High-Strength Carbon Nanotube Fibers from Purity Control by Atomized Catalytic Pyrolysis and Alignment Improvement by Continuous Large Prestraining.

Transferring the high strength of individual carbon nanotubes (CNTs) to macroscopic fibers is still a major technical challenge. In this study, CNT fibers are wound from a hollow cylindrical assembly. In particular, atomized catalytic pyrolysis is utilized to produce the fiber and control its purity. The pristine fiber is then continuously prestrained to have a highly aligned structure for subsequent full densification. Experimental measurements show that the final fiber possesses a high tensile strength (8.0 GPa), specific strength (5.54 N tex-1 (tex: the weight (g) of a fiber of 1 km long)), Young's modulus (350 GPa), and elongation at break (4%). Such an excellent combination is superior to that of any other existing fiber and attributed to the efficient stress transfer among the highly aligned and packed CNTs. Our study provides a new strategy involving atomized catalysis for developing superstrong CNT assemblies such as fibers and films for practical applications.

Large improvement of the tensile strength of carbon nanotube films in harsh wet environments by carbon infiltration.

Carbon nanotube (CNT) materials show large degradation in tensile strength when they are exposed in chemically active environments due to the loss of inter-tube bonding. Here, we report the suppression of such degradation by chemical vapor infiltration of amorphous carbon into CNT films. The amorphous carbon generated by the thermal decomposition of the gaseous hydrocarbon of acetylene is firmly bonded on the CNT sidewalls and intersections. Based on the improved inter-tube bonding and restriction of inter-tube sliding, the tensile strength of the film is improved to be 3 times of the original level. More importantly, the bonding is so strong and stable that the high tensile strength remains with little loss even in harsh wet environments such as boiling alcoholic, acidic, alkaline solutions and seawater. Such harsh environments-tolerant properties, which were rarely observed before, could open new windows for the CNT/C composite material to be applied from functional devices to structural components under extreme corrosive conditions.

[Two new steroidal alkaloids from ripe berries of Solanum nigrum].

Two previously undescribed steroidal alkaloids, compounds 1-2, along with two known ones(3-4), were isolated from the 80% ethanol extract of ripe berries of Solanum nigrum by chromatographic methods, including silica gel, ODS, and HPLC. Based on spectroscopic and chemical evidence, including IR, NMR, and HR-ESI-MS data, the structures of the isolated compounds were identified as 12ß,27-dihydroxy solasodine-3-O-ß-D-glucopyranoside(1), 27-hydroxy solasodine-3-O-ß-D-glucopyranosyl-(1→4)-α-L-rhamnopyranosyl-(1→2)-[α-L-rhamnopyranosyl-(1→4)]-ß-D-glucopyranoside(2), solalyraine A(3), and 12ß,27-dihydroxy solasodine(4). Compounds 1-2 were tested for their potential effects against the proliferation of A549 cells, which revealed that compounds 1-2 had weak cytotoxic activity.

[Research and application of quality standard for standard decoction of Chrysanthemi Flos].

Standard decoction of traditional Chinese medicine (TCM) is prepared by standardized process, and can be used as references to evaluate the quality of dosage forms such as decoction and dispensing granules. In order to determine the quality evaluation method for standard decoction of Chrysanthemi Flos and investigate its application, 10 batches of white chrysanthemum of Hangzhou were collected to prepare the standard decoction of white chrysanthemum of Hangzhou with standardized process parameters. Parameters such as traits, relative density, pH value, extraction ratio, transfer rate and fingerprint were selected as the indexes for quality evaluation. The established quality evaluation method for standard decoction of Chrysanthemi Flos was applied in the detection of two types of commercial Chrysanthemum dispensing granules. The results showed that the standard decoction of Chrysanthemi Flos was a clear yellow-brown aqueous solution; the relative density was 1.007-1.011; the pH value was between 5.37-5.56; the average extraction ratio was 23.6%, ranging from 19.93% to 29.69%; the average transfer ratewas 56.2% in terms of chlorogenic acid, 57.4% in terms of luteoloside and 30.6% in terms of 3,5-O-dicaffeoylquinic acid. Fingerprint similarity was between 0.864-0.989.The method showed good precision, stability and repeatability in fingerprint analysis, indicating reliable and representative results for standard decoction of Chrysanthemi Flos, and it can be used to evaluate and standardize other dosage forms.

[Calcium mobilizing effect of hawthorn leaf procyanidins in vascular endothelial cells].

The hawthorn leaves have the effect of activating blood, removing blood stasis, regulating qi through the veins, dissolving turbidity and lowering lipid. Procyanidinis is one of its main active components and plays an important role in regulating vasoactivity. Previous studies showed that the regulating effect of procyanidins was related to its regulation on nitric oxide secretion from vascular endothelial cells, and this effect was dependent on the extracellular calcium concentration, suggesting that the changes in intracellular calcium ion concentration in endothelial cells may play a key role in this process. However, the research on this issue is still insufficient so far. This study is aimed to observe the effect of hawthorn leaf oligomeric procyanidins (HLP) on calcium mobilization of vascular endothelial cells, and investigate the underlying mechanism. Human umbilical vein endothelial cells (HUVEC) were cultured in vitro and labeled with Fura-2. HUVEC were treated with HLP at concentrations of 6.25, 12.5, 25 and 50 mg·L⁻¹, and the intracellular calcium concentrations were measured with a living cell microscope for 30 min. HLP increased the intracellular calcium concentration of HUVEC in a concentration dependent manner; and the intracellular calcium concentrations in 25 and 50 mg·L⁻¹ HLP groups were significantly higher than that in the normal group. With the use of calcium-free incubation buffer, addition of calcium chelating agent EGTA in incubation buffer, or use of inhibitors for sodium calcium exchanger, the effect of HLP was significantly inhibited. On the other hand, the effect of HLP could also be weakened by inhibiting the calcium release from the intracellular storage. In conclusion, these results suggest that HLP can elicit calcium mobilization in vascular endothelial cells, which may be one of the mechanisms for its vascular modulatory activity; and this calcium mobilizing effect may be achieved through promoting both extracellular calcium influx and intracellular calcium release, additionally the former may be related to activating the reverse transport of Na⁺-Ca²âº exchangers on the cell membrane.

High-Strength Carbon Nanotube Film from Improving Alignment and Densification.

A new method is reported for preparing carbon nanotube (CNT) films. This method involves the continuous production of a hollow cylindrical CNT assembly and its condensation on a winding drum. The alignment and densification of CNTs in the film are improved by controlling the winding rate and imposition of mechanical rolling, respectively. The prepared film has a strength of 9.6 GPa, which is well above those for all other man-made films and fibers.

[Advantages of population pharmacokinetics and its application in the field of traditional Chinese medicine].

The accurate medical treatment is based on the information of the genome, which is the best treatment for the patients. Population pharmacokinetic study can be formulated according to the individual differences of patients to the dose, in the accurate medical model which has a unique advantage. At present, there are many problems such as adverse drug reaction in Chinese traditional medicine, and it is necessary to introduce a group of medicine on the basis of precise medical treatment. However, due to the different characteristics of traditional Chinese medicine and chemical medicine, it is necessary to combine the population pharmacokinetics, genetics and statistical methods to establish a research method which is in line with the characteristics of Chinese medicine. The key scientific problem is to make clear the active components of Chinese medicine metabolism of the drug metabolic enzyme gene, and pay attention to the analysis of the polymorphism of the overall role of drug metabolism enzymes in the human body. Clear key scientific issues and break through the bottleneck, so as to achieve the precise medical treatment, to international.

[Study on the chemical constituents of the PTP 1B inhibitory effective parts of Paeoniae Rubra Radix].

OBJECTIVE: To study the chemical constituents of the PTP 1B inhibitory effective parts of Paeoniae Rubra Radix. METHODS: The effective part of Paeoniae Rubra Radix was enriched by Sephadex LH-20. Compounds were isolated by various column chromatography and their structures were elucidated through spectroscopic analysis. RESULTS: Thirteen compounds were identified as: benzoylpaeoniflorin(1), albiflorin(2), paeoniflorigenone(3), methyl gallate(4), adenosine(5),2-amino adenosine(6), 3,3'-Di-O-methylellagic acid(7), 3,3',4-trimethyl ellagic acid(8), dihydrokaempferol(9), glycerol(10), dibutyl phthalate(11). CONCLUSION: Compounds 5-11 are obtained from this plant for the first time.

[Expert consensus on population pharmacokinetics of Chinese medicine ( draft version for comments)].

In population pharmacokinetic (PPK) research of Chinese medicines with narrow therapeutic windows of toxicity, or when the target population is not homogeneous, or when there are frequent adverse reactions to parenterally administered Chinese medicine, select those that have a definite therapeutic effect, and in which the compositions of the toxic substances compositions are known, for study, and use complete PPK sampling design to take samples at specific time points. Use gas chromatography, HPLC, and LC-MS methods for the detection of target components. Finally, use total quantity statistical moment analysis, to account for each component of the PPK parameters. Thus, PPK model can reflect the overall trend of Chinese medicine, to provide the basis for reasonable clinical dosage adjustments.

[Normative research on bacteriostasis and relieving itching external therapeutic function of kochiae fructus].

OBJECTIVE: To normalize bacteriostasis and relieving itching external therapeutic function of Kochiae Fructus. METHODS: Itching guinea pig model caused by histamine, itching mice model, eczema guinea pig model caused by OVA, and inhibitory effect on pathogens in vitro were used to observe the itching threshold, symptoms and other related physiological index, as well as the inhibitory effect on the normal skin fungi by water extraction of Kochiae Fructus to evaluate the external therapeutic function of Kochiae Fructus. RESULTS: The itching threshold of guinea pig itching model treated by water extraction of Kochiae Fructus at high, medium and low three dosage level, could be significantly increased when compared with negative control group (P < 0.05 or P < 0.01); Red speckle of OVA guinea pig model treated by water extraction of Kochiae Fructus at high, medium and low three dosage level, could be significantly decreased when compared with negative control group (P < 0.05 or P < 0.01); The number of itching and total time of itching within 30 minutes of mice model caused by R-glycose anhydride treated by water extraction of Kochiae Fructus at high, medium and low three dosage level, could be significantly decreased when compared with negative control group (P < 0.05 or P < 0.01); Several common skin fungi could be significantly inhibited by the water extraction of Kochiae Fructus. MIC of the water extraction of Kochiae Fructus on Trichophyton mentagrophytes, Trichophyton rubrum, Microsporum canis, Trichophyton violaceum, and Trichophyton schoenleini were 3.12%, 0.78%, 0.78%, 0.78%, 0.78%, respectively. CONCLUSION: Kochiae fructus has the effect of bacteriostasis and relieving itching.

Steroidal alkaloids from Solanum nigrum and their cytotoxic activities.

Eight undescribed, along with five known steroidal alkaloids were isolated from Solanum nigrum L., a plant used in traditional Chinese medicine. Their structures were elucidated by NMR, HR-ESI-MS, and IR spectroscopy. Two compounds displayed an unusual structure in steroidal alkaloids with an open E-ring and without an F-ring present. To evaluate their bioactivities, nine compounds were selected to intervene five human cancer cell lines including H1299, HepG2, HeLa, HCT116, and MCF7 respectively. All compounds exhibited inhibitory effects for the five cell lines, revealing potential anti-tumor activities from Solanum nigrum.

Carbon dioxide-boosted growth of high-density and vertically aligned carbon nanotube arrays on a stainless steel mesh.

Vertically aligned carbon nanotubes (VACNTs), a unique group of highly aligned CNTs normal to a substrate, have been extensively studied during the past decades. However, it is a long-standing challenge to improve the height of VACNTs due to the incidental deactivation of catalysts during growth. Herein, we demonstrate a facile strategy toward synthesizing high-density and well-aligned CNT arrays from in situ formed Fe-based catalysts on a stainless steel (SS) mesh. These catalysts were generated by direct oxidation-reduction treatment to the SS, which had excellent adhesion on the mesh substrate, and thus suppressed catalyst aggregation and promoted CNT growth under the flow of C2H2. In particular, by feeding additional CO2 at an optimal rate, the height of CNT arrays could be boosted from ca. 15 µm to ca. 80.0 µm, one of the highest heights observed for VACNTs on SS-based substrates so far. This is attributed to the prolonged activity of the catalysts by CO2 induced removal of extra carbon. Our study might provide an insight into the development of efficient strategies for VACNT growth on conductive substrates.

Impurity effect on weak antilocalization in the topological insulator Bi2Te3.

We study the weak antilocalization (WAL) effect in topological insulator Bi(2)Te(3) thin films at low temperatures. The two-dimensional WAL effect associated with surface carriers is revealed in the tilted magnetic field dependence of magnetoconductance. Our data demonstrate that the observed WAL is robust against deposition of nonmagnetic Au impurities on the surface of the thin films, but it is quenched by the deposition of magnetic Fe impurities which destroy the π Berry phase of the topological surface states. The magnetoconductance data of a 5 nm Bi(2)Te(3) film suggests that a crossover from symplectic to unitary classes is observed with the deposition of Fe impurities.

A direct foaming approach for carbon nanotube aerogels with ultra-low thermal conductivity and high mechanical stability.

Thermally insulating materials (TIMs) with ultra-low thermal conductivity, fire-retardancy, and mechanical stability are demanded to improve energy efficiency in many fields, such as petrochemical plants, energy-saving buildings, and aerospace. However, traditional polymer-based TIMs could not meet these demands. Herein, we propose a direct foaming strategy for obtaining carbon nanotube (CNT) aerogels by the gradual expansion of CNT films with H2O2 as a foaming agent at room temperature. The obtained CNT aerogels have hierarchical cellular structures and possess an ultra-low density (4.6 mg cm-3) and thermal conductivity (16.5 mW m-1 K-1) as well as excellent mechanical robustness and fire-resistance. Our results show that such CNT aerogels have promising applications in the field of thermal insulation and present a facile pathway for the design of thermally insulating, fire-retardant materials based on CNTs.

Highly flexible and free-standing carbon nanotube/hollow carbon nanocage hybrid films for high-performance supercapacitors.

Carbon nanotubes (CNTs) have been considered as promising electrode materials for energy storage devices, especially flexible electronics owing to their excellent electrical, physicochemical and mechanical properties. However, the severe aggregation between CNTs significantly reduces the electrochemically active surface areas and thus degrades the electrochemical properties. In this study, we demonstrate a facile layer-by-layer strategy toward preparing a CNT/hollow carbon nanocage (HCNC) hybrid film. Through electrochemically removing the impurities in CNT films and optimizing the concentrations of HCNC, the hybrid film exhibits a high specific capacitance of 183.7 F g-1 at 10 mV s-1 and good cycling stability of 85% retention after 5000 cycles at 1 A g-1. Our study provides potential scale-up synthesis of free-standing CNT electrode materials for high-performance supercapacitors.

[Studies on the chemical constituents of radix Boehmeriae].

OBJECTIVE: To study the chemical constituents from Radix Boehmeriae. METHODS: Compounds were isolated by various column chromatographies with silica gel, their structures were elucidated by spectral analysis and chemical evidence. RESULTS: Eight compounds were isolated and their structures were identified as emodin (1), emodin-8-O-beta-glucopyranoside (2), physcion (3), polydatin (4), catechin (5), epicatechin (6), potassium nitrate (7), sitosterol (8). CONCLUSION: Among these compounds, 3 -7 are isolated from Radix Boehmeriae for the first time.

A carbon nanotube approach for efficient thermally insulating material with high mechanical stability and fire-retardancy.

For applications in energy-saving buildings, aerospace industry, and wearable electronic devices, thermally insulating materials (TIMs) are required to possess not only low thermal conductivity but also light weight, mechanical robustness, and environmental stability. However, conventional TIMs can rarely meet these requirements. To overcome this shortcoming, we propose a new strategy for preparing TIMs. This is based on the design of a highly porous structure from carbon nanotubes (CNTs). The CNT structure is constructed by continuous winding of a hollow cylindrical CNT assembly from a high-temperature furnace and subsequent modification by the deposition of amorphous carbon (AC). The resultant sponge-like material is shown to have a record-low density of 2-4 mg cm-3 and a record-low thermal conductivity of 10-14 mW m-1 K-1. Combined with this thermal property, the sponge material also possesses fire-retardancy during burning, mechanical robustness after repeated loading and unloading to a high strain of 90%, and environmental stability from 535 to -196 °C. Such a combination of physical and mechanical properties results from the strengthening of the porous structure by virtue of AC deposition on CNT surfaces and junctions. The high performance of the new TIM constitutes the foundation for it to be used in wide areas, especially under the harsh conditions requiring multifunctionality.

Construction of Carbon Nanotube Sponges to Have High Optical Antireflection and Mechanical Stability.

Antireflective (AR) materials are required to possess high optical antireflection and mechanical stability for their practical applications in optical, opto-electronic, and electron-optical devices. However, the AR materials developed so far can hardly meet these requirements. Here, we report the construction of a highly porous and sponge-like material based on carbon nanotubes (CNTs). This is achieved by continuous winding of a hollow cylindrical CNT assembly and subsequent modification with amorphous carbon (AC). The resultant material is shown to have very low optical reflectance at the visible and infra-red wavelengths over a wide range of incident angles and undergoes little degradation even after long-lasting compressive cycling between 0 and 90% strains or a large change of environmental temperature from -196 to 300 °C. Besides, the AR sponge material can recover fast after bending, stretching, and compression from high elastic strains. Such an excellent combination of broadband and omnidirectional antireflection, mechanical stability, and elastic flexibility results from the strong light absorption by the highly porous CNT structures strengthened by AC deposition on CNT surfaces and junctions, and the new AR material has potential applications in the renewable energy and military fields.

Steroidal glycoalkaloids from Solanum lyratum inhibit the pro-angiogenic activity of A549-derived exosomes.

In this study, seven previously undescribed steroidal glycoalkaloids, compounds 1-7, were isolated from Solanum lyratum, along with two known ones (8 and 9). Comprehensive spectroscopy techniques were used to determine their structures. Although 1-8 only showed a weak inhibitory effect on the proliferation of the tumor-derived vascular endothelial cells, however, in a former study we found both total steroidal glycoalkaloids from Solanum lyratum (TSGS) and 9 significantly inhibited tumor angiogenesis and its mechanism was linked to its ability to interfere with cell membrane lipid rafts. Lipid rafts are closely related to the functions of tumor-derived exosomes, a vital factor in cancer progression. Thus, we investigated the impacts of TSGS and 9 on the functions of A549-derived exosomes. Our results indicated that A549-derived exosomes can significantly enhance the angiogenesis abilities of human umbilical vein endothelial cells, whereas the intervention of TSGS or 9 significantly inhibited this activity of A549-derived exosomes. These findings suggest that TSGS and 9 exert anti-tumor angiogenesis by inhibiting the pro-angiogenic activity of A549-derived exosomes.

A novel self-cleaning coating with silicon carbide nanowires.

A novel self-cleaning glass was successfully achieved by coating macroscopical SiC nanowires (SiCNWs) in tetraethyl orthosilicate (TEOS) solution. The water contact angle (CA) was high, up to approximately 160 degrees, and the sliding angle was low, down to approximately 5 degrees, when SiCNWs were coated through 10 cycles, with a high roughness Ra of 1928.9 nm. High chemical stability was obtained even after immersing the sample in water for 14 days (336 h). The calculated data by using nano/micropillar composite structure model displayed a beneficial understanding on thehydrophobic property. The feasible coating on any substrate, high CA, and long lifetime make SiCNW a potential superhydrophobic material in various self-cleaning fields.