Unique establishment of procephalic head segments is supported by the identification of cis-regulatory elements driving segment-specific segment polarity gene expression in Drosophila

Anterior head segmentation is governed by different regulatory mechanisms than those that control trunk segmentation in Drosophila. For segment polarity genes, both initial mode of activation as well as cross-regulatory interactions among them differ from the typical genetic circuitry in the trunk and are unique for each of the procephalic segments. In order to better understand the segment-specific gene network responsible for the procephalic expression of the earliest active segment polarity genes wingless and hedgehog, we started to identify and analyze cis-regulatory DNA elements of these genes. For hedgehog, we could identify a cis-regulatory element, ic-CRE, that mediates expression specifically in the posterior part of the intercalary segment and requires promoter-specific interaction for its function. The intercalary stripe is the last part of the metameric hedgehog expression pattern that appears during embryonic development, which probably reflects the late and distinct establishment of this segment. The identification of a cis-regulatory element that is specific for one head segment supports the mutant-based observation that the expression of segment polarity genes is governed by a unique gene network in each of the procephalic segments. This provides further indication that the anterior-most head segments represent primary segments, which are set up independently, in contrast to the secondary segments of the trunk, which resemble true repetitive units

Study of Women, Infant feeding, and Type 2 diabetes mellitus after GDM pregnancy (SWIFT), a prospective cohort study: methodology and design

<p>Abstract</p> <p>Background</p> <p>Women with history of gestational diabetes mellitus (GDM) are at higher risk of developing type 2 diabetes within 5 years after delivery. Evidence that lactation duration influences incident type 2 diabetes after GDM pregnancy is based on one retrospective study reporting a null association. The Study of Women, Infant Feeding and Type 2 Diabetes after GDM pregnancy (SWIFT) is a prospective cohort study of postpartum women with recent GDM within the Kaiser Permanente Northern California (KPNC) integrated health care system. The primary goal of SWIFT is to assess whether prolonged, intensive lactation as compared to formula feeding reduces the 2-year incidence of type 2 diabetes mellitus among women with GDM. The study also examines whether lactation intensity and duration have persistent favorable effects on blood glucose, insulin resistance, and adiposity during the 2-year postpartum period. This report describes the design and methods implemented for this study to obtain the clinical, biochemical, anthropometric, and behavioral measurements during the recruitment and follow-up phases.</p> <p>Methods</p> <p>SWIFT is a prospective, observational cohort study enrolling and following over 1, 000 postpartum women diagnosed with GDM during pregnancy within KPNC. The study enrolled women at 6-9 weeks postpartum (baseline) who had been diagnosed by standard GDM criteria, aged 20-45 years, delivered a singleton, term (greater than or equal to 35 weeks gestation) live birth, were not using medications affecting glucose tolerance, and not planning another pregnancy or moving out of the area within the next 2 years. Participants who are free of type 2 diabetes and other serious medical conditions at baseline are screened for type 2 diabetes annually within the first 2 years after delivery. Recruitment began in September 2008 and ends in December 2011. Data are being collected through pregnancy and early postpartum telephone interviews, self-administered monthly mailed questionnaires (3-11 months postpartum), a telephone interview at 6 months, and annual in-person examinations at which a 75 g 2-hour OGTT is conducted, anthropometric measurements are obtained, and self- and interviewer-administered questionnaires are completed.</p> <p>Discussion</p> <p>This is the first, large prospective, community-based study involving a racially and ethnically diverse cohort of women with recent GDM that rigorously assesses lactation intensity and duration and examines their relationship to incident type 2 diabetes while accounting for numerous potential confounders not assessed previously.</p

New horizons for future research - Critical issues to consider for maximizing research excellence and impact.

We live in an era in which the pace of research and the obligation to integrate new discoveries into a field's conceptual framework are rapidly increasing. At the same time, uncertainties about resources, funding, positions and promotions, the politics of science, publishing (the drive to publish in so-called high-impact journals) and many other concerns are mounting. To consider many of these phenomena in depth, a meeting was recently convened to discuss issues critical to conducting research with an emphasis on the neurobiology of metabolism and related areas. Attendees included a mix of senior and junior investigators from the United States, Latin America, and Western Europe, representing several relevant disciplines. Participants were initially assigned to small groups to consider specific questions in depth, and the results of those deliberations were then presented and discussed over several plenary sessions. Although there was spirited discussion with sometimes differing opinions on some issues, in general there was good consensus among individuals and the various groups. While the discussions were wide-ranging, we have condensed the topics into three (albeit often overlapping) major areas: 1) General research issues applicable to multiple areas of translational research; for instance, animal models, sex and gender differences, examples of emerging technologies, as well as the issue of data reproducibility and related topics. 2) Funding issues, such as how to secure industry funding without compromising research direction or academic integrity, and the training of students and fellows, with a focus on how to optimally prepare trainees for the diverse potential career paths available. 3) Finally, specific research topics of interest were discussed, including whether peptides or other signaling compounds, or specific brain areas, have “thematic functions” or the challenges associated with investigating the function of G-protein-coupled receptors (GPCR) in the brain

Cooling performance of a narrow impingement channel including the introduction of cross flow upstream of the first hole

Impingement channels are often used in turbine blade cooling configurations. This paper examines the heat transfer performance of a typical integrally cast impingement channel. Detailed heat transfer coefficient distributions on all heat transfer surfaces were obtained in a series of low temperature experiments carried out in a large-scale model of a turbine cooling system using liquid crystal techniques. All experiments were performed on a model of a 19-hole, low aspect ratio impingement channel. The effect of flow introduced at the inlet to the channel on the impingement heat transfer within the channel was investigated. A novel test technique has been applied to determine the effect of the initial cross flow on jet penetration. The experiments were performed at an engine representative Reynolds number of 20,000 and examined the effect of additional initial cross flow up to 10% of the total mass flow

A novel transient liquid crystal technique to determine heat transfer coefficient distributions and adiabatic wall temperature in a three-temperature problem

Transient liquid crystal techniques are widely used for experimental heat transfer measurements. In many instances it is necessary to model the heat transfer resulting from the temperature difference between a mixture of two gas streams and a solid surface. To nondimensionally characterize the heat transfer from scale models it is necessary to know both the heat transfer coefficient and adiabatic wall temperature of the model. Traditional techniques rely on deducing both parameters from a single test. This is a poorly conditioned problem. A novel strategy is proposed in which both parameters are deduced from a well-conditioned three-test strategy. The heat transfer coefficient is first calculated in a single test; the contribution from each driving gas stream is then deduced using additional tests. Analytical techniques are developed to deal with variations in the temperature profile and transient start time of each flow. The technique is applied to the analysis of the heat transfer within a low aspect ratio impingement channel with initial cross flow

The effect of initial cross flow on the cooling performance of a narrow impingement channel

Impingement channels are often used in turbine blade cooling configurations. This paper examines the heat transfer performance of a typical integrally cast impingement channel. Detailed heat transfer coefficient distributions on all heat transfer surfaces were obtained in a series of low temperature experiments carried out in a large-scale model of a turbine cooling system using liquid crystal techniques. All experiments were performed on a model of a 19-hole, low aspect ratio impingement channel. The effect of flow introduced at the inlet to the channel on the impingement heat transfer within the channel was investigated. A novel test technique has been applied to determine the effect of the initial cross flow on jet penetration. The experiments were performed at an engine representative Reynolds number of 20,000 and examined the effect of additional initial cross flow up to 10 percent of the total mass flow. It was shown that initial cross flow strongly influenced the heat transfer performance with just 10 percent initial cross flow able to reduce the mean target plate jet effectiveness by 57 percent. Copyright © 2005 by ASME