The rheological properties of shear thickening fluid reinforced with SiC nanowires

The rheological properties of shear thickening fluid (STF) reinforced with SiC nanowires were investigated in this paper. Pure STF consists of 56 vol% silica nano-particles and polyethylene glycol 400 (PEG 400) solvent was fabricated; and a specific amount of SiC nanowires were dispersed into this pure STF, and then the volume fraction of PEG400 was adjusted to maintain the volume fraction of solid phase in the STF at a constant of 56%. The results showed there was almost 30% increase in the initial and shear thickening viscosity of the STF reinforced with SiC nanowires compared to the pure STF. Combining with the hydrodynamic cluster theory, the effect of the mechanism of SiC nanowire on the viscosity of STF was discussed, and based on the experimental results, an analytical model of viscosity was used to describe the rheological properties of STF, which agreed with the experimental results

Insect-Specific microRNA Involved in the Development of the Silkworm Bombyx mori

MicroRNAs (miRNAs) are endogenous non-coding genes that participate in post-transcription regulation by either degrading mRNA or blocking its translation. It is considered to be very important in regulating insect development and metamorphosis. We conducted a large-scale screening for miRNA genes in the silkworm Bombyx mori using sequence-by-synthesis (SBS) deep sequencing of mixed RNAs from egg, larval, pupal, and adult stages. Of 2,227,930 SBS tags, 1,144,485 ranged from 17 to 25 nt, corresponding to 256,604 unique tags. Among these non-redundant tags, 95,184 were matched to the silkworm genome. We identified 3,750 miRNA candidate genes using a computational pipeline combining RNAfold and TripletSVM algorithms. We confirmed 354 miRNA genes using miRNA microarrays and then performed expression profile analysis on these miRNAs for all developmental stages. While 106 miRNAs were expressed in all stages, 248 miRNAs were egg- and pupa-specific, suggesting that insect miRNAs play a significant role in embryogenesis and metamorphosis. We selected eight miRNAs for quantitative RT-PCR analysis; six of these were consistent with our microarray results. In addition, we searched for orthologous miRNA genes in mammals, a nematode, and other insects and found that most silkworm miRNAs are conserved in insects, whereas only a small number of silkworm miRNAs has orthologs in mammals and the nematode. These results suggest that there are many miRNAs unique to insects

Dynamic response of shear thickening fluid reinforced with SiC nanowires under high strain rates

In this letter, SiC nanowires were adopted to reinforce the nanoparticle-based shear thickening fluid (STF) to improve its rheological properties. The reinforced STF showed a significant increase in viscosity. A Split-Hopkinson pressure bar was implemented to evaluate the dynamic response of STF at strain rates in the range of 3 × 103–1.2 × 104/s. For the pure STF, the flow stress reaches a saturation value with increasing strain rates and shows almost no strain rate sensitivity, whereas the flow stress of the reinforced STF increases with strain rates, and the strain rate sensitivity to flow stress is obvious owing to the resistance of nanowires. The essence of this study is to reveal that there is a limiting value of the flow stress of traditional nanoparticle-based STF at high strain rates due to the lubrication force among particles. SiC nanowires can be used to break this limitation of the nanoparticle-based STF

The rheological properties of shear thickening fluid reinforced with SiC nanowires

The rheological properties of shear thickening fluid (STF) reinforced with SiC nanowires were investigated in this paper. Pure STF consists of 56 vol% silica nano-particles and polyethylene glycol 400 (PEG 400) solvent was fabricated; and a specific amount of SiC nanowires were dispersed into this pure STF, and then the volume fraction of PEG400 was adjusted to maintain the volume fraction of solid phase in the STF at a constant of 56%. The results showed there was almost 30% increase in the initial and shear thickening viscosity of the STF reinforced with SiC nanowires compared to the pure STF. Combining with the hydrodynamic cluster theory, the effect of the mechanism of SiC nanowire on the viscosity of STF was discussed, and based on the experimental results, an analytical model of viscosity was used to describe the rheological properties of STF, which agreed with the experimental results. Keywords: Shear thickening fluid (STF), Nanowire, Rheology, Viscosity, Analytical mode

Effect and mechanism of thrombospondin-1 on the angiogenesis potential in human endothelial progenitor cells: an in vitro study.

Coronary collateral circulation plays a protective role in patients with coronary artery disease (CAD). We investigated whether thrombospondin-1(TSP-1) has an inhibitory effect on angiogenesis potential in endothelial progenitor cells(EPCs) and tested whether TSP-1 are altered in plasma of patients who had chronic total occlusion (CTO) in at least one coronary artery and with different collateral stages(according to Rentrop grading system).We isolated early and late EPCs from human cord blood and investigated a dose-dependent effect of TSP-1 on their angiogenesis potential by Matrigel angiogenesis assay. We found that TSP-1 (5 µg/ml) inhibited early EPCs incorporation into tubules after pretreatment for 1, 6 and 12 hours, respectively (83.3±11.9 versus 50.0±10.1 per field for 1 hour,161.7±12.6 versus 124.0±14.4 for 6 hours, 118.3±12.6 versus 68.0±20.1 for 12 hours, p<0.05). TSP-1 also inhibited late EPCs tubule formation at 1 µg/ml (6653.4±422.0 µm/HPFversus 5552.8±136.0 µm/HPF, p<0.05), and the inhibition was further enhanced at 5 µg/ml (6653.4±422.0 µm/HPF versus 2118.6±915.0 µm/HPF p<0.01). To explore the mechanism involved, a small interfering RNA was used. In vitro, CD47 siRNA significantly attenuated TSP-1's inhibition of angiogenesis on late EPCs and similar results were obtained after functional blocking by anti-CD47 antibody. Then we investigated pathways downstream of CD47 and found TSP-1 regulated VEGF-induced VEGFR2 phosphorylation via CD47. Furthermore, we examined plasma TSP-1 levels in patients with CTO who developed different stages of collaterals and found a paradoxical higher level of TSP-1 in patients with good collaterals compared with bad ones (612.9±554.0 ng/ml versus 224.4±132.4 ng/ml, p<0.05).TSP-1 inhibited angiogenesis potential of early and late EPCs in vitro. This inhibition may be regulated by TSP-1's interaction with CD47, resulting in down regulation of VEGFR2 phosphorylation. In patients with CTO, there may be a self-adjustment mechanism in bad collaterals which is shown as low level of angiogenesis inhibitor TSP-1, and thus favoring collateral formation

Identification of MicroRNAs in Helicoverpa armigera and Spodoptera litura Based on Deep Sequencing and Homology Analysis

The current identification of microRNAs (miRNAs) in insects is largely dependent on genome sequences. However, the lack of available genome sequences inhibits the identification of miRNAs in various insect species. In this study, we used a miRNA database of the silkworm Bombyx mori as a reference to identify miRNAs in Helicoverpa armigera and Spodoptera litura using deep sequencing and homology analysis. Because all three species belong to the Lepidoptera, the experiment produced reliable results. Our study identified 97 and 91 conserved miRNAs in H. armigera and S. litura, respectively. Using the genome of B. mori and BAC sequences of H. armigera as references, 1 novel miRNA and 8 novel miRNA candidates were identified in H. armigera, and 4 novel miRNA candidates were identified in S. litura. An evolutionary analysis revealed that most of the identified miRNAs were insect-specific, and more than 20 miRNAs were Lepidoptera-specific. The investigation of the expression patterns of miR-2a, miR-34, miR-2796-3p and miR-11 revealed their potential roles in insect development. miRNA target prediction revealed that conserved miRNA target sites exist in various genes in the 3 species. Conserved miRNA target sites for the Hsp90 gene among the 3 species were validated in the mammalian 293T cell line using a dual-luciferase reporter assay. Our study provides a new approach with which to identify miRNAs in insects lacking genome information and contributes to the functional analysis of insect miRNAs.</p

Clinical characteristics and serum TSP-1 level in all patients.

<p>LVEF indicates left ventricular ejection fraction, previous MI indicates previous myocardial infarction,eGFR indicates estimated glomerular filtration rate, TC indicates total cholesterol, TG indicates total triglyceride, LDL-C indicates low-density lipoprotein-cholesterol, HDL-C indicates high-density lipoprotein-cholesterol.</p>*<p>p<0.01 compared with control, #p<0.05 compared with control,$<0.05 compared with Collateral group I.</p

TSP-1 inhibits VEGF induced VEGFR2 phosphorylation through CD47.

<p>(A) Late EPCs were treated with VEGF (25 ng/ml) for 0, 5, 10, 15 min respectively. Total protein was extracted and the expression of FLK-1, phospho-VEGFR2 (Tyr1175) was determined by Western blot. (B)Seventy-two hrs after transfection of CD47-specific siRNA or control siRNA, the expression of CD47 in late EPCs was determined by western blotting analysis in three independent experiments (#p<0.05 versus control siRNA). (C)Seventy-two hrs after transfection of CD47-specific siRNA or control siRNA, late EPCs were treated with TSP-1(2 µg/ml) for 30 min and then VEGF(25 ng/ml) for 5 min. Total protein was extracted and the expression of FLK-1, phospho-VEGFR2 (Tyr1175) was determined by Western blot analysis. (D) Quantification of VEGFR2 phosphorylation normalized to VEGFR2 in three independent experiments(#p<0.05 versus control siRNA, *p<0.01 versus control siRNA).</p

TSP-1 inhibited late EPCs tubule formation on Matrigel.

<p>(A) Late EPCs were plated on Matrigel with TSP-1 at different concentrations for 8 hrs (Scale bar = 200 µm, 100×magnification). (B) Quantification of total tube length per high power field (HPF, 100×magnification) was presented as mean±S.D. of three independent experiments (#p<0.05 versus no TSP-1 intervention, *p<0.01 versus no TSP-1 intervention).</p

TSP-1 inhibited early EPCs incorporation into tube-like structure.

<p>(A) Early EPCs pretreated with TSP-1 at different concentrations for 1 hr were labeled with a DiI fluorescent marker(red) and coplated with HUVECs(transparent) to form tubule structures on Matrigel(Scale bar = 200 µm,100×magnification). (B–D) Early EPCs pretreated with TSP-1 at different concentrations for 1 hr(B), 6 hrs(C), 12 hrs(D) were coplated with HUVECs on Matrigel. Quantifications of incorporated EPCs per field were presented as mean±S.D of three independent experiments (#p<0.05 versus no TSP-1 intervention).</p