Magnetic-based Fano resonance of hybrid silicon-gold nanocavities in the near-infrared region

Direct interference between the orthogonal electric and magnetic modes in a hybrid silicon-gold nanocavity is demonstrated to induce a pronounced asymmetric magnetic-based Fano resonance in the total scattering spectrum at near-infrared frequencies. Differing from the previously reported magnetic-based Fano resonances in metal nanoparticle clusters, the narrow discrete mode provided by the silicon magnetic dipole resonance can be directly excited by external illumination, and greatly enhanced electric and magnetic fields are simultaneously obtained at the Fano dip.

Laser ranging at few-photon level by photon-number-resolving detection

Sensitive laser ranging was demonstrated at few-photon level using photon-number-resolving (PNR) detectors. The reflected photon pulses from a non-cooperation remote target were distinguished in a sunlight environment of 2.5×103  lx by setting the discrimination threshold at 5-photon level. By comparing the detected photon numbers, two remote targets with different reflection coefficients were well recognized. PNR detection facilitated remote laser ranging of few-photon sensitivity with similar capabilities of linear optical detectors. This technique avoids photon-counting saturation and is important for ultra-long distance LIDAR and 3D imaging at a few photon level.

1550-nm time-of-flight ranging system employing laser with multiple repetition rates for reducing the range ambiguity

We demonstrated a time-of-flight (TOF) ranging system employing laser pulses at 1550 nm with multiple repetition rates to decrease the range ambiguity, which was usually found in high-repetition TOF systems. The time-correlated single-photon counting technique with an InGaAs/InP avalanche photodiode based single-photon detector, was applied to record different arrival time of the scattered return photons from the non-cooperative target at different repetition rates to determine the measured distance, providing an effective and convenient method to increase the absolute range capacity of the whole system. We attained hundreds of meters range with millimeter accuracy by using laser pulses of approximately 10-MHz repetition rates.

Lyn regulates cytotoxicity in respiratory epithelial cells challenged by cigarette smoke extracts

Cigarette smoking is associated with a series of lung diseases such as cancer, chronic obstructive pulmonary disease (COPD), and asthma. Despite the intense interest, the underlying molecular mechanism in smoking-related diseases is incompletely understood. Here, we show that Lyn is involved in cytotoxicity of respiratory epithelial cells induced by cigarette smoke extracts (CSE), an in vitro culture model for evaluating tobacco toxicity. In addition, exposure to CSE promotes the activation of JAK2 and STAT1, which is responsible for CSE-induced cytotoxicity. Moreover, a Lyn specific siRNA, Lyn dominant negative construct and pharmacological inhibitor all alleviated CSE-induced cytotoxicity in lung cells to different extents, respectively. Furthermore, Lyn also influences the phagocytosis of bacteria by murine alveolar macrophages, extending its impact on innate immunity. Taken together, these findings indicate that Lyn may play a role in the regulation of cigarette smoking-induced lung cell death, and may be a potential novel therapeutic target for cigarette smoking related lung diseases.

Natural history of acalculous biliary symptoms

INTRODUCTION

The radiological criteria for the diagnosis of gallbladder disease rely largely on the detection of calculi using ultrasonography. Patients may, however, suffer symptoms typical of biliary pain without detectable gallstones. The aim of this study was to identify a cohort of patients presenting with recurrent episodes of biliary symptoms in the absence of identifiable pathology on ultrasonography and to record the outcome of subsequent imaging investigations.

METHODS

Records of patients having abdominal ultrasonography during a four-month period in 2006 were accessed retrospectively and those with symptoms suggesting biliary disease were identified. Radiology records were reviewed over a five-year follow-up period to identify patients undergoing further imaging for recurrent biliary symptoms and outcomes were recorded.

RESULTS

A total of 512 patients had ultrasonography for investigation of symptoms consistent with biliary disease. Almost half (41.2%) of these were found to have gallbladder pathology on ultrasonography and 4.7% of patients went on to have further investigations for similar symptoms without achieving a diagnosis. The median age of this group was 47 years and 75% of these patients were female. During the follow-up period, 2.6% of patients with biliary symptoms and initially normal ultrasonography developed gallstones and in 1.3% pancreatitis was demonstrated on imaging.

CONCLUSIONS

A small minority of patients who present with biliary symptoms and have no abnormality on ultrasonography present with recurrent symptoms or develop significant biliary pathology. These patients should be identified by interview at routine follow-up visits and further investigations should be considered.

Fabrication of nitrogen vacancy color centers by femtosecond pulse laser illumination

We report on a novel method to fabricate single, multiple and large-area high-density ensembles of nitrogen vacancy (NV) color centers in synthetic type Ib bulk diamond by femtosecond laser illumination. Electron beams generated in propagation of intense infrared laser pulses in air sputtered on a diamond sample under high temperature aroused by the laser illumination, creating NV color centers. Typical photoluminescence (PL) spectra of NV centers could be observed on the illuminated spots. Photon streams from individual photoluminescent points exhibited anti-bunching effect by the second-order correlation measurement, evidencing single and multiple photon-emitters around the laser illuminated spots.

Ultrasensitive polarized up-conversion of Tm(3+)-Yb3+ doped β-NaYF4 single nanorod

Up-conversion luminescence in rare earth ions (REs) doped nanoparticles has attracted considerable research attention for the promising applications in solid-state lasers, three-dimensional displays, solar cells, biological imaging, and so forth. However, there have been no reports on REs doped nanoparticles to investigate their polarized energy transfer up-conversion, especially for single particle. Herein, the polarized energy transfer up-conversion from REs doped fluoride nanorods is demonstrated in a single particle spectroscopy mode for the first time. Unique luminescent phenomena, for example, sharp energy level split and singlet-to-triplet transitions at room temperature, multiple discrete luminescence intensity periodic variation with polarization direction, are observed upon excitation with 980 nm linearly polarized laser. Furthermore, nanorods with the controllable aspect ratio and symmetry are fabricated for analysis of the mechanism of polarization anisotropy. The comparative experiments suggest that intraions transition properties and crystal local symmetry dominate the polarization anisotropy, which is also confirmed by density functional theory calculations. Taking advantage of the REs based up-conversion, potential application in polarized microscopic multi-information transportation is suggested for the polarization anisotropy from REs doped fluoride single nanorod or nanorod array.

Attendance at iron deficiency anaemia clinic: audit of outcomes 5 years on

AIM

To determine the long-term outcomes of patients in whom no initial cause for their anaemia is established.

METHOD

Six hundred and thirty-nine patients presenting to an iron deficiency anaemia pathway were prospectively entered onto a database. Initial assessment included haematological review, coeliac screen, oesophagogastroduodenoscopy and colonic imaging as per British Society of Gastroenterology guidelines. A 5-year audit of outcomes was undertaken using patient medical records and hospital laboratory databases.

RESULTS

A diagnosis was found initially in 266 (42%) patients, with 124 (19%) having a gastrointestinal (GI) luminal neoplasm, 54 (8%) of which were malignant. Twelve patients had a nonluminal or non-GI malignancy. Eighty-eight (14%) had benign upper GI bleeding and 23 (4%) had coeliac disease. One hundred and forty-three (22%) did not have confirmed iron deficiency anaemia on review of haematinics. Complete records were available for 595 (93%) patients at 5 years. Of the 373 patients in whom a cause was not initially diagnosed, 6 (2%) were ultimately diagnosed with a GI luminal malignancy and 18 (5%) with a nonluminal or non-GI malignancy. There was no difference in the incidence of malignancies between those with or without confirmed iron deficiency.

CONCLUSIONS

Most patients in whom no cause was found at initial investigation resolve on oral iron supplements. Patients with normal ferritin values had as high an incidence of GI malignancies as those with low values and should be investigated. In the over 50s if the anaemia remains after a course of iron further investigation is recommended as there is a significant incidence of both GI and non-GI pathology.

Safety and feasibility of adjunctive regadenoson injection at peak exercise during exercise myocardial perfusion imaging: The Both Exercise and Regadenoson Stress Test (BERST) trial

BACKGROUND

The data existing in the literature regarding the safety of using regadenoson with symptom-limited exercise are limited, which motivated the authors to undertake this randomized study.

METHODS

We offered patients scheduled to undergo vasodilator stress nuclear myocardial perfusion imaging the opportunity to exercise instead. Patients who failed to reach target heart rate (THR) were randomized to (1) receive regadenoson at peak exercise or (2) stop exercise and receive regadenoson at rest. Patients who reached THR received a standard Tc-99m sestamibi injection with no regadenoson.

RESULTS

200 patients were included (66% male, mean age 52.5 ± 13.6). 125 patients (62%) reached THR with exercise alone. All stress protocols were well tolerated, and there were no significant adverse events. There were no statistically significant differences in the extent of perfusion abnormalities, image quality, or rate of referral to cardiac catheterization within 60 days between the groups. In fully adjusted logistic regression models, beta-blocker use and diabetes remained significant univariate predictors of failure to reach THR (OR 0.21, 95% CI 0.1-0.5, P < .0001, OR 0.34, 95% CI 0.2-0.7, P = .004, respectively).

CONCLUSIONS

A protocol combining regadenoson at peak exercise in patients unable to reach THR with exercise is feasible, well-tolerated, and yields comparable imaging results to a standard regadenoson injection at rest. In addition, pharmacologic stress testing may be over-ordered in current clinical practice, as patients referred for such testing were often able to exercise.

Gold nanoparticle surface deposition induced quantum efficiency enhancement for Si-multi-pixel photon counters

With recent development of nanotechnology, novel devices with nanostructures arise to improve the performance of photodetectors. Here, we demonstrated that by surface decoration with gold nanoparticles on the active area, the quantum detection efficiency of a multi-pixel photon counter was increased due to surface plasmon resonance enhancement. The deposited gold nano-particles actually brought about almost the same enhancement factor for any photon-number fields. As a result, the photon-number-resolving capability of the multi-pixel photon counter was well reserved with the gold nano-particle deposition induced efficiency augment. This result provides guidance to the development of the high-efficiency photon-number-resolving detectors.

Abstract P5-19-02: Selective PI3K and dual PI3K/mTOR inhibitors enhance the efficacy of endocrine therapies in breast cancer models

Purpose: Phosphoinositide 3-kinases (PI3K) are lipid kinases that can regulate breast tumor cell growth, migration and survival. Standard of care drugs such as estrogen receptor (ER) antagonists including fulvestrant and tamoxifen, and aromatase inhibitors such as letrozole are indicated for the treatment of hormone receptor positive breast cancer. The current study is focused on investigating preclinical activity in breast cancer models, for GDC-0941, a class I PI3K inhibitor, GDC-0032, a PI3K inhibitor, and GDC-0980, a dual mTOR kinase and class I PI3K inhibitor. Investigation into PI3K inhibitor efficacy in combination with endocrine therapies is also explored.

Experimental Design: A panel of ER+ breast cancer cell lines were treated with GDC-0941, GDC-0032 and GDC-0980 either as single agents or in combination with fulvestrant or tamoxifen and assayed for cellular effects. MCF-7 cells ectopically expressing aromatase were utilized to test the efficacy of aromatase inhibitors in combination with PI3K inhibitors in vitro. In addition, human xenografts of breast cancer cell lines were employed to assess combination efficacy of PI3K inhibitors with fulvestrant and tamoxifen in vivo.

Results: Combination of GDC-0941, GDC-0032 or GDC-0980 with endocrine therapies resulted in a decrease in cellular viability and an increase in cell death. Synergy of PI3K inhibitor combinations with fulvestrant or tamoxifen was assessed using Combination Index (C.I.), and C.I. values as low as 0.1 indicated strong synergy in some contexts. Combination activity of PI3K inhibitors and letrozole was also observed in MCF7 cells expressing aromatase. In MCF-7 xenografts, the combination of GDC-0980, GDC-0032 and GDC-0941 enhanced activity of fulvestrant resulting in tumor regressions and tumor growth delay (116% tumor growth inhibition (TGI) for GDC-0980 and 91% TGI for GDC-0941 and GDC-0032). In addition, the combination of GDC-0941 or GDC-0032 with tamoxifen enhanced the efficacy of tamoxifen in vivo (83%TGI for GDC-0941 and 102%TGI for GDC-0032). Mechanism of action and biomarker studies are underway.

Conclusion: Collectively, the non-clinical efficacy data provide a strong rationale to evaluate the combination of PI3K inhibitors with anti-estrogen therapy in hormone receptor positive breast cancer.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P5-19-02.

Polarization properties of surface plasmon enhanced photoluminescence from a single Ag nanowire

Metallic nanowires are of great research interest due to their applications in surface plasmon polariton coupling of light. The efficiency is much dependent on the polarization of the light due to the phase matching requirement in the light-surface plasmon polariton coupling. By scanning confocal microscope, the photoluminescence from a single Ag nanowire was demonstrated strongly dependent on the excitation laser polarization, showing good consistency with the theoretical simulation. Meanwhile strong avalanche photoluminescence from a single Ag nanowire was observed when the excitation laser was polarized along the long axis of the Ag nanowire. The photoluminescence emission exhibited a polarization-sensitive spatial distribution. This may stimulate promising applications in designing polarization-controllable nanoscale plasmonic devices.

Xanthones from mangosteen extracts as natural chemopreventive agents: potential anticancer drugs

Despite decades of research, the treatment and management of malignant tumors still remain a formidable challenge for public health. New strategies for cancer treatment are being developed, and one of the most promising treatment strategies involves the application of chemopreventive agents. The search for novel and effective cancer chemopreventive agents has led to the identification of various naturally occurring compounds. Xanthones, from the pericarp, whole fruit, heartwood, and leaf of mangosteen (Garcinia mangostana Linn., GML), are known to possess a wide spectrum of pharmacologic properties, including antioxidant, anti- tumor, anti-allergic, anti-inflammatory, anti-bacterial, anti-fungal, and anti-viral activities. The potential chemopreventive and chemotherapeutic activities of xanthones have been demonstrated in different stages of carcinogenesis (initiation, promotion, and progression) and are known to control cell division and growth, apoptosis, inflammation, and metastasis. Multiple lines of evidence from numerous in vitro and in vivo studies have confirmed that xanthones inhibit proliferation of a wide range of human tumor cell types by modulating various targets and signaling transduction pathways. Here we provide a concise and comprehensive review of preclinical data and assess the observed anticancer effects of xanthones, supporting its remarkable potential as an anticancer agent.

Anti-cancer activities of tea epigallocatechin-3-gallate in breast cancer patients under radiotherapy

The purpose of this study was to test the hypothesis that administration of epigallocatechin-3-gallate (EGCG), a polyphenol present in abundance in widely consumed tea, inhibits cell proliferation, invasion, and angiogenesis in breast cancer patients. EGCG in 400 mg capsules was orally administered three times daily to breast cancer patients undergoing treatment with radiotherapy. Parameters related to cell proliferation, invasion, and angiogenesis were analyzed while blood samples were collected at different time points to determine efficacy of the EGCG treatment. Compared to patients who received radiotherapy alone, those given radiotherapy plus EGCG for an extended time period (two to eight weeks) showed significantly lower serum levels of vascular endothelial growth factor (VEGF), hepatocyte growth factor (HGF), and reduced activation of metalloproteinase-9 and metalloproteinase-2 (MMP9/MMP2). Addition of sera obtained from patients treated with combination of radiotherapy and EGCG feeding for 2-8 weeks to in vitro cultures of highly-metastatic human MDA-MB-231 breast cancer cells resulted in the following significant changes: (1) suppression of cell proliferation and invasion; (2) arrest of cell cycles at the G0/G1 phase; (3) reduction of activation of MMP9/MMP2, expressions of Bcl-2/Bax, c-Met receptor, NF-κB, and the phosphorylation of Akt. MDA-MB-231 cells exposed to 5-10 µM EGCG also showed significant augmentation of the apoptosis inducing effects of γ-radiation, concomitant with reduced NF-κB protein level and AKT phosphorylation. These results provide hitherto unreported evidence that EGCG potentiated efficacy of radiotherapy in breast cancer patients, and raise the possibility that this tea polyphenol has potential to be a therapeutic adjuvant against human metastatic breast cancer.