Integrated optical gyroscope using active long-range surface plasmon-polariton waveguide resonator.

Optical gyroscopes with high sensitivity are important rotation sensors for inertial navigation systems. Here, we present the concept of integrated resonant optical gyroscope constructed by active long-range surface plasmon-polariton (LRSPP) waveguide resonator. In this gyroscope, LRSPP waveguide doped gain medium is pumped to compensate the propagation loss, which has lower pump noise than that of conventional optical waveguide. Peculiar properties of single-polarization of LRSPP waveguide have been found to significantly reduce the polarization error. The metal layer of LRSPP waveguide is electro-optical multiplexed for suppression of reciprocal noises. It shows a limited sensitivity of ~10(-4) deg/h, and a maximum zero drift which is 4 orders of magnitude lower than that constructed by conventional single-mode waveguide.

Role of bone marrow-derived mesenchymal stem cells in a rat model of severe acute pancreatitis.

AIM: To investigate the role and potential mechanisms of bone marrow mesenchymal stem cells (MSCs) in severe acute peritonitis (SAP). METHODS: Pancreatic acinar cells from Sprague Dawley rats were randomly divided into three groups: non-sodium deoxycholate (SDOC) group (non-SODC group), SDOC group, and a MSCs intervention group (i.e., a co-culture system of MSCs and pancreatic acinar cells + SDOC). The cell survival rate, the concentration of malonaldehyde (MDA), the density of superoxide dismutase (SOD), serum amylase (AMS) secretion rate and lactate dehydrogenase (LDH) leakage rate were detected at various time points. In a separate study, Sprague Dawley rats were randomly divided into either an SAP group or an SAP + MSCs group. Serum AMS, MDA and SOD, interleukin (IL)-6, IL-10, and tumor necrosis factor (TNF)-α levels, intestinal mucosa injury scores and proliferating cells of small intestinal mucosa were measured at various time points after injecting either MSCs or saline into rats. In both studies, the protective effect of MSCs was evaluated. RESULTS: In vitro, The cell survival rate of pancreatic acinar cells and the density of SOD were significantly reduced, and the concentration of MDA, AMS secretion rate and LDH leakage rate were significantly increased in the SDOC group compared with the MSCs intervention group and the Non-SDOC group at each time point. In vivo, Serum AMS, IL-6, TNF-α and MAD level in the SAP + MSCs group were lower than the SAP group; however serum IL-10 level was higher than the SAP group. Serum SOD level was higher than the SAP group at each time point, whereas a significant between-group difference in SOD level was only noted after 24 h. Intestinal mucosa injury scores was significantly reduced and the proliferating cells of small intestinal mucosa became obvious after injecting MSCs. CONCLUSION: MSCs can effectively relieve injury to pancreatic acinar cells and small intestinal epithelium, promote the proliferation of enteric epithelium and repair of the mucosa, attenuate systemic inflammation in rats with SAP.

Vascular exclusion by preserving tumor-contralateral branch of hepatic artery in hepatectomy in treatment liver cancer with cirrhosis.

BACKGROUND/AIMS: To investigate the effectiveness and safety of vascular exclusion by preserving tumor-contralateral branch of hepatic artery in hepatectomy in treatment liver cancer with cirrhosis. METHODOLOGY: The clinical data of 10 cases treated with hepatectomy for liver cancer were analyzed retrospectively. Vascular exclusion by preserving tumor-contralateral branch of hepatic artery was applied to control bleeding. Blood loss, operative time and postoperative hepatic function were observed. RESULTS: The average blood loss was 515mL, the operative time was 191 minutes and the mean time of exclusion was 30.20 minutes. There is no significant difference between hepatic function (serum total bilirubin, alanine transaminase) of postoperative day 7 and that of pre-operation. CONCLUSIONS: Vascular exclusion by preserving tumor-contralateral branch of hepatic artery could effectively control bleeding and preserve hepatic function and is proved to be applicable to patients of liver cancer with cirrhosis.

Self-assembly of large-scale and ultrathin silver nanoplate films with tunable plasmon resonance properties.

We describe a rapid, simple, room-temperature technique for the production of large-scale metallic thin films with tunable plasmonic properties assembled from size-selected silver nanoplates (SNPs). We outline the properties of a series of ultrathin monolayer metallic films (8-20 nm) self-assembled on glass substrates in which the localized surface plasmon resonance can be tuned over a range from 500 to 800 nm. It is found that the resonance peaks of the films are strongly dependent on the size of the nanoplates and the refractive index of the surrounding dielectric. It is also shown that the bandwidth and the resonance peak of the plasmon resonance spectrum of the metallic films can be engineered by simply controlling aggregation of the SNP. A three-dimensional finite element method was used to investigate the plasmon resonance properties for individual SNPs in different dielectrics and plasmon coupling in SNP aggregates. A 5-17 times enhancement of scattering from these SNP films has been observed experimentally. Our experimental results, together with numerical simulations, indicate that this self-assembly method shows great promise in the production of nanoscale metallic films with enormous electric-field enhancements at visible and near-infrared wavelengths. These may be utilized in biochemical sensing, solar photovoltaic, and optical processing applications.

Tunable microring resonator based on dielectric-loaded surface plasmon polariton waveguides.

Integrated optical ring resonators are essential elemental components for integrated optical circuits. An ultrasmall thermo-optical microring resonator with two bus waveguide-configuration based on surface plasmon polariton waveguide is theoretically analyzed. The thermo-optical coefficient, the temperature-dependent amplitude attenuation coefficient and the temperature distribution properties of the waveguide are investigated numerically by finite element method. The critical resonant conditions of the microring resonator are discussed by considering the propagation losses in the plasmonic ring cavity. The transmission characteristics and the tunability of the ring resonator with different structural parameters are investigated. The results show that the proposed ring resonator with a low driving power and high efficient tunability has potential to develop nano-scope wavelength tunable channel drop filters, low power optical switches, attenuators, and other high compact integrated optical devices.

Numerical analysis of deep sub-wavelength integrated plasmonic devices based on Semiconductor-Insulator-Metal strip waveguides.

We report the first study of nanoscale integrated photonic devices constructed with semiconductor-insulator-metal strip (SIMS) waveguides for use at telecom wavelengths. These waveguides support hybrid plasmonic modes transmitting through a 5-nm thick insulating region with a normalized intensity of 200-300 µm(-2). Their fundamental mode, unique transmission and dispersion properties are consistent with photonic devices for guiding and routing of signals in communication applications. It has been demonstrated using Finite Element Methods (FEM) that the high performance SIMS waveguide can be used to fabricate deep sub-wavelength integrated plasmonic devices such as directional couplers with the ultra short coupling lengths, sharply bent waveguides, and ring resonators having a functional size of ≈1 µm and with low insertion losses and nearly zero radiation losses.