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.

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.

[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.

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.

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.

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 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.

Remarkable Improvement of the Catalytic Performance of PtFe Nanoparticles by Structural Ordering and Doping.

To achieve fuel cell commercialization, the performance improvement and cost reduction of catalysts are still the main challenges. To enhance the catalytic activity and durability for oxygen reduction reaction (ORR), we prepare Au-PtFe particles entrapped in a porous carbon and then convert them to have a fine-grained and highly ordered intermetallic structure. The optimal Au-PtFe particles in catalyzing ORR exhibit initial specific and mass activities 9 times higher than the commercial catalyst of Pt/C. Such a large enhancement is much higher than most of the Pt-based ordered intermetallic catalysts reported in the literature. Accelerated durability testing induces little degradation of the catalytic activity to the ordered structure, particularly the Au-doped one, after potential cycling for many thousands of cycles under harsh electrochemical conditions involving an acidic medium and a high potential range of 0.66-1.3 V. This is in big contrast with the large degradation shown by most previous catalysts. The excellent activity and durability are attributed to synergistic effects of the fine-grained and ordered structure of the particles, the confining support of the porous carbon, and the homogeneous incorporation of a trace amount of Au. The new intermetallic catalyst of Au-PtFe/C represents a new strategy for performance enhancement and cost reduction and thus promotes practical applications of proton-exchange membrane fuel cells.

An-te-xiao capsule inhibits tumor growth in non-small cell lung cancer by targeting angiogenesis.

An-te-xiao capsule consists of total alkaloids from the dried whole plantof Solanum lyratum, and showed antitumor effects in our previous study. However, its inhibitory effect on multiple non-small cell lung cancer (NSCLC) cell lines and the underlying mechanisms have not been elucidated clearly. This study sought to investigate the inhibitory effects of An-te-xiao capsule on three main types of NSCLC cell lines (A549, NCI-H460, and NCI-H520) in vitro and in vivo and the underlying mechanisms of action including its potential anti-angiogenesis effects. An-te-xiao capsule showed no acute oral toxicity in mice, and significantly prolonged survival time in a mouse model of Lewis tumor xenograft. The inhibition of A549, NCI-H460, and NCI-H520 cells by An-te-xiao capsule was reflected in its effects on tumor growth, histopathological changes, tumor microvessel density (MVD), cell cycle regulatory proteins, and cell apoptosis. In vitro, An-te-xiao capsule repressed migration, invasion, and tube formation of tumor-derived vascular endothelial cells (Td-ECs), which were obtained using a co-culture system, in the presence or absence of vascular endothelial growth factor (VEGF) at safe concentrations selected using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Moreover, An-te-xiao capsule inhibited the secretion of VEGF by A549 cells in the co-culture system and suppressed the phosphorylation of VEGF receptor 2 (VEGFR2). Taken together, An-te-xiao capsule has potential for treating NSCLC.

[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.

Continuous Preparation of Carbon Nanotube Film and Its Applications in Fuel and Solar Cells.

So far, simultaneously realizing the continuous, controllable, and scalable preparation of carbon nanotube (CNT) film has remained a big challenge. Here, we report a scalable approach to continuously prepare CNT film with good control of film size and thickness. This is achieved through the layer-by-layer condensation and deposition of a cylindrical CNT assembly that is continuously produced from a floating catalyst CVD reactor on a paper strip. The promising applications of such a film are demonstrated by directly using it as an effective protecting layer for the Pt/C catalyst in proton exchange membrane fuel cells and as an efficient counter electrode material in quantum-dot-sensitized solar cells.

High-Performance Carbon Nanotube/Polymer Composite Fiber from Layer-by-Layer Deposition.

So far, preparation of high-performance carbon nanotube (CNT)/polymer composites still faces big challenges mainly due to the limited control of CNT dispersion, fraction, and alignment in polymers. Here, a new "layer-by-layer deposition" method is put forward for preparing CNT/polymer composite fibers using poly(vinyl alcohol) (PVA) as an exemplary polymer. This is based on the continuous production of a hollow cylindrical CNT assembly from a high temperature reactor and its shrinking by a PVA-containing solution and deposition on a removable substrate wire. The in situ mixing of the two composite components at the molecular level allows CNTs to disperse and PVA to infiltrate into the fiber efficiently. As a result, remarkable effects of the CNT reinforcement on the PVA matrix are observed, including a strength improvement from ∼50 to 1255 MPa and electrical conductivity from ∼0 to 1948 S cm(-1). The new method offers good controllability of CNT dispersion and fraction in the polymer matrix, variability for making composite fibers using different polymers, and suitability for scaled up production. This study thus provides a new research direction for preparing CNT-reinforced composites and future performance maximization.

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.

Continuous Preparation of Copper/Carbon Nanotube Composite Films and Application in Solar Cells.

Realizing the continuous and large scale preparation of particle/carbon nanotube (CNT) composites with enhanced functionalities, and broad applications in energy conversion, harvesting, and storage systems, remains as a big challenge. Here, we report a scalable strategy to continuously prepare particle/CNT composite films in which particles are confined by CNT films. This is achieved by the continuous condensation and deposition of a cylindrical assembly of CNTs on a paper strip and the in situ incorporation of particles during the layer-by-layer deposition process. A Cu/CNT composite film is prepared as an example; such a film exhibits very high power conversion efficiency when it is used as a counter electrode in a solar cell, compared with previous materials under otherwise identical conditions. The proposed method can be extended to other CNT-based composite films with excellent functionalities for wide applications.

Study design and implementation for population pharmacokinetics of Chinese medicine: An expert consensus.

Although many population pharmacokinetics (PPK) researches have been conducted on chemical drugs, few have been in the field of Chinese medicine (CM). Each ingredient in CMs possesses different pharmacokinetic characteristics, therefore, it is important to develop methods of PPK studies on them to identify the differences in CM drug safety and efficacy among the population subgroups and to conduct quantitative studies on the determinants of CM drug concentrations. To develop an expert consensus on study design and implementation for PPK of CM, in August 2013, 6 experts in the field of PPK, CMs pharmacology, and statistics discussed problems on the PPK research protocol of CMs, and a consensus was reached. The medicines with toxicity and narrow therapeutic windows and with wide range of target population or with frequent adverse reactions were selected. The compositions with definite therapeutic effects were selected as indices, and specific time points and sample sizes were designed according to standard PPK design methods. Target components were tested through various chromatography methods. Total quantity statistical moment analysis was used to estimate PPK parameters of each component and PPK models reflecting the trend of CMs (which assists in reasonable adjustments on clinical dosage). This consensus specifies the study design and implementation process of PPK. It provides guidance for the following: post-marketing clinical studies, in vivo investigations related to the metabolism in different populations, and development and clinical adjustment of dosages of CMs.

[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.