Frequency stability characterization of a broadband fiber Fabry-Perot interferometer

An optical etalon illuminated by a white light source provides a broadband comb-like spectrum that can be employed as a calibration source for astronomical spectrographs in radial velocity (RV) surveys for extrasolar planets. For this application the frequency stability of the etalon is critical, as its transmission spectrum is susceptible to frequency fluctuations due to changes in cavity temperature, optical power and input polarization. In this paper we present a laser frequency comb measurement technique to characterize the frequency stability of a custom-designed fiber Fabry-Perot interferometer (FFP). Simultaneously probing the stability of two etalon resonance modes, we assess both the absolute stability of the etalon and the long-term stability of the cavity dispersion. We measure mode positions with MHz precision, which corresponds to splitting the FFP resonances by a part in 500 and to RV precision of ~1 m/s. We address limiting systematic effects, including the presence of parasitic etalons, that need to be overcome to push the metrology of this system to the equivalent RV precision of 10 cm/s. Our results demonstrate a means to characterize environmentally-driven perturbations of etalon resonance modes across broad spectral bandwidths, as well as motivate the benefits and challenges of FFPs as spectrograph calibrators.Comment: 15 pages, 9 figures, accepted to Opt. Expres

Between HIV diagnosis and initiation of antiretroviral therapy: Assessing the effectiveness of care for people living with HIV in the public primary care service in Cape Town, South Africa

BACKGROUND: While much is written about the scale up of HIV counselling and testing (HCT) and antiretroviral therapy (ART), little research has been done on the expansion of routine preART HIV care. OBJECTIVE: To assess the quality of preART care in Cape Town and its continuity with HCT and ART. METHODS: The scale up of the HCT, preART and ART service platform and programmatic support in Cape Town is described. Data from the August 2010 routine annual HIV/TB/STI evaluation, from interviews with 133 facility managers and a folder review of 634 HCT s who tested positive and 1115 clients receiving preART HIV care are analysed. RESULTS: Historically the implementation and management of preART care has been relatively neglected compared with the scale-up of HCT and ART. The CD4 count was done on 77.5% positive HCT clients and 46.6% were clinically staged - crucial steps that determine the care path. There were: gaps in quality of care - 32.2% of women had a PAP smear; missed opportunities for integrated care - 67% were symptomatically screened for tuberculosis; and positive prevention - 48.3% had contraceptive needs assessed. Breaks in the continuity of care of preART clients occurred with only 47.2% of eligible clients referred appropriately to the ARV service. CONCLUSION: While a package of preART care has been clearly defined in Cape Town, it has not been fully implemented. There are weaknesses in the continuity and quality service delivered that undermine the programme objectives of provision of positive prevention and timeous access to ART

Surgical trial of novel pro-angiogenic compounds that may accelerate wound healing

Chronic wounds and wounds that are difficult to heal are a major concern for Australian healthcare expenditure and a source of misery for those who suffer from them. For example, in Australia in 2012, there were an estimated 433,000 people suffering from these, costing an estimated AUD2.6 billion dollars for the year to July. Novel ways of healing wounds are continually being sought. Two strategies used to accelerate wound healing are augmenting angiogenesis and through manipulation of wound healing growth factors. The method of stimulating angiogenesis proposed in this research was through the use of a topically applied flavonoid or lignan molecule. Two compounds in particular, the lignan erythro-guaiacylglycerol-8-O-4’-coniferyl alcohol (T1) and the flavonoid naringenin, have demonstrated pro-angiogenic activity based on in vitro testing but they had not been trialled previously in vivo. C57BL/6J mice were used in techniques building on previous studies. Wounds were created with a control, positive control, and T1 and naringenin topically applied at varying concentrations. The compounds tested were applied at 3-day intervals, aiming for wound healing within 12 days. A second group was used to analyse the wounds and compounds trialled at day 3 after wounding, the day of maximal angiogenesis. The wounds were recorded and measured using pictorial and digital-image analysis. Results showed that both the flavonoid (naringenin) and the lignan (T1) when applied to wounds actually increased the size of the wounds and the length of time required for the wounds to heal. Subsequent histological analysis revealed that wounds treated with both T1 and naringenin, although not healing faster, produced higher amounts of granulation tissue and collagen deposition. Based on these data it is hypothesised that the above compounds caused an excessive deposition of granulation tissue, preventing effective wound healing. Although the wounds did not heal effectively, the results obtained from this study may be useful when applied to wounds that are difficult and slow to heal, such as diabetic ulcers. In conclusion, further studies are required to confirm that these novel compounds increase angiogenesis, granulation tissue and collagen deposition within wounds. If so, new studies to find optimal dosage and application regimes may provide useful approaches to accelerating wound healing in the future

Immune activation by combination human lymphokine-activated killer and dendritic cell therapy.

BACKGROUND: Optimal cellular immunotherapy for cancer should ideally harness both the innate and adaptive arms of the immune response. Lymphokine-activated killer cells (LAKs) can trigger early innate killing of tumour targets, whereas long-term adaptive-specific tumour control requires priming of CD8+ cytotoxic lymphocytes (CTLs) following acquisition of tumour-associated antigens (TAAs) by antigen-presenting cells such as dendritic cells (DCs). As DCs stimulate both innate and adaptive effectors, combination cell therapy using LAKs and DCs has the potential to maximise anti-tumour immune priming. METHODS: Reciprocal activation between human clinical grade LAKs and DCs on co-culture, and its immune consequences, was monitored by cell phenotype, cytokine release and priming of both innate and adaptive cytotoxicity against melanoma targets. RESULTS: Co-culture of DCs and LAKs led to phenotypic activation of natural killer (NK) cells within the LAK population, which was associated with increased production of inflammatory cytokines and enhanced innate cytotoxicity against tumour cell targets. The LAKs reciprocally matured DCs, and the combination of LAKs and DCs, on addition of melanoma cells, supported priming of specific anti-tumour CTLs better than DCs alone. CONCLUSION: Clinical-grade LAKs/DCs represents a practical, effective combination cell immunotherapy for stimulation of both innate and adaptive anti-tumour immunity in cancer patients

Photosynthesis and Cellular Respiration (LS1): A Hands-On Approach Supporting the NGSS and ELA CCSS

We will combine hands-on science investigations with supporting literacy activities to help students build conceptual models of photosynthesis

The Anoikis Effector Bit1 Displays Tumor Suppressive Function in Lung Cancer Cells.

The mitochondrial Bit1 (Bcl-2 inhibitor of transcription 1) protein is a part of an apoptotic pathway that is uniquely regulated by integrin-mediated attachment. As an anoikis effector, Bit1 is released into the cytoplasm following loss of cell attachment and induces a caspase-independent form of apoptosis. Considering that anoikis resistance is a critical determinant of transformation, we hypothesized that cancer cells may circumvent the Bit1 apoptotic pathway to attain anchorageindependence and tumorigenic potential. Here, we provide the first evidence of the tumor suppressive effect of Bit1 through a mechanism involving anoikis induction in human lung adenocarcinoma derived A549 cells. Restitution of Bit1 in anoikis resistant A549 cells is sufficient to induce detachment induced-apoptosis despite defect in caspase activation and impairs their anchorage-independent growth. Conversely, stable downregulation of Bit1 in these cells significantly enhances their anoikis resistance and anchorage-independent growth. The Bit1 knockdown cells exhibit significantly enhanced tumorigenecity in vivo. It has been previously shown that the nuclear TLE1 corepressor is a putative oncogene in lung cancer, and we show here that TLE1 blocks Bit1 mediated anoikis in part by sequestering the pro-apoptotic partner of Bit1, the Amino-terminal Enhancer of Split (AES) protein, in the nucleus. Taken together, these findings suggest a tumor suppressive role of the caspase-independent anoikis effector Bit1 in lung cancer. Consistent with its role as a tumor suppressor, we have found that Bit1 is downregulated in human non-small cell lung cancer (NSCLC) tissues

Screening for Human Immunodeficiency Virus in Inner City Females With Abnormal Cervical Cytology

Objective: This report evaluates the acceptance, results, and predictors of human immunodeficiency virus (HIV) infection in inner city women referred to a colposcopy clinic for abnormal cervical cytology