Footprints of local adaptation span hundreds of linked genes in the Atlantic silverside genome.

The study of local adaptation in the presence of ongoing gene flow is the study of natural selection in action, revealing the functional genetic diversity most relevant to contemporary pressures. In addition to individual genes, genome-wide architecture can itself evolve to enable adaptation. Distributed across a steep thermal gradient along the east coast of North America, Atlantic silversides () exhibit an extraordinary degree of local adaptation in a suite of traits, and the capacity for rapid adaptation from standing genetic variation, but we know little about the patterns of genomic variation across the species range that enable this remarkable adaptability.

Mercury bioaccumulation increases with latitude in a coastal marine fish (Atlantic silverside, Menidia menidia).

Human exposure to the neurotoxic methylmercury (MeHg) occurs primarily via the consumption of marine fish, but the processes underlying large-scale spatial variations in fish MeHg concentrations [MeHg], which influence human exposure, are not sufficiently understood. We used the Atlantic silverside (), an extensively studied model species and important forage fish, to examine latitudinal patterns in total Hg [Hg] and [MeHg]. Both [Hg] and [MeHg] significantly increased with latitude (0.

Initial Experience with a Cone-beam Breast Computed Tomography-guided Biopsy System.

Objective: To evaluate our initial experience with a cone-beam breast computed tomography (BCT)-guided breast biopsy system for lesion retrieval in phantom studies for use with a cone-beam BCT imaging system.

Materials And Methods: Under the Institutional Review Board approval, a phantom biopsy study was performed using a dedicated BCT-guided biopsy system. Fifteen biopsies were performed on each of the small, medium, and large anthropomorphic breast phantoms with both BCT and stereotactic guidance for comparison.

Genome Sequences of Gordonia terrae Bacteriophages Phinally and Vivi2.

Bacteriophages Phinally and Vivi2 were isolated from soil from Pittsburgh, Pennsylvania, USA, using host Gordonia terrae 3612. The Phinally and Vivi2 genomes are 59,265 bp and 59,337 bp, respectively, and share sequence similarity with each other and with GTE6. Fewer than 25% of the 87 to 89 putative genes have predictable functions.

Pattern and scale of geographic variation in environmental sex determination in the Atlantic silverside, Menidia menidia.

The Atlantic silverside, Menidia menidia (Pisces: Atherinidae), exhibits an exceptionally high level of clinal variation in sex determination across its geographic range. Previous work suggested linear changes in the level of temperature-dependent sex determination (TSD) with increasing latitude. Based on comparisons at 31 sites encompassing the entire species' range, we find that the change in level of TSD with latitude is instead highly nonlinear.

Cone beam breast CT with multiplanar and three dimensional visualization in differentiating breast masses compared with mammography.

Objective: This pilot study was to evaluate cone beam breast computed tomography (CBBCT) with multiplanar and three dimensional (3D) visualization in differentiating breast masses in comparison with two-view mammograms.

Methods: Sixty-five consecutive female patients (67 breasts) were scanned by CBBCT after conventional two-view mammography (Hologic, Motarget, compression factor 0.8).

Evaluation of malignant breast lesions in the diagnostic setting with cone beam breast computed tomography (Breast CT): feasibility study.

To investigate the feasibility of noncontrast and contrast-enhanced cone beam breast Computed Tomography (CT) in demonstrating malignant breast lesions in the diagnostic setting. This Institutional Review Board approved, Health Information Portability and Accountability Act compliant, prospective study enrolled BI-RADS four and five patients from 2008 to 2010. Eighty-seven subjects had noncontrast breast CT, 42 had contrast-enhanced breast CT (CE-breast CT) with 70 pathologically confirmed cancer diagnoses.

Investigating the use of texture features for analysis of breast lesions on contrast-enhanced cone beam CT.

Cone beam computed tomography (CBCT) has found use in mammography for imaging the entire breast with sufficient spatial resolution at a radiation dose within the range of that of conventional mammography. Recently, enhancement of lesion tissue through the use of contrast agents has been proposed for cone beam CT. This study investigates whether the use of such contrast agents improves the ability of texture features to differentiate lesion texture from healthy tissue on CBCT in an automated manner.

Personalized estimates of radiation dose from dedicated breast CT in a diagnostic population and comparison with diagnostic mammography.

This study retrospectively analyzed the mean glandular dose (MGD) to 133 breasts from 132 subjects, all women, who participated in a clinical trial evaluating dedicated breast CT in a diagnostic population. The clinical trial was conducted in adherence to a protocol approved by institutional review boards and the study participants provided written informed consent. Individual estimates of MGD to each breast from dedicated breast CT was obtained by combining x-ray beam characteristics with estimates of breast dimensions and fibroglandular fraction from volumetric breast CT images, and using normalized glandular dose coefficients.

Circulating levels of plasma IGF-I during recovery from size-selective harvesting in Menidia menidia.

Selection for growth-related traits in domesticated fishes often results in predictable changes within the growth hormone-insulin-like growth factor (GH-IGF-1) axis. Little is known about the mechanisms controlling changes in growth capacity resulting from fishery-induced evolution. We took advantage of a long-term study where Menidia menidia were selected for size at age over multiple generations to mimic fisheries-induced selection.

Investigation of Moiré Pattern-based Phase Retrieval Approach for Differential Phase-contrast Cone Beam CT Imaging Using a Hospital-grade Tube.

The phase stepping algorithm is commonly used for phase retrieval in grating-based differential phase-contrast (DPC) imaging, which requires multiple intensity images to compute one DPC image. It is not efficient for data acquisition, especially in the case of dynamic imaging using either DPC imaging or DPC-based come beam CT (DPC-CBCT) imaging. A Fourier transform-based approach has been developed for fringe pattern analysis in optics, and it was recently implemented into a synchrotron-based DPC tomography system.

The response of correlated traits following cessation of fishery-induced selection.

The application of evolutionary principles to the management of fisheries has gained considerable attention recently. Harvesting of fish may apply directional or disruptive selection to key life-history traits, and evidence for fishery-induced evolution is growing. The traits that are directly selected upon are often correlated (genetically or phenotypically) with a suite of interrelated physiological, behavioral, and morphological characters.

Performance Investigation of a Hospital-grade X-ray Tube-based Differential Phase-contrast Cone Beam CT System.

Differential phase contrast technique could be the next breakthrough in the field of CT imaging. While traditional absorption-based X-ray CT imaging is inefficient at differentiating soft tissues, phase-contrast technique offers great advantage as being able to produce higher contrast images utilizing the phase information of objects. Our long term goal is to develop a gantry-based hospital-grade X-ray tube differential phase contrast cone-beam CT (DPC-CBCT) technology which is able to achieve higher contrast noise ratio (CNR) in soft tissue imaging without increasing the dose level.

Dynamic cone beam CT angiography of carotid and cerebral arteries using canine model.

Purpose: This research is designed to develop and evaluate a flat-panel detector-based dynamic cone beam CT system for dynamic angiography imaging, which is able to provide both dynamic functional information and dynamic anatomic information from one multirevolution cone beam CT scan.

Methods: A dynamic cone beam CT scan acquired projections over four revolutions within a time window of 40 s after contrast agent injection through a femoral vein to cover the entire wash-in and wash-out phases. A dynamic cone beam CT reconstruction algorithm was utilized and a novel recovery method was developed to correct the time-enhancement curve of contrast flow.

Investigation of Source Grating Stepping for Differential Phase-contrast Cone Beam CT (DPC-CBCT) System.

Differential phase contrast (DPC) imaging, which utilizes phase shift information of X-ray, has the potential of dramatically increasing the contrast in biological sample imaging compared to attenuation-based method that relies on X-ray absorption information, since the X-ray phase is much more sensitive than the attenuation during transmission. In a DPC imaging system, the phase stepping method is widely used to obtain DPC images: at each angle the phase grating is shifted incrementally to produce a set of images and then the so obtained images are used to retrieve DPC image. However, DPC imaging requires a high mechanical precision to perform phase stepping, which is generally one order higher than the period of phase grating.

Scatter correction for clinical cone beam CT breast imaging based on breast phantom studies.

In flat-panel detector-based cone beam CT breast imaging (CBCTBI) systems, scattering is an important factor that degrades image quality. It is not practical to measure the scattering profiles of a breast for all view angles in a patient study, but it is possible to develop a method to estimate the scattering profiles based on information acquired from breast phantom studies. A new scattering correction method is proposed for clinical CBCTBI in this study.

High connectivity among locally adapted populations of a marine fish (Menidia menidia).

Patterns of connectivity are important in understanding the geographic scale of local adaptation in marine populations. While natural selection can lead to local adaptation, high connectivity can diminish the potential for such adaptation to occur. Connectivity, defined as the exchange of individuals among subpopulations, is presumed to be significant in most marine species due to life histories that include widely dispersive stages.

Adaptation to climate change: contrasting patterns of thermal-reaction-norm evolution in Pacific versus Atlantic silversides.

How organisms may adapt to rising global temperatures is uncertain, but concepts can emerge from studying adaptive physiological trait variations across existing spatial climate gradients. Many ectotherms, particularly fish, have evolved increasing genetic growth capacities with latitude (i.e.

Regional differentiation and post-glacial expansion of the Atlantic silverside, an annual fish with high dispersal potential.

The coastal marine environment of the Northwest Atlantic contains strong environmental gradients that create distinct marine biogeographic provinces by limiting dispersal, recruitment, and survival. This region has also been subjected to numerous Pleistocene glacial cycles, resulting in repeated extirpations and recolonizations in northern populations of marine organisms. In this study, we examined patterns of genetic structure and historical demography in the Atlantic silverside, an annual marine fish with high dispersal potential but with well-documented patterns of clinal phenotypic adaptation along the environmental gradients of the Northwest Atlantic.

Cone-beam CT for breast imaging: Radiation dose, breast coverage, and image quality.

Objective: The primary objectives of this pilot study were to evaluate the radiation dose, breast coverage, and image quality of cone-beam breast CT compared with a conventional mammographic examination. Image quality analysis was focused on the concordance of cone-beam breast CT with conventional mammography in terms of mammographic findings.

Subjects And Methods: This prospective study was performed from July 2006 through August 2008.

Measurements of the modulation transfer function, normalized noise power spectrum and detective quantum efficiency for two flat panel detectors: a fluoroscopic and a cone beam computer tomography flat panel detectors.

The physical performance of two Flat Panel Detectors has been evaluated. The first Flat Panel Detector is for Fluoroscopic applications, Varian PaxScan 2520, and the second is for Cone Beam Computer Tomography applications, Varian PaxScan 4030CB. First, the spectrum of the X-ray source was measured.