923 research outputs found

    Seasonal activity patterns of the frog, Crinia signifera (Anura: Myobatrachidae), in southern Tasmania, Australia

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    We investigated the seasonal adaptations of the myobatrachid frog Girard, 1863 in a commercial forest in southern Tasmania, Australia. Seasonal variation in activity patterns, body size and body condition was investigated. Although C does not hibernate over winter, activity levels arc much reduced during this time. Females trapped in summer were smaller than those captured throughout the remainder of the year. We interpreted seasonal variation in the condition of captured frogs as an indication that breeding in spring and early summer is metabolically costly and fat stores are replenished by extensive foraging in summer. Fat stores accumulated in summer and autumn by males are used for body maintenance over winter and breeding in the following spring

    Method and Apparatus for Controlling Acoustic Signal Bandwidth in an Ultrasonic Diagnostic Imaging System

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    An ultrasonic imaging system includes a receive beam former that generates analog receive signals and a scan converter. A receive signal processing path interconnects the receive beamformer and the scan converter, and this processing path includes both an A/D converter characterized by a selectable sampling rate and at least one filter characterized by at least one filter parameter. The filter parameter is selected as a function of the sampling rate to provide enhanced image quality

    Enabling Real-Time Ultrasound Imaging of Soft Tissue Mechanical Properties by Simplification of the Shear Wave Motion Equation

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    Ultrasound based shear wave elastography (SWE) is a technique used for non-invasive characterization and imaging of soft tissue mechanical properties. Robust estimation of shear wave propagation speed is essential for imaging of soft tissue mechanical properties. In this study we propose to estimate shear wave speed by inversion of the firstorder wave equation following directional filtering. This approach relies on estimation of first-order derivatives which allows for accurate estimations using smaller smoothing filters than when estimating second-order derivatives. The performance was compared to three current methods used to estimate shear wave propagation speed: direct inversion of the wave equation (DIWE), time-to-peak (TTP) and crosscorrelation (CC). The shear wave speed of three homogeneous phantoms of different elastic moduli (gelatin by weight of 5%, 7%, and 9%) were measured with each method. The proposed method was shown to produce shear speed estimates comparable to the conventional methods (standard deviation of measurements being 0.13 m/s, 0.05 m/s, and 0.12 m/s), but with simpler processing and usually less time (by a factor of 1, 13, and 20 for DIWE, CC, and TTP respectively). The proposed method was able to produce a 2-D speed estimate from a single direction of wave propagation in about four seconds using an off-the-shelf PC, showing the feasibility of performing real-time or near real-time elasticity imaging with dedicated hardware

    Studies of the oak leafminer Phyllonorycter messaniella (Zeller) (Lepidoptera: Gracillariidae) in southern Tasmania

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    The establishment of the oak leafminer on many Quercus species in southern Tasmania is recorded and indications of parasitisation levels given

    Foliage insect diversity in dry eucalypt forests in eastern Tasmania

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    Species numbers and composition of the insect fauna occurring on trees and shrubs were studied in dry eucalypt forests in eastern Tasmania over nine years. In all, 1164 named and putative species representing 17 orders and 157 families were collected. The bulk of the species belonged to the orders Coleoptera (28%), Hymenoptera (25%), Hemiptera (18%), Lepidoptera (14%) and Diptera (10%). Of the species collected, 388 -- about one-third -- were identified at least to genus or species level. These included 21 named species not previously listed in the Tasmanian insect fauna and 90 undescribed species. A list of 22 host plants for 171 insect species was compiled from records of 132 insect species observed feeding during the study and from previous records ofinsect/host plant associations for 39 insect species found on the study plots. Most insects were feeding on eucalypts (127 insect species) and acacias (38 species). The most widely distributed and commonly collected species were several well-known pests of eucalypts: Gonipterus scutellatus (Coleoptera: Curculionidae), Uraba lugens (Lepidoptera: N octuidae), Amorbus obscuricornis (Hemiptera: Coreidae), Chaetophyes compacta (Hemiptera: Machaerotidae) and Eriococcus coriaceous(Hemiptera: Eriococcidae). Host plants supporting the richest insect fauna were Eucalyptus amygdalina (74 species), E. obliqua (64), E. viminalis (46), Acacia dealbata (35), E. dalrympleana (33), E. sieberi (31), E. delegatensis (30), E. pulchella (24) and E. globulus (19). The broad-striped ghost moth, Fraus latistria Walker (Lepidoptera: Hepialidae), was collected during the study. This species is classified as 'rare' on the list of Tasmania's threatened fauna and the collection established a new locality record

    Ultrasound Based Quantitative Motion Measurement using Speckle Size Estimation

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    An ultrasound system determines the relative movement in a first direction (F1) of first matter, such as blood flow, and second matter, such as an artery wall, in a subject under study (S). A beam (B1) of ultrasound waves defining a plurality of beam positions (BP1 and BP2) and beam axes (A1 and A2) are moved in scan direction having components parallel to direction F1. First and second blocks of data representing the first and second matter, respectively, are generated. A processor (20) performs an estimation of speckle size on first data to obtain a first result, and performs analysis of the second block of data to obtain a second result. The two results are analyzed to obtain a measure of the relative movement of the first and second matter

    Epstein-Barr virus nuclear protein EBNA3C directly induces expression of AID and somatic mutations in B cells

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    Activation-induced cytidine deaminase (AID), the enzyme responsible for induction of sequence variation in immunoglobulins (Igs) during the process of somatic hypermutation (SHM) and also Ig class switching, can have a potent mutator phenotype in the development of lymphoma. Using various Epstein-Barr virus (EBV) recombinants, we provide definitive evidence that the viral nuclear protein EBNA3C is essential in EBV-infected primary B cells for the induction of AID mRNA and protein. Using lymphoblastoid cell lines (LCLs) established with EBV recombinants conditional for EBNA3C function, this was confirmed, and it was shown that transactivation of the AID gene (AICDA) is associated with EBNA3C binding to highly conserved regulatory elements located proximal to and upstream of the AICDA transcription start site. EBNA3C binding initiated epigenetic changes to chromatin at specific sites across the AICDA locus. Deep sequencing of cDNA corresponding to the IgH V-D-J region from the conditional LCL was used to formally show that SHM is activated by functional EBNA3C and induction of AID. These data, showing the direct targeting and induction of functional AID by EBNA3C, suggest a novel role for EBV in the etiology of B cell cancers, including endemic Burkitt lymphoma

    Identification of structural brain alterations in adolescents with depressive symptomatology

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    Introduction: Depressive symptoms can emerge as early as childhood and may lead to adverse situations in adulthood. Studies have examined structural brain alternations in individuals with depressive symptoms, but findings remain inconclusive. Furthermore, previous studies have focused on adults or used a categorical approach to assess depression. The current study looks to identify grey matter volumes (GMV) that predict depressive symptomatology across a clinically concerning sample of adolescents. Methods: Structural MRI data were collected from 338 clinically concerning adolescents (mean age = 15.30 SD=2.07; mean IQ = 101.01 SD=12.43; 132 F). Depression symptoms were indexed via the Mood and Feelings Questionnaire (MFQ). Freesurfer was used to parcellate the brain into 68 cortical regions and 14 subcortical regions. GMV was extracted from all 82 brain areas. Multiple linear regression was used to look at the relationship between MFQ scores and region-specific GMV parameter. Follow up regressions were conducted to look at potential effects of psychiatric diagnoses and medication intake. Results: Our regression analysis produced a significant model (R2 = 0.446, F(86, 251) = 2.348, p \u3c 0.001). Specifically, there was a negative association between GMV of the left parahippocampal (B = -0.203, p = 0.005), right rostral anterior cingulate (B = -0.162, p = 0.049), and right frontal pole (B = -0.147, p = 0.039) and a positive association between GMV of the left bank of the superior temporal sulcus (B = 0.173, p = 0.029). Follow up analyses produced results proximal to the main analysis. Conclusions: Altered regional brain volumes may serve as biomarkers for the development of depressive symptoms during adolescence. These findings suggest a homogeneity of altered cortical structures in adolescents with depressive symptoms

    Supraspinatus tendon micromorphology in individuals with subacromial pain syndrome

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    Study Design: Cross-sectional cohort. Introduction: Tendon collagen organization can be estimated by peak spatial frequency radius (PSFR) on ultrasound images. Characterizing PSFR can define the contribution of collagen disruption to shoulder symptoms. Purpose of the Study: The purpose of this was to characterize the (1) supraspinatus tendon PSFR in participants with sub acromial pain syndrome (SPS) and healthy controls; (2) PSFR between participants grouped on a tendon visual quality score; and (3) relationship between PSFR with patient-reported pain, function, and shoulder strength. Methods: Participants with SPS (n ¼ 20) and age, sex, and arm-dominance matched healthy controls (n ¼ 20) completed strength testing in scaption and external rotation, and patient-reported pain, and functional outcomes. Supraspinatus tendon ultrasound images were acquired, and PSFR was calculated for a region of interest 15 mm medial to the supraspinatus footprint. PSFR was compared between groups using an independent t-test and an analysis of variance to compare between 3 groups for visually qualitatively rated tendon abnormalities. Relationships between PSFR with pain, function, and strength were assessed using Pearson correlation coefficient. Results: Supraspinatus tendon PSFR was not different between groups (P ¼ .190) or tendon qualitative ratings (P ¼ .556). No relationship was found between PSFR and pain, functional loss, and strength (P \u3e .05). Conclusions: Collagen disruption (PSFR) measured via ultrasound images of the supraspinatus tendon was not different between participants with SPS or in those with visually rated tendon defects. PSFR is not related to shoulder pain, function, and strength, suggesting that supraspinatus tendon collagen disorganization may not be a contributing factor to shoulder SPS. However, collagen disruption may not be isolated to a single region of interest. Level of Evidence: 3b: case-control study

    Flowcell Systems for Single Molecule Detection

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    The present invention provides compounds, methods and systems for sequencing nucleic acid using single molecule detection. Using labeled NPs that exhibit charge-switching behavior, single-molecule DNA sequencing in a microchannel sorting system is realized. In operation, sequencing products are detected enabling real-time sequencing as successive detectable moieties flow through a detection channel. By electrically sorting charged molecules, the cleaved product molecules are detected in isolation without interference from unincorporated NPs and without illuminating the polymerase-DNA complex
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