Dye aggregation and concomitant reduction of dye excited-state lifetimes and electron-injection yields constitute a significant mechanism for diminution of light-to-electrical energy conversion ...efficiencies in many dye-sensitized solar cells (DSCs). For TiO2-based DSCs prepared with an archetypal donor–acceptor organic dye, (E)-2-cyano-3-(5′-(5′′-(p-(diphenylamino)phenyl)-thiophen-2′′-yl)thiophen-2′-yl)acrylic acid (OrgD), we find, in part via ultrafast spectroscopy measurements, that postdye-adsorption atomic layer deposition (ALD) of ultrathin layers of either TiO2 or Al2O3 effectively reverses residual aggregation. Notably, the ALD treatment is significantly more effective than the widely used aggregation-inhibiting coadsorbent, chenodeoxycholic acid. Primarily because of reversal of OrgD aggregation, and resulting improved injection yields, ALD post-treatment engenders a 30+% increase in overall energy conversion efficiency. A secondary contributor to increased currents and efficiencies is an ALD-induced attenuation of the rate of interception of injected electrons, resulting in slightly more efficient charge collection.
Korean Red Ginseng (KRG) is an ethnopharmacological plant that is traditionally used to improve the body’s immune functions and ameliorate the symptoms of various diseases. However, the ...antitumorigenic effects of KRG and its underlying molecular and cellular mechanisms are not fully understood in terms of its individual components. In this study, in vitro and in vivo antitumorigenic activities of KRG were explored in water extract (WE), saponin fraction (SF), and nonsaponin fraction (NSF).
In vitro antitumorigenic activities of WE, SF, and NSF of KRG were investigated in the C6 glioma cell line using cytotoxicity, migration, and proliferation assays. The underlying molecular mechanisms of KRG fractions were determined by examining the signaling cascades of apoptotic cell death by semiquantitative reverse transcriptase polymerase chain reaction and Western blot analysis. The in vivo antitumorigenic activities of WE, SF, and NSF were investigated in a xenograft mouse model.
SF induced apoptotic death of C6 glioma cells and suppressed migration and proliferation of C6 glioma cells, whereas WE and NSF neither induced apoptosis nor suppressed migration of C6 glioma cells. SF downregulated the expression of the anti-apoptotic gene B-cell lymphoma-2 (Bcl-2) and upregulated the expression of the pro-apoptotic gene Bcl-2-associated X protein (BAX) in C6 glioma cells but had no effect on the expression of the p53 tumor-suppressor gene. Moreover, SF treatment resulted in activation of caspase-3 as evidenced by increased levels of cleaved caspase-3. Finally, WE, SF, and NSF exhibited in vivo antitumorigenic activities in the xenograft mouse model by suppressing the growth of grafted CT-26 carcinoma cells without decreasing the animal body weight.
These results suggest that WE, SF, and NSF of KRG are able to suppress tumor growth via different molecular and cellular mechanisms, including induction of apoptosis and activation of immune cells.
High-performance energy harvesting for human-sensing applications has been achieved through recent progress in piezoelectric-based wearable devices. Piezoelectric nanomaterials can be leveraged for ...flexibility and biocompatibility while also enhancing piezoelectricity. However, such nanomaterials exhibit low piezoelectricity, limits the industrial-scale development of highly efficient piezoelectric devices. Hence, design of novel materials to significantly enhance piezoelectricity is necessitated. Herein, we demonstrate that a peapod-inspired design in which ZnSnO3 anchored on surface-modified carbon nanotubes (CNT) allows significant enhancement of the piezoelectricity produced by poly(vinylidene fluoride-co-trifluoroethylene)-based (P(VDF-TrFE)-based) nanofibers (a piezoelectric material). The piezoelectric properties were exploited for the application of the as-prepared nanofibers (NFs) in flexible NFs in energy-harvesting and pulse-sensing systems, which demonstrated high output power ((97.5 V and 1.16 μA) as well as imperceptible pulse detection even in posterior tibial arteries. This work provides the scientific and engineering framework for delivering ZnSnO3-surface-modified CNT-P(VDF-TrFE) NFs excellent piezoelectric performance for use in piezoelectric devices.
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•ZnSnO3 nanoparticles were anchored on the surface modified CNT (ZnSnO3-SMC) by pulsed laser ablation process.•ZnSnO3-SMC were reinforced within P(VDF-TrFE) nanofibers.•ZnSnO3-SMC-P(VDF-TrFE) nanofibers show excellent piezoelectric performance as well as imperceptible pulsed detection.
An artificial blood vessel with a tubular structure was additively manufactured via fused deposition modeling (FDM) starting from a single strand of polyvinyl alcohol (PVA) filament coated with a ...specific thickness of biocompatible polydimethylsiloxane (PDMS), followed by removal of the inner core via hydrogen peroxide leaching under sonication. In particular, we examined the relationship between the extruded deposition diameter and the filament migration speed/nozzle control speed (referred to as the filament/nozzle transition ratio), which is almost independent of the extruded deposition flow rate due to the weak die-swelling and memory effects of the extruded PVA arising from its intrinsically low viscoelasticity. The chemical stability of the PDMS during sonication in the hydrogen peroxide solution was then determined by spectroscopic techniques. The PDMS displayed no mechanical degradation in the hydrogen peroxide solution, resulting in similar fracture elongation and yield strength to those of the pristine specimen without the leaching treatment. As a further advantage, the inside surface of the PDMS was smooth regardless of the hydrogen peroxide leaching under sonication. The potential application of the as-developed scaffold in soft tissue engineering (particularly that involving vascular tissue regeneration) was demonstrated by the successful transplantation of the artificial blood vessel in a right-hand surgical replica used in a clinical simulation.
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•A single strand of PVA was additively manufactured via FDM.•The PVA was dip-coated with a specific thickness of biocompatible PDMS.•PVA was removed from the PVA/PDMS structure with H2O2 leaching under sonication.•The tubular structure of PDMS exhibits chemical stability and mechanical reliability.•The artificial blood vessel was transplanted into a right-hand surgical replica.
Background: Korean Red Ginseng (KRG) is an ethnopharmacological plant that is traditionally used to improve the body's immune functions and ameliorate the symptoms of various diseases. However, the ...antitumorigenic effects of KRG and its underlying molecular and cellular mechanisms are not fully understood in terms of its individual components. In this study, in vitro and in vivo antitumorigenic activities of KRG were explored in water extract (WE), saponin fraction (SF), and nonsaponin fraction (NSF). Methods: In vitro antitumorigenic activities of WE, SF, and NSF of KRG were investigated in the C6 glioma cell line using cytotoxicity, migration, and proliferation assays. The underlying molecular mechanisms of KRG fractions were determined by examining the signaling cascades of apoptotic cell death by semiquantitative reverse transcriptase polymerase chain reaction and Western blot analysis. The in vivo antitumorigenic activities of WE, SF, and NSF were investigated in a xenograft mouse model. Results: SF induced apoptotic death of C6 glioma cells and suppressed migration and proliferation of C6 glioma cells, whereas WE and NSF neither induced apoptosis nor suppressed migration of C6 glioma cells. SF downregulated the expression of the anti-apoptotic gene B-cell lymphoma-2 (Bcl-2) and upregulated the expression of the pro-apoptotic gene Bcl-2-associated X protein (BAX) in C6 glioma cells but had no effect on the expression of the p53 tumor-suppressor gene. Moreover, SF treatment resulted in activation of caspase-3 as evidenced by increased levels of cleaved caspase-3. Finally, WE, SF, and NSF exhibited in vivo antitumorigenic activities in the xenograft mouse model by suppressing the growth of grafted CT-26 carcinoma cells without decreasing the animal body weight. Conclusion: These results suggest that WE, SF, and NSF of KRG are able to suppress tumor growth via different molecular and cellular mechanisms, including induction of apoptosis and activation of immune cells.
Background: Although Korean Red Ginseng (KRG) has been traditionally used for a long time, its anti-inflammatory role and underlying molecular and cellular mechanisms have been poorly understood. In ...this study, the anti-inflammatory roles of KRG-derived components, namely, water extract (KRG-WE), saponin fraction (KRG-SF), and nonsaponin fraction (KRG-NSF), were investigated. Methods: To check saponin levels in the test fractions, KRG-WE, KRG-NSF, and KRG-SF were analyzed using high-performance liquid chromatography. The anti-inflammatory roles and underlying cellular and molecular mechanisms of these components were investigated using a macrophage-like cell line (RAW264.7 cells) and an acute gastritis model in mice. Results: Of the tested fractions, KGR-SF (but not KRG-NSF and KRG-WE) markedly inhibited the viability of RAW264.7 cells, and splenocytes at more than 500 mg/mL significantly suppressed NO production at $100{\mu}g/mL$, diminished mRNA expression of inflammatory genes such as inducible nitric oxide synthase, cyclooxygenase-2, tumor necrosis factor-${\alpha}$, and interferon-${\beta}$ at $200{\mu}g/mL$, and completely blocked phagocytic uptake by RAW264.7 cells. All three fractions suppressed luciferase activity triggered by interferon regulatory factor 3 (IRF3), but not that triggered by activator protein-1 and nuclear factor-kappa B. Phospho-IRF3 and phospho-TBK1 were simultaneously decreased in KRG-SF. Interestingly, all these fractions, when orally administered, clearly ameliorated the symptoms of gastric ulcer in HCl/ethanol-induced gastritis mice. Conclusion: These results suggest that KRG-WE, KRG-NSF, and KRG-SF might have anti-inflammatory properties, mostly because of the suppression of the IRF3 pathway.
Ginseng total saponins (GTS) injected intracerebroventricularly (i.c.v.) at doses of 0.1-1 microg inhibited the i.c.v. injection stress-induced plasma corticosterone levels in mice. The inhibitory ...action of GTS was blocked by co-administered N(G)-nitro-L-arginine methyl ester (L-NAME; 1.5 microg, i.c.v.), an inhibitor of nitric oxide synthase (NOS). Of the ginsenosides Rb1, Rb2, Rc, Rd, Re, Rf, Rg1, 20(S)-Rg3 and 20(R)-Rg3 injected i.c.v. at doses of 0.01-1 microg, 20(S)-Rg3 and Rc significantly inhibited the i.c.v. injection stress-induced plasma corticosterone levels. The inhibitory actions of 20(S)-Rg3 and Rc were blocked by co-administered L-NAME (1.5 microg, i.c.v.). These results suggest that GTS, 20(S)-Rg3 and Rc may inhibit the i.c.v. injection stress-induced hypothalamo-pituitary-adrenal response by inducing NO production in the brain.
Gate induced drain leakage (GIDL) characteristics were investigated with the recessed channel array transistor (RCAT) for DRAM, using the elevated source drain (ESD). The lower doping concentration ...of a source-drain region in the ESD structure reduces the electric field, which reduces drain leakage current and also the fluctuation of leakage current. These reductions can enhance the data retention time of DRAM. The reduced electric field also improves hot carrier immunity of the cell transistor as well
When forming microscopic patterns in sub-0.17/sup /spl middot// /spl middot/process, in order to secure stable DOF margin at photo lithography, inorganic SiO/sub x/N/sub y/ is often used for ...antireflective coating (ARC) for patterning line and contact hole through depositing plasma CVD method. In our gigabit process, SiO/sub x/N/sub y/ ARC is also being used for gate fabrication in deep-UV lithography. We've been leaving ARC on gate in order to secure insulation margin between gate and SAC (Self Aligned Contact) poly-Si pad. However there have occasionally been malfunctions in devices due to the generation of leakage current through ARC on gate between SAC pads. In this paper we discuss never-been-reported leakage current behaviors due to remained SiO/sub x/N/sub y/ ARC on gate in sub-0.17/sup /spl middot// /spl middot/gigabit process with a point of view of the effect of process parameters (the high frequency (HF) power of ARC deposition, metal contamination and implanted phosphorus ions) and the method of improving failure.
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