Towards a full characterization of a plasmonic nanostructure with a fluorescent near-field probe

We report on the experimental and theoretical study of the spatial fluctuations of the local density of states (EM-LDOS) and of the fluorescence intensity in the near-field of a gold nanoantenna. EM-LDOS, fluorescence intensity and topography maps are acquired simultaneously by scanning a fluorescent nanosource grafted on the tip of an atomic force microscope at the surface of the sample. The results are in good quantitative agreement with numerical simulations. This work paves the way for a full near-field characterization of an optical nanoantenna.

The Rheological and Mechanical Properties of PVC-Lignin Blends

The rheological and mechanical properties of PVC-lignin blends were studied, and their alterations were investigated after lignin was treated with poly(ethyl acrylate-co-maleic anhydride). The addition of lignin changes the early rheological properties of the blend comparing with PVC control because the rigidity of lignin particles leads to more intensive shearing in the system, but has little effect on its rheology during the equilibrium period. The processing stability slightly decreases with the increase of lignin content in the blend. The mechanical properties of the blends are worse than that of PVC control. The rheological properties of the blends are little influenced after lignin is treated with polyacrylate, but the mechanical properties, especially toughness, are improved, and the maximum impact strength is 37.7% higher than that of PVC control.

Study on the Synthesis and Surface Activities of Novel Alkyl Sulfonate Gemini Surfactants

Three novel dialkyl disulfonate gemini surfactants (Cn-6-Cn, n = 6, 8, 12; n is carbon number of hydrophobic chain) were synthesized from cyanuric chloride, aliphatic amine and taurine. The chemical structures of the prepared compounds were confirmed by 1H NMR, 13C NMR, IR spectra and ESI-MS. Their critical micelle concentrations (CMC) in the aqueous solutions at 25°C were determined by surface-tension method. With the increasing length of the hydrophobic carbon chain, the values of their CMC decreased. The surface tension measurements of Cn-6-Cn give low CMC, great efficiency in lowering the surface tension, and strong adsorption at air–water interface. In addition, adsorption and micellization behavior of Cn-6-Cn were estimated by the parameter of pC20, the minimum average area per surfactant molecule (Amin).

Management and outcome of ovarian malignancy complicating pregnancy: an analysis of 41 cases and review of the literature

OBJECTIVE

The aims of this study are to summarize our experience of managing ovarian malignancy complicating pregnancy, to discuss the maternal and fetal outcomes, and to review the literature concerned.

METHODS

Forty-one patients with ovarian malignancies complicating pregnancy at Peking Union Medical College Hospital between 1990 and 2012 were retrospectively reviewed.

RESULTS

Of the 41 patients, malignancies included epithelial ovarian cancers (13/41, 31.7 %), epithelial borderline ovarian tumors (12/41, 29.3 %), ovarian malignant germ cell tumors (10/41, 24.4 %), sexcord stromal tumors (3/41, 7.3 %), metastatic ovarian tumors (2/41, 4.9 %), and primary ovarian choriocarcinoma (1/41, 2.4 %). The median overall survival was 30 months (range 3-165), with an overall mortality rate of 24.4 %. The pregnancy outcomes included termination in the first trimester (8/41, 19.5 %), full-term vaginal delivery (7/41, 17.0 %), full-term cesarean section (17/41, 41.5 %), and therapeutic cesarean section for premature birth (9/41, 22.0 %). One preterm newborn died, and the remaining 32 survived in healthy status. All patients underwent surgery, and those who deliberately delayed radical surgery had gloomy prognosis. Two patients received chemotherapy during pregnancy, and 24 patients started chemotherapy after pregnancy termination.

CONCLUSIONS

Management priority should be given to the malignancy of ovarian tumors at any stage of pregnancy. Surgical intervention is the main treatment modality, and delaying of radical surgery is not recommended for patients with suspicion of high malignancy. Early diagnosis and appropriate treatment could offer satisfactory prognosis.

MO-B-211-01: Linac-Based IMRT/VMAT Commissioning and QA Program Development

Intensity modulated radiotherapy (IMRT) has been used clinically for many years. Reports from the RPC indicate that up to 30% of the institutions fail to pass RPC IMRT credentialing process on the first attempt. While volumetric modulated arc therapy (VMAT) has been introduced more recently, it has quickly gained wide clinical use. In spite of the long history with IMRT and rapid adoption of VMAT, commissioning and developing a quality assurance (QA) program continues to be a challenge especially in busy departments. These points indicate that a review of commissioning and quality assurance for IMRT is still very much needed. In this session, the development of an overall IMRT/VMAT QA program, the role of team members and on-going program functions will be described including aspects of both quality and safety. General issues and specifics of IMRT/VMAT commissioning and quality assurance will be covered. While the general principles of commissioning and QA apply to any device capable of intensity-modulation, specific examples will be provided for Elekta and Varian linear accelerators. Strategies for commission and useful checklists will be discussed as well as some differences between Elekta and Varian technologies. There will also be a focus on practical advice towards the implementation and on-going QA of linac-based IMRT and VMAT. Patient- specific QA strategies along with the comparison of different QA equipment and techniques will be presented. Lastly, differences will be highlighted between IMRT and VMAT for patient-specific QA.

LEARNING OBJECTIVES

1. Understand approaches to IMRT/VMAT commissioning and QA 2. Describe most relevant issues in patient-specific QA for IMRT/VMAT 3. Discuss issues with IMRT /VMAT QA equipment and techniques.

Electronic sensitivity of a single-walled carbon nanotube to internal electrolyte composition

Carbon nanotubes (CNTs) are well known as materials for nanoelectronics and show great potential to be used as the sensing elements in chemical and biological sensors. Recently, CNTs have been shown to be effective nanofluidic channels and the transport of substances through small diameter CNTs is intrinsically fast, selective, and operates at the single molecule level. It has been shown that the transport characteristics of semiconducting single-walled CNT (SWCNT) field effect transistors (FETs) are sensitive to internal water wetting. We report here that the characteristics of semiconducting SWCNT FETs are also sensitive to the concentration, pH and ion type of the ionic solution when the electrolyte is inside the CNT. Such sensitivity is not observed at the outside surface of a semiconducting SWCNT. This opens a new avenue for building new types of CNT sensor devices in which the SWCNT concurrently functions as a nanochannel and an electronic detector.

Preclinical evaluation of Mab CC188 for ovarian cancer imaging

Cancer stem cells (CSCs) have been successfully isolated from solid tumors and are believed to be initiating cells of primary, metastatic and recurrent tumors. Imaging and therapeutic reagents targeted to CSCs have potential to detect subclinical tumors and completely eradicate the disease. Previously, we have demonstrated that Mab CC188 binds to colon cancer CD133- and CD133+ (CSCs) cells. In this study, we examined the reactivity of Mab CC188 to ovarian cancer cells including CD133+ cells and primary tumor tissues using immunofluorescence staining methods and tissue microarray technique. We also explored the feasibility of using NIR dye-labeled Mab CC188 probe to image ovarian tumors in vivo. Mab CC188 stains both CD133- and CD133+ cells of ovarian cancer. Tissue microarray analysis reveals that 75% (92/123) of ovarian cancer cases are positively stained with Mab CC188. Weak positive (±), positive (+), strong positive (++) and very strong positive (+++) stains are 14.8, 3.7, 11 and 24.4%, respectively. In contrast, Mab CC188 staining is low in normal cells and tissues. In vivo study show that significant amounts of the probe accumulates in the excretion organs in the early period postinjection. At 24 hr, the imaging probes have largely accumulates in the tumor, while the intensity of the imaging probe decreases in the liver. The tumor uptake was still evident at 120-hr postinjection. Our work suggests that Mab CC188-based imaging and therapeutic reagents are capable of detecting early stage ovarian tumors and effectively treating the tumor.

Loss of breast epithelial marker hCLCA2 promotes epithelial-to-mesenchymal transition and indicates higher risk of metastasis

Transition between epithelial and mesenchymal states is a feature of both normal development and tumor progression. We report that expression of chloride channel accessory protein hCLCA2 is a characteristic of epithelial differentiation in the immortalized MCF10A and HMLE models, while induction of EMT by cell dilution, TGFbeta, or mesenchymal transcription factors sharply reduces hCLCA2 levels. Attenuation of hCLCA2 expression by lentiviral shRNA caused cell overgrowth and focus formation, enhanced migration and invasion, and increased mammosphere formation in methylcellulose. These changes were accompanied by downregulation of E-cadherin and upregulation of mesenchymal markers such as vimentin and fibronectin. Moreover, hCLCA2 expression is greatly downregulated in breast cancer cells with a mesenchymal or claudin-low profile. These observations suggest that loss of hCLCA2 may promote metastasis. We find that higher-than-median expression of hCLCA2 is associated with a one-third lower rate of metastasis over an 18 year period among breast cancer patients compared to lower-than-median (n=344, unfiltered for subtype). Thus, hCLCA2 is required for epithelial differentiation, and its loss during tumor progression contributes to metastasis. Overexpression of hCLCA2 has been reported to inhibit cell proliferation and is accompanied by increases in chloride current at the plasma membrane and reduced intracellular pH (pHi). We found that knockdown cells have sharply reduced chloride current and higher pHi, both characteristics of tumor cells. These results suggest a mechanism for the effects on differentiation. Loss of hCLCA2 may allow escape from pHi homeostatic mechanisms, permitting the higher intracellular and lower extracellular pH that are characteristic of aggressive tumor cells.

A placebo-controlled trial of exenatide twice-daily added to thiazolidinediones alone or in combination with metformin

AIM

To test the hypothesis that glycaemic control with exenatide added to thiazolidinediones (TZDs) with or without metformin was superior to placebo.

METHODS

A 26-week, multi-country (Canada, Mexico, Romania, South Africa and the USA), randomized, double-blind, placebo-controlled study compared exenatide twice-daily vs. placebo in 165 subjects suboptimally controlled with TZDs with or without metformin [HbA(1c) 8.2% (s.d. 0.9), fasting serum glucose 9.1 (2.6) mmol/l, body weight 93.9 (17.8) kg, diabetes duration 6.4 (4.3) years]. After a 2-week, single-blind, lead-in period, subjects were randomly assigned (2 : 1) to add exenatide or placebo to current regimens. The primary endpoint was HbA(1c) change at endpoint (Week 26 or last-observation-carried-forward).

RESULTS

Only 8 subjects were treated with concomitant TZD alone. Exenatide reduced HbA(1c) significantly more than placebo [-0.84% (s.e. 0.20) vs. -0.10% (0.23), treatment difference -0.74% (0.16), p < 0.001)]. Mean reductions in body weight were similar in both treatments at endpoint [exenatide, -1.4 (s.e. 0.6) kg vs. placebo, -0.8 (0.7) kg, p = 0.176)]. Nearly 71% of subjects had both a reduction in HbA(1c) and body weight with exenatide compared with 54% with placebo. The most common adverse events (exenatide vs. placebo) were nausea (12% vs. 2%, p = 0.037), vomiting (8% vs. 0%, p = 0.031) and headache (4% vs. 4%). Confirmed (blood glucose <3.0 mmol/l) minor hypoglycaemia was experienced by 4 and 2% of subjects treated with exenatide and placebo, respectively. Incidence of hypoglycaemia was not significantly different between groups.

CONCLUSIONS

Exenatide added to TZDs alone or in combination with metformin significantly improved glycaemic control as determined by significant improvement in HbA(1c) without associated hypoglycaemia.