insulating templates. To tackle this, we have developed a facile synthetic strategy by introducing an ultrathin (10 nm-thick) titanium (Ti) film on a quartz glass substrate as the adhesion layer, for plasma-enhanced chemical vapor deposition (PECVD) growth of VG films. This synthetic process induces the formation of Ti, oxygen (O), carbon (C)-containing adhesion layer (Ti (O, C)), offering improved interfacial adhesion due to the formation of chemical bonds among Ti and C atoms. Dramatically improved surface and interface stabilities have been achieved, with regard to its counterpart without a Ti adhesion layer. Moreover, we have also realized precise controls of the transparent/conductive property, surface roughness, and hydrophobicity, etc., by varying the VG film growth time. We have also demonstrated the very intriguing application potentials of the hybrids in light-dimming related fields, that is, electro-heating defogging lenses and neutral density filters toward medical endoscope defogging and camera photography.

Chemical characters and protective effect of Baqi Lingmao formula on experimental liver injury.

OBJECTIVE: To investigate the chemical characters of water-extract of Baqi Lingmao formula (BQLM formula) and its effects on anti-liver injury in model mice and live cells. METHODS: BQLM formula was composed of ten herbal medicines. We determined the contents of alkaloids, saponins, phenolic acids and flavonoid in BQLM formula by UV spectrophotometry. The active components of alkaloids and phenolic acids in BQLM formula were identified by HPLC chromatography. The anti-hepatic injury effects of BQLM formula were investigated with concanavalin A (ConA)-induced hepatitis model of mice, human liver LO2 and HepG2.2.15 cells. RESULTS: BQLM formula (2 and 10 g/kg, orally) significantly improved the damages of liver tissues and functions caused by ConA in mice, reduced the infiltration of inflammatory cells into liver and inhibited the inflammatory cytokine secretion of interferon-γ, tumor necrosis factor-α and interleukin-6. BQLM formula simultaneously decreased the levels of alanine aminotransferase and aspartate aminotransferase of liver and serum, and recovered the superoxide dismutase and catalase activities of liver to normal levels in ConA-induced hepatic-injury mice. The serum of BQLM formula group stimulated the human liver LO2 cell proliferation in vitro. Further, BQLM formula obviously promoted the proliferation of normal hepatocytes (LO2 cells) and inhibited the hepatocytes death induced by ConA. It also significantly inhibited the proliferation of HepG2.2.15 cells and decreased the secretion of HBsAg and HBeAg in vitro. CONCLUSIONS: BQLM formula has anti-inflammation and anti-hepatitis virus Beffects, and is capable of improving liver injury in vivo and in vitro.

Ethanol-Precursor-Mediated Growth and Thermochromic Applications of Highly Conductive Vertically Oriented Graphene on Soda-Lime Glass.

Direct growth of vertically oriented graphene (VG) nanowalls on soda-lime glass has practical significance in extending the application of graphene to daily-life-related areas, such as gas sensors and conductive electrodes, via combining their complementary properties and applications. However, VG films derived by low-temperature deposition (e.g., on glass) usually present relatively low conductivity and optical transparency. To tackle this issue, an ethanol-precursor-based, radio-frequency plasma-enhanced chemical vapor deposition (rf-PECVD) route for the synthesis of VG nanowalls is developed in this research, at around the softening temperature of soda-lime glass (∼600 °C) templates. The average sheet resistance, i.e., ∼2.4 kΩ·sq-1 (at transmittance ∼81.6%), is only one-half of that achieved by a traditional methane-precursor-based PECVD route. Based on the highly conductive and optically transparent VG/glass, as well as its scalable size up to 25 in. scale, high-performance reversible thermochromic devices were successfully constructed using VG/glass as transparent heaters. Hereby, this work should propel the scalable synthesis and applications of highly conductive VG films on glass in next-generation transparent electronics and switchable windows.

Highly Conductive Nitrogen-Doped Vertically Oriented Graphene toward Versatile Electrode-Related Applications.

The direct growth of vertically oriented graphene (VG) on low-priced, easily accessible soda-lime glass can propel its applications in transparent electrodes and energy-relevant areas. However, graphene deposited at low temperature (∼600 °C) on the catalysis-free insulating substrates usually presents high defect density, poor crystalline quality, and unsatisfactory electrical conductivity. To tackle this issue, we select high borosilicate glass as the growth substrate (softening point ∼850 °C), which can resist higher growth temperature and thus afford higher graphene crystalline quality, by using a radio-frequency plasma-enhanced chemical vapor deposition (rf-PECVD) route. A nitrogen doping strategy is also combined to tailor the carrier concentration through a methane/acetonitrile-precursor-based synthetic strategy. The sheet resistance of as-grown nitrogen-doped (N-doped) VG films on high borosilicate glass can thus be lowered down to ∼2.3 kΩ·sq-1 at a transmittance of 88%, less than half of the methane-precursor-based PECVD product. Significantly, this synthetic route allows the achievement of 30-inch-scale uniform N-doped graphene glass, thus promoting its applications as excellent electrodes in high-performance switchable windows. Additionally, such N-doped VG films were also employed as efficient electrocatalysts for electrocatalytic hydrogen evolution reaction.

Polysaccharide PCP-I isolated from Poria cocos enhances the immunogenicity and protection of an anthrax protective antigen-based vaccine.

Polysaccharides isolated from natural plants may represent a novel source of vaccine adjuvants. In this research, we focused on a natural plant polysaccharide, PCP-I, which is derived from Poria cocos, a Chinese traditional herbal medicine. We chose the anthrax protective antigen (PA) as a model to evaluate the adjuvant ability of PCP-I in enhancing the immunogenicity and protection of a PA-based anthrax vaccine. According to our results, PCP-I could significantly enhance anthrax specific anti-PA antibodies, toxin-neutralizing antibodies, anti-PA antibody affinity, as well as IgG1 and IgG2a levels. Besides, PCP-I increased the frequency of PA-specific memory B cells, increased the proliferation of PA-specific splenocytes, significantly stimulated the secretion of IL-4, and enhanced the activation of Dendritic cells (DCs) in vitro. The combination of PCP-I and CpG significantly enhanced the level of anti-PA antibodies and neutralizing antibodies, particularly PA-specific IgG2a, and shifted the Th2-bias to a Th1/Th2 balanced response. In addition, PCP-I with or without CpG could significantly improve the survival rate of immunized mice following challenge with the anthrax lethal toxin. These findings suggest that PCP-I may be a promising vaccine adjuvant that warrants further study.

Identification of alpha-D-glucose-1-phosphate cytidylyltransferase involved in Ebosin biosynthesis of Streptomyces sp. 139.

Ebosin, a novel exopolysaccharide produced by Streptomyces sp. 139 has antagonist activity for IL-1R in vitro and remarkable anti-rheumatic arthritis activity in vivo. Its biosynthesis gene cluster (ste) has been identified. In this study, gene ste17 was expressed in Escherichia coli BL21 and the recombinant protein was purified. With CTP and alpha-D-glucose-1-phosphate as substrates, the recombinant Ste17 protein was found capable of catalyzing the production of CDP-D-glucose and pyrophosphate, demonstrating its identity as an alpha-D-glucose-1-phosphate-cytidylyltransferase (CDP-D-glucose synthase). To investigate the function of ste17 in Ebosin biosynthesis, the gene was disrupted with a double crossover via homologous recombination. The monosaccharide composition of exopolysaccharide (EPS) produced by the mutant Streptomyces sp. 139 (ste17 (-)) was found significantly altered from that of Ebosin, with glucose becoming undetectable. This gene knockout also negatively affected the antagonist activity for IL-1R of EPS. These results indicate that the CDP-D: -glucose synthase encoded by ste17 gene is involved in the formation of nucleotide sugar (CDP-D-glucose) as glucose precursor in Ebosin biosynthesis.