•The molecular structure of flaxseed mucilage arabinoxylan was deduced.•The relationship of primary structure and conformation was established.•The structures of major flaxseed dietary fibers ...fractions were compared.
The structure of neutral fraction gum from flaxseed mucilage (FM-NFG) was studied for better understanding of the relationship between primary structure and conformation. Based on methylation/GC–MS, nuclear magnetic resonance (NMR) spectroscopy, the structure of FM-NFG was proposed as arabinoxylans. Flaxseed mucilage arabinoxylans contained β-1,4-linked xylose backbones, which were mainly substituted at O-2 and/or O-3 positions by 1–3 sugar residues. The possible branches included → 5)-α-l-Araf-(1 → (17.3 mol%), → 3)-α-l-Araf-(1 → (4.9 mol%), and → 4)-α-d-Glcp-(1 → (3.5 mol%), which were ended with three terminal sugar units: T-β-d-Xylp-(1 → (15.5 mol%), T-α-d-Glap-(1 → (4.5 mol%), and T-α-l-Araf-(1 → (2.6 mol%). The weight average molecular weight (Mw) of flaxseed mucilage arabinoxylans was calculated to be 1747 kDa by static light scattering (SLS), and it exhibited random coil conformation. The proposed structure and conformational models confirmed that different backbone sugar units especially substitution positions directly contributed to the conformational diversity and rigidity of polysaccharide molecules.
The natural resonance appears at 16
GHz for (Fe, Ni)/C nanocapsules with (Fe, Ni) alloys as cores and graphite as shells. Reflection loss (RL) exceeding −10
dB was obtained in the whole Ku-band ...(12.4–18
GHz) for an absorber thickness of 2.0
mm, while it exceeds −20
dB over the 13.6–16.6
GHz range. In addition, the bandwidth does not change dramatically for the thicknesses of 1.87–2.1
mm for the RL values exceeding −10
dB. The (Fe, Ni)/C nanocapsules with wide bandwidth absorption can be used as excellent electromagnetic-wave-absorption materials in the whole Ku-band.
Emerging evidence has shown that cancer stem cells (CSCs) are the cellular determinants to promote cancer invasion and metastasis. However, the mechanism underlying CSC invasion remains unknown. ...MicroRNAs are evolutionally conserved small noncoding RNAs that are critical for the regulation of gene expression, and their expressions are often dysregulated in cancers. In the present study, we demonstrated that two functionally related microRNAs, miR-20a and -106a (miR-20a/106a), were capable of enhancing the invasiveness of CD133(+) glioma stem cells (GSCs) isolated from both glioblastoma cell line U87 and primary human glioma specimens. We found that the level of miR-20a/106a in GSCs was significantly higher than that in the committed CD133(-) glioma cells, and correlated with the invasive capability of GSCs. By bioinformatic analysis, we identified tissue inhibitor of metalloproteinases-2 (TIMP-2) as one of the miR-20a/106a-targeted genes. TIMP-2 level correlated inversely with miR-20/106 expression. Directly targeting by miR-20a/106a on 3'-untranslation region (3'-UTR) of TIMP-2 mRNA was confirmed by 3'-UTR dual-luciferase reporter assay. Knockdown of miR-20a/106a in GSCs increased endogenous TIMP-2 protein abundance, thereby inhibiting GSC invasion. We also found that Nordy, a synthetic lipoxygenase inhibitor, inhibited GSC invasiveness by elevating the expression of TIMP-2 via downregulation of miR-20a/106a. Our results indicate that miR-20a/106a has a key role in GSC invasion and may serve as targets for treatment of glioblastoma.
Soluble dietary fibre with low viscosity has the potential to deliver acceptable mouthfeel and texture when included in the diet in a significant amount to show health benefits. Soluble flaxseed gum ...(SFG) was reported to have low viscosity, thus has potential in applications as a fibre fortifier. In the present work, SFG extracted from flaxseed hulls was fractionated into a neutral fraction gum (NFG) and an acidic fraction gum (AFG) using ion exchange chromatography. The protein content in SFG (11.8%) and AFG (8.1%) were completely removed by protease to obtain two more protein-free fractions, SFGnP and AFGnP; NFG contained no protein. The uronic acid content in NFG (1.8%) was mostly eliminated, whereas in AFC increased to 38.7%. NFG consisted of high molecular weight (MW) (1470 kDa) arabinoxylans and exhibited pseudoplastic flow behaviour; whereas AFG was mainly composed of rhamnogalacturonans with a higher MW fraction (1510 kDa) and a lower MW fraction (341 kDa) and showed Newtonian flow behaviour. The ranking of intrinsic viscosities (mL g−1) in decreasing order was: SFG (446.0) > NFG (377.5) > AFG (332.5). AFG was expected to have higher chain flexibility for its lower value of Huggins constant (0.16) compared to that of NFG (0.54) and SFG (0.48). In comparison with SFGnP, AFGnP and NFG, SFG and AFG showed better surface activities and emulsifying stabilities due to the presence of protein in both fractions.
The intrinsic viscosity (a) and the dependence of viscosity on concentration (b–d) of SFG, NFG and AFG. Display omitted
► Soluble flaxseed gum (SFG) was extracted from flaxseed hulls. ► Neutral and acidic fractions were separated by ion exchange chromatography. ► Physical and functional properties were characterized.
Degradable metals have been suggested as biomaterials with revolutionary potential for bone-related therapies. Of these candidate metals, magnesium alloys appear to be particularly attractive ...candidates because of their non-toxicity and outstanding mechanical properties. Despite their having been widely studied as orthopedic implants for bone replacement/regeneration, their undesirably rapid corrosion rate under physiological conditions has limited their actual clinical application. This study reports the use of a novel biomimetic peptide coating for Mg alloys to improve the alloy corrosion resistance. A 3DSS biomimetic peptide is designed based on the highly acidic, bioactive bone and dentin extracellular matrix protein, phosphophoryn. Surface characterization techniques (scanning electron microscopy, energy dispersive X-ray spectroscopy and diffuse-reflectance infrared spectroscopy) confirmed the feasibility of coating the biomimetic 3DSS peptide onto Mg alloy AZ31B. The 3DSS peptide was also used as a template for calcium phosphate deposition on the surface of the alloy. The 3DSS biomimetic peptide coating presented a protective role of AZ31B in both hydrogen evolution and electrochemical corrosion tests.
Naturally deposited clays are often unsaturated and overconsolidated. Within the frameworks of the Barcelona Basic model (BBM) for normally consolidated unsaturated clays and the unified hardening ...(UH) model for overconsolidated saturated clays, a three-dimensional constitutive model for overconsolidated unsaturated clays is proposed in this paper. This model can be reduced to the original UH model for overconsolidated saturated clays when suction becomes zero and the BBM when the overconsolidated behaviour disappears. Compared with existing constitutive models for unsaturated clays, the influence of a high overconsolidation ratio (OCR) on wetting deformation can be adequately described. Also, many other characteristics of overconsolidated unsaturated clays can be modelled, including strain-hardening, softening, shear dilatancy, and stress path–dependence behaviour. Compared with the BBM, the proposed model requires no additional material parameter. The validity of the UH model for overconsolidated unsaturated clays has been confirmed by data from two groups of wetting tests performed by the authors and previous triaxial tests in the literature.
An overview of Sun–Sky Radiometer Observation Network (SONET) measurements in China is presented. Based on observations at 16 distributed SONET sites in China, atmospheric aerosol parameters are ...acquired via standardization processes of operational measurement, maintenance, calibration, inversion, and quality control implemented since 2010. A climatology study is performed focusing on total columnar atmospheric aerosol characteristics, including optical (aerosol optical depth, ÅngstrÖm exponent, fine-mode fraction, single-scattering albedo), physical (volume particle size distribution), chemical composition (black carbon; brown carbon; fine-mode scattering component, coarse-mode component; and aerosol water), and radiative properties (aerosol radiative forcing and efficiency). Data analyses show that aerosol optical depth is low in the west but high in the east of China. Aerosol composition also shows significant spatial and temporal variations, leading to noticeable diversities in optical and physical property patterns. In west and north China, aerosols are generally affected by dust particles, while monsoon climate and human activities impose remarkable influences on aerosols in east and south China. Aerosols in China exhibit strong light-scattering capability and result in significant radiative cooling effects.
Background
Benign strictures at the cardia are troublesome for patients and often require repeated endoscopic treatments. Paclitaxel can reduce fibrosis. This study evaluated a biodegradable ...paclitaxel‐eluting nanofibre‐covered metal stent for the treatment of benign cardia stricture in vitro and in vivo.
Methods
Drug release was investigated in vitro at pH 7·4 and 4·0. Eighty dogs were divided randomly into four groups (each n = 20): controls (no stent), bare stent (retained for 1 week), and two drug‐eluting stent (DES) groups with retention for either 1 week (DES‐1w) or 4 weeks (DES‐4w). Lower oesophageal sphincter pressure (LOSP) and 5‐min barium height (5‐mBH) were assessed before, immediately after stent deployment, at 1 week, and 1, 3 and 6 months later. Five dogs in each group were killed for histological examination at each follow‐up point.
Results
Stent migration rates were similar (0 bare stent versus 2 DES; P = 0·548). The percentage and amount of paclitaxel released in vitro was higher at pH 4·0 than at pH 7·4. After 6 months, LOSP and 5‐mBH were both improved in the DES‐1w (P = 0·004 and P = 0·049) and DES‐4w (both P < 0·001) groups compared with the bare‐stent group, with better relief when the stent was retained for 4 weeks (P = 0·004 and P = 0·007). The DES was associated with a reduced peak inflammatory reaction and less scar formation compared with bare stents, especially when inserted for 4 weeks.
Conclusion
The DES was more effective for the treatment of benign cardia stricture than bare stents in a canine model. Retention of the DES for 4 weeks led to a better clinical and pathological outcome than 1 week.
Surgical relevance
Retrievable stent placement has evolved as a promising treatment for benign cardia strictures. Localized paclitaxel‐eluting stents have been shown to prevent inflammatory cell proliferation in other locations.
A novel paclitaxel‐eluting stent has been developed that provides stable drug release over an insertion period of up to 4 weeks, with a 100 per cent success rate for placement and a low migration rate. Animals with cardia strictures that underwent drug‐eluting stent insertion had a better barium clearance and lower oesophageal sphincter pressure remission, reduced inflammatory reaction and less scar formation than those that underwent bare‐stent insertion.
A drug‐eluting stent designed to limit fibrotic scarring has been shown to be effective in a large animal model. This may become a safe and effective method for the treatment of benign cardia strictures in clinical practice, such as in patients with achalasia who are unfit for surgery or those with reflux‐induced strictures in whom simple dilatation has proved ineffective.
A new approach to benign strictures
We present X-ray timing results of the new black hole candidate MAXI J1535−571 during its 2017 outburst from Hard X-ray Modulation Telescope (Insight-HXMT) observations taken from 2017 September 6 to ...23. Following the definitions given by Belloni, we find that the source exhibits transitions from the low/hard state to the hard intermediate state, and eventually to the soft intermediate state. Quasi-periodic oscillations (QPOs) are found in the intermediate states, which suggest different types of QPOs. With the large effective area of Insight-HXMT at high energies, we are able to present the energy dependence of the QPO amplitude and centroid frequency up to 100 keV, which has rarely been explored by previous satellites. We also find that the phase lag at the type-C QPOs centroid frequency is negative (soft lag) and strongly correlated with the centroid frequency. Assuming a geometrical origin of type-C QPOs, the source is consistent with being a high-inclination system.
Purple sweet potato is a nutritive food rich in anthocyanins that possess antioxidant effects. Drosophila melanogaster owns short growth cycle, fast reproduction, less chromosomes, more mutants, ...small individuals, therefore, which is an appropriate genetic model organism.
To investigate the anti-aging activity of Purple Sweet Potato Extract (PSPE) in male Drosophila melanogaster and explore the underlying mechanism.
PSPE-induced longevity was associated with improvements in climbing ability and tolerance to stressors such as paraquat and hydrogen peroxide (H2O2). Furthermore, PSPE supplementation increased the activity of superoxide dismutase (SOD) and catalase (CAT), as well as expression of SOD and CAT genes, but decreased malondialdehyde (MDA) content. Meanwhile, PSPE decreased the intestinal stem cells (ISCs) proliferation and improved intestinal homeostasis, which was measured by Smurf assay and colony-forming units (CFUs) measurement in aging flies. Additionally, PSPE markedly inhibited the expression of upstream genes AKT-1, PI3K and mTOR and elevated the downstream gene 4E-BP, which further activated the expression of autophagy-related genes (Atg1, Atg5, Atg8a and Atg8b). Moreover, the production of lysosomes increased, indicating that the autophagy pathway was activated.
The results provided direct evidence of PSPE anti-aging effects on an organism level, indicating PSPE could be developed for use in effective anti-aging products.
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