measurement-scattering-nonlinearities-from-single-plasmonic

Measurement of Scattering Nonlinearities from a Single Plasmonic Nanoparticle

Plasmonics, which are based on the collective oscillation of electrons due to light excitation, involve strongly enhanced local electric fields and thus ...

National Taiwan University

The Peripherally Inserted Central Catheter (PICC) is still in its infancy in Taiwan. It has many advantages, including safety, simplicity, and few complications during the insertion process. It is suitable for patients who need long-term parenteral administration of medication or chemotherapy. However, the duration of PICC implantation is around six months, or even up to one year. As a result, it is very important to educate patients to take care of themselves throughout the implantation period in order to prevent complications. This report describes the experience of nursing a forty-four-year old male patient who suffered from acute lymphocytic leukemia and received a PICC implantation while undergoing chemotherapy treatment. As a PICC case manager, the author utilized self-efficacy theory and devoted herself to nursing care, interviews and phone calls to collect valuable information. During the process of PICC implantation, the author analyzed the characteristics of this case and assisted the patient and his primary care giver in choosing a suitable catheter and self-care techniques to achieve minimal complications during implantation. It is hoped that, by sharing in her experience, nursing staff may enhance their ability to assist patients with PICC and to help them to maintain their quality of life.

[An experience in nursing an acute lymphocytic leukemia patient with Peripherally Inserted Central Catheter].

Serum amyloid A (SAA) reduces fat deposition in adipocytes and hepatoma cells. Human SAA1 mRNA is increased by docosahexaenoic acid (DHA) treatment in human cells. These studies asked whether DHA decreases fat deposition through SAA1 and explored the mechanisms involved. We demonstrated that DHA increased human SAA1 and C/EBPbeta mRNA expression in human hepatoma cells, SK-HEP-1. Utilizing a promoter deletion assay, we found that a CCAAT/enhancer-binding protein beta (C/EBPbeta)-binding site in the SAA1 promoter region between -242 and -102 bp was critical for DHA-mediated SAA1 expression. Mutation of the putative C/EBPbeta-binding site suppressed the DHA-induced SAA1 promoter activity. The addition of the protein kinase A inhibitor H89 negated the DHA-induced increase in C/EBPbeta protein expression. The up-regulation of SAA1 mRNA and protein by DHA was also inhibited by H89. We also demonstrated that DHA increased protein kinase A (PKA) activities. These data suggest that C/EBPbeta is involved in the DHA-regulated increase in SAA1 expression via PKA-dependent mechanisms. Furthermore, the suppressive effect of DHA on triacylglycerol accumulation was abolished by H89 in SK-HEP-1 cells and adipocytes, indicating that DHA also reduces lipid accumulation via PKA. The observation of increased SAA1 expression coupled with reduced fat accumulation mediated by DHA via PKA suggests that SAA1 is involved in DHA-induced triacylglycerol breakdown. These findings provide new insights into the complicated regulatory network in DHA-mediated lipid metabolism and are useful in developing new approaches to reduce body fat deposition and fatty liver.

Docosahexaenoic acid enhances hepatic serum amyloid A expression via protein kinase A-dependent mechanism.

We show that scattering from a single gold nanoparticle is saturable for the first time. Wavelength-dependent study reveals that the saturation behavior is governed by depletion of surface plasmon resonance, not the thermal effect. We observed interesting flattening of the point spread function of scattering from a single nanoparticle due to saturation. By extracting the saturated part of scattering via temporal modulation, we achieve λ/8 point spread function in far-field imaging with unambiguous separation of adjacent particles.

Measurement of a saturated emission of optical radiation from gold nanoparticles: application to an ultrahigh resolution microscope.

Nonlinear plasmonics has attracted a lot of interests due to its wide applications. Recently, we demonstrated saturation and reverse saturation of scattering from a single plasmonic nanoparticle, which exhibits extremely narrow side lobes and central peaks in scattering images [ACS Photonics 1(1), 32 (2014)]. It is desirable to extract the reversed saturated part to further enhance optical resolution. However, such separation is not possible with conventional confocal microscope. Here we combine reverse saturable scattering and saturated excitation (SAX) microscopy. With quantitative analyses of amplitude and phase of SAX signals, unexpectedly high-order nonlinearities are revealed. Our result provides greatly reduced width in point spread function of scattering-based optical microscopy. It will find applications in not only nonlinear material analysis, but also high-resolution biomedical microscopy.

Hsuan Lee

Department of Physics

National Taiwan University

Measurement of Scattering Nonlinearities from a Single Plasmonic Nanoparticle

Hsuan Lee

.css-o250i3{font-size:18px;font-family:Open Sans,sans-serif;line-height:21.6px;}Department of Physics

National Taiwan University

Measurement of Scattering Nonlinearities from a Single Plasmonic Nanoparticle

Department of Physics