Preparation and characterization of starch-based composite films reinforced by quinoa (Chenopodium quinoa Willd.) straw cellulose nanocrystals.

The development of green and biodegradable nanomaterials is significant for the sustainable utilization of renewable lignocellulosic biomass. This work aimed to obtain the cellulose nanocrystals from quinoa straws (QCNCs) by acid hydrolysis. The optimal extraction conditions were investigated by response surface methodology, and the physicochemical properties of QCNCs were evaluated. The maximum yield of QCNCs (36.58 ± 1.42 %) was obtained under the optimal extraction conditions of 60 % (w/w) sulfuric acid concentration, 50 °C reaction temperature, and 130 min reaction time. The characterization results of QCNCs showed that it is a rod-like material with an average length of 190.29 ± 125.25 nm, an average width of 20.34 ± 4.69 nm, excellent crystallinity (83.47 %), good water dispersibility (Zeta potential = -31.34 mV) and thermal stability (over 200 °C). The addition of 4-6 wt% QCNCs could significantly improve the elongation at break and water resistance of high-amylose corn starch films. This study will pave the route for improving the economic value of quinoa straw, and provide relevant proof of QCNCs for the preliminary application in starch-based composite films with the best performance.

New sesquiterpeniod esters form Blumea balsamifera (L.) DC. and their anti-influenza virus activity.

Phytochemical studies led to the isolation of five new sesquiterpeniod esters, named balsamiferine N-R, along with ten known compounds (6-15) from the leaves of Blumea balsamifera (L.) DC. The skeletons of nine known sesquiterpeniods belong to guaiane and eudesmane. The structures of the new compounds including their absolute configurations were elucidated by comprehensive spectroscopic analysis, and quantum-chemical electronic circular dichroism (ECD) calculation. Compounds 3 and 4 showed significant inhibitory effects on influenza A virus (H3N2) with IC50 values of 46.23 µg/mL and 38.49 µg/mL, respectively. It was the first report on the anti-influenza A virus constituents from B. balsamifera.

3D Printing of Aniline Tetramer-Grafted-Polyethylenimine and Pluronic F127 Composites for Electroactive Scaffolds.

Electroactive hydrogel scaffolds are fabricated by the 3D-printing technique using composites of 30% Pluronic F127 and aniline tetramer-grafted-polyethylenimine (AT-PEI) copolymers with various contents from 2.5% to 10%. The synthesized AT-PEI copolymers can self-assemble into nanoparticles with the diameter of ≈50 nm and display excellent electroactivity due to AT conjugation. The copolymers are then homogeneously distributed into 30% Pluronic F127 solution by virtue of the thermosensitivity of F127, denoted as F/AT-PEI composites. Macroscopic photographs of latticed scaffolds elucidate their excellent printability of F/AT-PEI hydrogels for the 3D-printing technique. The conductivities of the printed F/AT-PEI scaffolds are all higher than 2.0 × 10-3 S cm-1 , which are significantly improved compared with that of F127 scaffold with only 0.94 × 10-3 S cm-1 . Thus, the F/AT-PEI scaffolds can be considered as candidates for application in electrical stimulation of tissue regeneration such as repair of muscle and cardiac nerve tissue.

Enhanced conductivity of rGO/Ag NPs composites for electrochemical immunoassay of prostate-specific antigen.

Electrode materials play a vital role in the development of electrochemical immunosensors (EIs), particularly of label-free EIs. In this study, composites containing reduced graphene oxide with silver nanoparticles (rGO/Ag NPs) were synthesized using binary reductants, i.e. hydrazine hydrate and sodium citrate. Due to the fact that graphene oxide (GO) was fully restored to rGO, and rGO stacking was effectively inhibited by insertion of small Ag NPs between the graphene sheets, the electrical conductivity of rGO/Ag NPs composites was significantly improved compared to rGO alone, with an enhancement factor of 346% at 40wt% of rGO. Moreover, the conducting path between rGO and Ag NPs formed because the structural defects in rGO were effectively repaired by decoration with Ag NPs. Subsequently, based on a screen-printed three-electrode system, a label-free EI for detecting prostate-specific antigen (PSA) was constructed using rGO/Ag NPs composites as a support material. The fabricated EIs demonstrated a wide linear response range (1.0-1000ng/ml), low detection limit (0.01ng/ml) and excellent specificity, reproducibility and stability. Thus, the proposed EIs based on rGO/Ag NPs composites can be easily extended for the ultrasensitive detection of different protein biomarkers.

Effects of Leptin on Na+/Ca2+ Exchanger in PC12 Cells.

BACKGROUND/AIMS: Alzheimer's disease (AD) is known to be related to alterations in neuronal intracellular calcium activity ([Ca2+]i). The present study revealed the distinct role of leptin in Na+/Ca2+-exchanger activity. METHODS: [Ca2+]i was determined utilizing Fura-2 fluorescence. The activity of NCX was measured by removal of extracellular Na+ in the presence of external Ca2+. Na+/Ca2+-exchanger activity was further quantified from whole cell currents following removal of extracellular Na+. Na+/Ca2+-exchanger isoform NCX1 transcript levels and protein abundance were quantified by RT-PCR and Western blotting, respectively. RESULTS: Exposure of PC12 cells to 30 µM amyloid (Aß42) increased [Ca2+]i, an effect significantly blunted by 6 hours incubation with leptin before Aß42 treatment. Moreover, leptin treatment significantly increased Na+/Ca2+-exchanger mediated Ca+ transport and current, NCX1 transcript level as well as NCX1 membrane protein abundance. CONCLUSION: We show that leptin blunts Aß42-evoked [Ca2+]i increase by increasing expression and activity of Na+/Ca2+-exchanger NCX1.

Leptin Regulates Tau Phosphorylation through Wnt Signaling Pathway in PC12 Cells.

BACKGROUND/AIMS: Leptin, an adipocytokine produced endogenously in the brain, is decreased in Alzheimer's disease(AD) and has also been shown to reduce Aß levels in vitro and in vivo. Sets of evidence show that leptin reduces Aß production and tau phosphorylation in neuronal cells and transgenic mice models of AD. Herein, we investigated the signaling pathway activated by leptin, to better understand its mechanism of action. METHODS: Western blotting was performed to assess the levels of phosphor-tau and Bax, RT-PCR to check the mRNA level of Bax. RESULTS: Leptin treatment significantly blunted Aß-evoked tau phosphorylation and Bax levels, effects of which could be reversed by antagonist of Wnt signaling. CONCLUSION: The data indicate that Leptin may provide a novel therapeutic approach to AD treatment via wnt signaling.

[Chemical Constituents of Lowering LDL-C in Effective Part of Oroxylum indicum].

Objective: To investigate the chemical constituents of effective part of Oroxylum indicum which related to lowering LDLC action. Methods: The compounds were isolated with chromatography methods such as silica gel,polyamide and Sephadex LH-20. The structures were identified by physiochemical properties and spectral analysis. Results: 14 compounds were isolated from 95% alcohol extract and elucidated as ß-sitosterol( 1), hexadecanoic acid( 2), oroxin A( 3), oroxin B( 4), chrysin( 5), quercetin( 6),quercetin-3-Orutinoside( 7),5,4'-dihydroxy-3,6,7-trimethoxyflavone( 8), diosmetin( 9), geniposide( 10),isoorientin( 11), quercitroside( 12), apigenin( 13) and gallicacid( 14). Conclusion: Compounds 2,7 ~ 12 and 14 are reported from this plants for the first time.

Exploring the biologically relevant chemical space for drug discovery.

Both recent studies and our calculation suggest that the physicochemical properties of launched drugs changed continuously over the past decades. Besides shifting of commonly used properties, the average biological relevance (BR) and similarity to natural products (NPs) of launched drugs decreased, reflecting the fact that current drug discovery deviated away from NPs. To change the current situation characterized by high investment but low productivity in drug discovery, efforts should be made to improve the BR of the screening library and hunt drugs more effectively in the biologically relevant chemical space. Additionally, a multiple dimensional molecular descriptor, named the biologically relevant spectrum (BRS) was proposed for quantitative structure-activity relationships (QSAR) study or screening library preparation. Prediction models for 43 biological activity categories were developed with BRS and support vector machine (SVM). In most cases, the overall prediction accuracies were around 95% and the Matthew's correlation coefficients (MCC) were over 0.8. Thirty-seven out of 48 drug-activity associations were successfully predicted for drugs that launched from 2006 to 2012, which were not included in the training data set. A web-server named BioRel ( http://ibi.hzau.edu.cn/biorel ) was developed to provide services including BR, BRS calculation, activity class, and pharmacokinetic property prediction.