20 potentially new compounds and 11 new bioactive constituents found in Smilacis Glabrae Rhizoma utilizing HPLC-DAD-ESI-IT-TOF-MSn.

INTRODUCTION: Smilacis Glabrae Rhizoma (SGR) is rich in chemical constituents with a variety of pharmacological activities. However, in-depth research has yet to be conducted on the chemical and pharmacodynamic constituents of SGR. MATERIALS AND METHODS: In this study, the chemical constituents of SGR were analyzed using liquid chromatography-mass spectrometry, and the pharmacodynamic compounds responsible for the medicinal effects of SGR were elucidated through a literature review. RESULTS: In total, 20 potentially new compounds, including 16 flavonoids (C19, C20, and C27-C40) and four phenylpropanoids (C107, C112, C113, and C118), together with 161 known ones were identified in the ethanol extract of SGR using liquid chromatography-mass spectrometry, and 25 of them were unequivocally identified by comparison with reference compounds. Moreover, 17 known constituents of them were identified in the plants of genus Smilax for the first time, and 16 were identified in the plant Smilax glabra Roxb. for the first time. Of 161 known compounds, 84 constituents (including isomers) have been reported to have 17 types of pharmacological activities, covering all known pharmacological activities of SGR; among these 84 bioactive constituents, six were found in the plants of genus Smilax for the first time and five were found in S. glabra for the first time, which are new bioactive constituents found in the plants of genus Smilax and the plant S. glabra, respectively. CONCLUSION: The results provide further information on the chemical composition of SGR, laying the foundation for the elucidation of the pharmacodynamic substances of SGR.

Uniform Lithium Plating for Dendrite-Free Lithium Metal Batteries: Role of Dipolar Channels in Poly(vinylidene fluoride) and PbZrxTi1-xO3 Interface.

Conventional polymer/ceramic composite solid-state electrolytes (CPEs) have limitations in inhibiting lithium dendrite growth and fail to meet the contradictory requirements of anodes and cathodes. Herein, an asymmetrical poly(vinylidene fluoride) (PVDF)-PbZrxTi1-xO3 (PZT) CPE was prepared. The CPE incorporates high dielectric PZT nanoparticles, which enrich a dense thin layer on the anode side, making their dipole ends strongly electronegative. This attracts lithium ions (Li+) at the PVDF-PZT interface to transport through dipolar channels and promotes the dissociation of lithium salts into free Li+. Consequently, the CPE enables homogeneous lithium plating and suppresses dendrite growth. Meanwhile, the PVDF-enriched region at the cathode side ensures intermediate contact with positive active materials. Therefore, Li/PVDF-PZT CPE/Li symmetrical cells exhibit a stable cycling performance exceeding 1900 h at 0.1 mA cm-2 at 25 °C, outperforming Li/PVDF solid-state electrolyte/Li cells that fail after 120 h. The LiNi0.8Co0.1Mo0.1O2/PVDF-PZT CPE/Li cells show low interfacial impedances and maintain stable cycling performance for 500 cycles with a capacity retention of 86.2% at 0.5 C and 25 °C. This study introduces a strategy utilizing dielectric ceramics to construct dipolar channels, providing a uniform Li+ transport mechanism and inhibiting dendrite growth.

Rheology of graphene oxide stabilized Pickering emulsions.

Pickering emulgels stabilized by graphene oxide (GO) with didodecyldimethylammonium bromide (DDAB) as an auxiliary surfactant and liquid paraffin as the oil phase have proved to be an excellent 3D printable ink. This paper elucidates the structure of such emulgels by a combination of microscopy before and after intensive shear as well as broadband dielectric spectroscopy and rheology in the linear and nonlinear regime. An increase of the DDAB surfactant and GO-contents leads to a systematic increase of modulus and viscosity, a reduction of the limits of the nonlinear regime and a more complicated variation of the normal forces, with negative normal forces at high shear rate  for low GO-contents and positive normal forces at high GO-contents. The interfacial jamming behavior studied by morphology, rheology and dielectric spectroscopy is explained based on droplet deformation, jamming and recovery phenomena.

The relationship between obstructive sleep apnea and circulating tau levels: A meta-analysis.

BACKGROUND: Alzheimer's disease (AD) is an irreversible, progressive brain disorder that impairs memory, thinking, language, and, eventually, the ability to carry out the simplest of tasks. Tau protein, the major component of neurofibrillary tangles, is considered a key mediator of AD pathogenesis. The association between obstructive sleep apnea (OSA) and circulating tau remains unclear. The aim of the present meta-analysis was to evaluate the relationship between OSA and circulating tau via quantitative analysis. METHODS: A systematic search of Pubmed, Embase, and Web of Science were performed. The mean values of circulating total tau (T-tau) and phosphorylated tau (P-tau) in OSA and control groups were extracted. Standardized mean difference (SMD) with 95% confidence interval (CI) was calculated by using a random-effect model or fixed-effect model. RESULTS: A total of seven studies comprising 233 controls and 306 OSA patients were included in this study. The meta-analysis showed that the circulating T-tau level was significantly higher in OSA patients than those in the control group (SMD = 1.319, 95% CI = 0.594 to 2.044, z = 3.56, p < .001). OSA patients also had significantly higher circulating P-tau level than control group (SMD = 0.343, 95% CI = 0.122 to 0.564, z = 3.04, p = .002). CONCLUSIONS: The present meta-analysis demonstrated that both circulating T-tau and P-tau levels were significantly increased in OSA subjects when compared with non-OSA subjects. Larger sample-size studies on the association between OSA and circulating tau are still required to further validate our results.

High Dielectric Poly(vinylidene fluoride)-Based Polymer Enables Uniform Lithium-Ion Transport in Solid-State Ionogel Electrolytes.

Ionic liquids (ILs)-incorporated solid-state polymer electrolytes (iono-SPEs) have high ionic conductivities but show non-uniform Li+ transport in different phases. This work greatly promotes Li+ transport in polymer phases by employing a poly (vinylidene fluoride-trifluoroethylene-chlorotrifluoroethylene) [P(VDF-TrFE-CTFE), PTC] as the framework of ILs to prepare iono-SPEs. Unlike PVDF, PTC with suitable polarity shows weaker adsorption energy on IL cations, reducing their possibility of occupying Li+ -hopping sites. The significantly higher dielectric constant of PTC than PVDF facilitates the dissociation of Li-anions clusters. These two factors motivate Li+ transport along PTC chains, narrowing the difference in Li+ transport among varied phases. The LiFePO4 /PTC iono-SPE/Li cells cycle steadily with capacity retention of 91.5 % after 1000 cycles at 1 C and 25 °C. This work paves a new way to induce uniform Li+ flux in iono-SPEs through polarity and dielectric design of polymer matrix.

Influence of Cellulose Nanofibers on the Behavior of Pickering Emulsions. Part 1. Microscopy and Startup Flow Test.

The dispersibility of flexible polymer chains present at the emulsion's interface between the dispersed and continuous phase has obvious effects on rheology and dielectric properties of the whole emulsion. Cellulose nanofiber (CNF)-based Pickering emulsions are good systems to research these properties with respect to their microscopic phase structure, dielectric, and rheological properties by using CNF as a water-dispersible Pickering emulsifier, liquid paraffin as an oil phase, and didodecyldimethylammonium bromide (DDAB) as a cationic auxiliary surfactant. The CNF and DDAB contents were systematically varied while the water-to-paraffin oil ratio was kept constant to discern the influence of the Pickering emulsifiers. Polarized optical microscopic images reveal that the droplets tend to shrink at higher CNF content but grow bigger when increasing the DDAB content, which is proved by fluorescence analysis of the CNF dispersibility with varying DDAB content. The dielectric damping exhibits a minimum, whose value decreases with increasing DDAB and CNF content. Increasing the DDAB content promotes the solubilization of CNF in the aqueous phase, which will increase the overall viscosity and yield points. Similarly, a higher CNF content leads to a higher viscosity and yield point, but at high DDAB contents, the viscosity function exhibits an S-shape at intermediate CNF contents. To evaluate the results further, they were compared with CNF dispersions (without oil phase), which showed a surfactant effect slightly on maximum stress but strongly on yield stress τy, indicating that DDAB can promote the formation of a CNF network rather than the viscosity of the whole system. This paper provides information on how a systematical variation of the composition influences morphology and physico-chemical interactions as detected by broadband dielectric spectroscopy and rheological behavior.

[Chemical constituents and anti-liver fibrosis mechanism of Meconopsis quintuplinervia based on UPLC-Q-Exactive-MS/MS and network pharmacology].

In this study, UPLC-Q-Exactive-MS/MS was used to rapidly analyze the chemical constituents of Meconopsis quintupli-nervia, and the anti-liver fibrosis mechanism of M. quintuplinervia was preliminarily analyzed by network pharmacology, molecular docking, and cell experiments. The chemical constituents of M. quintuplinervia were identified according to the information of MS~1 and MS~2, as well as the data in the literature and databases. SwissTargetPrediction and TargetNet were used to predict the potential targets. The targets related to liver fibrosis were collected from GeneCards and OMIM. The protein-protein interaction(PPI) network was constructed by STRING. Cytoscape 3.6.1 was used to construct and analyze the "constituent-target-disease" network to obtain key targets and their corresponding constituents in the network. DAVID 6.8 was used for GO analysis and KEGG signaling pathway enrichment analysis. Finally, the preliminary verification was carried out by molecular docking and cell experiments. As a result, 106 chemical constituents were identified from M. quintuplinervia, including 66 flavonoids, 16 alkaloids, 18 phenolic acids, 1 anthocyanin, and 5 other constituents. Among them, 3 constituents were identified as potential new compounds, and 59 constituents were reported in M. quintuplinervia for the first time. Network pharmacology analysis showed that M. quintuplinervia presumably acted on AKT1, SRC, JUN, EGFR, STAT3, HSP90 AA1, MAPK3, and other core targets through luteolin, isorhamnetin, quercetin, apigenin, kaempferide, amurine, 2-methylflavinantine, allocryptopine, the multi and other active compounds, thereby regulating the PI3 K/AKT signaling pathway, pathways in cancer, proteoglycans in cancer, FoxO signaling pathway, and other pathways to exert anti-liver fibrosis effects. M. quintuplinervia extract(MQE) could significantly down-regulate PI3 K and AKT protein levels in the HSC-T6 cell model induced by TGF-ß1, suggesting that MQE may have the ability to regulate the PI3 K/AKT signaling pathway. The findings of this study indicated that the anti-liver fibrosis effect of M. quintuplinervia had multi-constituent, multi-target, and multi-pathway characteristics, which may provide a scientific basis for the research on the pharmacodynamic materials, action mechanism, and quality markers of M. quintupli-nervia.

Effect of positive airway pressure on cardiac troponins in patients with sleep-disordered breathing: A meta-analysis.

BACKGROUND: Cardiac troponins are highly sensitive and specific biomarkers for cardiac injury. Previous studies evaluating the effect of positive airway pressure (PAP) on cardiac troponins in patients with sleep-disordered breathing (SDB) have yielded conflicting results. The meta-analysis was performed to examine the effect of PAP on cardiac troponins in SDB patients. METHODS: PubMed, Web of Science, and EMBASE before September 2021 on original English language studies were searched. The data on cardiac troponins in both baseline and post-PAP treatment were extracted from all studies. The data on the change of cardiac troponins in both PAP and control group were extracted from randomized controlled trials. Standardized mean difference (SMD) was used to synthesize quantitative results. RESULTS: A total of 11 studies were included. PAP treatment was not associated with a significant change in cardiac troponin T between the baseline and post-PAP treatment (SMD = -0.163, 95% confidence interval [CI] = -0.652 to 0.326, z = 0.65, p = .514). The pooled estimate of SMD of cardiac troponin I between the pre- and post-PAP treatment was 0.287, and the 95% CI was -0.586 to 1.160 (z = 0.64, p = .519). The pooled SMD of change of cardiac troponin T between the PAP group and control group was -0.473 (95% CI = -1.198 to 0.252, z = 1.28, p = .201). CONCLUSIONS: This meta-analysis revealed that PAP treatment was not associated with any change of cardiac troponin in SDB patients.

[Chemical constituents of phenylethanoid glycosides from Forsythiae Fructus and their antitumor activities].

Four phenylethanoid glycosides were isolated from the 75% EtOH extract of Forsythiae Fructus by various column chromatography methods(MCI, silica gel, ODS and semi-preparative HPLC). Their structures were identified as forsythenside M(1), forsythenside K(2), forsythoside I(3) and forsythoside A(4) by physicochemical properties and extensive spectroscopic analysis(UV, 1 D and 2 D NMR, HR-ESI-MS). Among them, compound 1 was one new phenylethanoid glycoside. The in vitro cytotoxic activities of these compounds against MCF-7, A-375, SGC-7901 and B16 F10 were evaluated. The results showed that compounds 1-4 had cytotoxic activities against MCF-7, A-375, SGC-7901 and B16 F10 at 40 µmol·L~(-1).

[Isolation and Identification of the Plant Endophyte R-13 and Its Effect on Cadmium Accumulation in Solanum nigrum L.]

The combination of endophytes and hyperaccumulator plants can significantly improve the efficiency of heavy metal phytoremediation in contaminated soil. A plant endophyte named Herbaspirillum R-13 was isolated from rice roots in a cadmium (Cd) contaminated paddy field. This strain exhibited a strong tolerance to Cd2+ and could grow on a solid medium with a Cd2+ concentration of 300 mg·kg-1. The R-13 strain was able to produce siderophores and Indole acetic acid (IAA), through color reactions. In addition, Pikovskaya's and Ashby's solid medium tests showed that the R-13 strain had a lower capacity for dissolving phosphorus but a higher capacity for fixing nitrogen. In the pot experiment, high-throughput sequencing technology was used to track the colonization of the R-13 strain in Solanum nigrum L. roots. Three days after inoculation, the relative abundance of Herbaspirillum in the root of Solanum nigrum L. had increased by 201.88% compared to the blank control (CK) and after two inoculations, the relative abundance of Herbaspirillum in the root of Solanum nigrum L. had increased by 1182.44% compared to CK. The relative abundance of Herbaspirillum in the root of Solanum nigrum L. began to decrease significantly from 5 days after inoculation. Inoculation with 20 mL·pot-1 of R-13 fermentation broth resulted in no significant effects on the Cd content of roots, stems, leaves, or fruits of S. nigrum L. With 40 mL·pot-1 of fermentation broth, the Cd content of vegetative organs and fruits was significantly increased. When it reached 200 mL·pot-1, the Cd content of vegetative organs was the highest, with Cd concentrations in the roots, stems, leaves, and fruits increasing by 84.42%, 43.67%, 64.06%, and 20.29%, respectively. In conclusion, root inoculation with endophytic Herbaspirillum R-13 can significantly increase the relative content of Herbaspirillum in the root system and enhance Cd absorption of S. nigrum L. Therefore, this strain has excellent prospects for application in the phytoremediation of soil contaminated with Cd.

Surface Epitaxial Crystallization-Directed Nanotopography for Accelerating Preosteoblast Proliferation and Osteogenic Differentiation.

Surface nanotopography provides a physical stimulus to direct cell fate, especially in the case of osteogenic differentiation. However, fabrication of nanopatterns usually suffers from complex procedures. Herein, a feasible and versatile method was presented to create unique nanosheets on a poly(ε-caprolactone) (PCL) substrate via surface epitaxial crystallization. The thickness, periodic distance, and root-mean-square nanoroughness of surface nanosheets were tunable by simply altering the PCL concentration in the growth solution. Epitaxial nanosheets possessed an identical composition as the substrate, being a prerequisite to revealing the independent effect of biophysical linkage on the osteogenic mechanism of the patterned surface. Preosteoblasts' response to the epitaxial nanosheets was examined in the aspect of preosteoblast proliferation and osteogenic differentiation. The expression of alkaline phosphatase, collagen type I, osteopontin, and osteocalcin as well as mineralization was significantly promoted by the epitaxial nanosheets. Acceleration of osteogenic differentiation was attributed to activating the TAZ/RUNX2 signaling pathway. The findings demonstrate that surface epitaxial crystallization is a feasible approach to design and construct nanotopography for bone tissue engineering.

Comprehensive chemical profiling of monascus-fermented rice product and screening of lipid-lowering compounds other than monacolins.

ETHNOPHARMACOLOGICAL RELEVANCE: Monascus-fermented rice product (MFRP) has been regarded as a dietary supplement and traditional medicine with circulation-promoting effects in China and other countries for centuries. AIM OF THE STUDY: This study was carried out to profile the chemical components in MFRP, and provide available information for elucidating the potential lipid-lowering compounds other than monacolins. MATERIALS AND METHODS: High-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (HPLC-QTOF MS) and gas chromatography coupled with mass spectrometry (GC-MS) methods were applied to comprehensive analysis of chemical components in MFRP. Potential small molecules were identified by comparing with reference standards, or tentatively characterized by comparing their retention time and high-resolution mass spectral data with previous literature. The lipid-lowering properties of ten major non-monacolin compounds were evaluated in cholesterol-fed zebrafish larvae. And one with optimum lipid-lowering activity was subsequently evaluated in high fat diet-fed C57BL/6 J mice, with the dyslipidemia and ectopic lipid deposition being investigated. RESULTS: A total of 99 compounds were characterized in MFRP, including 38 monacolins, 5 decalins, 6 isoflavones, 13 pigments, 8 azaphilonoids, 11 amino acids, 4 nucleosides, 9 lipid acids, 4 phytosterols and glycerol. The preliminary screening showed that ergosterol remarkably reduced cholesterol levels in zebrafish larvae. Moreover, ergosterol delayed body weight gain and decreased circulating total cholesterol, triglyceride, low density lipoprotein cholesterol levels in high fat diet-fed mice. Ectopic lipid accumulation was also ameliorated in the liver and heart of obese mice. CONCLUSION: Global analysis of chemical components and screening of lipid-lowering non-monacolin compounds in MFRP have improved our understanding of its therapeutic material basis.

Bone-like Polymeric Composites with a Combination of Bioactive Glass and Hydroxyapatite: Simultaneous Enhancement of Mechanical Performance and Bioactivity.

An ideal bone substitute requires not only high bioactivity but also sufficient mechanical performance, which is however inaccessible due to the lack of rational structure and composition design. Here, bioactive glass (BG)/hydroxyapatite (HA)/polyethylene (PE) composites with bone-like structure were prepared via a structuring injection molding. The strong and reciprocating shear field offered by the modified injection molding induced plenty of interlocked shish kebabs, mimicking the aligned collagen fibers in the natural bone. Such a bone-like structure enhanced the strength and toughness of the BG/HA/PE composites simultaneously, compensating the mechanical loss caused by the presence of BG. In vitro cell culture assays demonstrated that the combination of BG and HA significantly promoted cell attachment, proliferation, and alkaline phosphatase activity compared to the use of HA alone. It was attributed to upregulated expression of ß-catenin stimulated by BG. The mineralization in simulated body fluid revealed that the BG/HA/PE composite exhibited apatite-forming ability stronger than that of the HA/PE counterpart. The integration of excellent mechanical performance and high bioactivity demonstrated the significant potential of the structured BG/HA/PE composites as load-bearing bone substitutes.

Protein phosphatase 2ACα gene knock-out results in cortical atrophy through activating hippo cascade in neuronal progenitor cells.

Protein phosphatase 2ACα (PP2ACα), a vital member of the protein phosphatase family, has been studied primarily as a regulator for the development, growth and protein synthesis of a lot of cell types. Dysfunction of PP2ACα protein results in neurodegenerative disease; however, this finding has not been directly confirmed in the mouse model with PP2ACα gene knock-out. Therefore, in this study presented here, we generated the PP2ACα gene knock-out mouse model by the Cre-loxP targeting gene system, with the purpose to directly observe the regulatory role of PP2ACα gene in the development of mouse's cerebral cortex. We observe that knocking-out PP2ACα gene in the central nervous system (CNS) results in cortical neuronal shrinkage, synaptic plasticity impairments, and learning/memory deficits. Further study reveals that PP2ACα gene knock-out initiates Hippo cascade in cortical neuroprogenitor cells (NPCs), which blocks YAP translocation into the nuclei of NPCs. Notably, p73, directly targeted by Hippo cascade, can bind to the promoter of glutaminase2 (GLS2) that plays a dominant role in the enzymatic regulation of glutamate/glutamine cycle. Finally, we find that PP2ACα gene knock-out inhibits the glutamine synthesis through up-regulating the activity of phosphorylated-p73 in cortical NPCs. Taken together, it concludes that PP2ACα critically supports cortical neuronal growth and cognitive function via regulating the signaling transduction of Hippo-p73 cascade. And PP2ACα indirectly modulates the glutamine synthesis of cortical NPCs through targeting p73 that plays a direct transcriptional regulatory role in the gene expression of GLS2.

Injection-molded hydroxyapatite/polyethylene bone-analogue biocomposites via structure manipulation.

Due to insufficient mechanical performance, such as low tensile strength, the application of hydroxyapatite (HA)/high-density polyethylene (HDPE) biocomposites has been limited to use as minor load-bearing bone substitutes. In the current work, we propose to impose an intense shear flow during injection molding to tune the microstructure of the HA/HDPE biocomposites, by which an anisotropic biomimetic structure and superior mechanical properties were gained. Morphological observations manifested that the imposed intense shear induced a large amount of oriented self-reinforced superstructure, i.e., interlocked shish-kebabs, which brought not only structure similarity with the natural bone but also considerable mechanical reinforcement. For the 20 wt% HA/HDPE biocomposite, the tensile strength and bending strength of the structured sample rose from 22.4 and 20.2 MPa for the normal sample to 60.4 and 44.0 MPa, increasing by 169% and 118%, respectively, which already reaches the bounds of human cortical bone. The Young's modulus increased to 1462.0 MPa, with an augment of 37%. The impact toughness of the structured biocomposite (64.6 kJ m-2) showed as over 5 times larger than the normal biocomposite (10.1 kJ m-2). Besides, the dispersion of the HA in the biocomposites especially at the high filler content was enhanced, playing a positive role in sustaining the bioactivity. All these results indicate that the structured HA/HDPE biocomposites hold great promise for use in high load-bearing orthopedic applications.

[Research on the neas infrared focal plane array detector imaging technology used in the laser warning].

In order to achieve the incoming laser's accurate position, it is necessary to improve the detected laser's direction resolution. The InGaAs focal plane array detector with the type of FPA-320 x 256-C was selected as the core component of the diffraction grating laser warning device. The detection theory of laser wavelength and direction based on diffraction grating was introduced. The drive circuit was designed through the analysis of the detector's performance and parameters. Under the FPGA' s timing control, the detector's analog output was sampled by the high-speed AD. The data was cached to FPGA's extended SRAM, and then transferred to a PC through USB. Labview on a PC collects the raw data for processing and displaying. The imaging experiments were completed with the above method. With the wavelength of 1550 nm and 980 nm laser from different directions the diffraction images were detected. Through analysis the location of the zero order and one order can be determined. According to the grating diffraction theory, the wavelength and the direction of the two-dimensional angle can be calculated. It indicates that the wavelength error is less than 10 nm, and the angle error is less than 1 degrees.

[Research of dual-photoelastic-modulator-based beat frequency modulation and Fourier-Bessel transform imaging spectrometer].

As the existing photoelastic-modulator(PEM) modulating frequency in the tens of kHz to hundreds of kHz between, leading to frequency of modulated interference signal is higher, so ordinary array detector cannot effectively caprure interference signal..A new beat frequency modulation method based on dual-photoelastic-modulator (Dual-PEM) and Fourier-Bessel transform is proposed as an key component of dual-photoelastic-modulator-based imaging spectrometer (Dual-PEM-IS) combined with charge coupled device (CCD). The dual-PEM are operated as an electro-optic circular retardance modulator, Operating the PEMs at slightly different resonant frequencies w1 and w2 respectively, generates a differential signal at a much lower heterodyne frequency that modulates the incident light. This method not only retains the advantages of the existing PEM, but also the frequency of modulated photocurrent decreased by 2-3 orders of magnitude (10-500 Hz) and can be detected by common array detector, and the incident light spectra can be obtained by Fourier-Bessel transform of low frequency component in the modulated signal. The method makes the PEM has the dual capability of imaging and spectral measurement. The basic principle is introduced, the basic equations is derived, and the feasibility is verified through the corresponding numerical simulation and experiment. This method has' potential applications in imaging spectrometer technology, and analysis of the effect of deviation of the optical path difference. This work provides the necessary theoretical basis for remote sensing of new Dual-PEM-IS and for engineering implementation of spectra inversion.

Mechanical properties and biocompatibility of melt processed, self-reinforced ultrahigh molecular weight polyethylene.

The low efficiency of fabrication of ultrahigh molecular weight polyethylene (UHMWPE)-based artificial knee joint implants is a bottleneck problem because of its extremely high melt viscosity. We prepared melt processable UHMWPE (MP-UHMWPE) by addition of 9.8 wt% ultralow molecular weight polyethylene (ULMWPE) as a flow accelerator. More importantly, an intense shear flow was applied during injection molding of MP-UHMWPE, which on one hand, promoted the self-diffusion of UHMWPE chains, thus effectively reducing the structural defects; on the other hand, increased the overall crystallinity and induced the formation of self-reinforcing superstructure, i.e., interlocked shish-kebabs and oriented lamellae. Aside from the good biocompatibility, and the superior fatigue and wear resistance to the compression-molded UHMWPE, the injection-molded MP-UHMWPE exhibits a noteworthy enhancement in tensile properties and impact strength, where the yield strength increases to 46.3 ± 4.4 MPa with an increment of 128.0%, the ultimate tensile strength and Young's modulus rise remarkably up to 65.5 ± 5.0 MPa and 1248.7 ± 45.3 MPa, respectively, and the impact strength reaches 90.6 kJ/m(2). These results suggested such melt processed and self-reinforced UHMWPE parts hold a great application promise for use of knee joint implants, particularly for younger and more active patients. Our work sets up a new method to fabricate high-performance UHMWPE implants by tailoring the superstructure during thermoplastic processing.

[Determination of quercetin and kaempferol in Fagopyrum spp. of different species and different parts by HPLC].

OBJECTIVE: An HPLC method was established for determination of quercetin and kaempferol in Fagopyrum spp. of differrent species and different plant parts. METHODS: The chromatographic separation was carried out on a DIKMA diamonsil (250 mm x 4.6 mm, 5 µm) chromatographic column. The mobile phase was acetonitrile (A) and 0.1% phosphoric acid solution (B) at the flow rate of 1.0 mL/min. The detection wavelength was set at 260 nm and the column temperature was 25 degrees C. RESULTS: The descending order of quercetin content in the samples of different parts of Fagopyrum tataricum was seed (6.12 mg/g) > leaf (1.47 mg/g) > stem (0.34 mg/g); quercetin was not found in root. Only a few kaempferol was found in seed (0.42 mg/g) and leaf of Xiqiao 1 (0.09 mg/g) of Fagopyrum tataricum. There were a few quercetin was determined in the whole plant of Fagopyrum esculentum, and kaempferol was not been found. The total and mean value concentration of quercetin and kaempferol of Fagopyrum tataricum were much higher than that of Fagopyrum esculentum. In different species of Fagopyrum tataricum planted in the same area, the content of quercetin and kaempferol was similar, they were not been found in Fagopyrum esculentum. CONCLUSION: This method is simple, rapid, accurate and reliable for quality evaluation of Fagopyrum spp. and its commercial products.