Carbon nanotubes (CNTs) have received extensive attention due to their extraordinary properties in electronic conduction, [ 1 ] heat transfer, [ 2 ] and mechanical strength. [ 3 ] Materials with unparallel performance, such as super-strong, lightweight e-textiles, can be fabricated from CNTs, suggesting a future revolution in materials science. Thus, the emerging CNT technology will largely depend on the development of effective spinning and post-spinning processes to realize such unprecedented materials. Two widely implemented strategies for fabricating CNT fi bers are in-solution [4][5][6][7] and solid-state spinning techniques. The in-solution spinning of CNTs can produce continuous CNT fi bers; however, homogeneous dispersion of CNTs in the solvent is necessary for proper spinning. Moreover, the properties of the CNT fi bers strongly depend on the methods of CNT dispersion. An alternative strategy is solid-state spinning, [8][9][10][11][12][13][14][15][16][17] which allows avoidance of CNT dispersion in solvents and for various post-spinning processes to be applied with ease. Twisting, [10][11][12][13][14][15][16] densifi cation, [ 9 , 18 ] and infi ltration [ 8 , 19,20 ] are examples of post-spinning processes, and the main purpose of the spinning and post-spinning processes is to enhance the mechanical properties of CNT fi bers. Despite the effort that has been made, however, fabrication of strong CNT fi bers remains a great challenge.The strong protein-based adhesives found in marine mussel Mytilus edulis , provide an important insight into the development of post-spinning processes of CNT fi bers. The mussel secretes special adhesive foot proteins that undergo rapid solidifi cation in seawater. At a molecular level, the unusual amino acid 3,4-dihydroxy-L -phenylalanine (DOPA) found in the adhesive proteins functions as a molecule that is responsible for the solidifi cation by oxidative chemical crosslinking. [21][22][23][24] From a chemical point of view, covalent crosslinking with amines and/or catechol (a side chain of DOPA) or metal coordination are the reactions involved with DOPA, and the reactions are responsible for mechanical reinforcement of the adhesive materials of mussels. [ 25 ] Here, inspired by the molecular mechanics of mussel adhesive formation, we demonstrate a new postspinning process for the fabrication of CNT fi bers ( Figure 1 a,b). By infi ltration of mussel-mimetic adhesive polymers and curing through thermal and metal oxidation, we demonstrate an increase in the tensile strength of CNT fi bers by up to 470%. The study described suggests a general post-spinning approach for enhancement of the mechanical properties of CNT fi bers prepared by various spinning techniques.Vertically well-aligned CNT arrays were grown on Fe-catalystimmobilized (1.7-nm-thick) silicon substrates by plasmaenhanced chemical vapor deposition. Methane (CH 4 ) was used as the carbon source to synthesize CNTs, with argon (Ar), hydrogen (H 2 ), and oxygen (O 2 ) carrier gases. In the presence of Ar gas fl ow...
Magnetofection has been utilized as a powerful tool to enhance gene transfection efficiency via magnetic field-enforced cellular transport processes. The accelerated accumulation of nucleic acid molecules by applying an external magnetic force enables the rapid and improved transduction efficiency. In this study, we developed magnetite nanocrystal clusters (PMNCs) cross-linked with polyethylenimine (PEI) to magnetically trigger intracellular delivery of small interfering RNA (siRNA). PMNCs were produced by cross-linked assembly of catechol-functionalized branched polyethylenimine (bPEI) around magnetite nanocrystals through an oil-in-water (O/W) emulsion and solvent evaporation method. The physical properties of PMNC were characterized by TEM, DLS, TSA, and FT-IR. Finely tuned formulation of clustered magnetite nanocrystals with controlled size and shape exhibited superior saturation of magnetization value. Magnetite nanocrystal clusters could form nanosized polyelectrolyte complexes with negatively charged siRNA molecules, enabling efficient delivery of siRNA into cells upon exposure to an external magnetic field within a short time. This study introduces a new class of magnetic nanomaterials that can be utilized for magnetically driven intracellular siRNA delivery.
This study was to investigate the role of complementary and alternative medicine in the prevention and treatment of benign prostatic hyperplasia. For this purpose, a randomized, double-blind, placebo-controlled trial was performed over 12 months on 47 benign prostatic hyperplasia patients with average age of 53.3 years and international prostate symptom score over 8. Subjects received either sweet potato starch (group A, placebo, 320 mg/day), pumpkin seed oil (group B, 320 mg/day), saw palmetto oil (group C, 320 mg/day) or pumpkin seed oil plus saw palmetto oil (group D, each 320 mg/day). International prostate symptom score, quality of life, serum prostate specific antigen, prostate volume and maximal urinary flow rate were measured. In groups B, C and D, the international prostate symptom score were reduced by 3 months. Quality of life score was improved after 6 months in group D, while those of groups B and C were improved after 3 months, compared to the baseline value. Serum prostate specific antigen was reduced only in group D after 3 months, but no difference was observed in prostate volume in all treatment groups. Maximal urinary flow rate were gradually improved in groups B and C, with statistical significance after 6 months in group B and after 12 months in group C. None of the parameters were significantly improved by combined treatment with pumpkin seed oil and saw palmetto oil. From these results, it is suggested that administrations of pumpkin seed oil and saw palmetto oil are clinically safe and may be effective as complementary and alternative medicine treatments for benign prostatic hyperplasia.
Abstract-Neointimal formation, the leading cause of restenosis, is caused by proliferation of vascular smooth muscle cells (VSMCs). Patients with diabetes mellitus have higher restenosis rates after coronary angioplasty than nondiabetic patients. Cilostazol, a selective type 3 phosphodiesterase inhibitor, is currently used to treat patients with diabetic vascular complications. Cilostazol is a potent antiplatelet agent that inhibits VSMC proliferation. In the present study, we examine whether the antiproliferative effect of cilostazol on VSMCs is mediated by inhibition of an important cell cycle transcription factor, E2F. Cilostazol inhibited the proliferation of human VSMCs in response to high glucose in vitro and virtually abolished neointimal formation in rats subjected to carotid artery injury in vivo. Moreover, the compound suppressed high-glucose-induced E2F-DNA binding activity, and the expression of E2F1, E2F2, cyclin A, and PCNA proteins. These data suggest that the beneficial effects of cilostazol on high-glucose-stimulated proliferation of VSMCs are mediated by the downregulation of E2F activity and expression of its downstream target genes, including E2F1, E2F2, cyclin A, and PCNA. The transcription factor, E2F, has been implicated in the periodic regulation of cellular genes required for transition through G1 and entry into the S phase, including dihydrofolate reductase, c-myc, DNA polymerase, cdc2, and proliferating cell nuclear antigen (PCNA). 5-7 E2F activity is regulated by interactions with RB family members. As cells progress toward S phase, RB family proteins are phosphorylated by G1 cyclin-complexes, resulting in the release of transcriptionally active E2F, which then leads to the activation of genes required for cell cycle progression. 8 -10 We recently showed that high glucose activates the DNA-binding activity of E2F, and decoy oligodeoxynucleotides against E2F inhibit the proliferation of VSMCs. 11 These data suggest that downregulation of E2F could constitute a therapeutic target to prevent restenosis after angioplasty in patients with diabetes.Cilostazol increases intracellular cAMP concentrations by selectively blocking phosphodiesterase type III. The clinical implications and pharmacokinetics with respect to the effects and safety of this drug have been well-established, especially in peripheral vascular disease. 12 Cilostazol is a potent antiplatelet agent currently used in clinical practice to treat patients with diabetic vascular complications. [13][14][15] Several lines of evidence indicate that cilostazol additionally inhibits the proliferation of VSMCs, reduces neointimal formation in balloon-injured rat carotid arteries, 16 -18 and inhibits restenosis after percutaneous transluminal coronary angioplasty. 19,20 One mechanism by which cilostazol may inhibit VSMC proliferation is via an increase in intracellular cAMP, because cAMP inhibits the proliferation of VSMCs by induction of p53-mediated and p21-mediated apoptosis. 21 However, Nadri et al demonstrated that increased cAMP...
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