High refractive index composite materials for THz waveguides: trade-off between index contrast and absorption loss

Polymer compounds from titania-doped polyethylene are fabricated and their linear optical properties characterized by THz-TDS. We show that high concentration of dopants not only enhances the refractive index of the composite material, but also can dramatically raise its absorption coefficient. We demonstrate that the design of Bragg reflectors based on lossy composite polymers depends on finding a compromise between index contrast and corresponding losses. A small absorption value is also shown to be favorable, compared to an ideal lossless reflector, as it enables to smooth the transmission passbands. Transmission measurements of a fabricated hollowcore Bragg fiber confirm simulation results

Positron Emission Tomography-Computed Tomography Compared with Invasive Mediastinal Staging in Non-small Cell Lung Cancer: Results of Mediastinal Staging in the Early Lung Positron Emission Tomography Trial

IntroductionPatients with non-small cell lung cancer (NSCLC) require careful preoperative staging to define resectability for potential cure. 18Fluorodeoxyglucose positron emission tomography combined with computed tomography (18FDG PET-CT) is widely used to stage NSCLC. If the mediastinum is positive on PET-CT examination, some practitioners conclude that the patient is inoperable and refer the patient for nonsurgical treatment.MethodsIn this analysis of a previously reported trial comparing PET-CT with conventional imaging in the diagnostic work-up of patients with clinical stage I, II, or IIIA NSCLC, we determined the accuracy of PET-CT in mediastinal staging compared with invasive mediastinal staging either by mediastinoscopy alone or by mediastinoscopy combined with thoracotomy.ResultsAll 149 patients had mediastinal nodal staging at mediastinoscopy alone (14), thoracotomy alone (64), or both (71). The sensitivity of PET-CT was 70% (95% confidence interval [CI], 48–85%), and specificity was 94% (95% CI, 88–97%). Of 22 patients with a PET-CT interpreted as positive for mediastinal nodes, 8 did not have tumor. The positive predictive value and negative predictive value were 64% (95% CI, 43–80%) and 95% (95% CI, 90–98%), respectively. Based on PET-CT alone, eight patients would have been denied potentially curative surgery if the mediastinal abnormalities detected by PET-CT had not been evaluated with an invasive mediastinal procedure.ConclusionsPET-CT assessment of the mediastinum is associated with a clinically relevant false-positive result. Our study confirms the need for pathologic confirmation of mediastinal lymph node abnormalities detected by PET-CT

A 50-Gene Intrinsic Subtype Classifier for Prognosis and Prediction of Benefit from Adjuvant Tamoxifen

Gene expression profiling classifies breast cancer into intrinsic subtypes based on the biology of the underlying disease pathways. We have used material from a prospective randomized trial of tamoxifen versus placebo in premenopausal women with primary breast cancer (NCIC CTG MA.12) to evaluate the prognostic and predictive significance of intrinsic subtypes identified by both the PAM50 gene set and by immunohistochemistry

Maternal mental health predicts risk of developmental problems at 3 years of age: follow up of a community based trial

<p>Abstract</p> <p>Background</p> <p>Undetected and untreated developmental problems can have a significant economic and social impact on society. Intervention to ameliorate potential developmental problems requires early identification of children at risk of future learning and behaviour difficulties. The objective of this study was to estimate the prevalence of risk for developmental problems among preschool children born to medically low risk women and identify factors that influence outcomes.</p> <p>Methods</p> <p>Mothers who had participated in a prenatal trial were followed up three years post partum to answer a telephone questionnaire. Questions were related to child health and development, child care, medical care, mother's lifestyle, well-being, and parenting style. The main outcome measure was risk for developmental problems using the Parents' Evaluation of Developmental Status (PEDS).</p> <p>Results</p> <p>Of 791 children, 11% were screened by the PEDS to be at high risk for developmental problems at age three. Of these, 43% had previously been referred for assessment. Children most likely to have been referred were those born preterm. Risk factors for delay included: male gender, history of ear infections, a low income environment, and a mother with poor emotional health and a history of abuse. A child with these risk factors was predicted to have a 53% chance of screening at high risk for developmental problems. This predicted probability was reduced to 19% if the child had a mother with good emotional health and no history of abuse.</p> <p>Conclusion</p> <p>Over 10% of children were identified as high risk for developmental problems by the screening, and more than half of those had not received a specialist referral. Risk factors for problems included prenatal and perinatal maternal and child factors. Assessment of maternal health and effective screening of child development may increase detection of children at high risk who would benefit from early intervention.</p> <p>Trial registration</p> <p>Current Controlled Trials ISRCTN64070727</p

The African Cichlid Fish Astatotilapia burtoni Uses Acoustic Communication for Reproduction: Sound Production, Hearing, and Behavioral Significance

Sexual reproduction in all animals depends on effective communication between signalers and receivers. Many fish species, especially the African cichlids, are well known for their bright coloration and the importance of visual signaling during courtship and mate choice, but little is known about what role acoustic communication plays during mating and how it contributes to sexual selection in this phenotypically diverse group of vertebrates. Here we examined acoustic communication during reproduction in the social cichlid fish, Astatotilapia burtoni. We characterized the sounds and associated behaviors produced by dominant males during courtship, tested for differences in hearing ability associated with female reproductive state and male social status, and then tested the hypothesis that female mate preference is influenced by male sound production. We show that dominant males produce intentional courtship sounds in close proximity to females, and that sounds are spectrally similar to their hearing abilities. Females were 2–5-fold more sensitive to low frequency sounds in the spectral range of male courtship sounds when they were sexually-receptive compared to during the mouthbrooding parental phase. Hearing thresholds were also negatively correlated with circulating sex-steroid levels in females but positively correlated in males, suggesting a potential role for steroids in reproductive-state auditory plasticity. Behavioral experiments showed that receptive females preferred to affiliate with males that were associated with playback of courtship sounds compared to noise controls, indicating that acoustic information is likely important for female mate choice. These data show for the first time in a Tanganyikan cichlid that acoustic communication is important during reproduction as part of a multimodal signaling repertoire, and that perception of auditory information changes depending on the animal's internal physiological state. Our results highlight the importance of examining non-visual sensory modalities as potential substrates for sexual selection contributing to the incredible phenotypic diversity of African cichlid fishes

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

Large expert-curated database for benchmarking document similarity detection in biomedical literature search

Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe

Definition of binding of human serum transferrin to transferrin receptor

Intracellular iron levels affect cell division and cell existence; hence the viability of a cell is dependent on the presence of iron. In vertebrates, transferrin is responsible for the transport of iron, helping to control the available iron levels for conservation and bacteriostatic effect, and protecting cells against the toxic effects of free iron. Uptake of iron in cells occurs predominantly by the receptormediated endocytosis of diferric transferrin bound to the transferrin receptor on the cell surface. To date, limited information is available as to the nature of the interaction of transferrin with the transferrin receptor. High affinity monoclonal antibodies are useful as probes to determine regions of transferrin involved in binding to the transferrin receptor. For example, monoclonal antibodies raised against the N-lobe and C-lobe of chicken ovotransferrin have been used to demonstrate that both lobes of ovotransferrin must be present and associated for the binding to the ovotransferrin receptor to occur. As well, different affinities of the monoclonal antibodies to apoovotransferrin and holo-ovotansferrin have been used as evidence that local structural changes occur upon iron binding. Monoclonal antibodies against human serum transferrin have been raised and characterized. Some but not all of such antibodies inhibit the binding of serum transferrin to its receptor. In this study, the objective was to determine the antigenic epitope on human serum transferrin recognized by a monoclonal antibody that inhibits the binding of transferrin to its receptor. A bacterial cell culture system was used for the expression of N-lobe, Clobe and C-lobe fragments of human serum transferrin as a fusion protein with glutathione S-transferase. Using this expression system, the epitope of the antitransferrin antibody to C-lobe, designated as F-11, was identified to a small region on human serum transferrin. Comparison of the F-11 epitope with the known three-dimensional structure of human serum transferrin facilitated theMedicine, Faculty ofBiochemistry and Molecular Biology, Department ofGraduat