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1.
Opt Express ; 28(3): 3280-3288, 2020 Feb 03.
Article in English | MEDLINE | ID: mdl-32122000

ABSTRACT

We present and characterize a narrow-linewidth external-cavity diode laser at 2 µm, and show that it represents a low-cost, high-performance alternative to fiber lasers for research into 2 µm photonic technologies for next-generation gravitational-wave detectors. A linewidth of 20 kHz for a 10 ms integration time was measured without any active stabilization, with frequency noise of ∼ 15 Hz/Hz between 3 kHz and 100 kHz. This performance is suitable for the generation of quantum squeezed light, and we measure intensity noise comparable to that of master oscillators used in current gravitational wave interferometers. The laser wavelength is tunable over a 120 nm range, and both the frequency and intensity can be modulated at up to 10 MHz by modulating the diode current. These features also make it suitable for other emerging applications in the 2 µm wavelength region including gas sensing, optical communications and LIDAR.

2.
Phys Rev Lett ; 123(23): 231107, 2019 Dec 06.
Article in English | MEDLINE | ID: mdl-31868462

ABSTRACT

The Laser Interferometer Gravitational Wave Observatory (LIGO) has been directly detecting gravitational waves from compact binary mergers since 2015. We report on the first use of squeezed vacuum states in the direct measurement of gravitational waves with the Advanced LIGO H1 and L1 detectors. This achievement is the culmination of decades of research to implement squeezed states in gravitational-wave detectors. During the ongoing O3 observation run, squeezed states are improving the sensitivity of the LIGO interferometers to signals above 50 Hz by up to 3 dB, thereby increasing the expected detection rate by 40% (H1) and 50% (L1).

3.
Opt Lett ; 44(21): 5386-5389, 2019 Nov 01.
Article in English | MEDLINE | ID: mdl-31675014

ABSTRACT

We demonstrate phase control for vacuum-squeezed light at a 2 µm wavelength, which is a necessary technology for proposed future gravitational wave observatories. The control scheme allowed examination of noise behavior at frequencies below 1 kHz and indicated that squeezing below this frequency was limited by dark noise and scattered light. We directly measure 3.9±0.2 dB of squeezing from 2 kHz to 80 kHz and 14.2±0.3 dB of antisqueezing relative to the shot noise level. The observed maximum level of squeezing is currently limited by photodetector quantum efficiency and laser instabilities at this new wavelength for squeezed light. Accounting for all losses, we conclude the generation of 11.3 dB of squeezing at the optical parametric oscillator.

4.
Cancer Epidemiol ; 61: 1-7, 2019 08.
Article in English | MEDLINE | ID: mdl-31082704

ABSTRACT

BACKGROUND: The relationship between comorbid disease and health service use and risk of cancer of unknown primary site (CUP) is uncertain. METHODS: A prospective cohort of 266,724 people aged 45 years and over in New South Wales, Australia. Baseline questionnaire data were linked to cancer registration, health service records 4-27 months prior to diagnosis, and mortality data. We compared individuals with incident registry-notified CUP (n = 327; 90% C80) to two sets of randomly selected controls (3:1): (i) incident metastatic cancer of known primary site (n = 977) and (ii) general cohort population (n = 981). We used conditional logistic regression to estimate adjusted odds ratios (ORs) and 95% confidence intervals (CIs). RESULTS: In fully adjusted models incorporating sociodemographic and lifestyle factors, people with cancer registry-notified CUP were more likely to have fair compared with excellent self-rated overall health (OR 1.78, 95% CI 1.01-3.14) and less likely to self-report anxiety (OR 0.48, 95% CI 0.24-0.97) than those registered with metastatic cancer of known primary. Compared to general cohort population controls, people registered with CUP were more likely to have poor rather than excellent self-rated overall health (OR 6.22, 95% CI 1.35-28.6), less likely to self-report anxiety (OR 0.28, 95% CI 0.12-0.63), and more likely to have a history of diabetes (OR 1.89, 95% CI 1.15-3.10) or cancer (OR 1.62, 95% CI 1.03-2.57). Neither tertiary nor community-based health service use independently predicted CUP risk. CONCLUSION: Low self-rated health may be a flag for undiagnosed cancer, and an investigation of its clinical utility in primary care appears warranted.


Subject(s)
Neoplasms, Unknown Primary/epidemiology , Cohort Studies , Female , Humans , Male , Middle Aged , Prospective Studies
5.
Cancer Epidemiol ; 60: 156-161, 2019 06.
Article in English | MEDLINE | ID: mdl-31015097

ABSTRACT

BACKGROUND: Little is known about the risk factors for cancer of unknown primary site (CUP). We examined the demographic, social and lifestyle risk factors for CUP in a prospective cohort of 266,724 people aged 45 years and over in New South Wales, Australia. METHODS: Baseline questionnaire data were linked to cancer registration, hospitalisation, emergency department admission, and mortality data. We compared individuals with incident cancer registry-notified CUP (n = 327) to two sets of controls randomly selected (3:1) using incidence density sampling with replacement: (i) incident cancer registry-notified metastatic cancer of known primary site (n = 977) and (ii) general cohort population (n = 981). We used conditional logistic regression to estimate adjusted odds ratios (ORs) and 95% confidence intervals (CIs). RESULTS: In a fully adjusted model incorporating self-rated overall health and comorbidity, people diagnosed with CUP were more likely to be older (OR 1.05, 95% CI 1.04-1.07 per year) and more likely to have low educational attainment (OR 1.77, 95% CI 1.24-2.53) than those diagnosed with metastatic cancer of known primary. Similarly, compared to general cohort population controls, people diagnosed with CUP were older (OR 1.10, 95% CI 1.08-1.12 per year), of low educational attainment (OR 1.69, 95% CI 1.08-2.64), and current (OR 3.42, 95% CI 1.81-6.47) or former (OR 1.95, 95% CI 1.33-2.86) smokers. CONCLUSION: The consistent association with educational attainment suggests low health literacy may play a role in CUP diagnosis. These findings highlight the need to develop strategies to achieve earlier identification of diagnostically challenging malignancies in people with low health literacy.


Subject(s)
Neoplasms, Unknown Primary/epidemiology , Aged , Aged, 80 and over , Cohort Studies , Demography , Female , Humans , Life Style , Male , Prospective Studies , Registries , Risk Factors , Social Behavior
6.
Biomark Res ; 6: 37, 2018.
Article in English | MEDLINE | ID: mdl-30619609

ABSTRACT

BACKGROUND: Altered mitochondrial function and large-scale changes to DNA methylation patterns in the nuclear genome are both hallmarks of colorectal cancer (CRC). Mitochondria have multiple copies of a 16 kb circular genome that contains genes that are vital for their function. While DNA methylation is known to alter the nuclear genome in CRC, it is not clear whether it could have a similar influence in mtDNA; indeed, currently, the issue of whether mitochondrial genome (mtDNA) methylation occurs is controversial. Thus our goal here was to determine whether the methylation state of mtDNA is linked to mitochondrial gene transcription in colorectal adenomas, and to assess its suitability as a biomarker in CRC. METHODS: To investigate the relationship between DNA methylation and mitochondrial transcripts in adenomas, we performed RNA-sequencing and Whole Genome Bisulphite Sequencing (WGBS) of mtDNA-enriched DNA from normal mucosa and paired adenoma patient samples. RESULTS: Transcriptional profiling indicated that adenomas had reduced mitochondrial proton transport versus normal mucosa, consistent with altered mitochondrial function. The expression of 3 tRNAs that are transcribed from mtDNA were also decreased in adenoma. Overall methylation of CG dinucleotides in the nuclear genome was reduced in adenomas (68%) compared to normal mucosa (75%, P < 0.01). Methylation in mtDNA was low (1%) in both normal and adenoma tissue but we observed clusters of higher methylation at the ribosomal RNA genes. Levels of methylation within these regions did not differ between normal and adenoma tissue. CONCLUSIONS: We provide evidence that low-level methylation of specific sites does exist in the mitochondrial genome but that it is not associated with mitochondrial gene transcription changes in adenomas. Furthermore, as no large scale changes to mtDNA methylation were observed it is unlikely to be a suitable biomarker for early-stage CRC.

7.
Sci Rep ; 7(1): 14546, 2017 11 06.
Article in English | MEDLINE | ID: mdl-29109531

ABSTRACT

Precise optical control of microscopic particles has been mastered over the past three decades, with atoms, molecules and nano-particles now routinely trapped and cooled with extraordinary precision, enabling rapid progress in the study of quantum phenomena. Achieving the same level of control over macroscopic objects is expected to bring further advances in precision measurement, quantum information processing and fundamental tests of quantum mechanics. However, cavity optomechanical systems dominated by radiation pressure - so-called 'optical springs' - are inherently unstable due to the delayed dynamical response of the cavity. Here we demonstrate a fully stable, single-beam optical trap for a gram-scale mechanical oscillator. The interaction of radiation pressure with thermo-optic feedback generates damping that exceeds the mechanical loss by four orders of magnitude. The stability of the resultant spring is robust to changes in laser power and detuning, and allows purely passive self-locking of the cavity. Our results open up a new way of trapping and cooling macroscopic objects for optomechanical experiments.

8.
Ann Oncol ; 28(5): 1145-1151, 2017 May 01.
Article in English | MEDLINE | ID: mdl-28453708

ABSTRACT

BACKGROUND: While next generation sequencing has enhanced our understanding of the biological basis of malignancy, current knowledge on global practices for sequencing cancer samples is limited. To address this deficiency, we developed a survey to provide a snapshot of current sequencing activities globally, identify barriers to data sharing and use this information to develop sustainable solutions for the cancer research community. METHODS: A multi-item survey was conducted assessing demographics, clinical data collection, genomic platforms, privacy/ethics concerns, funding sources and data sharing barriers for sequencing initiatives globally. Additionally, respondents were asked as to provide the primary intent of their initiative (clinical diagnostic, research or combination). RESULTS: Of 107 initiatives invited to participate, 59 responded (response rate = 55%). Whole exome sequencing (P = 0.03) and whole genome sequencing (P = 0.01) were utilized less frequently in clinical diagnostic than in research initiatives. Procedures to identify cancer-specific variants were heterogeneous, with bioinformatics pipelines employing different mutation calling/variant annotation algorithms. Measurement of treatment efficacy varied amongst initiatives, with time on treatment (57%) and RECIST (53%) being the most common; however, other parameters were also employed. Whilst 72% of initiatives indicated data sharing, its scope varied, with a number of restrictions in place (e.g. transfer of raw data). The largest perceived barriers to data harmonization were the lack of financial support (P < 0.01) and bioinformatics concerns (e.g. lack of interoperability) (P = 0.02). Capturing clinical data was more likely to be perceived as a barrier to data sharing by larger initiatives than by smaller initiatives (P = 0.01). CONCLUSIONS: These results identify the main barriers, as perceived by the cancer sequencing community, to effective sharing of cancer genomic and clinical data. They highlight the need for greater harmonization of technical, ethical and data capture processes in cancer sample sequencing worldwide, in order to support effective and responsible data sharing for the benefit of patients.


Subject(s)
Genetic Association Studies , Neoplasms/genetics , DNA Mutational Analysis , Databases, Genetic , Genetic Predisposition to Disease , Genome, Human , Humans , Molecular Sequence Annotation , Surveys and Questionnaires , Exome Sequencing
9.
Rev Sci Instrum ; 87(6): 063104, 2016 Jun.
Article in English | MEDLINE | ID: mdl-27370423

ABSTRACT

With the recent detection of gravitational waves, non-classical light sources are likely to become an essential element of future detectors engaged in gravitational wave astronomy and cosmology. Operating a squeezed light source under high vacuum has the advantages of reducing optical losses and phase noise compared to techniques where the squeezed light is introduced from outside the vacuum. This will ultimately provide enhanced sensitivity for modern interferometric gravitational wave detectors that will soon become limited by quantum noise across much of the detection bandwidth. Here we describe the optomechanical design choices and construction techniques of a near monolithic glass optical parametric oscillator that has been operated under a vacuum of 10(-6) mbar. The optical parametric oscillator described here has been shown to produce 8.6 dB of quadrature squeezed light in the audio frequency band down to 10 Hz. This performance has been maintained for periods of around an hour and the system has been under vacuum continuously for several months without a degradation of this performance.

10.
Oncogene ; 35(19): 2475-84, 2016 05 12.
Article in English | MEDLINE | ID: mdl-26300002

ABSTRACT

Transcription factor Myb is overexpressed in most colorectal cancers (CRC). Patients with CRC expressing the highest Myb are more likely to relapse. We previously showed that mono-allelic loss of Myb in an Adenomatous polyposis coli (APC)-driven CRC mouse model (Apc(Min/+)) significantly improves survival. Here we directly investigated the association of Myb with poor prognosis and how Myb co-operates with tumor suppressor genes (TSGs) (Apc) and cell cycle regulator, p27. Here we generated the first intestinal-specific, inducible transgenic model; a MybER transgene encoding a tamoxifen-inducible fusion protein between Myb and the estrogen receptor-α ligand-binding domain driven by the intestinal-specific promoter, Gpa33. This was to mimic human CRC with constitutive Myb activity in a highly tractable mouse model. We confirmed that the transgene was faithfully expressed and inducible in intestinal stem cells (ISCs) before embarking on carcinogenesis studies. Activation of the MybER did not change colon homeostasis unless one p27 allele was lost. We then established that MybER activation during CRC initiation using a pro-carcinogen treatment, azoxymethane (AOM), augmented most measured aspects of ISC gene expression and function and accelerated tumorigenesis in mice. CRC-associated symptoms of patients including intestinal bleeding and anaemia were faithfully mimicked in AOM-treated MybER transgenic mice and implicated hypoxia and vessel leakage identifying an additional pathogenic role for Myb. Collectively, the results suggest that Myb expands the ISC pool within which CRC is initiated while co-operating with TSG loss. Myb further exacerbates CRC pathology partly explaining why high MYB is a predictor of worse patient outcome.


Subject(s)
Carcinogenesis , Colonic Neoplasms/metabolism , Colonic Neoplasms/pathology , Intestinal Mucosa/metabolism , Intestines/pathology , Proto-Oncogene Proteins c-myb/metabolism , Animals , Colonic Neoplasms/genetics , Gene Expression Regulation, Neoplastic , Genes, Tumor Suppressor , Mice , Mice, Transgenic , Organ Specificity , Stem Cells/pathology , Tumor Hypoxia , Vascular Endothelial Growth Factor A/genetics
11.
J Phys Condens Matter ; 27(16): 164202, 2015 Apr 29.
Article in English | MEDLINE | ID: mdl-25835029

ABSTRACT

Energy relaxation of hot Dirac fermions in bilayer epitaxial graphene is experimentally investigated by magnetotransport measurements on Shubnikov-de Haas oscillations and weak localization. The hot-electron energy loss rate is found to follow the predicted Bloch-Grüneisen power-law behaviour of T(4) at carrier temperatures from 1.4 K up to ∼100 K, due to electron-acoustic phonon interactions with a deformation potential coupling constant of 22 eV. A carrier density dependence n(e)(-1.5) in the scaling of the T(4) power law is observed in bilayer graphene, in contrast to the n(e)(-0.5) dependence in monolayer graphene, leading to a crossover in the energy loss rate as a function of carrier density between these two systems. The electron-phonon relaxation time in bilayer graphene is also shown to be strongly carrier density dependent, while it remains constant for a wide range of carrier densities in monolayer graphene. Our results and comparisons between the bilayer and monolayer exhibit a more comprehensive picture of hot carrier dynamics in graphene systems.

12.
J Cancer Res Clin Oncol ; 141(2): 243-54, 2015 Feb.
Article in English | MEDLINE | ID: mdl-25209439

ABSTRACT

PURPOSE: Wnt signalling has been implicated in breast cancer, and in particular aberrant ß-catenin-independent Wnt signalling has been associated with breast cancer metastasis and Tamoxifen resistance. Despite Wnt pathway involvement in many human cancers, attempts to target the pathway therapeutically have been disappointing. The recent discovery that the receptor tyrosine kinase-like orphan receptor 2 (ROR2) is a novel Wnt receptor provides a potential new therapeutic and diagnostic target. METHODS: To clarify the role of ROR2 in breast cancer, we investigated its expression via ROR2 immunohistochemistry in a clinical cohort of breast cancer patients, and via in vitro studies incorporating both overexpression and knock-down of ROR2. RESULTS: ROR2 was expressed in the majority of breast cancer patients (87%), including those classed as triple negative. Breast cancer patients expressing ROR2 had a significantly shorter overall survival than those lacking ROR2 expression (P < 0.05). Overexpression of ROR2 in the mammary epithelial cell line, MCF10A, increased both ß-catenin-dependent and ß-catenin-independent targets and decreased cell adhesion. Knock-down of ROR2 in the breast cancer cell lines, MDA-MB-453 and HCC1143, decreased both ß-catenin-dependent and ß-catenin-independent targets and increased cell adhesion. Treatment of ROR2-expressing breast cancer cells with the novel berberine derivative, NAX53, significantly inhibited cell proliferation and migration. CONCLUSIONS: This is the first study to report the expression of ROR2 in breast cancer. Breast cancer patients expressing ROR2 had a significantly worse prognosis than those lacking ROR2. ROR2 may regulate both ß-catenin-dependent and ß-catenin-independent Wnt signalling pathways, and represents a potential diagnostic and therapeutic target.


Subject(s)
Gene Expression Regulation, Neoplastic , Receptor Tyrosine Kinase-like Orphan Receptors/metabolism , Signal Transduction , Triple Negative Breast Neoplasms/metabolism , Wnt Proteins/metabolism , beta Catenin/metabolism , Apoptosis , Blotting, Western , Breast/cytology , Breast/metabolism , Cell Adhesion , Cell Movement , Cell Proliferation , Cells, Cultured , Cohort Studies , Female , Follow-Up Studies , Humans , Immunoenzyme Techniques , Neoplasm Invasiveness , Neoplasm Staging , Prognosis , RNA, Messenger/genetics , Real-Time Polymerase Chain Reaction , Receptor Tyrosine Kinase-like Orphan Receptors/genetics , Reverse Transcriptase Polymerase Chain Reaction , Survival Rate , Tissue Array Analysis , Triple Negative Breast Neoplasms/mortality , Triple Negative Breast Neoplasms/pathology , Wnt Proteins/genetics , beta Catenin/genetics
13.
Gynecol Oncol ; 134(2): 338-45, 2014 Aug.
Article in English | MEDLINE | ID: mdl-24924122

ABSTRACT

OBJECTIVE: Aberrant Wnt signalling has previously been associated with gynaecological cancers, and the aim of this study was to investigate the expression of Wnt5a in epithelial ovarian cancer, and clarify its role in activating or inhibiting ß-catenin dependent and independent Wnt signalling pathways. METHOD: Wnt5a expression was investigated in a large cohort of epithelial ovarian cancer patient samples using immunohistochemistry and correlated with clinicopathological variables. Wnt5a function was investigated in vitro in ovarian cell lines. RESULTS: Wnt5a expression was found to be upregulated in all major subtypes (serous, endometrioid, clear cell and mucinous) of epithelial ovarian cancer compared to borderline tumours and benign controls. Treatment of ovarian surface epithelial cells with recombinant Wnt5a decreased cell adhesion and was associated with increased epithelial to mesenchymal transition (EMT). In addition, downstream targets of ß-catenin dependent Wnt signalling were inhibited, and ß-catenin independent targets increased following Wnt5a upregulation. Knockdown of Wnt5a in ovarian cancer cells was associated with a mesenchymal to epithelial transition (MET), but had no significant effect on cell migration or proliferation. CONCLUSION: This study adds to the increasing evidence that Wnt signalling may play an important role in ovarian cancer development. Utilising an unparalleled large cohort of 623 patients, Wnt5a protein expression was shown to be significantly higher in ovarian cancer patients when compared to benign and borderline ovarian tumours and healthy control patients. In addition, we have utilised in vitro models to show for the first time in ovarian cancer that Wnt5a driven non-canonical pathways can alter epithelial to mesenchymal transition (EMT).


Subject(s)
Epithelial-Mesenchymal Transition , Neoplasms, Glandular and Epithelial/etiology , Ovarian Neoplasms/etiology , Proto-Oncogene Proteins/biosynthesis , Up-Regulation , Wnt Proteins/biosynthesis , Carcinoma, Ovarian Epithelial , Female , Humans , Signal Transduction , Tumor Cells, Cultured , Wnt-5a Protein
14.
Br J Cancer ; 110(6): 1606-13, 2014 Mar 18.
Article in English | MEDLINE | ID: mdl-24548858

ABSTRACT

BACKGROUND: RAD21 is a component of the cohesion complex and is integral to chromosome segregation and error-free DNA repair. RAD21 is functionally important in tumour progression but its role in colorectal carcinoma (CRC) is unclear. We therefore assessed its clinicopathological and prognostic significance in CRC, as well as its effect on chemosensitivity. METHODS: A retrospective observation study examined RAD21 expression in 652 CRCs using a tissue microarray approach. Correlation with clinicopathological factors including gender, tumour grade, mucinous subtype, TNM stage, disease-specific survival (DSS), BRAF and KRAS mutation status, tumour p53 immunostaining, tumour microsatellite instability and tumour CpG island methylator phenotype was performed. Colorectal cancer cell clones with stable RAD21 knockdown were generated and tested for cellular sensitivity to conventional chemotherapeutic drugs. RESULTS: RAD21 expression was significantly correlated with male gender (56.7% vs 43.3%, P=0.02), well-differentiated histology (14.4% vs 4.0%, P=0.0001), higher T-stage (36.1% vs 27.0%, P=0.01), presence of metastasis (18.8% vs 12.6%, P=0.03), and shorter DSS (hazard ratio (HR) 1.4, 95% CI 1.1 to 1.9, P=0.01) in both univariate and multivariate analysis. RAD21 expression was associated with shorter DSS in patients with KRAS mutant tumours (HR:2.6, 95% CI:1.4-4.3, P=0.001) and in patients receiving adjuvant chemoradiotherapy (HR:1.9, 95% CI:1.2-3.0, P=0.008). Colorectal cancer cells with RAD21 knockdown exhibited enhanced sensitivity to 5-fluorouracil, either alone or in combination with oxaliplatin. CONCLUSIONS: RAD21 expression in CRC is associated with aggressive disease especially in KRAS mutant tumours and resistance to chemoradiotherapy. RAD21 may be an important novel therapeutic target.


Subject(s)
Biomarkers, Tumor/biosynthesis , Colorectal Neoplasms/genetics , Colorectal Neoplasms/metabolism , Mutation , Nuclear Proteins/biosynthesis , Phosphoproteins/biosynthesis , Proto-Oncogene Proteins/genetics , ras Proteins/genetics , Adult , Aged , Aged, 80 and over , Biomarkers, Tumor/genetics , Cell Cycle Proteins , Colorectal Neoplasms/pathology , DNA-Binding Proteins , Female , Humans , Male , Middle Aged , Neoplasm Staging , Nuclear Proteins/genetics , Phosphoproteins/genetics , Prognosis , Proto-Oncogene Proteins p21(ras) , Retrospective Studies , Sex Factors , Tissue Array Analysis
15.
Phys Rev Lett ; 111(7): 077402, 2013 Aug 16.
Article in English | MEDLINE | ID: mdl-23992081

ABSTRACT

We report on the polarization selection rules of inter-Landau-level transitions using reflection-type optical Hall effect measurements from 600 to 4000 cm(-1) on epitaxial graphene grown by thermal decomposition of silicon carbide. We observe symmetric and antisymmetric signatures in our data due to polarization preserving and polarization mixing inter-Landau-level transitions, respectively. From field-dependent measurements, we identify that transitions in coupled graphene monolayers are governed by polarization mixing selection rules, whereas transitions in decoupled graphene monolayers are governed by polarization preserving selection rules. The selection rules may find explanation by different coupling mechanisms of inter-Landau-level transitions with free charge carrier magneto-optic plasma oscillations.

16.
Oncogene ; 32(39): 4675-82, 2013 Sep 26.
Article in English | MEDLINE | ID: mdl-23085758

ABSTRACT

Biallelic protein-truncating mutations in the adenomatous polyposis coli (APC) gene are prevalent in sporadic colorectal cancer (CRC). Mutations may not be fully inactivating, instead producing WNT/ß-catenin signalling levels 'just-right' for tumourigenesis. However, the spectrum of optimal APC genotypes accounting for both hits, and the influence of clinicopathological features on genotype selection remain undefined. We analysed 630 sporadic CRCs for APC mutations and loss of heterozygosity (LOH) using sequencing and single-nucleotide polymorphism microarrays, respectively. Truncating APC mutations and/or LOH were detected in 75% of CRCs. Most truncating mutations occurred within a mutation cluster region (MCR; codons 1282-1581) leaving 1-3 intact 20 amino-acid repeats (20AARs) and abolishing all Ser-Ala-Met-Pro (SAMP) repeats. Cancers commonly had one MCR mutation plus either LOH or another mutation 5' to the MCR. LOH was associated with mutations leaving 1 intact 20AAR. MCR mutations leaving 1 vs 2-3 intact 20AARs were associated with 5' mutations disrupting or leaving intact the armadillo-repeat domain, respectively. Cancers with three hits had an over-representation of mutations upstream of codon 184, in the alternatively spliced region of exon 9, and 3' to the MCR. Microsatellite unstable cancers showed hyper-mutation at MCR mono- and di-nucleotide repeats, leaving 2-3 intact 20AARs. Proximal and distal cancers exhibited different preferred APC genotypes, leaving a total of 2 or 3 and 0 to 2 intact 20AARs, respectively. In conclusion, APC genotypes in sporadic CRCs demonstrate 'fine-tuned' interdependence of hits by type and location, consistent with selection for particular residual levels of WNT/ß-catenin signalling, with different 'optimal' thresholds for proximal and distal cancers.


Subject(s)
Adenomatous Polyposis Coli/genetics , Cell Transformation, Neoplastic/genetics , Colorectal Neoplasms/genetics , Genes, APC , Wnt Signaling Pathway , Adult , Aged , Aged, 80 and over , Codon/genetics , Colonic Neoplasms/genetics , Colonic Neoplasms/pathology , Colorectal Neoplasms/pathology , Female , Genotype , Humans , Loss of Heterozygosity , Male , Microsatellite Instability , Middle Aged , Mutation , Organ Specificity , Rectal Neoplasms/genetics , Rectal Neoplasms/pathology , Sequence Deletion , Sigmoid Neoplasms/genetics , Sigmoid Neoplasms/pathology , Wnt Signaling Pathway/genetics
17.
Nano Lett ; 12(4): 1749-56, 2012 Apr 11.
Article in English | MEDLINE | ID: mdl-22352833

ABSTRACT

We demonstrate the first successful growth of large-area (200 × 200 µm(2)) bilayer, Bernal stacked, epitaxial graphene (EG) on atomically flat, 4H-SiC (0001) step-free mesas (SFMs) . The use of SFMs for the growth of graphene resulted in the complete elimination of surface step-bunching typically found after EG growth on conventional nominally on-axis SiC (0001) substrates. As a result heights of EG surface features are reduced by at least a factor of 50 from the heights found on conventional substrates. Evaluation of the EG across the SFM using the Raman 2D mode indicates Bernal stacking with low and uniform compressive lattice strain of only 0.05%. The uniformity of this strain is significantly improved, which is about 13-fold decrease of strain found for EG grown on conventional nominally on-axis substrates. The magnitude of the strain approaches values for stress-free exfoliated graphene flakes. Hall transport measurements on large area bilayer samples taken as a function of temperature from 4.3 to 300 K revealed an n-type carrier mobility that increased from 1170 to 1730 cm(2) V(-1) s(-1), and a corresponding sheet carrier density that decreased from 5.0 × 10(12) cm(-2) to 3.26 × 10(12) cm(-2). The transport is believed to occur predominantly through the top EG layer with the bottom layer screening the top layer from the substrate. These results demonstrate that EG synthesized on large area, perfectly flat on-axis mesa surfaces can be used to produce Bernal-stacked bilayer EG having excellent uniformity and reduced strain and provides the perfect opportunity for significant advancement of epitaxial graphene electronics technology.

18.
Intern Med J ; 42(1): 57-64, 2012 Jan.
Article in English | MEDLINE | ID: mdl-20546055

ABSTRACT

BACKGROUND: EviQ is a web-based oncology protocol system launched across Australia in 2005 (http://www.eviq.org.au). We evaluated eviQ use at the point-of-care and determined the factors impacting on its uptake and routine use in the first three years of operation. METHODS: We conducted a suite of qualitative and quantitative studies with over 200 Australian oncology physicians, nurses and pharmacists working at treatment centres in diverse geographical locations. RESULTS: EviQ was part of routine care at many hospitals; however, the way in which it was used at the point-of-care varies according to clinician roles and hospital location. We identified a range of factors impacting on eviQ uptake and routine use. Infrastructure, such as availability of point-of-care computers, and formal policies endorsing eviQ are fundamental to increasing uptake. Furthermore, the level of clinical and computer experience of end-users, the attitudes and behaviour of clinicians, endorsement and promotion strategies, and level and type of eviQ education all need to be considered and managed to ensure that the system is being used to its full potential. CONCLUSION: Our findings show that the dissemination of web-based treatment protocols does not guarantee widespread use. Organisational, environmental and clinician-specific factors play a role in uptake and utilisation. The deployment of sufficient computer infrastructure, implementation of targeted training programmes and hospital policies and investment in marketing approaches are fundamental to uptake and continued use. This study highlights the value of ongoing monitoring and evaluation to ensure systems like eviQ achieve their primary purpose - reducing treatment variation and improving quality of care.


Subject(s)
Clinical Protocols , Internet , Medical Oncology/organization & administration , Point-of-Care Systems/statistics & numerical data , Attitude of Health Personnel , Attitude to Computers , Australia , Cancer Care Facilities/statistics & numerical data , Focus Groups , Health Care Surveys , Hospitals/statistics & numerical data , Humans , Interviews as Topic , Medical Staff, Hospital/psychology , Microcomputers/supply & distribution , Nursing Staff, Hospital/psychology , Oncology Service, Hospital/statistics & numerical data , Pharmacists/psychology , Program Evaluation , Quality Improvement
19.
Intern Med J ; 42(11): 1229-35, 2012 Nov.
Article in English | MEDLINE | ID: mdl-21981464

ABSTRACT

BACKGROUND: Cardiotoxicity is a concern in patients on trastuzumab therapy, and cardiac function assessment is a recommended practice. In 2006, trastuzumab was publically subsidised for human epidermal growth factor receptor-2 early stage breast cancer with a requirement for cardiac testing prior to and during treatment. AIM: To investigate the spillover effects of this requirement on testing rates in metastatic patients treated with trastuzumab where no monitoring requirements are applied. METHODS: We examined cardiac testing (echocardiography or multiple-gated acquisition scan) in 3779 women with metastatic breast cancer receiving trastuzumab between December 2001 and February 2010 and used interrupted time-series analyses to estimate changes in testing rates. The main outcome measures were the proportion of eligible patients, by quarter, receiving a cardiac function test pretreatment and during trastuzumab therapy. RESULTS: Only 21% of women had a cardiac function test pretreatment, and 47% were tested at some point during the first year of trastuzumab therapy. The introduction of mandatory cardiac testing for early breast cancer was associated with an immediate 8% increase (95% confidence interval, 2-14%) in pretreatment cardiac testing and an immediate 7% increase (95% confidence interval, 4-10%) in testing during therapy in metastatic patients. Testing rates during therapy increased steadily from early 2005, coinciding with the release of interim results from several trastuzumab trials reporting cardiac-safety outcomes. CONCLUSION: The introduction of mandatory cardiac testing for early stage disease spilled over to the metastatic setting. While deviation from guidelines may be warranted in some cases, this study suggests underutilisation of cardiac testing among patients treated with trastuzumab in the metastatic setting.


Subject(s)
Adenocarcinoma/secondary , Antibodies, Monoclonal, Humanized/adverse effects , Breast Neoplasms/drug therapy , Cardiomyopathies/chemically induced , Heart Function Tests/statistics & numerical data , Insurance, Pharmaceutical Services/legislation & jurisprudence , National Health Programs/legislation & jurisprudence , Adenocarcinoma/chemistry , Adenocarcinoma/drug therapy , Antibodies, Monoclonal, Humanized/therapeutic use , Australia , Breast Neoplasms/chemistry , Cancer Care Facilities/statistics & numerical data , Cardiomyopathies/diagnosis , Cardiomyopathies/prevention & control , Chemotherapy, Adjuvant , Drug Monitoring/methods , Echocardiography/statistics & numerical data , Female , Gated Blood-Pool Imaging/statistics & numerical data , Guideline Adherence , Humans , Molecular Targeted Therapy/adverse effects , Neoplasm Proteins/analysis , Receptor, ErbB-2/analysis , Trastuzumab
20.
Intern Med J ; 42(2): 127-31, 2012 Feb.
Article in English | MEDLINE | ID: mdl-21241439

ABSTRACT

BACKGROUND: In 2007, New South Wales Health mandated the separation of ethical and scientific review from research governance at all New South Wales public health sites based on their distinction in the National Health and Medical Research Council National Statement. This separation allowed for single-site ethical review of multicentre studies. AIMS: To investigate the time taken for governance approval of multicentre studies through the site-specific approval (SSA) process. METHODS: A retrospective audit of the SSA process for five non-interventional studies proposed by a university cancer research unit. RESULTS: The median total governance approval time for all submissions (n= 28) was 12 weeks (range 2.5-64); median time from starting the SSA to submission was 8 weeks (range 1-48) and median time for governance approval was 5 weeks (range 0.3-40). Approval times were shorter for public compared to private institutions. Reasons for delays in finalising submissions for approval were the absence of institutional governance officers, lack of clarity regarding signatories, the need to identify a principal investigator employed by the institution, and lack of recognition of ethical approval by private institutions. The need to develop legal agreements between the university and hospital was the main reason for lengthy delays in obtaining approval. CONCLUSIONS: The advantages of a harmonised single ethical review process were undermined by the coexistence of a fragmented, complex and lengthy governance approval process. This experience has implications for the success of the national Harmonisation of Multi-Centre Ethical Review (HoMER) model. A harmonised and fully supported national approach to research governance should be developed contemporaneously with HoMER.


Subject(s)
Biomedical Research/standards , Ethical Review/standards , Learning , Multicenter Studies as Topic/ethics , Multicenter Studies as Topic/standards , Biomedical Research/methods , Humans , New South Wales , Retrospective Studies , Time Factors
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