Dosimetric comparison of stopping power calibration with dual-energy CT and single-energy CT in proton therapy treatment planning

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhu, Jiahua; Penfold, Scott N., E-mail: scott.penfold@adelaide.edu.au

Purpose: The accuracy of proton dose calculation is dependent on the ability to correctly characterize patient tissues with medical imaging. The most common method is to correlate computed tomography (CT) numbers obtained via single-energy CT (SECT) with proton stopping power ratio (SPR). CT numbers, however, cannot discriminate between a change in mass density and change in chemical composition of patient tissues. This limitation can have consequences on SPR calibration accuracy. Dual-energy CT (DECT) is receiving increasing interest as an alternative imaging modality for proton therapy treatment planning due to its ability to discriminate between changes in patient density and chemicalmore » composition. In the current work we use a phantom of known composition to demonstrate the dosimetric advantages of proton therapy treatment planning with DECT over SECT. Methods: A phantom of known composition was scanned with a clinical SECT radiotherapy CT-simulator. The phantom was rescanned at a lower X-ray tube potential to generate a complimentary DECT image set. A set of reference materials similar in composition to the phantom was used to perform a stoichiometric calibration of SECT CT number to proton SPRs. The same set of reference materials was used to perform a DECT stoichiometric calibration based on effective atomic number. The known composition of the phantom was used to assess the accuracy of SPR calibration with SECT and DECT. Intensity modulated proton therapy (IMPT) treatment plans were generated with the SECT and DECT image sets to assess the dosimetric effect of the imaging modality. Isodose difference maps and root mean square (RMS) error calculations were used to assess dose calculation accuracy. Results: SPR calculation accuracy was found to be superior, on average, with DECT relative to SECT. Maximum errors of 12.8% and 2.2% were found for SECT and DECT, respectively. Qualitative examination of dose difference maps clearly showed the dosimetric advantages of DECT imaging, compared to SECT imaging for IMPT dose calculation for the case investigated. Quantitatively, the maximum dose calculation error in the SECT plan was 7.8%, compared to a value of 1.4% in the DECT plan. When considering the high dose target region, the root mean square (RMS) error in dose calculation was 2.1% and 0.4% for SECT and DECT, respectively. Conclusions: DECT-based proton treatment planning in a commercial treatment planning system was successfully demonstrated for the first time. DECT is an attractive imaging modality for proton therapy treatment planning owing to its ability to characterize density and chemical composition of patient tissues. SECT and DECT scans of a phantom of known composition have been used to demonstrate the dosimetric advantages obtainable in proton therapy treatment planning with DECT over the current approach based on SECT.« less

Microscopic dual-energy CT (microDECT): a flexible tool for multichannel ex vivo 3D imaging of biological specimens.

PubMed

Handschuh, S; Beisser, C J; Ruthensteiner, B; Metscher, B D

2017-07-01

Dual-energy computed tomography (DECT) uses two different x-ray energy spectra in order to differentiate between tissues, materials or elements in a single sample or patient. DECT is becoming increasingly popular in clinical imaging and preclinical in vivo imaging of small animal models, but there have been only very few reports on ex vivo DECT of biological samples at microscopic resolutions. The present study has three main aims. First, we explore the potential of microscopic DECT (microDECT) for delivering isotropic multichannel 3D images of fixed biological samples with standard commercial laboratory-based microCT setups at spatial resolutions reaching below 10 μm. Second, we aim for retaining the maximum image resolution and quality during the material decomposition. Third, we want to test the suitability for microDECT imaging of different contrast agents currently used for ex vivo staining of biological samples. To address these aims, we used microCT scans of four different samples stained with x-ray dense contrast agents. MicroDECT scans were acquired with five different commercial microCT scanners from four companies. We present a detailed description of the microDECT workflow, including sample preparation, image acquisition, image processing and postreconstruction material decomposition, which may serve as practical guide for applying microDECT. The MATLAB script (The Mathworks Inc., Natick, MA, USA) used for material decomposition (including a graphical user interface) is provided as a supplement to this paper (https://github.com/microDECT/DECTDec). In general, the presented microDECT workflow yielded satisfactory results for all tested specimens. Original scan resolutions have been mostly retained in the separate material fractions after basis material decomposition. In addition to decomposition of mineralized tissues (inherent sample contrast) and stained soft tissues, we present a case of double labelling of different soft tissues with subsequent material decomposition. We conclude that, in contrast to in vivo DECT examinations, small ex vivo specimens offer some clear advantages regarding technical parameters of the microCT setup and the use of contrast agents. These include a higher flexibility in source peak voltages and x-ray filters, a lower degree of beam hardening due to small sample size, the lack of restriction to nontoxic contrast agents and the lack of a limit in exposure time and radiation dose. We argue that microDECT, because of its flexibility combined with already established contrast agents and the vast number of currently unexploited stains, will in future represent an important technique for various applications in biological research. © 2017 The Authors Journal of Microscopy © 2017 Royal Microscopical Society.

SU-E-I-98: Dose Comparison for Pulmonary Embolism CT Studies: Single Energy Vs. Dual Energy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mahmood, U; Erdi, Y

Purpose: The purpose of this study was to assess and compare the size specific dose estimate (SSDE), dose length product (DLP) and noise relationship for pulmonary embolism studies evaluated by single source dual energy computed tomography (DECT) against conventional CT (CCT) studies in a busy cancer center and to determine the dose savings provided by DECT. Methods: An IRB-approved retrospective study was performed to determine the CTDIvol and DLP from a subset of patients scanned with both DECT and CCT over the past five years. We were able to identify 30 breast cancer patients (6 male, 24 female, age rangemore » 24 to 81) who had both DECT and CCT studies performed. DECT scans were performed with a GE HD 750 scanner (140/80 kVp, 480 mAs and 40 mm) and CCT scans were performed with a GE Lightspeed 16 slice scanner (120 kVp, 352 mAs, 20 mm). Image noise was measured by placing an ROI and recording the standard deviation of the mean HU along the descending aorta. Results: The average DECT patient size specific dose estimate was to be 14.2 ± 1.7 mGy as compared to 22.4 ± 2.7 mGy from CCT PE studies, which is a 37% reduction in the SSDE. The average DECT DLP was 721.8 ± 84.6 mGy-cm as compared to 981.8 ± 106.1 mGy-cm for CCT, which is a 26% decrease. Compared to CCT the image noise was found to decrease by 19% when using DECT for PE studies. Conclusion: DECT SSDE and DLP measurements indicate dose savings and image noise reduction when compared to CCT. In an environment that heavily debates CT patient doses, this study confirms the effectiveness of DECT in PE imaging.« less

Dual-layer DECT for multiphasic hepatic CT with 50 percent iodine load: a matched-pair comparison with a 120 kVp protocol.

PubMed

Nagayama, Yasunori; Nakaura, Takeshi; Oda, Seitaro; Utsunomiya, Daisuke; Funama, Yoshinori; Iyama, Yuji; Taguchi, Narumi; Namimoto, Tomohiro; Yuki, Hideaki; Kidoh, Masafumi; Hirata, Kenichiro; Nakagawa, Masataka; Yamashita, Yasuyuki

2018-04-01

To evaluate the image quality and lesion conspicuity of virtual-monochromatic-imaging (VMI) with dual-layer DECT (DL-DECT) for reduced-iodine-load multiphasic-hepatic CT. Forty-five adults with renal dysfunction who had undergone hepatic DL-DECT with 300-mgI/kg were included. VMI (40-70-keV, DL-DECT-VMI) was generated at each enhancement phase. As controls, 45 matched patients undergoing standard 120-kVp protocol (120-kVp, 600-mgI/kg, and iterative reconstruction) were included. We compared the size-specific dose estimate (SSDE), image noise, CT attenuation, and contrast-to-noise ratio (CNR) between protocols. Two radiologists scored the image quality and lesion conspicuity. SSDE was significantly lower in DL-DECT group (p < 0.01). Image noise of DL-DECT-VMI was almost constant at each keV (differences of ≤15%) and equivalent to or lower than of 120-kVp. As the energy decreased, CT attenuation and CNR gradually increased; the values of 55-60 keV images were almost equivalent to those of standard 120-kVp. The highest scores for overall quality and lesion conspicuity were assigned at 40-keV followed by 45 to 55-keV, all of which were similar to or better than of 120-kVp. For multiphasic-hepatic CT with 50% iodine-load, DL-DECT-VMI at 40- to 55-keV provides equivalent or better image quality and lesion conspicuity without increasing radiation dose compared with standard 120-kVp protocol. • 40-55-keV yields optimal image quality for half-iodine-load multiphasic-hepatic CT with DL-DECT. • DL-DECT protocol decreases radiation exposure compared with 120-kVp scans with iterative reconstruction. • 40-keV images maximise conspicuity of hepatocellular carcinoma especially at hepatic-arterial phase.

Comparison of diffraction-enhanced computed tomography and monochromatic synchrotron radiation computed tomography of human trabecular bone.

PubMed

Connor, D M; Hallen, H D; Lalush, D S; Sumner, D R; Zhong, Z

2009-10-21

Diffraction-enhanced imaging (DEI) is an x-ray-based medical imaging modality that, when used in tomography mode (DECT), can generate a three-dimensional map of both the apparent absorption coefficient and the out-of-plane gradient of the index of refraction of the sample. DECT is known to have contrast gains over monochromatic synchrotron radiation CT (SRCT) for soft tissue structures. The goal of this experiment was to compare contrast-to-noise ratio (CNR) and resolution in images of human trabecular bone acquired using SRCT with images acquired using DECT. All images were acquired at the National Synchrotron Light Source (Upton, NY, USA) at beamline X15 A at an x-ray energy of 40 keV and the silicon [3 3 3] reflection. SRCT, apparent absorption DECT and refraction DECT slice images of the trabecular bone were created. The apparent absorption DECT images have significantly higher spatial resolution and CNR than the corresponding SRCT images. Thus, DECT will prove to be a useful tool for imaging applications in which high contrast and high spatial resolution are required for both soft tissue features and bone.

Computation of Calcium Score with Dual Energy CT: A Phantom Study

PubMed Central

Kumar, Vidhya; Min, James K.; He, Xin; Raman, Subha V.

2016-01-01

Dual energy computed tomography (DECT) improves material and tissue characterization compared to single energy CT (SECT); we sought to validate coronary calcium quantification in advancing cardiovascular DECT. In an anthropomorphic phantom, agreement between measurements was excellent, and Bland-Altman analysis demonstrated minimal bias. Compared to the known calcium mass for each phantom, calcium mass by DECT was highly accurate. Noncontrast DECT yields accurate calcium measures, and warrants consideration in cardiac protocols for additional tissue characterizations. PMID:27680414

Diagnostic performance of dual-energy CT stress myocardial perfusion imaging: direct comparison with cardiovascular MRI.

PubMed

Ko, Sung Min; Song, Meong Gun; Chee, Hyun Kun; Hwang, Hweung Kon; Feuchtner, Gudrun Maria; Min, James K

2014-12-01

The purpose of this study was to assess the diagnostic performance of stress perfusion dual-energy CT (DECT) and its incremental value when used with coronary CT angiography (CTA) for identifying hemodynamically significant coronary artery disease. One hundred patients with suspected or known coronary artery disease without chronic myocardial infarction detected with coronary CTA underwent stress perfusion DECT, stress cardiovascular perfusion MRI, and invasive coronary angiography (ICA). Stress perfusion DECT and cardiovascular stress perfusion MR images were used for detecting perfusion defects. Coronary CTA and ICA were evaluated in the detection of ≥50% coronary stenosis. The diagnostic performance of coronary CTA for detecting hemo-dynamically significant stenosis was assessed before and after stress perfusion DECT on a per-vessel basis with ICA and cardiovascular stress perfusion MRI as the reference standard. The performance of stress perfusion DECT compared with cardiovascular stress perfusion MRI on a per-vessel basis in the detection of perfusion defects was sensitivity, 89%; specificity, 74%; positive predictive value, 73%; negative predictive value, 90%. Per segment, these values were sensitivity, 76%; specificity, 80%; positive predictive value, 63%; and negative predictive value, 88%. Compared with ICA and cardiovascular stress perfusion MRI per vessel territory the sensitivity, specificity, positive predictive value, and negative predictive value of coronary CTA were 95%, 61%, 61%, and 95%. The values for stress perfusion DECT were 92%, 72%, 68%, and 94%. The values for coronary CTA and stress perfusion DECT were 88%, 79%, 73%, and 91%. The ROC AUC increased from 0.78 to 0.84 (p=0.02) with the use of coronary CTA and stress perfusion DECT compared with coronary CTA alone. Stress perfusion DECT plays a complementary role in enhancing the accuracy of coronary CTA for identifying hemodynamically significant coronary stenosis.

TU-FG-BRB-02: The Impact of Using Dual-Energy CT for Determining Proton Stopping Powers: Comparison Between Theory and Experiments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baer, E; Jee, K; Zhang, R

Purpose: To evaluate the clinical performance of dual-energy CT (DECT) in determining proton stopping power ratios (SPR) and demonstrate advantages over conventional single-energy CT (SECT). Methods: SECT and DECT scans of tissue-equivalent plastics as well as animal meat samples are performed with a Siemens SOMATOM Definition Flash. The methods of Schneider et al. (1996) and Bourque et al. (2014) are used to determine proton SPR on SECT and DECT images, respectively. Waterequivalent path length (WEPL) measurements of plastics and tissue samples are performed with a 195 MeV proton beam. WEPL values are determined experimentally using the depth-dose shift and dosemore » extinction methods. Results: Comparison between CT-based and experimental WEPL is performed for 12 tissue-equivalent plastic as well as 6 meat boxes containing animal liver, kidney, heart, stomach, muscle and bones. For plastic materials, results show a systematic improvement in determining SPR with DECT, with a mean absolute error of 0.4% compared to 1.7% for SECT. For the meat samples, preliminary results show the ability for DECT to determine WEPL with a mean absolute value of 1.1% over all meat boxes. Conclusion: This work demonstrates the potential in using DECT for determining proton SPR with plastic materials in a clinical context. Further work is required to show the benefits of DECT for tissue samples. While experimental uncertainties could be a limiting factor to show the benefits of DECT over SECT for the meat samples, further work is required to adapt the DECT formalism in the context of clinical use, where noise and artifacts play an important role.« less

Value of monoenergetic dual-energy CT (DECT) for artefact reduction from metallic orthopedic implants in post-mortem studies.

PubMed

Filograna, Laura; Magarelli, Nicola; Leone, Antonio; Guggenberger, Roman; Winklhofer, Sebastian; Thali, Michael John; Bonomo, Lorenzo

2015-09-01

The aim of this ex vivo study was to assess the performance of monoenergetic dual-energy CT (DECT) reconstructions to reduce metal artefacts in bodies with orthopedic devices in comparison with standard single-energy CT (SECT) examinations in forensic imaging. Forensic and clinical impacts of this study are also discussed. Thirty metallic implants in 20 consecutive cadavers with metallic implants underwent both SECT and DECT with a clinically suitable scanning protocol. Extrapolated monoenergetic DECT images at 64, 69, 88, 105, 120, and 130 keV and individually adjusted monoenergy for optimized image quality (OPTkeV) were generated. Image quality of the seven monoenergetic images and of the corresponding SECT image was assessed qualitatively and quantitatively by visual rating and measurements of attenuation changes induced by streak artefact. Qualitative and quantitative analyses showed statistically significant differences between monoenergetic DECT extrapolated images and SECT, with improvements in diagnostic assessment in monoenergetic DECT at higher monoenergies. The mean value of OPTkeV was 137.6 ± 4.9 with a range of 130 to 148 keV. This study demonstrates that monoenergetic DECT images extrapolated at high energy levels significantly reduce metallic artefacts from orthopedic implants and improve image quality compared to SECT examination in forensic imaging.

Reconstruction of limited-angle dual-energy CT using mutual learning and cross-estimation (MLCE)

NASA Astrophysics Data System (ADS)

Zhang, Huayu; Xing, Yuxiang

2016-03-01

Dual-energy CT (DECT) imaging has gained a lot of attenuation because of its capability to discriminate materials. We proposes a flexible DECT scan strategy which can be realized on a system with general X-ray sources and detectors. In order to lower dose and scanning time, our DECT acquires two projections data sets on two arcs of limited-angular coverage (one for each energy) respectively. Meanwhile, a certain number of rays from two data sets form conjugate sampling pairs. Our reconstruction method for such a DECT scan mainly tackles the consequent limited-angle problem. Using the idea of artificial neural network, we excavate the connection between projections at two different energies by constructing a relationship between the linear attenuation coefficient of the high energy and that of the low one. We use this relationship to cross-estimate missing projections and reconstruct attenuation images from an augmented data set including projections at views covered by itself (projections collected in scanning) and by the other energy (projections estimated) for each energy respectively. Validated by our numerical experiment on a dental phantom with rather complex structures, our DECT is effective in recovering small structures in severe limited-angle situations. This DECT scanning strategy can much broaden DECT design in reality.

Application of single- and dual-energy CT brain tissue segmentation to PET monitoring of proton therapy.

PubMed

Berndt, Bianca; Landry, Guillaume; Schwarz, Florian; Tessonnier, Thomas; Kamp, Florian; Dedes, George; Thieke, Christian; Würl, Matthias; Kurz, Christopher; Ganswindt, Ute; Verhaegen, Frank; Debus, Jürgen; Belka, Claus; Sommer, Wieland; Reiser, Maximilian; Bauer, Julia; Parodi, Katia

2017-03-21

The purpose of this work was to evaluate the ability of single and dual energy computed tomography (SECT, DECT) to estimate tissue composition and density for usage in Monte Carlo (MC) simulations of irradiation induced β + activity distributions. This was done to assess the impact on positron emission tomography (PET) range verification in proton therapy. A DECT-based brain tissue segmentation method was developed for white matter (WM), grey matter (GM) and cerebrospinal fluid (CSF). The elemental composition of reference tissues was assigned to closest CT numbers in DECT space (DECT dist ). The method was also applied to SECT data (SECT dist ). In a validation experiment, the proton irradiation induced PET activity of three brain equivalent solutions (BES) was compared to simulations based on different tissue segmentations. Five patients scanned with a dual source DECT scanner were analyzed to compare the different segmentation methods. A single magnetic resonance (MR) scan was used for comparison with an established segmentation toolkit. Additionally, one patient with SECT and post-treatment PET scans was investigated. For BES, DECT dist and SECT dist reduced differences to the reference simulation by up to 62% when compared to the conventional stoichiometric segmentation (SECT Schneider ). In comparison to MR brain segmentation, Dice similarity coefficients for WM, GM and CSF were 0.61, 0.67 and 0.66 for DECT dist and 0.54, 0.41 and 0.66 for SECT dist . MC simulations of PET treatment verification in patients showed important differences between DECT dist /SECT dist and SECT Schneider for patients with large CSF areas within the treatment field but not in WM and GM. Differences could be misinterpreted as PET derived range shifts of up to 4 mm. DECT dist and SECT dist yielded comparable activity distributions, and comparison of SECT dist to a measured patient PET scan showed improved agreement when compared to SECT Schneider . The agreement between predicted and measured PET activity distributions was improved by employing a brain specific segmentation applicable to both DECT and SECT data.

Impact of dual energy characterization of urinary calculus on management.

PubMed

Habashy, David; Xia, Ryan; Ridley, William; Chan, Lewis; Ridley, Lloyd

2016-10-01

Dual energy CT (DECT) is a recent technique that is increasingly being used to differentiate between calcium and uric acid urinary tract calculi. The aim of this study is to determine if urinary calculi composition analysis determined by DECT scanning results in a change of patient management. All patients presenting with symptoms of renal colic, who had not previously undergone DECT scanning underwent DECT KUB. DECT data of all patients between September 2013 and July 2015 were reviewed. Urinary calculi composition based on dual energy characterization was cross-matched with patient management and outcome. A total of 585 DECT KUB were performed. 393/585 (67%) DECT scans revealed urinary tract calculi. After excluding those with isolated bladder or small asymptomatic renal stones, 303 patients were found to have symptomatic stone(s) as an explanation for their presentation. Of these 303 patients, there were 273 (90.1%) calcium calculi, 19 (6.3%) uric acid calculi and 11 (3.4%) mixed calculi. Of those with uric acid calculi, 15 were commenced on dissolution therapy. Twelve of those commenced on dissolution therapy had a successful outcome, avoiding need for surgical intervention (lithotripsy or stone retrieval). Three patients failed dissolution therapy and required operative intervention for definitive management of the stone. Predicting urinary tract calculi composition by DECT plays an important role in identifying patients who may be managed with dissolution therapy. Identification of uric acid stone composition altered management in 15 of 303 (5.0%) patients, and was successful in 12, thereby avoiding surgery and its attendant risks. © 2016 The Royal Australian and New Zealand College of Radiologists.

75 FR 33220 - Unlicensed Personal Communications Services Devices in the 1920-1930 MHz Band

Federal Register 2010, 2011, 2012, 2013, 2014

2010-06-11

... required minimum number of channels and transmit on the channels with the lowest power. According to DECT... interference to adjacent-band Advanced Wireless Service (AWS) and PCS services. 3. DECT claims that its... with the lowest power and an alternative approach suggested by DECT--could require affected systems to...

Dual-Energy CT: Basic Principles, Technical Approaches, and Applications in Musculoskeletal Imaging (Part 1).

PubMed

Omoumi, Patrick; Becce, Fabio; Racine, Damien; Ott, Julien G; Andreisek, Gustav; Verdun, Francis R

2015-12-01

In recent years, technological advances have allowed manufacturers to implement dual-energy computed tomography (DECT) on clinical scanners. With its unique ability to differentiate basis materials by their atomic number, DECT has opened new perspectives in imaging. DECT has been used successfully in musculoskeletal imaging with applications ranging from detection, characterization, and quantification of crystal and iron deposits; to simulation of noncalcium (improving the visualization of bone marrow lesions) or noniodine images. Furthermore, the data acquired with DECT can be postprocessed to generate monoenergetic images of varying kiloelectron volts, providing new methods for image contrast optimization as well as metal artifact reduction. The first part of this article reviews the basic principles and technical aspects of DECT including radiation dose considerations. The second part focuses on applications of DECT to musculoskeletal imaging including gout and other crystal-induced arthropathies, virtual noncalcium images for the study of bone marrow lesions, the study of collagenous structures, applications in computed tomography arthrography, as well as the detection of hemosiderin and metal particles. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Dual-Energy CT: Basic Principles, Technical Approaches, and Applications in Musculoskeletal Imaging (Part 2).

PubMed

Omoumi, Patrick; Verdun, Francis R; Guggenberger, Roman; Andreisek, Gustav; Becce, Fabio

2015-12-01

In recent years, technological advances have allowed manufacturers to implement dual-energy computed tomography (DECT) on clinical scanners. With its unique ability to differentiate basis materials by their atomic number, DECT has opened new perspectives in imaging. DECT has been successfully used in musculoskeletal imaging with applications ranging from detection, characterization, and quantification of crystal and iron deposits, to simulation of noncalcium (improving the visualization of bone marrow lesions) or noniodine images. Furthermore, the data acquired with DECT can be postprocessed to generate monoenergetic images of varying kiloelectron volts, providing new methods for image contrast optimization as well as metal artifact reduction. The first part of this article reviews the basic principles and technical aspects of DECT including radiation dose considerations. The second part focuses on applications of DECT to musculoskeletal imaging including gout and other crystal-induced arthropathies, virtual noncalcium images for the study of bone marrow lesions, the study of collagenous structures, applications in computed tomography arthrography, as well as the detection of hemosiderin and metal particles. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Iodine concentration calculated by dual-energy computed tomography (DECT) as a functional parameter to evaluate thyroid metabolism in patients with hyperthyroidism.

PubMed

Binh, Duong Duc; Nakajima, Takahito; Otake, Hidenori; Higuchi, Tetsuya; Tsushima, Yoshito

2017-07-19

Thyroid function in patients with Grave's disease is usually evaluated by thyroid scintigraphy with radioactive iodine. Recently, dual-energy computed tomography (DECT) with two different energy X-rays can calculate iodine concentrations and can be applied for iodine measurements in thyroid glands. This study aimed to assess the potential use of DECT for the functional assessment of the thyroid gland. Thirteen patients with Grave's disease treated at our hospital from May to September 2015 were included in this retrospective study. Before treatments, all subjects had undergone both iodine scintigraphy [three and 24 h after oral administration of 123 I (20 μCi)] and non-enhanced DECT. The region of interests (ROIs) were placed in both lobes of the thyroid glands, and CT values (HU: Hounsfield unit) and iodine concentrations (mg/mL) calculated from DECT images were measured. The correlation between CT values and iodine concentrations from DECT in the thyroid gland was evaluated and then the iodine concentrations were compared with radioactive iodine uptake ratios by thyroid scintigraphy. Mean (±SD) 123 I uptake increased from 46.3 (±22.2) % (range, 11.1-80.1) at 3 h, to 66.5 (±15.2) % (range, 40.0-86.1) at 24 h (p < 0.01). CT values ranged from 34.5 to 98.7 HU [mean: 67.8 (±18.6)], while the iodine concentrations calculated with DECT ranged from 0.0 to 1.3 mg/mL [mean: 0.5 (±0.4)]. A moderate positive correlation between CT values and the calculated iodine concentrations in the thyroid gland was seen (R = 0.429, p < 0.05). A significant negative correlation between 123 I uptake at 3 h and iodine concentration by DECT were seen (R = -0.680, p < 0.05), although no correlation was observed between 123 I uptake at 3 h and CT values (p = 0.087). No correlation was observed between 123 I uptake at 24 h and CT values (p = 0.153) or that between 123 I uptake at 24 h and iodine concentration by DECT (p = 0.073). The negative correlation of 123 I uptake at 3 h with iodine concentration evaluated by DECT was better than that observed with simple CT value. DECT may have a potential role in the evaluation of iodine turnover in hyperthyroid patients.

Comparison of proton therapy treatment planning for head tumors with a pencil beam algorithm on dual and single energy CT images

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hudobivnik, Nace; Dedes, George; Parodi, Katia

2016-01-15

Purpose: Dual energy CT (DECT) has recently been proposed as an improvement over single energy CT (SECT) for stopping power ratio (SPR) estimation for proton therapy treatment planning (TP), thereby potentially reducing range uncertainties. Published literature investigated phantoms. This study aims at performing proton therapy TP on SECT and DECT head images of the same patients and at evaluating whether the reported improved DECT SPR accuracy translates into clinically relevant range shifts in clinical head treatment scenarios. Methods: Two phantoms were scanned at a last generation dual source DECT scanner at 90 and 150 kVp with Sn filtration. The firstmore » phantom (Gammex phantom) was used to calibrate the scanner in terms of SPR while the second served as evaluation (CIRS phantom). DECT images of five head trauma patients were used as surrogate cancer patient images for TP of proton therapy. Pencil beam algorithm based TP was performed on SECT and DECT images and the dose distributions corresponding to the optimized proton plans were calculated using a Monte Carlo (MC) simulation platform using the same patient geometry for both plans obtained from conversion of the 150 kVp images. Range shifts between the MC dose distributions from SECT and DECT plans were assessed using 2D range maps. Results: SPR root mean square errors (RMSEs) for the inserts of the Gammex phantom were 1.9%, 1.8%, and 1.2% for SECT phantom calibration (SECT{sub phantom}), SECT stoichiometric calibration (SECT{sub stoichiometric}), and DECT calibration, respectively. For the CIRS phantom, these were 3.6%, 1.6%, and 1.0%. When investigating patient anatomy, group median range differences of up to −1.4% were observed for head cases when comparing SECT{sub stoichiometric} with DECT. For this calibration the 25th and 75th percentiles varied from −2% to 0% across the five patients. The group median was found to be limited to 0.5% when using SECT{sub phantom} and the 25th and 75th percentiles varied from −1% to 2%. Conclusions: Proton therapy TP using a pencil beam algorithm and DECT images was performed for the first time. Given that the DECT accuracy as evaluated by two phantoms was 1.2% and 1.0% RMSE, it is questionable whether the range differences reported here are significant.« less

Water/cortical bone decomposition: A new approach in dual energy CT imaging for bone marrow oedema detection. A feasibility study.

PubMed

Biondi, M; Vanzi, E; De Otto, G; Banci Buonamici, F; Belmonte, G M; Mazzoni, L N; Guasti, A; Carbone, S F; Mazzei, M A; La Penna, A; Foderà, E; Guerreri, D; Maiolino, A; Volterrani, L

2016-12-01

Many studies aimed at validating the application of Dual Energy Computed Tomography (DECT) in clinical practice where conventional CT is not exhaustive. An example is given by bone marrow oedema detection, in which DECT based on water/calcium (W/Ca) decomposition was applied. In this paper a new DECT approach, based on water/cortical bone (W/CB) decomposition, was investigated. Eight patients suffering from marrow oedema were scanned with MRI and DECT. Two-materials density decomposition was performed in ROIs corresponding to normal bone marrow and oedema. These regions were drawn on DECT images using MRI informations. Both W/Ca and W/CB were considered as material basis. Scatter plots of W/Ca and W/CB concentrations were made for each ROI in order to evaluate if oedema could be distinguished from normal bone marrow. Thresholds were defined on the scatter plots in order to produce DECT images where oedema regions were highlighted through color maps. The agreement between these images and MR was scored by two expert radiologists. For all the patients, the best scores were obtained using W/CB density decomposition. In all cases, DECT color map images based on W/CB decomposition showed better agreement with MR in bone marrow oedema identification with respect to W/Ca decomposition. This result encourages further studies in order to evaluate if DECT based on W/CB decomposition could be an alternative technique to MR, which would be important when short scanning duration is relevant, as in the case of aged or traumatic patients. Copyright © 2016 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

Dual-energy CT for the diagnosis of gout: an accuracy and diagnostic yield study.

PubMed

Bongartz, Tim; Glazebrook, Katrina N; Kavros, Steven J; Murthy, Naveen S; Merry, Stephen P; Franz, Walter B; Michet, Clement J; Veetil, Barath M Akkara; Davis, John M; Mason, Thomas G; Warrington, Kenneth J; Ytterberg, Steven R; Matteson, Eric L; Crowson, Cynthia S; Leng, Shuai; McCollough, Cynthia H

2015-06-01

To assess the accuracy of dual-energy CT (DECT) for diagnosing gout, and to explore whether it can have any impact on clinical decision making beyond the established diagnostic approach using polarising microscopy of synovial fluid (diagnostic yield). Diagnostic single-centre study of 40 patients with active gout, and 41 individuals with other types of joint disease. Sensitivity and specificity of DECT for diagnosing gout was calculated against a combined reference standard (polarising and electron microscopy of synovial fluid). To explore the diagnostic yield of DECT scanning, a third cohort was assembled consisting of patients with inflammatory arthritis and risk factors for gout who had negative synovial fluid polarising microscopy results. Among these patients, the proportion of subjects with DECT findings indicating a diagnosis of gout was assessed. The sensitivity and specificity of DECT for diagnosing gout was 0.90 (95% CI 0.76 to 0.97) and 0.83 (95% CI 0.68 to 0.93), respectively. All false negative patients were observed among patients with acute, recent-onset gout. All false positive patients had advanced knee osteoarthritis. DECT in the diagnostic yield cohort revealed evidence of uric acid deposition in 14 out of 30 patients (46.7%). DECT provides good diagnostic accuracy for detection of monosodium urate (MSU) deposits in patients with gout. However, sensitivity is lower in patients with recent-onset disease. DECT has a significant impact on clinical decision making when gout is suspected, but polarising microscopy of synovial fluid fails to demonstrate the presence of MSU crystals. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Dual-energy CT revisited with multidetector CT: review of principles and clinical applications.

PubMed

Karçaaltıncaba, Muşturay; Aktaş, Aykut

2011-09-01

Although dual-energy CT (DECT) was first conceived in the 1970s, it was not widely used for CT indications. Recently, the simultaneous acquisition of volumetric dual-energy data has been introduced using multidetector CT (MDCT) with two X-ray tubes and rapid kVp switching (gemstone spectral imaging). Two major advantages of DECT are material decomposition by acquiring two image series with different kVp and the elimination of misregistration artifacts. Hounsfield unit measurements by DECT are not absolute and can change depending on the kVp used for an acquisition. Typically, a combination of 80/140 kVp is used for DECT, but for some applications, 100/140 kVp is preferred. In this study, we summarized the clinical applications of DECT and included images that were acquired using the dual-source CT and rapid kVp switching. In general, unenhanced images can be avoided by using DECT for body and neurological applications; iodine can be removed from the image, and a virtual, non-contrast (water) image can be obtained. Neuroradiological applications allow for the removal of bone and calcium from the carotid and brain CT angiography. Thorax applications include perfusion imaging in patients with pulmonary thromboemboli and other chest diseases, xenon ventilation-perfusion imaging and solitary nodule characterization. Cardiac applications include dual-energy cardiac perfusion, viability and cardiac iron detection. The removal of calcific plaques from arteries, bone removal and aortic stent graft evaluation may be achieved in the vascular system. Abdominal applications include the detection and characterization of liver and pancreas masses, the diagnosis of steatosis and iron overload, DECT colonoscopy and CT cholangiography. Urinary system applications are urinary calculi characterization (uric acid vs. non-uric acid), renal cyst characterization and mass characterization. Musculoskeletal applications permit the differentiation of gout from pseudogout and a reduction of metal artifacts. Recent introduction of iterative reconstruction techniques can increase the use of DECT techniques; the use of dual energy in patients with a high BMI is limited due to noise and the radiation dose. DECT may be a good alternative to PET-CT. Iodine map images can quantify iodine uptake, and this approach may be more effective than obtaining non-contrast and post-contrast images for the diagnosis of a solid mass. Thus, computer-aided detection may be used more effectively in CT applications. DECT is a promising technique with potential clinical applications.

Top 50 Highly Cited Articles on Dual Energy Computed Tomography (DECT) in Abdominal Radiology: A Bibliometric Analysis.

PubMed

Gong, Bo; Wu, Yuhao; O'Keeffe, Michael E; Berger, Ferco H; McLaughlin, Patrick D; Nicolaou, Savvas; Khosa, Faisal

2017-01-01

This study aims to identify the 50 most highly cited articles on dual energy computed tomography (DECT) in abdominal radiology Thomson Reuters Web of Science All Databases was queried without year or language restriction. Only original research articles with a primary focus on abdominal radiology using DECT were selected. Review articles, meta-analyses, and studies without human subjects were excluded. Fifty articles with the highest average yearly citation were identified. These articles were published between 2007 and 2017 in 12 journals, with the most in Radiology (12 articles). Articles had a median of 7 authors, with all first authors but one primarily affiliated to radiology departments. The United States of America produced the most articles (16), followed by Germany (13 articles), and China (7 articles). Most studies used Dual Source DECT technology (35 articles), followed by Rapid Kilovoltage Switching (14 articles), and Sequential Scanning (1 article). The top three scanned organs were the liver (24%), kidney (16%), and urinary tract (15%). The most commonly studied pathology was urinary calculi (28%), renal lesion/tumor (23%), and hepatic lesion/tumor (20%). Our study identifies intellectual milestones in the applications of DECT in abdominal radiology. The diversity of the articles reflects on the characteristics and quality of the most influential publications related to DECT.

Top 50 Highly Cited Articles on Dual Energy Computed Tomography (DECT) in Abdominal Radiology: A Bibliometric Analysis

PubMed Central

Gong, Bo; Wu, Yuhao; O’Keeffe, Michael E; Berger, Ferco H; McLaughlin, Patrick D; Nicolaou, Savvas

2017-01-01

Summary This study aims to identify the 50 most highly cited articles on dual energy computed tomography (DECT) in abdominal radiology Thomson Reuters Web of Science All Databases was queried without year or language restriction. Only original research articles with a primary focus on abdominal radiology using DECT were selected. Review articles, meta-analyses, and studies without human subjects were excluded. Fifty articles with the highest average yearly citation were identified. These articles were published between 2007 and 2017 in 12 journals, with the most in Radiology (12 articles). Articles had a median of 7 authors, with all first authors but one primarily affiliated to radiology departments. The United States of America produced the most articles (16), followed by Germany (13 articles), and China (7 articles). Most studies used Dual Source DECT technology (35 articles), followed by Rapid Kilovoltage Switching (14 articles), and Sequential Scanning (1 article). The top three scanned organs were the liver (24%), kidney (16%), and urinary tract (15%). The most commonly studied pathology was urinary calculi (28%), renal lesion/tumor (23%), and hepatic lesion/tumor (20%). Our study identifies intellectual milestones in the applications of DECT in abdominal radiology. The diversity of the articles reflects on the characteristics and quality of the most influential publications related to DECT. PMID:29657641

Poster — Thur Eve — 14: Improving Tissue Segmentation for Monte Carlo Dose Calculation using DECT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Di Salvio, A.; Bedwani, S.; Carrier, J-F.

2014-08-15

Purpose: To improve Monte Carlo dose calculation accuracy through a new tissue segmentation technique with dual energy CT (DECT). Methods: Electron density (ED) and effective atomic number (EAN) can be extracted directly from DECT data with a stoichiometric calibration method. Images are acquired with Monte Carlo CT projections using the user code egs-cbct and reconstructed using an FDK backprojection algorithm. Calibration is performed using projections of a numerical RMI phantom. A weighted parameter algorithm then uses both EAN and ED to assign materials to voxels from DECT simulated images. This new method is compared to a standard tissue characterization frommore » single energy CT (SECT) data using a segmented calibrated Hounsfield unit (HU) to ED curve. Both methods are compared to the reference numerical head phantom. Monte Carlo simulations on uniform phantoms of different tissues using dosxyz-nrc show discrepancies in depth-dose distributions. Results: Both SECT and DECT segmentation methods show similar performance assigning soft tissues. Performance is however improved with DECT in regions with higher density, such as bones, where it assigns materials correctly 8% more often than segmentation with SECT, considering the same set of tissues and simulated clinical CT images, i.e. including noise and reconstruction artifacts. Furthermore, Monte Carlo results indicate that kV photon beam depth-dose distributions can double between two tissues of density higher than muscle. Conclusions: A direct acquisition of ED and the added information of EAN with DECT data improves tissue segmentation and increases the accuracy of Monte Carlo dose calculation in kV photon beams.« less

Dual-energy computed tomography as a diagnostic tool for gout during intercritical periods.

PubMed

Breuer, Gabriel S; Bogot, Naama; Nesher, Gideon

2016-12-01

The aim of this study is to evaluate the diagnostic yield of dual-energy computed tomography (DECT) in detection of uric acid accumulation in joints or periarticular structures in patients suspected of having gout, in their intercritical period. Patients with a history of recurrent, short-lived mono- or oligo-arthralgia or arthritis, referred to the rheumatology clinic for diagnosis of their condition, were included in this retrospective evaluation. DECT confirmed the diagnosis of gout in 30 of 50 patients (60%). A positive DECT was present in 12 of 16 cases (75%) with serum uric acid > 8.5 mg/dL, compared to seven of 13 cases (54%) and two of five cases (40%) with levels of 6.1-8.5 mg/dL and ≤ 6 mg/dL, respectively. The diagnostic impact of screening hands and feet were highest (78% and 56%, respectively). Follow-up data were available for 24 of the 30 patients with urate deposits identified by DECT. Twenty-one were treated with urate-lowering agents, all responded with lowering of serum uric acid and cessation of flares. Follow-up data were available for 16 of the 20 patients with no urate deposits identified by DECT. Gout was diagnosed in two of them by synovial fluid examination during subsequent flares. Both positive and negative predictive values of DECT for diagnosing gout in this patient population were 87%. Following DECT, treatment regimen was modified to gout-specific therapy in 52% of the patients. The ability to make a definite diagnosis of gout by DECT imaging in a substantial number of asymptomatic patients in the intercritical period should help in treatment decision-making and improve patient adherence to long-term urate-lowering therapy. © 2016 Asia Pacific League of Associations for Rheumatology and John Wiley & Sons Australia, Ltd.

Dual-energy CT iodine maps as an alternative quantitative imaging biomarker to abdominal CT perfusion: determination of appropriate trigger delays for acquisition using bolus tracking.

PubMed

Skornitzke, Stephan; Fritz, Franziska; Mayer, Philipp; Koell, Marco; Hansen, Jens; Pahn, Gregor; Hackert, Thilo; Kauczor, Hans-Ulrich; Stiller, Wolfram

2018-05-01

Quantitative evaluation of different bolus tracking trigger delays for acquisition of dual energy (DE) CT iodine maps as an alternative to CT perfusion. Prior to this retrospective analysis of prospectively acquired data, DECT perfusion sequences were dynamically acquired in 22 patients with pancreatic carcinoma using dual source CT at 80/140 kV p with tin filtration. After deformable motion-correction, perfusion maps of blood flow (BF) were calculated from 80 kV p image series of DECT, and iodine maps were calculated for each of the 34 DECT acquisitions per patient. BF and iodine concentrations were measured in healthy pancreatic tissue and carcinoma. To evaluate potential DECT acquisition triggered by bolus tracking, measured iodine concentrations from the 34 DECT acquisitions per patient corresponding to different trigger delays were assessed for correlation to BF and intergroup differences between tissue types depending on acquisition time. Average BF measured in healthy pancreatic tissue and carcinoma was 87.6 ± 28.4 and 38.6 ± 22.2 ml/100 ml min -1 , respectively. Correlation between iodine concentrations and BF was statistically significant for bolus tracking with trigger delay greater than 0 s (r max = 0.89; p < 0.05). Differences in iodine concentrations between healthy pancreatic tissue and carcinoma were statistically significant for DECT acquisitions corresponding to trigger delays of 15-21 s (p < 0.05). An acquisition window between 15 and 21 s after exceeding bolus tracking threshold shows promising results for acquisition of DECT iodine maps as an alternative to CT perfusion measurements of BF. Advances in knowledge: After clinical validation, DECT iodine maps of pancreas acquired using bolus tracking with appropriate trigger delay as determined in this study could offer an alternative quantitative imaging biomarker providing functional information for tumor assessment at reduced patient radiation exposure compared to CT perfusion measurements of BF.

New state distribution and host records of North American Buprestidae (Coleoptera)

Treesearch

Jason A. Hansen; Toby R. Petrice; Robert A. Haack

2011-01-01

The following new state records are reported for buprestid species in the eastern United States: Agrilus egeniformis Champlain and Knull and Polyceta elata LeConte from Georgia, Agrilus defectus LeConte and Agrilus vittaticollis (Randall) from Minnesota and Agrilus...

Dual energy computed tomography for the head.

PubMed

Naruto, Norihito; Itoh, Toshihide; Noguchi, Kyo

2018-02-01

Dual energy CT (DECT) is a promising technology that provides better diagnostic accuracy in several brain diseases. DECT can generate various types of CT images from a single acquisition data set at high kV and low kV based on material decomposition algorithms. The two-material decomposition algorithm can separate bone/calcification from iodine accurately. The three-material decomposition algorithm can generate a virtual non-contrast image, which helps to identify conditions such as brain hemorrhage. A virtual monochromatic image has the potential to eliminate metal artifacts by reducing beam-hardening effects. DECT also enables exploration of advanced imaging to make diagnosis easier. One such novel application of DECT is the X-Map, which helps to visualize ischemic stroke in the brain without using iodine contrast medium.

WE-D-BRF-05: Quantitative Dual-Energy CT Imaging for Proton Stopping Power Computation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Han, D; Williamson, J; Siebers, J

2014-06-15

Purpose: To extend the two-parameter separable basis-vector model (BVM) to estimation of proton stopping power from dual-energy CT (DECT) imaging. Methods: BVM assumes that the photon cross sections of any unknown material can be represented as a linear combination of the corresponding quantities for two bracketing basis materials. We show that both the electron density (ρe) and mean excitation energy (Iex) can be modeled by BVM, enabling stopping power to be estimated from the Bethe-Bloch equation. We have implemented an idealized post-processing dual energy imaging (pDECT) simulation consisting of monogenetic 45 keV and 80 keV scanning beams with polystyrene-water andmore » water-CaCl2 solution basis pairs for soft tissues and bony tissues, respectively. The coefficients of 24 standard ICRU tissue compositions were estimated by pDECT. The corresponding ρe, Iex, and stopping power tables were evaluated via BVM and compared to tabulated ICRU 44 reference values. Results: BVM-based pDECT was found to estimate ρe and Iex with average and maximum errors of 0.5% and 2%, respectively, for the 24 tissues. Proton stopping power values at 175 MeV, show average/maximum errors of 0.8%/1.4%. For adipose, muscle and bone, these errors result range prediction accuracies less than 1%. Conclusion: A new two-parameter separable DECT model (BVM) for estimating proton stopping power was developed. Compared to competing parametric fit DECT models, BVM has the comparable prediction accuracy without necessitating iterative solution of nonlinear equations or a sample-dependent empirical relationship between effective atomic number and Iex. Based on the proton BVM, an efficient iterative statistical DECT reconstruction model is under development.« less

In vivo comparison of tantalum, tungsten, and bismuth enteric contrast agents to complement intravenous iodine for double-contrast dual-energy CT of the bowel

PubMed Central

Rathnayake, Samira; Mongan, John; Torres, Andrew S.; Colborn, Robert; Gao, Dong-Wei; Yeh, Benjamin M; Fu, Yanjun

2016-01-01

To assess the ability of dual-energy CT (DECT) to separate intravenous contrast of bowel wall from intraluminal contrast, we scanned 16 rabbits on a clinical DECT scanner: n=3 using only iodinated intravenous contrast; and n=13 double-contrast enhanced scans using iodinated intravenous contrast and experimental enteric non-iodinated contrast agents in the bowel lumen (5 bismuth-, 4 tungsten-, and 4 tantalum-based). Representative image pairs from conventional CT images and DECT iodine density maps of small bowel (116 pairs from 232 images) were viewed by four abdominal imaging attending radiologists to independently score each comparison pair on a visual analog scale (−100 to +100%) for: 1) preference in small bowel wall visualization; and 2) preference in completeness of intraluminal enteric contrast subtraction. Median small bowel wall visualization was scored 39 and 42 percentage points (95% CI: 30–44% and 36–45%, p<0.001 both) higher at double-contrast DECT than at conventional CT with enteric tungsten and tantalum contrast, respectively. Median small bowel wall visualization at double-contrast DECT was scored 29 and 35 percentage points (95% CI: 20–35% and 33–39%, p<0.001 both) higher with enteric tungsten and tantalum, respectively, than with bismuth contrast. Median completeness of intraluminal enteric contrast subtraction in double-contrast DECT iodine density maps was scored 28 and 29 percentage points (95% CI: 15–31% and 28–33%, p<0.001 both) higher with enteric tungsten and tantalum, respectively, than with bismuth contrast. Results suggest that in vivo double-contrast DECT with iodinated intravenous and either tantalum- or tungsten-based enteric contrast provide better visualization of small bowel than conventional CT. PMID:26892945

Personalized assessment of radiation risks from the one-stop-shop myocardial 256-slice CT examination.

PubMed

Perisinakis, Kostas; Seimenis, Ioannis; Tzedakis, Antonis; Pagonidis, Kostas; Papadakis, Antonios E; Damilakis, John

2013-10-15

This study provides data on the cumulative life attributable risk (LAR) of radiation-induced cancer from the combination of coronary CT angiography (CCTA), dynamic CT perfusion (CTP) and delayed enhancement (DE) CT scans, required for reliable risk-benefit analysis of the one-stop-shop CCTA + CTP + DECT cardiac examination. Monte Carlo simulation of the dynamic CTP and DECT exposures on 62 adult individuals was employed to determine radiation absorbed dose to exposed radiosensitive organs. Corresponding data for CCTA were derived using patient chest circumference and previously published data. Individual-specific LARs of cancer were estimated using organ/tissue-specific radiogenic cancer risk factors. Total LAR from CCTA + CTP + DECT scans' sequence were estimated and compared to nominal intrinsic risk of cancer. The main contribution, up to 80%, to cumulative radiation burden from CCTA + CTP + DECT scan-sequence was found to originate from the CTP scan. The total LAR from CCTA + CTP + DECT for females was found 4-6 times higher, compared to males. The mean cumulative risk of radiogenic cancer associated with the complete CCTA + CTP + DECT scan sequence was found to marginally increase the intrinsic risk for cancer induction by less than 0.6% and 0.1% for females and males, respectively. The radiation risk from the 256-slice CCTA + CTP + DECT scan sequence may be considered low and should not constitute an obstacle for the clinical endorsement of the one-stop-shop cardiac CT examination, given that its clinical value has been well verified. Nevertheless, every effort should be made towards optimization of the dynamic CTP component which is the main contributor to patient radiation burden. © 2013.

Ultrasound scans and dual energy CT identify tendons as preferred anatomical location of MSU crystal depositions in gouty joints.

PubMed

Yuan, Yuan; Liu, Chang; Xiang, Xi; Yuan, Tong-Ling; Qiu, Li; Liu, Yi; Luo, Yu-Bin; Zhao, Y; Herrmann, Martin

2018-05-01

The present study was performed to localize the articular deposition of monosodium urate (MSU) crystal in joints. We compare the detection efficiencies of dual-energy CT (DECT) and ultrasound scans. Analyses by DECT and ultrasound were performed with 184 bilateral joints of the lower limbs of 54 consecutive gout patients. All joints were categorized into (1) knee, (2) ankle, (3) MTP1, and (4) MTP2, and sorted into those with and those without detectable MSU deposition. The comparison of the positive rate between DECT and ultrasound and the agreement was performed using the McNemar test and the Cohen's κ coefficient, respectively. Next, we listed the MSU crystal deposition as assessed by ultrasound between the DECT-positive and -negative joints according to their interior structure. We included tendons, synovia, cartilage, subcutaneous tissue, etc. RESULTS: Among all joints, the percentages with MSU crystal deposition detected by DECT (99/184, 53.8%) and ultrasound (106/184, 57.6%) were comparable (P = 0.530 > 0.05). For MTP1 (21/34, 61.8%; 12/34, 35.3%; P < 0.05) and MTP2-5 (17/34, 50.0%; 10/34, 29.4%, P < 0.05), ultrasound and DECT were more efficient, respectively. The data concordance in 46 of 50 joints (92.00%; κ = 0.769, P < 0.05) for knee; and 27 of 34 joints (79.41%; κ = 0.588, P < 0.05) for MTP2-5 and suggested that tendons were the most frequent anatomical location of MSU crystal deposition. The tendons are the most frequent anatomical location of MSU crystal depositions. The concordance rate of knee joints and MTP2-5 joints shows good agreement between DECT and ultrasound depending on the location.

Comparison of the sensitivity and specificity of 5 image sets of dual-energy computed tomography for detecting first-pass myocardial perfusion defects compared with positron emission tomography.

PubMed

Li, Wenhuan; Zhu, Xiaolian; Li, Jing; Peng, Cheng; Chen, Nan; Qi, Zhigang; Yang, Qi; Gao, Yan; Zhao, Yang; Sun, Kai; Li, Kuncheng

2014-12-01

The sensitivity and specificity of 5 different image sets of dual-energy computed tomography (DECT) for the detection of first-pass myocardial perfusion defects have not systematically been compared using positron emission tomography (PET) as a reference standard. Forty-nine consecutive patients, with known or strongly suspected of coronary artery disease, were prospectively enrolled in our study. Cardiac DECT was performed at rest state using a second-generation 128-slice dual-source CT. The DECT data were reconstructed to iodine maps, monoenergetic images, 100 kV images, nonlinearly blended images, and linearly blended images by different postprocessing techniques. The myocardial perfusion defects on DECT images were visually assessed by 5 observers, using standard 17-segment model. Diagnostic accuracy of 5 image sets was assessed using nitrogen-13 ammonia PET as the gold standard. Discrimination was quantified using the area under the receiver operating characteristic curve (AUC), and AUCs were compared using the method of DeLong. The DECT and PET examinations were successfully completed in 30 patients and a total of 90 territories and 510 segments were analyzed. Cardiac PET revealed myocardial perfusion defects in 56 territories (62%) and 209 segments (41%). The AUC of iodine maps, monoenergetic images, 100 kV images, nonlinearly blended images, and linearly blended images were 0.986, 0.934, 0.913, 0.881, and 0.871, respectively, on a per-territory basis. These values were 0.922, 0.813, 0.779, 0.763, and 0.728, respectively, on a per-segment basis. DECT iodine maps shows high sensitivity and specificity, and is superior to other DECT image sets for the detection of myocardial perfusion defects in the first-pass myocardial perfusion.

Technical note: optimization for improved tube-loading efficiency in the dual-energy computed tomography coupled with balanced filter method.

PubMed

Saito, Masatoshi

2010-08-01

This article describes the spectral optimization of dual-energy computed tomography using balanced filters (bf-DECT) to reduce the tube loadings and dose by dedicating to the acquisition of electron density information, which is essential for treatment planning in radiotherapy. For the spectral optimization of bf-DECT, the author calculated the beam-hardening error and air kerma required to achieve a desired noise level in an electron density image of a 50-cm-diameter cylindrical water phantom. The calculation enables the selection of beam parameters such as tube voltage, balanced filter material, and its thickness. The optimal combination of tube voltages was 80 kV/140 kV in conjunction with Tb/Hf and Bi/Mo filter pairs; this combination agrees with that obtained in a previous study [M. Saito, "Spectral optimization for measuring electron density by the dual-energy computed tomography coupled with balanced filter method," Med. Phys. 36, 3631-3642 (2009)], although the thicknesses of the filters that yielded a minimum tube output were slightly different from those obtained in the previous study. The resultant tube loading of a low-energy scan of the present bf-DECT significantly decreased from 57.5 to 4.5 times that of a high-energy scan for conventional DECT. Furthermore, the air kerma of bf-DECT could be reduced to less than that of conventional DECT, while obtaining the same figure of merit for the measurement of electron density and effective atomic number. The tube-loading and dose efficiencies of bf-DECT were considerably improved by sacrificing the quality of the noise level in the images of effective atomic number.

White Paper of the Society of Computed Body Tomography and Magnetic Resonance on Dual-Energy CT, Part 1: Technology and Terminology.

PubMed

Siegel, Marilyn J; Kaza, Ravi K; Bolus, David N; Boll, Daniel T; Rofsky, Neil M; De Cecco, Carlo N; Foley, W Dennis; Morgan, Desiree E; Schoepf, U Joseph; Sahani, Dushyant V; Shuman, William P; Vrtiska, Terri J; Yeh, Benjamin M; Berland, Lincoln L

This is the first of a series of 4 white papers that represent Expert Consensus Documents developed by the Society of Computed Body Tomography and Magnetic Resonance through its task force on dual-energy computed tomography (DECT). This article, part 1, describes the fundamentals of the physical basis for DECT and the technology of DECT and proposes uniform nomenclature to account for differences in proprietary terms among manufacturers.

TH-CD-202-05: DECT Based Tissue Segmentation as Input to Monte Carlo Simulations for Proton Treatment Verification Using PET Imaging

DOE Office of Scientific and Technical Information (OSTI.GOV)

Berndt, B; Wuerl, M; Dedes, G

Purpose: To improve agreement of predicted and measured positron emitter yields in patients, after proton irradiation for PET-based treatment verification, using a novel dual energy CT (DECT) tissue segmentation approach, overcoming known deficiencies from single energy CT (SECT). Methods: DECT head scans of 5 trauma patients were segmented and compared to existing decomposition methods with a first focus on the brain. For validation purposes, three brain equivalent solutions [water, white matter (WM) and grey matter (GM) – equivalent with respect to their reference carbon and oxygen contents and CT numbers at 90kVp and 150kVp] were prepared from water, ethanol, sucrosemore » and salt. The activities of all brain solutions, measured during a PET scan after uniform proton irradiation, were compared to Monte Carlo simulations. Simulation inputs were various solution compositions obtained from different segmentation approaches from DECT, SECT scans, and known reference composition. Virtual GM solution salt concentration corrections were applied based on DECT measurements of solutions with varying salt concentration. Results: The novel tissue segmentation showed qualitative improvements in %C for patient brain scans (ground truth unavailable). The activity simulations based on reference solution compositions agree with the measurement within 3–5% (4–8Bq/ml). These reference simulations showed an absolute activity difference between WM (20%C) and GM (10%C) to H2O (0%C) of 43 Bq/ml and 22 Bq/ml, respectively. Activity differences between reference simulations and segmented ones varied from −6 to 1 Bq/ml for DECT and −79 to 8 Bq/ml for SECT. Conclusion: Compared to the conventionally used SECT segmentation, the DECT based segmentation indicates a qualitative and quantitative improvement. In controlled solutions, a MC input based on DECT segmentation leads to better agreement with the reference. Future work will address the anticipated improvement of quantification accuracy in patients, comparing different tissue decomposition methods with an MR brain segmentation. Acknowledgement: DFG-MAP and HIT-Heidelberg Deutsche Forschungsgemeinschaft (MAP); Bundesministerium fur Bildung und Forschung (01IB13001)« less

SU-F-J-195: On the Performance of Four Dual Energy CT Formalisms for Extracting Proton Stopping Powers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baer, E; Royle, G; Lalonde, A

Purpose: Dual energy CT can predict stopping power ratios (SPR) for ion therapy treatment planning. Several approaches have been proposed recently, however accuracy and practicability in a clinical workflow are unaddressed. The aim of this work is to provide a fair comparison of available approaches in a human-like phantom to find the optimal method for tissue characterization in a clinical situation. Methods: The SPR determination accuracy is investigated using simulated DECT images. A virtual human-like phantom is created containing 14 different standard human tissues. SECT (120 kV) and DECT images (100 kV and 140 kV Sn) are simulated using themore » software ImaSim. The single energy CT (SECT) stoichiometric calibration method and four recently published calibration-based DECT methods are implemented and used to predict the SPRs from simulated images. The difference between SPR predictions and theoretical SPR are compared pixelwize. Mean, standard deviation and skewness of the SPR difference distributions are used as measures for bias, dispersion and symmetry. Results: The average SPR differences and standard deviations are (0.22 ± 1.27)% for SECT, and A) (−0.26 ± 1.30)%, B) (0.08 ± 1.12)%, C) (0.06 ± 1.15)% and D) (−0.05 ± 1.05)% for the four DECT methods. While SPR prediction using SECT is showing a systematic error on SPR, the DECT methods B, C and D are unbiased. The skewness of the SECT distribution is 0.57%, and A) −0.19%, B) −0.56%, C) −0.29% and D) −0.07% for DECT methods respectively. Conclusion: The here presented DECT methods B, C and D outperform the commonly used SECT stoichiometric calibration. These methods predict SPR accurately without a bias and within ± 1.2% (68th percentile). This indicates that DECT potentially improves accuracy of range predictions in proton therapy. A validation of these findings using clinical CT images of real tissues is necessary.« less

Spectral optimization for measuring electron density by the dual-energy computed tomography coupled with balanced filter method.

PubMed

Saito, Masatoshi

2009-08-01

Dual-energy computed tomography (DECT) has the potential for measuring electron density distribution in a human body to predict the range of particle beams for treatment planning in proton or heavy-ion radiotherapy. However, thus far, a practical dual-energy method that can be used to precisely determine electron density for treatment planning in particle radiotherapy has not been developed. In this article, another DECT technique involving a balanced filter method using a conventional x-ray tube is described. For the spectral optimization of DECT using balanced filters, the author calculates beam-hardening error and air kerma required to achieve a desired noise level in electron density and effective atomic number images of a cylindrical water phantom with 50 cm diameter. The calculation enables the selection of beam parameters such as tube voltage, balanced filter material, and its thickness. The optimized parameters were applied to cases with different phantom diameters ranging from 5 to 50 cm for the calculations. The author predicts that the optimal combination of tube voltages would be 80 and 140 kV with Tb/Hf and Bi/Mo filter pairs for the 50-cm-diameter water phantom. When a single phantom calibration at a diameter of 25 cm was employed to cover all phantom sizes, maximum absolute beam-hardening errors were 0.3% and 0.03% for electron density and effective atomic number, respectively, over a range of diameters of the water phantom. The beam-hardening errors were 1/10 or less as compared to those obtained by conventional DECT, although the dose was twice that of the conventional DECT case. From the viewpoint of beam hardening and the tube-loading efficiency, the present DECT using balanced filters would be significantly more effective in measuring the electron density than the conventional DECT. Nevertheless, further developments of low-exposure imaging technology should be necessary as well as x-ray tubes with higher outputs to apply DECT coupled with the balanced filter method for clinical use.

WE-EF-207-07: Dual Energy CT with One Full Scan and a Second Sparse-View Scan Using Structure Preserving Iterative Reconstruction (SPIR)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, T; Zhu, L

Purpose: Conventional dual energy CT (DECT) reconstructs CT and basis material images from two full-size projection datasets with different energy spectra. To relax the data requirement, we propose an iterative DECT reconstruction algorithm using one full scan and a second sparse-view scan by utilizing redundant structural information of the same object acquired at two different energies. Methods: We first reconstruct a full-scan CT image using filtered-backprojection (FBP) algorithm. The material similarities of each pixel with other pixels are calculated by an exponential function about pixel value differences. We assume that the material similarities of pixels remains in the second CTmore » scan, although pixel values may vary. An iterative method is designed to reconstruct the second CT image from reduced projections. Under the data fidelity constraint, the algorithm minimizes the L2 norm of the difference between pixel value and its estimation, which is the average of other pixel values weighted by their similarities. The proposed algorithm, referred to as structure preserving iterative reconstruction (SPIR), is evaluated on physical phantoms. Results: On the Catphan600 phantom, SPIR-based DECT method with a second 10-view scan reduces the noise standard deviation of a full-scan FBP CT reconstruction by a factor of 4 with well-maintained spatial resolution, while iterative reconstruction using total-variation regularization (TVR) degrades the spatial resolution at the same noise level. The proposed method achieves less than 1% measurement difference on electron density map compared with the conventional two-full-scan DECT. On an anthropomorphic pediatric phantom, our method successfully reconstructs the complicated vertebra structures and decomposes bone and soft tissue. Conclusion: We develop an effective method to reduce the number of views and therefore data acquisition in DECT. We show that SPIR-based DECT using one full scan and a second 10-view scan can provide high-quality DECT images and accurate electron density maps as conventional two-full-scan DECT.« less

A phase I feasibility study of multi-modality imaging assessing rapid expansion of marrow fat and decreased bone mineral density in cancer patients

PubMed Central

Hui, Susanta K; Arentsen, Luke; Sueblinvong, Thanasak; Brown, Keenan; Bolan, Pat; Ghebre, Rahel G; Downs, Levi; Shanley, Ryan; Hansen, Karen E.; Minenko, Anne G.; Takhashi, Yutaka; Yagi, Masashi; Zhang, Yan; Geller, Melissa; Reynolds, Margaret; Lee, Chung K; Blaes, Anne H.; Allen, Sharon; Zobel, Bruno Beomonte; Le, Chap; Froelich, Jerry; Rosen, Clifford; Yee, Douglas

2014-01-01

Purpose Cancer survivors are at an increased risk for fractures, but lack of effective and economical biomarkers limits quantitative assessments of marrow fat (MF), bone mineral density (BMD) and their relation in response to cytotoxic cancer treatment. We report dual energy CT (DECT) imaging, commonly used for cancer diagnosis, treatment and surveillance, as a novel biomarker of MF and BMD. Methods We validated DECT in pre-clinical and Phase I clinical trials and verified with water-fat MRI (WF-MRI), quantitative CT (QCT) and dual-energy X-ray absorptiometry (DXA). Basis material composition framework was validated using water and small-chain alcohols simulating different components of bone marrow. Histologic validation was achieved by measuring percent adipocyte in cadaver vertebrae and compared with DECT and WF-MRI. For a Phase I trial, sixteen patients with gynecologic malignancies (treated with oophorectomy, radiotherapy or chemotherapy) underwent DECT, QCT, WF-MRI and DXA before and 12 months after treatment. BMD and MF percent and distribution were quantified in lumbar vertebrae and the right femoral neck. Results Measured precision (3 mg/cm3) was sufficient to distinguish test solutions. Adiposity in cadaver bone histology was highly correlated with MF measured using DECT and WF-MRI (r = 0.80 and 0.77, respectively). In the clinical trial, DECT showed high overall correlation (r = 0.77, 95% CI: 0.69, 0.83) with WF-MRI. MF increased significantly after treatment (p<0.002). Chemotherapy and radiation caused greater increases in MF than oophorectomy (p<0.032). L4 BMD decreased 14% by DECT, 20% by QCT, but only by 5% by DXA (p<0.002 for all). At baseline, we observed a statistically significant inverse association between MF and BMD which was dramatically attenuated after treatment. Conclusion Our study demonstrated that DECT, similar to WF-MRI, can accurately measure marrow adiposity. Both imaging modalities show rapid increase in MF following cancer treatment. Our results suggest that MF and BMD cannot be used interchangeably to monitor skeletal health following cancer therapy. PMID:25536285

A phase I feasibility study of multi-modality imaging assessing rapid expansion of marrow fat and decreased bone mineral density in cancer patients.

PubMed

Hui, Susanta K; Arentsen, Luke; Sueblinvong, Thanasak; Brown, Keenan; Bolan, Pat; Ghebre, Rahel G; Downs, Levi; Shanley, Ryan; Hansen, Karen E; Minenko, Anne G; Takhashi, Yutaka; Yagi, Masashi; Zhang, Yan; Geller, Melissa; Reynolds, Margaret; Lee, Chung K; Blaes, Anne H; Allen, Sharon; Zobel, Bruno Beomonte; Le, Chap; Froelich, Jerry; Rosen, Clifford; Yee, Douglas

2015-04-01

Cancer survivors are at an increased risk for fractures, but lack of effective and economical biomarkers limits quantitative assessments of marrow fat (MF), bone mineral density (BMD) and their relation in response to cytotoxic cancer treatment. We report dual energy CT (DECT) imaging, commonly used for cancer diagnosis, treatment and surveillance, as a novel biomarker of MF and BMD. We validated DECT in pre-clinical and phase I clinical trials and verified with water-fat MRI (WF-MRI), quantitative CT (QCT) and dual-energy X-ray absorptiometry (DXA). Basis material composition framework was validated using water and small-chain alcohols simulating different components of bone marrow. Histologic validation was achieved by measuring percent adipocyte in the cadaver vertebrae and compared with DECT and WF-MRI. For a phase I trial, sixteen patients with gynecologic malignancies (treated with oophorectomy, radiotherapy or chemotherapy) underwent DECT, QCT, WF-MRI and DXA before and 12months after treatment. BMD and MF percent and distribution were quantified in the lumbar vertebrae and the right femoral neck. Measured precision (3mg/cm(3)) was sufficient to distinguish test solutions. Adiposity in cadaver bone histology was highly correlated with MF measured using DECT and WF-MRI (r=0.80 and 0.77, respectively). In the clinical trial, DECT showed high overall correlation (r=0.77, 95% CI: 0.69, 0.83) with WF-MRI. MF increased significantly after treatment (p<0.002). Chemotherapy and radiation caused greater increases in MF than oophorectomy (p<0.032). L4 BMD decreased 14% by DECT, 20% by QCT, but only 5% by DXA (p<0.002 for all). At baseline, we observed a statistically significant inverse association between MF and BMD which was dramatically attenuated after treatment. Our study demonstrated that DECT, similar to WF-MRI, can accurately measure marrow adiposity. Both imaging modalities show rapid increase in MF following cancer treatment. Our results suggest that MF and BMD cannot be used interchangeably to monitor skeletal health following cancer therapy. Copyright © 2014 Elsevier Inc. All rights reserved.

Deriving concentrations of oxygen and carbon in human tissues using single- and dual-energy CT for ion therapy applications

NASA Astrophysics Data System (ADS)

Landry, Guillaume; Parodi, Katia; Wildberger, Joachim E.; Verhaegen, Frank

2013-08-01

Dedicated methods of in-vivo verification of ion treatment based on the detection of secondary emitted radiation, such as positron-emission-tomography and prompt gamma detection require high accuracy in the assignment of the elemental composition. This especially concerns the content in carbon and oxygen, which are the most abundant elements of human tissue. The standard single-energy computed tomography (SECT) approach to carbon and oxygen concentration determination has been shown to introduce significant discrepancies in the carbon and oxygen content of tissues. We propose a dual-energy CT (DECT)-based approach for carbon and oxygen content assignment and investigate the accuracy gains of the method. SECT and DECT Hounsfield units (HU) were calculated using the stoichiometric calibration procedure for a comprehensive set of human tissues. Fit parameters for the stoichiometric calibration were obtained from phantom scans. Gaussian distributions with standard deviations equal to those derived from phantom scans were subsequently generated for each tissue for several values of the computed tomography dose index (CTDIvol). The assignment of %weight carbon and oxygen (%wC,%wO) was performed based on SECT and DECT. The SECT scheme employed a HU versus %wC,O approach while for DECT we explored a Zeff versus %wC,O approach and a (Zeff, ρe) space approach. The accuracy of each scheme was estimated by calculating the root mean square (RMS) error on %wC,O derived from the input Gaussian distribution of HU for each tissue and also for the noiseless case as a limiting case. The (Zeff, ρe) space approach was also compared to SECT by comparing RMS error for hydrogen and nitrogen (%wH,%wN). Systematic shifts were applied to the tissue HU distributions to assess the robustness of the method against systematic uncertainties in the stoichiometric calibration procedure. In the absence of noise the (Zeff, ρe) space approach showed more accurate %wC,O assignment (largest error of 2%) than the Zeff versus %wC,O and HU versus %wC,O approaches (largest errors of 15% and 30%, respectively). When noise was present, the accuracy of the (Zeff, ρe) space (DECT approach) was decreased but the RMS error over all tissues was lower than the HU versus %wC,O (SECT approach) (5.8%wC versus 7.5%wC at CTDIvol = 20 mGy). The DECT approach showed decreasing RMS error with decreasing image noise (or increasing CTDIvol). At CTDIvol = 80 mGy the RMS error over all tissues was 3.7% for DECT and 6.2% for SECT approaches. However, systematic shifts greater than ±5HU undermined the accuracy gains afforded by DECT at any dose level. DECT provides more accurate %wC,O assignment than SECT when imaging noise and systematic uncertainties in HU values are not considered. The presence of imaging noise degrades the DECT accuracy on %wC,O assignment but it remains superior to SECT. However, DECT was found to be sensitive to systematic shifts of human tissue HU.

Review of the Eustrophinae (Coleoptera, Tetratomidae) of America north of Mexico

PubMed Central

Pollock, Darren A.

2012-01-01

Abstract The Nearctic fauna (north of Mexico) of Eustrophinae is reviewed, and consists of the following five genera and 12 species: Pseudoholostrophus (Pseudoholostrophus) impressicollis (LeConte), Pseudoholostrophus (Holostrophinus) discolor (Horn), Holostrophus bifasciatus (Say), Eustrophus tomentosus Say, Eustrophopsis confinis (LeConte), Eustrophopsis bicolor (Fabricius), Eustrophopsis brunneimarginatus (Dury), Eustrophopsis indistinctus (LeConte), Eustrophopsis arizonensis (Horn), Eustrophopsis ornatus (Van Dyke), Eustrophopsis crowdyi sp. n., and Synstrophus repandus (Horn). A lectotype is designated for Eustrophus brunneimarginatus Dury. A key is given to separate genera and species, supplemented with illustrations of relevant features, including aedeagi of all Nearctic species of Eustrophopsis. Detailed distribution (including Mexican records) and natural history data are provided. PMID:22611332

Determination of ureter stent appearance on dual-energy computed tomography scan.

PubMed

Jepperson, Maria A; Thiel, David D; Cernigliaro, Joesph G; Broderick, Gregory A; Parker, Alexander S; Haley, William E

2012-11-01

To examine the dual-energy computed tomography (DECT) properties of 7 commonly used ureteral stents to optimize stent selection for calculi monitored using DECT. The use of DECT to evaluate renal and ureteral calculi has recently increased. Seven stents were individually placed in a fish bowl phantom and imaged using a Siemens Somatom Definition Flash CT scanner. DECT peak tube potentials of 80 and 140 kVp and 100 and 140 kVp were used, reflecting our current dual-energy protocols. These were compared to 31 in vivo stents of known composition. The data were reconstructed on a multimodality WorkPlace (Siemens) using CT syngo Post-Processing Suite software. The average patient age was 64 years (range 27-90). The average body mass index was 31.9 kg/m(2) (range 24-51.6). Of the 27 patients, 4 had uric acid stones and 22 had calcium-based stones; 1 patient had undergone renal transplantation. No difference was seen in the dual-energy characterization of stents from the same manufacturer. All imaged Cook and Bard stents had a dual-energy characterization that approached that of calcium stones (blue). All Boston Scientific and Gyrus ACMI stents had a dual-energy characterization resembling that of uric acid stones (red). The present study evaluated the stent appearance on DECT for various stent manufacturers. This information will aid in the optimal stent selection for patients undergoing treatment of renal calculi and followed up with DECT. Copyright © 2012 Elsevier Inc. All rights reserved.

The Use of Monoterpenes as Kairomones by Ips latidens (LeConte) (Coleoptera: Scolytidae)

Treesearch

D.R. Miller; J.H. Borden

1990-01-01

The responses of Ips lutidens (LeConte) to multiple-funnel traps baited with various monoterpenes were determined in stands of lodgepole pine in British Columbia. ß-Phellandrene was attractive to I. lutidens in the absence of the pheromone ipsenol ß-Phellandrene increased the attraction of I. lutidens to...

(S)-(+)-Ipsdienol: Interspecific Inhibition of Ips latidens (LeConte) by Ips pini (Say) (Coleoptera: Scolytidae)

Treesearch

Daniel R. Miller; John H. Borden

1992-01-01

In south-central British Columbia, the attraction of Ips latidens (LeConte) to its pheromone, ipsenol, was inhibited by (S)-(+)-ipsdienol, a pheromone for I. pini (Say). (R)-(-)-Ipsdienol had no effect on I. latidens. (S)-(+)-lpsdienol probably plays a role in interspecific communication between the two species...

Larvae of the genus Eleodes (Coleoptera, Tenebrionidae): matrix-based descriptions, cladistic analysis, and key to late instars

PubMed Central

Smith, Aaron D.; Dornburg, Rebecca; Wheeler, Quentin D.

2014-01-01

Abstract Darkling beetle larvae (Coleoptera, Tenebrionidae) are collectively referred to as false wireworms. Larvae from several species in the genus Eleodes are considered to be agricultural pests, though relatively little work has been done to associate larvae with adults of the same species and only a handful of species have been characterized in their larval state. Morphological characters from late instar larvae were examined and coded to produce a matrix in the server-based content management system mx. The resulting morphology matrix was used to produce larval species descriptions, reconstruct a phylogeny, and build a key to the species included in the matrix. Larvae are described for the first time for the following 12 species: Eleodes anthracinus Blaisdell, Eleodes carbonarius (Say), Eleodes caudiferus LeConte, Eleodes extricatus (Say), Eleodes goryi Solier, Eleodes hispilabris (Say), Eleodes nigropilosus LeConte, Eleodes pilosus Horn, Eleodes subnitens LeConte, Eleodes tenuipes Casey, Eleodes tribulus Thomas, and Eleodes wheeleri Aalbu, Smith & Triplehorn. The larval stage of Eleodes armatus LeConte is redescribed with additional characters to differentiate it from the newly described congeneric larvae. PMID:25009429

Metallic artefact reduction with monoenergetic dual-energy CT: systematic ex vivo evaluation of posterior spinal fusion implants from various vendors and different spine levels.

PubMed

Guggenberger, R; Winklhofer, S; Osterhoff, G; Wanner, G A; Fortunati, M; Andreisek, G; Alkadhi, H; Stolzmann, P

2012-11-01

To evaluate optimal monoenergetic dual-energy computed tomography (DECT) settings for artefact reduction of posterior spinal fusion implants of various vendors and spine levels. Posterior spinal fusion implants of five vendors for cervical, thoracic and lumbar spine were examined ex vivo with single-energy (SE) CT (120 kVp) and DECT (140/100 kVp). Extrapolated monoenergetic DECT images at 64, 69, 88, 105 keV and individually adjusted monoenergy for optimised image quality (OPTkeV) were generated. Two independent radiologists assessed quantitative and qualitative image parameters for each device and spine level. Inter-reader agreements of quantitative and qualitative parameters were high (ICC = 0.81-1.00, κ = 0.54-0.77). HU values of spinal fusion implants were significantly different among vendors (P < 0.001), spine levels (P < 0.01) and among SECT, monoenergetic DECT of 64, 69, 88, 105 keV and OPTkeV (P < 0.01). Image quality was significantly (P < 0.001) different between datasets and improved with higher monoenergies of DECT compared with SECT (V = 0.58, P < 0.001). Artefacts decreased significantly (V = 0.51, P < 0.001) at higher monoenergies. OPTkeV values ranged from 123-141 keV. OPTkeV according to vendor and spine level are presented herein. Monoenergetic DECT provides significantly better image quality and less metallic artefacts from implants than SECT. Use of individual keV values for vendor and spine level is recommended. • Artefacts pose problems for CT following posterior spinal fusion implants. • CT images are interpreted better with monoenergetic extrapolation using dual-energy (DE) CT. • DECT extrapolation improves image quality and reduces metallic artefacts over SECT. • There were considerable differences in monoenergy values among vendors and spine levels. • Use of individualised monoenergy values is indicated for different metallic hardware devices.

Detection of occult, undisplaced hip fractures with a dual-energy CT algorithm targeted to detection of bone marrow edema.

PubMed

Reddy, T; McLaughlin, P D; Mallinson, P I; Reagan, A C; Munk, P L; Nicolaou, S; Ouellette, H A

2015-02-01

The purpose of this study is to describe our initial clinical experience with dual-energy computed tomography (DECT) virtual non-calcium (VNC) images for the detection of bone marrow (BM) edema in patients with suspected hip fracture following trauma. Twenty-five patients presented to the emergency department at a level 1 trauma center between January 1, 2011 and January 1, 2013 with clinical suspicion of hip fracture and normal radiographs were included. All CT scans were performed on a dual-source, dual-energy CT system. VNC images were generated using prototype software and were compared to regular bone reconstructions by two musculoskeletal radiologists in consensus. Radiological and/or clinical diagnosis of fracture at 30-day follow-up was used as the reference standard. Twenty-one patients were found to have DECT-VNC signs of bone marrow edema. Eighteen of these 21 patients were true positive and three were false positive. A concordant fracture was clearly seen on bone reconstruction images in 15 of the 18 true positive cases. In three cases, DECT-VNC was positive for bone marrow edema where bone reconstruction CT images were negative. Four patients demonstrated no DECT-VNC signs of bone marrow edema: two cases were true negative, two cases were false negative. When compared with the gold standard of hip fracture determined at retrospective follow-up, the sensitivity of DECT-VNC images of the hip was 90 %, specificity was 40 %, positive predictive value was 86 %, and negative predictive value was 50 %. Our initial experience would suggest that DECT-VNC is highly sensitive but poorly specific in the diagnosis of hip fractures in patients with normal radiographs. The value of DECT-VNC primarily lies in its ability to help detect fractures which may be subtle or undetectable on bone reconstruction CT images.

Determining the composition of urinary tract calculi using stone-targeted dual-energy CT: evaluation of a low-dose scanning protocol in a clinical environment

PubMed Central

Chaytor, Richard J; Rajbabu, Krishnamoorthy; Jones, Paul A

2016-01-01

Objective: This study will evaluate the accuracy of dual-energy CT (DECT) in characterizing urinary tract stone composition on patients presenting to a UK hospital with renal colic. The study will also assess the additional radiation dose burden of DECT over standard protocol. Methods: Data from 106 DECTs between October 2011 and October 2015 were retrospectively analyzed. Patients were imaged using a Toshiba Aquilion ONE™ CT scanner (Toshiba Medical Systems, Otawara-shi, Japan). All patients received a low-dose non-contrast CT of the abdomen and pelvis prior to stone-targeted DECT at 80 and 135 kVp and 40-mm field of view. Radiation dose output was evaluated using dose–length product (DLP). 19 stones were recovered and their compositions were analyzed using Fourier transform infrared spectroscopy. Results: 137 stones were characterized. Mean stone diameter was 8.8 mm (range 3–48 mm). There was an 18.7% increase in mean DLP for DECT over standard CT protocol (319.4 vs 269.1 mGy cm; p < 0.001). Infrared spectroscopy analysis of 19 recovered stones identified 15 stones as calcium, 2 stones as cystine and 2 stones as mixed composition. Dual energy correctly predicted 11 (78.6%) of 14 calcium stones, 2 (100%) of 2 mixed composition stones and 0 (0%) of 2 cystine stones, resulting in a fair agreement (Cohen's κ = 0.374, p = 0.009). Conclusion: DECT is able to determine the composition of urinary tract stones with fair accuracy. Its utility is offset by a small but significant supplementary radiation exposure. Advances in knowledge: DECT can provide urological surgeons with useful diagnostic stone material information prior to planning optimal management of stone disease. PMID:27587309

Life History and Biology of Ips latidens (LeConte) (Coleoptera: Scolytidae)\\t

Treesearch

D.R. Miller; J.H. Borden

1985-01-01

The life history and biology of Ips latidens (LeConte) were investigated using bark-sandwich and whole-log rearing methods. In contrast with other Ips spp., some females initiated galleries under conditions of female-biased sex ratios, and sometimes 2 or more males were present in a gallery. In general, however, I....

Polymorphism in Languria taedata LeConte, its occurrence in coastal Louisiana Spartina marshes, and clarification of some Motschulsky languriine types (Coleoptera: Erotylidae: Languriinae)

USDA-ARS?s Scientific Manuscript database

We clarify the diagnosis and geographic distribution of the widespread, variable eastern coastal species Languria taedata LeConte, 1854, in North America. After examining types and the range of variation and geographical distribution of the species, we propose synonymy of L. erythrocephalus Blatchle...

Image enhancement by spectral-error correction for dual-energy computed tomography.

PubMed

Park, Kyung-Kook; Oh, Chang-Hyun; Akay, Metin

2011-01-01

Dual-energy CT (DECT) was reintroduced recently to use the additional spectral information of X-ray attenuation and aims for accurate density measurement and material differentiation. However, the spectral information lies in the difference between low and high energy images or measurements, so that it is difficult to acquire accurate spectral information due to amplification of high pixel noise in the resulting difference image. In this work, an image enhancement technique for DECT is proposed, based on the fact that the attenuation of a higher density material decreases more rapidly as X-ray energy increases. We define as spectral error the case when a pixel pair of low and high energy images deviates far from the expected attenuation trend. After analyzing the spectral-error sources of DECT images, we propose a DECT image enhancement method, which consists of three steps: water-reference offset correction, spectral-error correction, and anti-correlated noise reduction. It is the main idea of this work that makes spectral errors distributed like random noise over the true attenuation and suppressed by the well-known anti-correlated noise reduction. The proposed method suppressed noise of liver lesions and improved contrast between liver lesions and liver parenchyma in DECT contrast-enhanced abdominal images and their two-material decomposition.

Extracting atomic numbers and electron densities from a dual source dual energy CT scanner: experiments and a simulation model.

PubMed

Landry, Guillaume; Reniers, Brigitte; Granton, Patrick Vincent; van Rooijen, Bart; Beaulieu, Luc; Wildberger, Joachim E; Verhaegen, Frank

2011-09-01

Dual energy CT (DECT) imaging can provide both the electron density ρ(e) and effective atomic number Z(eff), thus facilitating tissue type identification. This paper investigates the accuracy of a dual source DECT scanner by means of measurements and simulations. Previous simulation work suggested improved Monte Carlo dose calculation accuracy when compared to single energy CT for low energy photon brachytherapy, but lacked validation. As such, we aim to validate our DECT simulation model in this work. A cylindrical phantom containing tissue mimicking inserts was scanned with a second generation dual source scanner (SOMATOM Definition FLASH) to obtain Z(eff) and ρ(e). A model of the scanner was designed in ImaSim, a CT simulation program, and was used to simulate the experiment. Accuracy of measured Z(eff) (labelled Z) was found to vary from -10% to 10% from low to high Z tissue substitutes while the accuracy on ρ(e) from DECT was about 2.5%. Our simulation reproduced the experiments within ±5% for both Z and ρ(e). A clinical DECT scanner was able to extract Z and ρ(e) of tissue substitutes. Our simulation tool replicates the experiments within a reasonable accuracy. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

A life history study of the ash seed weevils, Thysanocnemis bischoffi Blatchley and T. Helvola leconte (Coleoptera: curculionidae)

Treesearch

Jack H. Barger; Ralph H. Davidson

1967-01-01

A life history study was made of the ash seed weevils, Thysanocnemis bischoffi Blatchley and T. helvola LeConte. Over-wintering occurs as larvae in ash seeds or in soil, with adults appearing in July and August. Adults soon deposit eggs within ash seeds, where larval development occurs. Only one generation...

Historical Winter Status of Three Upland Ammodramus Sparrows in South Carolina

DOE Office of Scientific and Technical Information (OSTI.GOV)

McNair, D.B.; Post, W.

2000-10-01

The wintering status of three upland sparrows were compared based upon collections. LeConte's sparrow was previously abundant during incursion years, but was less common on the coast. LeConte's and Henslow's were much more abundant 75-115 years ago. The later may result from breeding range reductions and habitat loss. The study demonstrates the usefulness of historical data.

Nonhost angiosperm volatiles and verbenone protect individual ponderosa pines from attack by western pine beetle and red turpentine beetle (Coleoptera: Curculionidae, Scolytinae)

Treesearch

Christopher J. Fettig; Christopher P. Dabney; Stepehen R. McKelvey; Dezene P.W. Huber

2008-01-01

Nonhost angiosperm volatiles (NAV) and verbenone were tested for their ability to protect individual ponderosa pines, Pinus ponderosa Dougl. ex. Laws., from attack by western pine beetle (WPB), Dendroctonus brevicomis LeConte, and red turpentine beetle (RTB), Dendroctonus valens LeConte (Coleoptera: Curculionidae, Scolytinae). A combination of (

Red Turpentine Beetle, Dendroctonus valens LeConte (Coleoptera: Scolytidae), Response to Host Semiochemicals in China

Treesearch

Jianghua Sun; Zhengwan Miao; Zhen Zhang; Zhongning Zhan; Nancy Gillette

2004-01-01

The response of the introduced red turpentine beetle, Dendroctonus valens LeConte, to host semiochemicals in Shanxi Province, China, was distinctly different from that reported in previous studies conducted in the western part of the native range of D. valens in the central Sierra Nevada, CA. This Þnding suggests either that...

MO-FG-204-06: A New Algorithm for Gold Nano-Particle Concentration Identification in Dual Energy CT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, L; Shen, C; Ng, M

Purpose: Gold nano-particle (GNP) has recently attracted a lot of attentions due to its potential as an imaging contrast agent and radiotherapy sensitiser. Imaging the GNP at its low contraction is a challenging problem. We propose a new algorithm to improve the identification of GNP based on dual energy CT (DECT). Methods: We consider three base materials: water, bone, and gold. Determining three density images from two images in DECT is an under-determined problem. We propose to solve this problem by exploring image domain sparsity via an optimization approach. The objective function contains four terms. A data-fidelity term ensures themore » fidelity between the identified material densities and the DECT images, while the other three terms enforces the sparsity in the gradient domain of the three images corresponding to the density of the base materials by using total variation (TV) regularization. A primal-dual algorithm is applied to solve the proposed optimization problem. We have performed simulation studies to test this model. Results: Our digital phantom in the tests contains water, bone regions and gold inserts of different sizes and densities. The gold inserts contain mixed material consisting of water with 1g/cm3 and gold at a certain density. At a low gold density of 0.0008 g/cm3, the insert is hardly visible in DECT images, especially for those with small sizes. Our algorithm is able to decompose the DECT into three density images. Those gold inserts at a low density can be clearly visualized in the density image. Conclusion: We have developed a new algorithm to decompose DECT images into three different material density images, in particular, to retrieve density of gold. Numerical studies showed promising results.« less

First Southeast U.S. records for Lacconotus punctatus Leconte (Coleoptera: Mycteridae), an early seasonal canopy specialist?

Treesearch

Michael Ulyshen; Scott Horn; James Hanula

2010-01-01

A recent project carried out within the Oconee River watershed in northeastern Georgia produced six specimens of Lacconotus punctatus LeConte, a species formerly known only from the northeastern United States (New Hampshire, Ohio, Pennsylvania, Michigan) and Canada (Ontario, Québec, Nova Scotia) ( Majka and Selig 2006, and references therein). Georgia represents a new...

Monte Carlo proton dose calculations using a radiotherapy specific dual-energy CT scanner for tissue segmentation and range assessment

NASA Astrophysics Data System (ADS)

Almeida, Isabel P.; Schyns, Lotte E. J. R.; Vaniqui, Ana; van der Heyden, Brent; Dedes, George; Resch, Andreas F.; Kamp, Florian; Zindler, Jaap D.; Parodi, Katia; Landry, Guillaume; Verhaegen, Frank

2018-06-01

Proton beam ranges derived from dual-energy computed tomography (DECT) images from a dual-spiral radiotherapy (RT)-specific CT scanner were assessed using Monte Carlo (MC) dose calculations. Images from a dual-source and a twin-beam DECT scanner were also used to establish a comparison to the RT-specific scanner. Proton ranges extracted from conventional single-energy CT (SECT) were additionally performed to benchmark against literature values. Using two phantoms, a DECT methodology was tested as input for GEANT4 MC proton dose calculations. Proton ranges were calculated for different mono-energetic proton beams irradiating both phantoms; the results were compared to the ground truth based on the phantom compositions. The same methodology was applied in a head-and-neck cancer patient using both SECT and dual-spiral DECT scans from the RT-specific scanner. A pencil-beam-scanning plan was designed, which was subsequently optimized by MC dose calculations, and differences in proton range for the different image-based simulations were assessed. For phantoms, the DECT method yielded overall better material segmentation with  >86% of the voxel correctly assigned for the dual-spiral and dual-source scanners, but only 64% for a twin-beam scanner. For the calibration phantom, the dual-spiral scanner yielded range errors below 1.2 mm (0.6% of range), like the errors yielded by the dual-source scanner (<1.1 mm, <0.5%). With the validation phantom, the dual-spiral scanner yielded errors below 0.8 mm (0.9%), whereas SECT yielded errors up to 1.6 mm (2%). For the patient case, where the absolute truth was missing, proton range differences between DECT and SECT were on average in  ‑1.2  ±  1.2 mm (‑0.5%  ±  0.5%). MC dose calculations were successfully performed on DECT images, where the dual-spiral scanner resulted in media segmentation and range accuracy as good as the dual-source CT. In the patient, the various methods showed relevant range differences.

Dosimetric impact of dual-energy CT tissue segmentation for low-energy prostate brachytherapy: a Monte Carlo study

NASA Astrophysics Data System (ADS)

Remy, Charlotte; Lalonde, Arthur; Béliveau-Nadeau, Dominic; Carrier, Jean-François; Bouchard, Hugo

2018-01-01

The purpose of this study is to evaluate the impact of a novel tissue characterization method using dual-energy over single-energy computed tomography (DECT and SECT) on Monte Carlo (MC) dose calculations for low-dose rate (LDR) prostate brachytherapy performed in a patient like geometry. A virtual patient geometry is created using contours from a real patient pelvis CT scan, where known elemental compositions and varying densities are overwritten in each voxel. A second phantom is made with additional calcifications. Both phantoms are the ground truth with which all results are compared. Simulated CT images are generated from them using attenuation coefficients taken from the XCOM database with a 100 kVp spectrum for SECT and 80 and 140Sn kVp for DECT. Tissue segmentation for Monte Carlo dose calculation is made using a stoichiometric calibration method for the simulated SECT images. For the DECT images, Bayesian eigentissue decomposition is used. A LDR prostate brachytherapy plan is defined with 125I sources and then calculated using the EGSnrc user-code Brachydose for each case. Dose distributions and dose-volume histograms (DVH) are compared to ground truth to assess the accuracy of tissue segmentation. For noiseless images, DECT-based tissue segmentation outperforms the SECT procedure with a root mean square error (RMS) on relative errors on dose distributions respectively of 2.39% versus 7.77%, and provides DVHs closest to the reference DVHs for all tissues. For a medium level of CT noise, Bayesian eigentissue decomposition still performs better on the overall dose calculation as the RMS error is found to be of 7.83% compared to 9.15% for SECT. Both methods give a similar DVH for the prostate while the DECT segmentation remains more accurate for organs at risk and in presence of calcifications, with less than 5% of RMS errors within the calcifications versus up to 154% for SECT. In a patient-like geometry, DECT-based tissue segmentation provides dose distributions with the highest accuracy and the least bias compared to SECT. When imaging noise is considered, benefits of DECT are noticeable if important calcifications are found within the prostate.

A unified material decomposition framework for quantitative dual- and triple-energy CT imaging.

PubMed

Zhao, Wei; Vernekohl, Don; Han, Fei; Han, Bin; Peng, Hao; Yang, Yong; Xing, Lei; Min, James K

2018-04-21

Many clinical applications depend critically on the accurate differentiation and classification of different types of materials in patient anatomy. This work introduces a unified framework for accurate nonlinear material decomposition and applies it, for the first time, in the concept of triple-energy CT (TECT) for enhanced material differentiation and classification as well as dual-energy CT (DECT). We express polychromatic projection into a linear combination of line integrals of material-selective images. The material decomposition is then turned into a problem of minimizing the least-squares difference between measured and estimated CT projections. The optimization problem is solved iteratively by updating the line integrals. The proposed technique is evaluated by using several numerical phantom measurements under different scanning protocols. The triple-energy data acquisition is implemented at the scales of micro-CT and clinical CT imaging with commercial "TwinBeam" dual-source DECT configuration and a fast kV switching DECT configuration. Material decomposition and quantitative comparison with a photon counting detector and with the presence of a bow-tie filter are also performed. The proposed method provides quantitative material- and energy-selective images examining realistic configurations for both DECT and TECT measurements. Compared to the polychromatic kV CT images, virtual monochromatic images show superior image quality. For the mouse phantom, quantitative measurements show that the differences between gadodiamide and iodine concentrations obtained using TECT and idealized photon counting CT (PCCT) are smaller than 8 and 1 mg/mL, respectively. TECT outperforms DECT for multicontrast CT imaging and is robust with respect to spectrum estimation. For the thorax phantom, the differences between the concentrations of the contrast map and the corresponding true reference values are smaller than 7 mg/mL for all of the realistic configurations. A unified framework for both DECT and TECT imaging has been established for the accurate extraction of material compositions using currently available commercial DECT configurations. The novel technique is promising to provide an urgently needed solution for several CT-based diagnostic and therapy applications, especially for the diagnosis of cardiovascular and abdominal diseases where multicontrast imaging is involved. © 2018 American Association of Physicists in Medicine.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nute, J; Jacobsen, M; Popnoe, D

Purpose: Intracranial hemorrhage and calcification with Single-Energy CT (SECT) attenuation below 100HU cannot be reliably identified using currently clinically available means. Calcification is typically benign but hemorrhage can carry a risk of intracranial bleeding and contraindicate use of anticoagulant therapies. A biologically-relevant phantom was used to investigate identification of unknown intracranial lesions using dual-energy CT (DECT) as a verification of prior lesion differentiation results. Methods: Prior phantom work investigating calcification and hemorrhage differentiation resulted in 3D-DECT raw data (water density, calcium density, 68keV) for a range of DECT protocol variations: image thicknesses (1.25, 2.5, 3.75, 5mm), CTDIvol (36.7 to 132.6mGy)more » and reconstruction algorithms (Soft, Standard, Detail). Acquisition-specific raw data were used to create a plane of optimal differentiation based on the geometric bisector of 3D-linear regression of the two lesion distributions. Verification hemorrhage and calcification lesions, ranging in size from 0.5 to 1.5cm, were created at varying attenuation from 50 to 100HU. Lesions were inserted into a biologically-relevant brain phantom and scanned using SECT (3.75mm images, Standard, 67mGy) and a range of DECT protocols (3.75mm images, Standard, [67, 105.6, 132.6mGy]). 3D-DECT data were collected and blinded for analysis. The 3D-DECT distribution of the lesion was then compared to the acquisition-matched geometric bisector plane and the mean lesion value’s position relative to the plane, indicating lesion identity, and the percentage of voxels on the identified side of the plane, indicating identification confidence, were derived. Results: 98% of the 120 lesions investigated were identified correctly as hemorrhage or calcification. 74% were identified with greater than 80% confidence. Increases in CTDIvol and lesion diameter were associated with increased identification confidence. Conclusion: Intracranial lesions of unknown etiology were identified with 80% confidence for 74% of lesions investigated. These phantom data suggest that the identification of intracranial lesions below 100HU is clinically feasible using DECT. This research was conducted at the MD Anderson Center for Advanced Biomedical Imaging in-part with equipment support from General Electric Healthcare.« less

Survey on the importance of mange in the aetiology of skin lesions in goats in Peninsular Malaysia.

PubMed

Dorny, P; Van Wyngaarden, T; Vercruysse, J; Symoens, C; Jalia, A

1994-05-01

A survey on mange mite infestations in the aetiology of skin lesions in goats in Peninsular Malaysia is described. Skin lesions were observed in 25 (93%) of the 27 goat farms investigated. Mange mites were found in 22 (88%) of these goat herds. Chorioptes texanus was found in 20.7%, Psoroptes cuniculi in 19.3%, Sarcoptes scabiei in 18.6% and Demodex canis var. caprae in 0.4% of the samples, taken from the skin lesions. Thirteen cases of generalised manage were diagnosed, from which 9 were caused by S. scabiei, 2 by P. cuniculi and one by C. texanus. All other cases had more or less localised lesions. No significant differences could be found in incidence and distribution of skin lesions between age classes.

Reevaluation of Chalcophora angulicollis (LeConte) and Chalcophora virginiensis (Drury) with a review and key to the North American species of Chalcophora DeJean (Coleoptera: Buprestidae)

Treesearch

Crystal A. Maier; Michael A. Ivie

2013-01-01

Chalcophora angulicollis (LeConte) and Chalcophora virginiensis (Drury) are shown to be valid allopatric species in the western and eastern forests of North America, respectively. The historic uncertainty regarding their status is reviewed, and new characters of the aedeagus, penultimate maxillary palpomere, and elytral serrations are utilized for their identification...

Dual-energy computed tomography for detection of coronary artery disease

PubMed Central

Danad, Ibrahim; Ó Hartaigh, Bríain; Min, James K.

2016-01-01

Recent technological advances in computed tomography (CT) technology have fulfilled the prerequisites for the cardiac application of dual-energy CT (DECT) imaging. By exploiting the unique characteristics of materials when exposed to two different x-ray energies, DECT holds great promise for the diagnosis and management of coronary artery disease. It allows for the assessment of myocardial perfusion to discern the hemodynamic significance of coronary disease and possesses high accuracy for the detection and characterization of coronary plaques, while facilitating reductions in radiation dose. As such, DECT enabled cardiac CT to advance beyond the mere detection of coronary stenosis expanding its role in the evaluation and management of coronary atherosclerosis. PMID:26549789

Dual-energy CT for detection of contrast enhancement or leakage within high-density haematomas in patients with intracranial haemorrhage.

PubMed

Watanabe, Yoshiyuki; Tsukabe, Akio; Kunitomi, Yuki; Nishizawa, Mitsuo; Arisawa, Atsuko; Tanaka, Hisashi; Yoshiya, Kazuhisa; Shimazu, Takeshi; Tomiyama, Noriyuki

2014-04-01

Our study aimed to elucidate the diagnostic performance of dual-energy CT (DECT) in the detection of contrast enhancement in intracranial haematomas (ICrH) with early phase dual-energy computed tomography angiography (CTA) and compare the results with those obtained by delayed CT enhancement. Thirty-six patients with ICrH were retrospectively included in this study. All patients had undergone single-energy non-contrast CT and contrast-enhanced dual-source DECT. DECT images were post-processed with commercial software, followed by obtaining iodine images and virtual non-contrast images and generating combined images that created the impression of 120-kVp images. Two neuroradiologists, blinded to the patients' data, reviewed two reading sessions: session A (non-contrast CT and combined CT) and session B (non-contrast CT, combined CT, and iodine images) for detection of contrast enhancement in the haematomas. Contrast leakage or enhancement was detected in 23 (57.5 %) out of 40 haemorrhagic lesions in 36 patients on delayed CT. Three enhanced lesions were depicted only in the DECT iodine images. The sensitivity, specificity, positive predictive value, and negative predictive value of session A were 82.6, 94.1, 95.0, and 80.0 %, respectively, and those of session B were 95.7, 94.1, 95.7, and 94.1 %, respectively. DECT emphasised the iodine enhancement and facilitated the detection of contrast enhancement or leakage.

SU-F-T-398: Improving Radiotherapy Treatment Planning Using Dual Energy Computed Tomography Based Tissue Characterization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tomic, N; Bekerat, H; Seuntjens, J

Purpose: Both kVp settings and geometric distribution of various materials lead to significant change of the HU values, showing the largest discrepancy for high-Z materials and for the lowest CT scanning kVp setting. On the other hand, the dose distributions around low-energy brachytherapy sources are highly dependent on the architecture and composition of tissue heterogeneities in and around the implant. Both measurements and Monte Carlo calculations show that improper tissue characterization may lead to calculated dose errors of 90% for low energy and around 10% for higher energy photons. We investigated the ability of dual-energy CT (DECT) to characterize moremore » accurately tissue equivalent materials. Methods: We used the RMI-467 heterogeneity phantom scanned in DECT mode with 3 different set-ups: first, we placed high electron density (ED) plugs within the outer ring of the phantom; then we arranged high ED plugs within the inner ring; and finally ED plugs were randomly distributed. All three setups were scanned with the same DECT technique using a single-source DECT scanner with fast kVp switching (Discovery CT750HD; GE Healthcare). Images were transferred to a GE Advantage workstation for DECT analysis. Spectral Hounsfield unit curves (SHUACs) were then generated from 50 to 140-keV, in 10-keV increments, for each plug. Results: The dynamic range of Hounsfield units shrinks with increased photon energy as the attenuation coefficients decrease. Our results show that the spread of HUs for the three different geometrical setups is the smallest at 80 keV. Furthermore, among all the energies and all materials presented, the largest difference appears at high Z tissue equivalent plugs. Conclusion: Our results suggest that dose calculations at both megavoltage and low photon energies could benefit in the vicinity of bony structures if the 80 keV reconstructed monochromatic CT image is used with the DECT protocol utilized in this work.« less

TU-G-204-02: Automatic Sclerotic Bone Metastases Detection in the Pelvic Region From Dual Energy CT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fehr, D; Schmidtlein, C; Hwang, S

Purpose: To automatically detect sclerotic bone metastases in the pelvic region using dual energy computed tomography (DECT). Methods: We developed a two stage algorithm to automatically detect sclerotic bone metastases in the pelvis from DECT for patients with multiple bone metastatic lesions and with hip implants. The first stage consists of extracting the bone and marrow regions by using a support vector machine (SVM) classifier. We employed a novel representation of the DECT images using multi-material decomposition, which represents each voxel as a mixture of different physical materials (e.g. bone+water+fat). Following the extraction of bone and marrow, in the secondmore » stage, a bi -histogram equalization method was employed to enhance the contrast to reveal the bone metastases. Next, meanshift segmentation was performed to separate the voxels by their intensity levels. Finally, shape-based filtering was performed to extract the possible locations of the metastatic lesions using multiple shape criteria. We used the following shape parameters: area, eccentricity, major and minor axis, perimeter and skeleton. Results: A radiologist with several years of experience with DECT manually labeled 64 regions consisting of metastatic lesions from 10 different patients. However, the patients had many more metastasic lesions throughout the pelvis. Our method correctly identified 46 of the marked 64 regions (72%). In addition, our method also identified several other lesions, which can then be validated by the radiologist. The missed lesions were typically very large elongated regions consisting of several islands of very small (<4mm) lesions. Conclusion: We developed an algorithm to automatically detect sclerotic lesions in the pelvic region from DECT. Preliminary assessment shows that our algorithm generated lesions agreeing with the radiologist generated candidate regions. Furthermore, our method reveals additional lesions that can be inspected by the radiologist, thereby, reducing radiologist effort in identifying all the lesions with poor contrast from the DECT images.« less

Differentiating Calcium Oxalate and Hydroxyapatite Stones In Vivo Using Dual-Energy CT and Urine Supersaturation and pH Values

PubMed Central

Liu, Yu; Qu, Mingliang; Carter, Rickey E.; Leng, Shuai; Ramirez-Giraldo, Juan Carlos; Jaramillo, Giselle; Krambeck, Amy E.; Lieske, John C.; Vrtiska, Terri J.; McCollough, Cynthia H.

2014-01-01

Rationale and Objectives Knowledge of urinary stone composition can guide therapeutic intervention for patients with calcium oxalate (CaOx) or hydroxyapatite (HA) stones. In this study, we determined the accuracy of noninvasive differentiation of these two stone types using dual-energy CT (DECT) and urine supersaturation (SS) and pH values. Materials and Methods Patients who underwent clinically indicated DECT scanning for stone disease and subsequent surgical intervention were enrolled. Stone composition was determined using infrared spectroscopy. DECT images were processed using custom-developed software that evaluated the ratio of CT numbers between low- and high-energy images. Clinical information, including patient age, gender, and urine pH and supersaturation profile, was obtained from electronic medical records. Simple and multiple logistic regressions were used to determine if the ratio of CT numbers could discriminate CaOx from HA stones alone or in conjunction with urine supersaturation and pH. Results Urinary stones (CaOx n = 43, HA n = 18) from 61 patients were included in this study. In a univariate model, DECT data, urine SS-HA, and urine pH had an area under the receiver operating characteristic curve of 0.78 (95% confidence interval [CI] 0.66–0.91, P = .016), 0.76 (95%CI 0.61–0.91, P = .003), and 0.60 (95% CI 0.44–0.75, P = .20), respectively, for predicting stone composition. The combination of CT data and the urinary SS-HA had an area under the receiver operating characteristic curve of 0.79 (95%CI 0.66–0.92, P = .007) for correctly differentiating these two stone types. Conclusions DECT differentiated between CaOx and HA stones similarly to SS-HA, whereas pH was a poor discriminator. The combination of DECT and urine SS or pH data did not improve this performance. PMID:24200478

WE-EF-207-09: Single-Scan Dual-Energy CT Using Primary Modulation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Petrongolo, M; Zhu, L

Purpose: Compared with conventional CT, dual energy CT (DECT) provides better material differentiation but requires projection data with two different effective x-ray spectra. Current DECT scanners use either a two-scan setting or costly imaging components, which are not feasible or available on open-gantry cone-beam CT systems. We propose a hardware-based method which utilizes primary modulation to enable single-scan DECT on a conventional CT scanner. The CT imaging geometry of primary modulation is identical to that used in our previous method for scatter removal, making it possible for future combination with effective scatter correction on the same CT scanner. Methods: Wemore » insert an attenuation sheet with a spatially-varying pattern - primary modulator-between the x-ray source and the imaged object. During the CT scan, the modulator selectively hardens the x-ray beam at specific detector locations. Thus, the proposed method simultaneously acquires high and low energy data. High and low energy CT images are then reconstructed from projections with missing data via an iterative CT reconstruction algorithm with gradient weighting. Proof-of-concept studies are performed using a copper modulator on a cone-beam CT system. Results: Our preliminary results on the Catphan(c) 600 phantom indicate that the proposed method for single-scan DECT is able to successfully generate high-quality high and low energy CT images and distinguish different materials through basis material decomposition. By applying correction algorithms and using all of the acquired projection data, we can reconstruct a single CT image of comparable image quality to conventional CT images, i.e., without primary modulation. Conclusion: This work shows great promise in using a primary modulator to perform high-quality single-scan DECT imaging. Future studies will test method performance on anthropomorphic phantoms and perform quantitative analyses on image qualities and DECT decomposition accuracy. We will use simulations to optimize the modulator material and geometry parameters.« less

TU-FG-BRB-01: Dual Energy CT Proton Stopping Power Ratio Calibration and Validation with Animal Tissues

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xie, Y; Yin, L; Ainsley, C

Purpose: The conversion of Hounsfield Unit (HU) to proton stopping power ratio (SPR) is a main source of uncertainty in proton therapy. In this study, the SPRs of animal tissues were measured and compared with prediction from dual energy CT (DECT) and single energy CT (SECT) calibrations. Methods: A stoichiometric calibration method for DECT was applied to predict the SPR using CT images acquired at 80 kVp and 140 kVp. The dual energy index was derived based on the HUs of the paired spectral images and used to calculate the SPRs of the materials. Tissue surrogates with known chemical compositionsmore » were used for calibration, and animal tissues (pig brain, liver, kidney; veal shank, muscle) were used for validation. The materials were irradiated with proton pencil beams, and SPRs were deduced from the residual proton range measured using a multi-layer ion chamber device. In addition, Gafchromic EBT3 films were used to measure the distal dose profiles after irradiation through the tissue samples and compared with those calculated by the treatment planning system using both DECT and SECT predicted SPRs. Results: The differences in SPR between DECT prediction and measurement were −0.31±0.36% for bone, 0.47±0.42% for brain, 0.67±0.15% for liver, 0.51±0.52% for kidney, and −0.96±0.15% for muscle. The corresponding results using SECT were 3.1±0.12%, 1.90±0.45%, −0.66±0.11%, 2.33±0.21%, and −1.70±0.17%. In the film measurements, average distances between film and calculated distal dose profiles were 0.35±0.12 mm for DECT calibration and −1.22±0.12 mm for SECT calibration for a beam with a range of 15.79 cm. Conclusion: Our study indicates that DECT is superior to SECT for proton SPR prediction and has the potential to reduce the range uncertainty to less than 2%. DECT may permit the use of tighter distal and proximal range uncertainty margins for treatment, thereby increasing the precision of proton therapy.« less

Correlation of iodine uptake and perfusion parameters between dual-energy CT imaging and first-pass dual-input perfusion CT in lung cancer.

PubMed

Chen, Xiaoliang; Xu, Yanyan; Duan, Jianghui; Li, Chuandong; Sun, Hongliang; Wang, Wu

2017-07-01

To investigate the potential relationship between perfusion parameters from first-pass dual-input perfusion computed tomography (DI-PCT) and iodine uptake levels estimated from dual-energy CT (DE-CT).The pre-experimental part of this study included a dynamic DE-CT protocol in 15 patients to evaluate peak arterial enhancement of lung cancer based on time-attenuation curves, and the scan time of DE-CT was determined. In the prospective part of the study, 28 lung cancer patients underwent whole-volume perfusion CT and single-source DE-CT using 320-row CT. Pulmonary flow (PF, mL/min/100 mL), aortic flow (AF, mL/min/100 mL), and a perfusion index (PI = PF/[PF + AF]) were automatically generated by in-house commercial software using the dual-input maximum slope method for DI-PCT. For the dual-energy CT data, iodine uptake was estimated by the difference (λ) and the slope (λHU). λ was defined as the difference of CT values between 40 and 70 KeV monochromatic images in lung lesions. λHU was calculated by the following equation: λHU = |λ/(70 - 40)|. The DI-PCT and DE-CT parameters were analyzed by Pearson/Spearman correlation analysis, respectively.All subjects were pathologically proved as lung cancer patients (including 16 squamous cell carcinoma, 8 adenocarcinoma, and 4 small cell lung cancer) by surgery or CT-guided biopsy. Interobserver reproducibility in DI-PCT (PF, AF, PI) and DE-CT (λ, λHU) were relatively good to excellent (intraclass correlation coefficient [ICC]Inter = 0.8726-0.9255, ICCInter = 0.8179-0.8842; ICCInter = 0.8881-0.9177, ICCInter = 0.9820-0.9970, ICCInter = 0.9780-0.9971, respectively). Correlation coefficient between λ and AF, and PF were as follows: 0.589 (P < .01) and 0.383 (P < .05). Correlation coefficient between λHU and AF, and PF were as follows: 0.564 (P < .01) and 0.388 (P < .05).Both the single-source DE-CT and dual-input CT perfusion analysis method can be applied to assess blood supply of lung cancer patients. Preliminary results demonstrated that the iodine uptake relevant parameters derived from DE-CT significantly correlated with perfusion parameters derived from DI-PCT.

Improved tissue assignment using dual-energy computed tomography in low-dose rate prostate brachytherapy for Monte Carlo dose calculation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Côté, Nicolas; Bedwani, Stéphane; Carrier, Jean-François, E-mail: jean-francois.carrier.chum@ssss.gouv.qc.ca

Purpose: An improvement in tissue assignment for low-dose rate brachytherapy (LDRB) patients using more accurate Monte Carlo (MC) dose calculation was accomplished with a metallic artifact reduction (MAR) method specific to dual-energy computed tomography (DECT). Methods: The proposed MAR algorithm followed a four-step procedure. The first step involved applying a weighted blend of both DECT scans (I {sub H/L}) to generate a new image (I {sub Mix}). This action minimized Hounsfield unit (HU) variations surrounding the brachytherapy seeds. In the second step, the mean HU of the prostate in I {sub Mix} was calculated and shifted toward the mean HUmore » of the two original DECT images (I {sub H/L}). The third step involved smoothing the newly shifted I {sub Mix} and the two original I {sub H/L}, followed by a subtraction of both, generating an image that represented the metallic artifact (I {sub A,(H/L)}) of reduced noise levels. The final step consisted of subtracting the original I {sub H/L} from the newly generated I {sub A,(H/L)} and obtaining a final image corrected for metallic artifacts. Following the completion of the algorithm, a DECT stoichiometric method was used to extract the relative electronic density (ρ{sub e}) and effective atomic number (Z {sub eff}) at each voxel of the corrected scans. Tissue assignment could then be determined with these two newly acquired physical parameters. Each voxel was assigned the tissue bearing the closest resemblance in terms of ρ{sub e} and Z {sub eff}, comparing with values from the ICRU 42 database. A MC study was then performed to compare the dosimetric impacts of alternative MAR algorithms. Results: An improvement in tissue assignment was observed with the DECT MAR algorithm, compared to the single-energy computed tomography (SECT) approach. In a phantom study, tissue misassignment was found to reach 0.05% of voxels using the DECT approach, compared with 0.40% using the SECT method. Comparison of the DECT and SECT D {sub 90} dose parameter (volume receiving 90% of the dose) indicated that D {sub 90} could be underestimated by up to 2.3% using the SECT method. Conclusions: The DECT MAR approach is a simple alternative to reduce metallic artifacts found in LDRB patient scans. Images can be processed quickly and do not require the determination of x-ray spectra. Substantial information on density and atomic number can also be obtained. Furthermore, calcifications within the prostate are detected by the tissue assignment algorithm. This enables more accurate, patient-specific MC dose calculations.« less

75 FR 30425 - Endangered and Threatened Species Permit Applications

Federal Register 2010, 2011, 2012, 2013, 2014

2010-06-01

..., during normal business hours at the U.S. Fish and Wildlife Service, 500 Gold Ave., SW., Room 6034... transport studies for Colorado pikeminnow (Ptychochelius lucius) and razorback sucker (Xyrauchen texanus) in...

Bullfrog tadpole (Rana catesbeiana) and red swamp crayfish (Procambarus clarkii) predation on early life stages of endangered razorback sucker (Xyrauchen texanus)

USGS Publications Warehouse

Mueller, G.A.; Carpenter, J.; Thornbrugh, D.

2006-01-01

Bullfrog tadpoles (Rana catesbeiana) and red swamp crayfish (Procambarus clarkii) are widespread introduced taxa that are problematic throughout the western United States. Their impact on native amphibians and crustaceans is well documented, but less is known regarding their influence on native fishes. Predator-prey tank tests showed both species consumed eggs and larvae of the endangered razorback sucker (Xyrauchen texanus) in a laboratory setting. Tadpoles consumed 2.2 razorback sucker eggs/d and 1.4 razorback sucker larvae/d, while crayfish ate 6.0 eggs/d and 3.5 larvae/d. Relatively high densities of bullfrog tadpoles and crayfish in razorback sucker spawning areas suggest that these nonnative taxa might pose a threat to the recruitment success of this and other imperiled native fish.

Technical Note: Improving proton stopping power ratio determination for a deformable silicone-based 3D dosimeter using dual energy CT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Taasti, Vicki Trier, E-mail: victaa@rm.dk; Høye, Ellen Marie; Hansen, David Christoffer

Purpose: The aim of this study was to investigate whether the stopping power ratio (SPR) of a deformable, silicone-based 3D dosimeter could be determined more accurately using dual energy (DE) CT compared to using conventional methods based on single energy (SE) CT. The use of SECT combined with the stoichiometric calibration method was therefore compared to DECT-based determination. Methods: The SPR of the dosimeter was estimated based on its Hounsfield units (HUs) in both a SECT image and a DECT image set. The stoichiometric calibration method was used for converting the HU in the SECT image to a SPR valuemore » for the dosimeter while two published SPR calibration methods for dual energy were applied on the DECT images. Finally, the SPR of the dosimeter was measured in a 60 MeV proton by quantifying the range difference with and without the dosimeter in the beam path. Results: The SPR determined from SECT and the stoichiometric method was 1.10, compared to 1.01 with both DECT calibration methods. The measured SPR for the dosimeter material was 0.97. Conclusions: The SPR of the dosimeter was overestimated by 13% using the stoichiometric method and by 3% when using DECT. If the stoichiometric method should be applied for the dosimeter, the HU of the dosimeter must be manually changed in the treatment planning system in order to give a correct SPR estimate. Using a wrong SPR value will cause differences between the calculated and the delivered treatment plans.« less

Robust x-ray based material identification using multi-energy sinogram decomposition

NASA Astrophysics Data System (ADS)

Yuan, Yaoshen; Tracey, Brian; Miller, Eric

2016-05-01

There is growing interest in developing X-ray computed tomography (CT) imaging systems with improved ability to discriminate material types, going beyond the attenuation imaging provided by most current systems. Dual- energy CT (DECT) systems can partially address this problem by estimating Compton and photoelectric (PE) coefficients of the materials being imaged, but DECT is greatly degraded by the presence of metal or other materials with high attenuation. Here we explore the advantages of multi-energy CT (MECT) systems based on photon-counting detectors. The utility of MECT has been demonstrated in medical applications where photon- counting detectors allow for the resolution of absorption K-edges. Our primary concern is aviation security applications where K-edges are rare. We simulate phantoms with differing amounts of metal (high, medium and low attenuation), both for switched-source DECT and for MECT systems, and include a realistic model of detector energy 0 resolution. We extend the DECT sinogram decomposition method of Ying et al. to MECT, allowing estimation of separate Compton and photoelectric sinograms. We furthermore introduce a weighting based on a quadratic approximation to the Poisson likelihood function that deemphasizes energy bins with low signal. Simulation results show that the proposed approach succeeds in estimating material properties even in high-attenuation scenarios where the DECT method fails, improving the signal to noise ratio of reconstructions by over 20 dB for the high-attenuation phantom. Our work demonstrates the potential of using photon counting detectors for stably recovering material properties even when high attenuation is present, thus enabling the development of improved scanning systems.

Reduction of dark-band-like metal artifacts caused by dental implant bodies using hypothetical monoenergetic imaging after dual-energy computed tomography.

PubMed

Tanaka, Ray; Hayashi, Takafumi; Ike, Makiko; Noto, Yoshiyuki; Goto, Tazuko K

2013-06-01

The aim of this study was to evaluate the usefulness of hypothetical monoenergetic images after dual-energy computed tomography (DECT) for assessment of the bone encircling dental implant bodies. Seventy-two axial images of implantation sites clipped out from image data scanned using DECT in dual-energy mode were used. Subjective assessment on reduction of dark-band-like artifacts (R-DBAs) and diagnosability of adjacent bone condition (D-ABC) in 3 sets of DECT images-a fused image set (DE120) and 2 sets of hypothetical monoenergetic images (ME100, ME190)-was performed and the results were statistically analyzed. With regards to R-DBAs and D-ABC, significant differences among DE120, ME100, and ME190 were observed. The ME100 and ME190 images revealed more artifact reduction and diagnosability than those of DE120. DECT imaging followed by hypothetical monoenergetic image construction can cause R-DBAs and increase D-ABC and may be potentially used for the evaluation of postoperative changes in the bone encircling implant bodies. Copyright © 2013 Elsevier Inc. All rights reserved.

Ecological Assessment of the Effects of Army Training Activities on a Desert Ecosystem. National Training Center, Fort Irwin, California

DTIC Science & Technology

1985-06-01

predators .) Several bird species ( black - throated sparrows , LeConte’s...7.3 7.7 12.5 33 28 23 24 39 Black - throated Sparrow - Amphispiza bilineata 5.0 0.3 6.7 7.7 4.5 16 1 21 24 14 Brewer’s Sparrow - Spizella breweri 6.5 0...identified as sensitive indicators of disturbances. The absence of black - throated sparrows and LeConte’s thrashers * indicate severely degraded habitats.

Revision of the new world species of Hylurgops LeConte, 1876 with the description of a new genus in the Hylastini (Coleoptera: Scolytinae) and comments on some Palearctic species

Treesearch

Javier E. Mercado-Velez; Jose F. Negron

2014-01-01

The New World species of the genus Hylurgops LeConte are revised and Hylurgops subcostulatus Mannerheim is transferred to the new genus Pachysquamus. A revised key to the tribe Hylastini which can be used for the world fauna is presented to include Pachysquamus. Our studies suggest that the Nearctic species H. knausi Swaine is a valid taxon, distinguishable from the...

Correlation of quantitative dual-energy computed tomography iodine maps and abdominal computed tomography perfusion measurements: are single-acquisition dual-energy computed tomography iodine maps more than a reduced-dose surrogate of conventional computed tomography perfusion?

PubMed

Stiller, Wolfram; Skornitzke, Stephan; Fritz, Franziska; Klauss, Miriam; Hansen, Jens; Pahn, Gregor; Grenacher, Lars; Kauczor, Hans-Ulrich

2015-10-01

Study objectives were the quantitative evaluation of whether conventional abdominal computed tomography (CT) perfusion measurements mathematically correlate with quantitative single-acquisition dual-energy CT (DECT) iodine concentration maps, the determination of the optimum time of acquisition for achieving maximum correlation, and the estimation of the potential for radiation exposure reduction when replacing conventional CT perfusion by single-acquisition DECT iodine concentration maps. Dual-energy CT perfusion sequences were dynamically acquired over 51 seconds (34 acquisitions every 1.5 seconds) in 24 patients with histologically verified pancreatic carcinoma using dual-source DECT at tube potentials of 80 kVp and 140 kVp. Using software developed in-house, perfusion maps were calculated from 80-kVp image series using the maximum slope model after deformable motion correction. In addition, quantitative iodine maps were calculated for each of the 34 DECT acquisitions per patient. Within a manual segmentation of the pancreas, voxel-by-voxel correlation between the perfusion map and each of the iodine maps was calculated for each patient to determine the optimum time of acquisition topt defined as the acquisition time of the iodine map with the highest correlation coefficient. Subsequently, regions of interest were placed inside the tumor and inside healthy pancreatic tissue, and correlation between mean perfusion values and mean iodine concentrations within these regions of interest at topt was calculated for the patient sample. The mean (SD) topt was 31.7 (5.4) seconds after the start of contrast agent injection. The mean (SD) perfusion values for healthy pancreatic and tumor tissues were 67.8 (26.7) mL per 100 mL/min and 43.7 (32.2) mL per 100 mL/min, respectively. At topt, the mean (SD) iodine concentrations were 2.07 (0.71) mg/mL in healthy pancreatic and 1.69 (0.98) mg/mL in tumor tissue, respectively. Overall, the correlation between perfusion values and iodine concentrations was high (0.77), with correlation of 0.89 in tumor and of 0.56 in healthy pancreatic tissue at topt. Comparing radiation exposure associated with a single DECT acquisition at topt (0.18 mSv) to that of an 80 kVp CT perfusion sequence (2.96 mSv) indicates that an average reduction of Deff by 94% could be achieved by replacing conventional CT perfusion with a single-acquisition DECT iodine concentration map. Quantitative iodine concentration maps obtained with DECT correlate well with conventional abdominal CT perfusion measurements, suggesting that quantitative iodine maps calculated from a single DECT acquisition at an organ-specific and patient-specific optimum time of acquisition might be able to replace conventional abdominal CT perfusion measurements if the time of acquisition is carefully calibrated. This could lead to large reductions of radiation exposure to the patients while offering quantitative perfusion data for diagnosis.

MO-FG-204-03: Using Edge-Preserving Algorithm for Significantly Improved Image-Domain Material Decomposition in Dual Energy CT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhao, W; Niu, T; Xing, L

2015-06-15

Purpose: To significantly improve dual energy CT (DECT) imaging by establishing a new theoretical framework of image-domain material decomposition with incorporation of edge-preserving techniques. Methods: The proposed algorithm, HYPR-NLM, combines the edge-preserving non-local mean filter (NLM) with the HYPR-LR (Local HighlY constrained backPRojection Reconstruction) framework. Image denoising using HYPR-LR framework depends on the noise level of the composite image which is the average of the different energy images. For DECT, the composite image is the average of high- and low-energy images. To further reduce noise, one may want to increase the window size of the filter of the HYPR-LR, leadingmore » resolution degradation. By incorporating the NLM filtering and the HYPR-LR framework, HYPR-NLM reduces the boost material decomposition noise using energy information redundancies as well as the non-local mean. We demonstrate the noise reduction and resolution preservation of the algorithm with both iodine concentration numerical phantom and clinical patient data by comparing the HYPR-NLM algorithm to the direct matrix inversion, HYPR-LR and iterative image-domain material decomposition (Iter-DECT). Results: The results show iterative material decomposition method reduces noise to the lowest level and provides improved DECT images. HYPR-NLM significantly reduces noise while preserving the accuracy of quantitative measurement and resolution. For the iodine concentration numerical phantom, the averaged noise levels are about 2.0, 0.7, 0.2 and 0.4 for direct inversion, HYPR-LR, Iter- DECT and HYPR-NLM, respectively. For the patient data, the noise levels of the water images are about 0.36, 0.16, 0.12 and 0.13 for direct inversion, HYPR-LR, Iter-DECT and HYPR-NLM, respectively. Difference images of both HYPR-LR and Iter-DECT show edge effect, while no significant edge effect is shown for HYPR-NLM, suggesting spatial resolution is well preserved for HYPR-NLM. Conclusion: HYPR-NLM provides an effective way to reduce the generic magnified image noise of dual–energy material decomposition while preserving resolution. This work is supported in part by NIH grants 7R01HL111141 and 1R01-EB016777. This work is also supported by the Natural Science Foundation of China (NSFC Grant No. 81201091), Fundamental Research Funds for the Central Universities in China, and Fund Project for Excellent Abroad Scholar Personnel in Science and Technology.« less

TU-FG-BRB-03: Basis Vector Model Based Method for Proton Stopping Power Estimation From Experimental Dual Energy CT Data

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, S; Politte, D; O’Sullivan, J

2016-06-15

Purpose: This work aims at reducing the uncertainty in proton stopping power (SP) estimation by a novel combination of a linear, separable basis vector model (BVM) for stopping power calculation (Med Phys 43:600) and a statistical, model-based dual-energy CT (DECT) image reconstruction algorithm (TMI 35:685). The method was applied to experimental data. Methods: BVM assumes the photon attenuation coefficients, electron densities, and mean excitation energies (I-values) of unknown materials can be approximated by a combination of the corresponding quantities of two reference materials. The DECT projection data for a phantom with 5 different known materials was collected on a Philipsmore » Brilliance scanner using two scans at 90 kVp and 140 kVp. The line integral alternating minimization (LIAM) algorithm was used to recover the two BVM coefficient images using the measured source spectra. The proton stopping powers are then estimated from the Bethe-Bloch equation using electron densities and I-values derived from the BVM coefficients. The proton stopping powers and proton ranges for the phantom materials estimated via our BVM based DECT method are compared to ICRU reference values and a post-processing DECT analysis (Yang PMB 55:1343) applied to vendorreconstructed images using the Torikoshi parametric fit model (tPFM). Results: For the phantom materials, the average stopping power estimations for 175 MeV protons derived from our method are within 1% of the ICRU reference values (except for Teflon with a 1.48% error), with an average standard deviation of 0.46% over pixels. The resultant proton ranges agree with the reference values within 2 mm. Conclusion: Our principled DECT iterative reconstruction algorithm, incorporating optimal beam hardening and scatter corrections, in conjunction with a simple linear BVM model, achieves more accurate and robust proton stopping power maps than the post-processing, nonlinear tPFM based DECT analysis applied to conventional reconstructions of low and high energy scans. Funding Support: NIH R01CA 75371; NCI grant R01 CA 149305.« less

Genome scan of hybridizing sunflowers from Texas (Helianthus annuus and H. debilis) reveals asymmetric patterns of introgression and small islands of genomic differentiation.

PubMed

Scascitelli, M; Whitney, K D; Randell, R A; King, Matthew; Buerkle, C A; Rieseberg, L H

2010-02-01

Although the sexual transfer of genetic material between species (i.e. introgression) has been documented in many groups of plants and animals, genome-wide patterns of introgression are poorly understood. Is most of the genome permeable to interspecific gene flow, or is introgression typically restricted to a handful of genomic regions? Here, we assess the genomic extent and direction of introgression between three sunflowers from the south-central USA: the common sunflower, Helianthus annuus ssp. annuus; a near-endemic to Texas, Helianthus debilis ssp. cucumerifolius; and their putative hybrid derivative, thought to have recently colonized Texas, H. annuus ssp. texanus. Analyses of variation at 88 genetically mapped microsatellite loci revealed that long-term migration rates were high, genome-wide and asymmetric, with higher migration rates from H. annuus texanus into the two parental taxa than vice versa. These results imply a longer history of intermittent contact between H. debilis and H. annuus than previously believed, and that H. annuus texanus may serve as a bridge for the transfer of alleles between its parental taxa. They also contradict recent theory suggesting that introgression should predominantly be in the direction of the colonizing species. As in previous studies of hybridizing sunflower species, regions of genetic differentiation appear small, whether estimated in terms of FST or unidirectional migration rates. Estimates of recent immigration and admixture were inconsistent, depending on the type of analysis. At the individual locus level, one marker showed striking asymmetry in migration rates, a pattern consistent with tight linkage to a Bateson-Dobzhansky-Muller incompatibility.

Myocardial Scar Imaging by Standard Single-Energy and Dual-Energy Late Enhancement Computed Tomography: Comparison to Pathology and Electroanatomical Map in an Experimental Chronic Infarct Porcine Model

PubMed Central

Truong, Quynh A.; Thai, Wai-ee; Wai, Bryan; Cordaro, Kevin; Cheng, Teresa; Beaudoin, Jonathan; Xiong, Guanglei; Cheung, Jim W.; Altman, Robert; Min, James K.; Singh, Jagmeet P.; Barrett, Conor D.; Danik, Stephan

2015-01-01

Background Myocardial scar is a substrate for ventricular tachycardia and sudden cardiac death. Late enhancement computed tomography (CT) imaging can detect scar, but it remains unclear whether newer late enhancement dual-energy (LE-DECT) acquisition has benefit over standard single-energy late enhancement (LE-CT). Objective We aim to compare late enhancement CT using newer LE-DECT acquisition and single-energy LE-CT acquisitions to pathology and electroanatomical map (EAM) in an experimental chronic myocardial infarction (MI) porcine study. Methods In 8 chronic MI pigs (59±5 kg), we performed dual-source CT, EAM, and pathology. For CT imaging, we performed 3 acquisitions at 10 minutes post-contrast: LE-CT 80 kV, LE-CT 100 kV, and LE-DECT with two post-processing software settings. Results Of the sequences, LE-CT 100 kV provided the best contrast-to-noise ratio (all p≤0.03) and correlation to pathology for scar (ρ=0.88). While LE-DECT overestimated scar (both p=0.02), LE-CT images did not (both p=0.08). On a segment basis (n=136), all CT sequences had high specificity (87–93%) and modest sensitivity (50–67%), with LE-CT 100 kV having the highest specificity of 93% for scar detection compared to pathology and agreement with EAM (κ 0.69). Conclusions Standard single-energy LE-CT, particularly 100kV, matched better to pathology and EAM than dual-energy LE-DECT for scar detection. Larger human trials as well as more technical-based studies that optimize varying different energies with newer hardware and software are warranted. PMID:25977115

Virtual non-contrast dual-energy CT compared to single-energy CT of the urinary tract: a prospective study.

PubMed

Lundin, Margareta; Lidén, Mats; Magnuson, Anders; Mohammed, Ahmed Abdulilah; Geijer, Håkan; Andersson, Torbjörn; Persson, Anders

2012-07-01

Dual-energy computed tomography (DECT) has been shown to be useful for subtracting bone or calcium in CT angiography and gives an opportunity to produce a virtual non-contrast-enhanced (VNC) image from a series where contrast agents have been given intravenously. High noise levels and low resolution have previously limited the diagnostic value of the VNC images created with the first generation of DECT. With the recent introduction of a second generation of DECT, there is a possibility of obtaining VNC images with better image quality at hopefully lower radiation dose compared to the previous generation. To compare the image quality of the single-energy series to a VNC series obtained with a two generations of DECT scanners. CT of the urinary tract was used as a model. Thirty patients referred for evaluation of hematuria were examined with an older system (Somatom Definition) and another 30 patients with a new generation (Somatom Definition Flash). One single-energy series was obtained before and one dual-energy series after administration of intravenous contrast media. We created a VNC series from the contrast-enhanced images. Images were assessed concerning image quality with a visual grading scale evaluation of the VNC series with the single-energy series as gold standard. The image quality of the VNC images was rated inferior to the single-energy variant for both scanners, OR 11.5-67.3 for the Definition and OR 2.1-2.8 for the Definition Flash. Visual noise and overall quality were regarded as better with Flash than Definition. Image quality of VNC images obtained with the new generation of DECT is still slightly inferior compared to native images. However, the difference is smaller with the new compared to the older system.

Validation of proton stopping power ratio estimation based on dual energy CT using fresh tissue samples

NASA Astrophysics Data System (ADS)

Taasti, Vicki T.; Michalak, Gregory J.; Hansen, David C.; Deisher, Amanda J.; Kruse, Jon J.; Krauss, Bernhard; Muren, Ludvig P.; Petersen, Jørgen B. B.; McCollough, Cynthia H.

2018-01-01

Dual energy CT (DECT) has been shown, in theoretical and phantom studies, to improve the stopping power ratio (SPR) determination used for proton treatment planning compared to the use of single energy CT (SECT). However, it has not been shown that this also extends to organic tissues. The purpose of this study was therefore to investigate the accuracy of SPR estimation for fresh pork and beef tissue samples used as surrogates of human tissues. The reference SPRs for fourteen tissue samples, which included fat, muscle and femur bone, were measured using proton pencil beams. The tissue samples were subsequently CT scanned using four different scanners with different dual energy acquisition modes, giving in total six DECT-based SPR estimations for each sample. The SPR was estimated using a proprietary algorithm (syngo.via DE Rho/Z Maps, Siemens Healthcare, Forchheim, Germany) for extracting the electron density and the effective atomic number. SECT images were also acquired and SECT-based SPR estimations were performed using a clinical Hounsfield look-up table. The mean and standard deviation of the SPR over large volume-of-interests were calculated. For the six different DECT acquisition methods, the root-mean-square errors (RMSEs) for the SPR estimates over all tissue samples were between 0.9% and 1.5%. For the SECT-based SPR estimation the RMSE was 2.8%. For one DECT acquisition method, a positive bias was seen in the SPR estimates, having a mean error of 1.3%. The largest errors were found in the very dense cortical bone from a beef femur. This study confirms the advantages of DECT-based SPR estimation although good results were also obtained using SECT for most tissues.

Dual-energy CT with virtual monochromatic images and metal artifact reduction software for reducing metallic dental artifacts.

PubMed

Cha, Jihoon; Kim, Hyung-Jin; Kim, Sung Tae; Kim, Yi Kyung; Kim, Ha Youn; Park, Gyeong Min

2017-11-01

Background Metallic dental prostheses may degrade image quality on head and neck computed tomography (CT). However, there is little information available on the use of dual-energy CT (DECT) and metal artifact reduction software (MARS) in the head and neck regions to reduce metallic dental artifacts. Purpose To assess the usefulness of DECT with virtual monochromatic imaging and MARS to reduce metallic dental artifacts. Material and Methods DECT was performed using fast kilovoltage (kV)-switching between 80-kV and 140-kV in 20 patients with metallic dental prostheses. CT data were reconstructed with and without MARS, and with synthesized monochromatic energy in the range of 40-140-kiloelectron volt (keV). For quantitative analysis, the artifact index of the tongue, buccal, and parotid areas was calculated for each scan. For qualitative analysis, two radiologists evaluated 70-keV and 100-keV images with and without MARS for tongue, buccal, parotid areas, and metallic denture. The locations and characteristics of the MARS-related artifacts, if any, were also recorded. Results DECT with MARS markedly reduced metallic dental artifacts and improved image quality in the buccal area ( P < 0.001) and the tongue ( P < 0.001), but not in the parotid area. The margin and internal architecture of the metallic dentures were more clearly delineated with MARS ( P < 0.001) and in the higher-energy images than in the lower-energy images ( P = 0.042). MARS-related artifacts most commonly occurred in the deep center of the neck. Conclusion DECT with MARS can reduce metallic dental artifacts and improve delineation of the metallic prosthesis and periprosthetic region.

Interference of mobile phones and digitally enhanced cordless telecommunications mobile phones in renal scintigraphy.

PubMed

Stegmayr, Armin; Fessl, Benjamin; Hörtnagl, Richard; Marcadella, Michael; Perkhofer, Susanne

2013-08-01

The aim of the study was to assess the potential negative impact of cellular phones and digitally enhanced cordless telecommunication (DECT) devices on the quality of static and dynamic scintigraphy to avoid repeated testing in infant and teenage patients to protect them from unnecessary radiation exposure. The assessment was conducted by performing phantom measurements under real conditions. A functional renal-phantom acting as a pair of kidneys in dynamic scans was created. Data were collected using the setup of cellular phones and DECT phones placed in different positions in relation to a camera head to test the potential interference of cellular phones and DECT phones with the cameras. Cellular phones reproducibly interfered with the oldest type of gamma camera, which, because of its single-head specification, is the device most often used for renal examinations. Curves indicating the renal function were considerably disrupted; cellular phones as well as DECT phones showed a disturbance concerning static acquisition. Variable electromagnetic tolerance in different types of γ-cameras could be identified. Moreover, a straightforward, low-cost method of testing the susceptibility of equipment to interference caused by cellular phones and DECT phones was generated. Even though some departments use newer models of γ-cameras, which are less susceptible to electromagnetic interference, we recommend testing examination rooms to avoid any interference caused by cellular phones. The potential electromagnetic interference should be taken into account when the purchase of new sensitive medical equipment is being considered, not least because the technology of mobile communication is developing fast, which also means that different standards of wave bands will be issued in the future.

Worsening respiratory function in mechanically ventilated intensive care patients: feasibility and value of xenon-enhanced dual energy CT.

PubMed

Hoegl, Sandra; Meinel, Felix G; Thieme, Sven F; Johnson, Thorsten R C; Eickelberg, Oliver; Zwissler, Bernhard; Nikolaou, Konstantin

2013-03-01

To evaluate the feasibility and incremental diagnostic value of xenon-enhanced dual-energy CT in mechanically ventilated intensive care patients with worsening respiratory function. The study was performed in 13 mechanically ventilated patients with severe pulmonary conditions (acute respiratory distress syndrome (ARDS), n=5; status post lung transplantation, n=5; other, n=3) and declining respiratory function. CT scans were performed using a dual-source CT scanner at an expiratory xenon concentration of 30%. Both ventilation images (Xe-DECT) and standard CT images were reconstructed from a single CT scan. Findings were recorded for Xe-DECT and standard CT images separately. Ventilation defects on xenon images were matched to morphological findings on standard CT images and incremental diagnostic information of xenon ventilation images was recorded if present. Mean xenon consumption was 2.95 l per patient. No adverse events occurred under xenon inhalation. In the visual CT analysis, the Xe-DECT ventilation defects matched with pathologic changes in lung parenchyma seen in the standard CT images in all patients. Xe-DECT provided additional diagnostic findings in 4/13 patients. These included preserved ventilation despite early pneumonia (n=1), more confident discrimination between a large bulla and pneumothorax (n=1), detection of an airway-to-pneumothorax fistula (n=1) and exclusion of a suspected airway-to-mediastinum fistula (n=1). In all 4 patients, the additional findings had a substantial impact on patients' management. Xenon-enhanced DECT is safely feasible and can add relevant diagnostic information in mechanically ventilated intensive care patients with worsening respiratory function. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Ex vivo validation of a stoichiometric dual energy CT proton stopping power ratio calibration

NASA Astrophysics Data System (ADS)

Xie, Yunhe; Ainsley, Christopher; Yin, Lingshu; Zou, Wei; McDonough, James; Solberg, Timothy D.; Lin, Alexander; Teo, Boon-Keng Kevin

2018-03-01

A major source of uncertainty in proton therapy is the conversion of Hounsfield unit (HU) to proton stopping power ratio relative to water (SPR). In this study, we measured and quantified the accuracy of a stoichiometric dual energy CT (DECT) SPR calibration. We applied a stoichiometric DECT calibration method to derive the SPR using CT images acquired sequentially at 80 kVp and 140 kVp . The dual energy index was derived based on the HUs of the paired spectral images and used to calculate the effective atomic number (Z eff), relative electron density ({{ρ }e} ), and SPRs of phantom and biological materials. Two methods were used to verify the derived SPRs. The first method measured the sample’s water equivalent thicknesses to deduce the SPRs using a multi-layer ion chamber (MLIC) device. The second method utilized Gafchromic EBT3 film to directly compare relative ranges between sample and water after proton pencil beam irradiation. Ex vivo validation was performed using five different types of frozen animal tissues with the MLIC and three types of fresh animal tissues using film. In addition, the residual ranges recorded on the film were used to compare with those from the treatment planning system using both DECT and SECT derived SPRs. Bland-Altman analysis indicates that the differences between DECT and SPR measurement of tissue surrogates, frozen and fresh animal tissues has a mean of 0.07% and standard deviation of 0.58% compared to 0.55% and 1.94% respectively for single energy CT (SECT) and SPR measurement. Our ex vivo study indicates that the stoichiometric DECT SPR calibration method has the potential to be more accurate than SECT calibration under ideal conditions although beam hardening effects and other image artifacts may increase this uncertainty.

New Staphylinidae (Coleoptera) records with new collection data from New Brunswick, Canada: Oxyporinae

PubMed Central

Webster, Reginald P.; DeMerchant, Ian

2012-01-01

Abstract Five species of Oxyporinae: Oxyporus occipitalis Fauvel, Oxyporus quinquemaculatus LeConte, Oxyporus major Gravenhorst, Oxyporus rufipennis LeConte, and Oxyporus stygicus Say, are newly recorded from New Brunswick, bringing the number of Oxyporinae known from the province to eight. The first documented records from New Brunswick are provided for Oxyporus kiteleyi reported by Majka et al. (2011). Oxyporus occipitalis and Oxyporus major are newly reported for the Maritime provinces of Canada. Collection and habitat data are presented for all these species. PMID:22577323

Can a dual-energy computed tomography predict unsuitable stone components for extracorporeal shock wave lithotripsy?

PubMed

Ahn, Sung Hoon; Oh, Tae Hoon; Seo, Ill Young

2015-09-01

To assess the potential of dual-energy computed tomography (DECT) to identify urinary stone components, particularly uric acid and calcium oxalate monohydrate, which are unsuitable for extracorporeal shock wave lithotripsy (ESWL). This clinical study included 246 patients who underwent removal of urinary stones and an analysis of stone components between November 2009 and August 2013. All patients received preoperative DECT using two energy values (80 kVp and 140 kVp). Hounsfield units (HU) were measured and matched to the stone component. Significant differences in HU values were observed between uric acid and nonuric acid stones at the 80 and 140 kVp energy values (p<0.001). All uric acid stones were red on color-coded DECT images, whereas 96.3% of the nonuric acid stones were blue. Patients with calcium oxalate stones were divided into two groups according to the amount of monohydrate (calcium oxalate monohydrate group: monohydrate≥90%, calcium oxalate dihydrate group: monohydrate<90%). Significant differences in HU values were detected between the two groups at both energy values (p<0.001). DECT improved the characterization of urinary stone components and was a useful method for identifying uric acid and calcium oxalate monohydrate stones, which are unsuitable for ESWL.

Bayesian calibration for electrochemical thermal model of lithium-ion cells

NASA Astrophysics Data System (ADS)

Tagade, Piyush; Hariharan, Krishnan S.; Basu, Suman; Verma, Mohan Kumar Singh; Kolake, Subramanya Mayya; Song, Taewon; Oh, Dukjin; Yeo, Taejung; Doo, Seokgwang

2016-07-01

Pseudo-two dimensional electrochemical thermal (P2D-ECT) model contains many parameters that are difficult to evaluate experimentally. Estimation of these model parameters is challenging due to computational cost and the transient model. Due to lack of complete physical understanding, this issue gets aggravated at extreme conditions like low temperature (LT) operations. This paper presents a Bayesian calibration framework for estimation of the P2D-ECT model parameters. The framework uses a matrix variate Gaussian process representation to obtain a computationally tractable formulation for calibration of the transient model. Performance of the framework is investigated for calibration of the P2D-ECT model across a range of temperatures (333 Ksbnd 263 K) and operating protocols. In the absence of complete physical understanding, the framework also quantifies structural uncertainty in the calibrated model. This information is used by the framework to test validity of the new physical phenomena before incorporation in the model. This capability is demonstrated by introducing temperature dependence on Bruggeman's coefficient and lithium plating formation at LT. With the incorporation of new physics, the calibrated P2D-ECT model accurately predicts the cell voltage with high confidence. The accurate predictions are used to obtain new insights into the low temperature lithium ion cell behavior.

Stochastic spectral projection of electrochemical thermal model for lithium-ion cell state estimation

NASA Astrophysics Data System (ADS)

Tagade, Piyush; Hariharan, Krishnan S.; Kolake, Subramanya Mayya; Song, Taewon; Oh, Dukjin

2017-03-01

A novel approach for integrating a pseudo-two dimensional electrochemical thermal (P2D-ECT) model and data assimilation algorithm is presented for lithium-ion cell state estimation. This approach refrains from making any simplifications in the P2D-ECT model while making it amenable for online state estimation. Though deterministic, uncertainty in the initial states induces stochasticity in the P2D-ECT model. This stochasticity is resolved by spectrally projecting the stochastic P2D-ECT model on a set of orthogonal multivariate Hermite polynomials. Volume averaging in the stochastic dimensions is proposed for efficient numerical solution of the resultant model. A state estimation framework is developed using a transformation of the orthogonal basis to assimilate the measurables with this system of equations. Effectiveness of the proposed method is first demonstrated by assimilating the cell voltage and temperature data generated using a synthetic test bed. This validated method is used with the experimentally observed cell voltage and temperature data for state estimation at different operating conditions and drive cycle protocols. The results show increased prediction accuracy when the data is assimilated every 30s. High accuracy of the estimated states is exploited to infer temperature dependent behavior of the lithium-ion cell.

ASSESSING CONTAMINANT SENSITIVITY OF ENDANGERED AND THREATENED SPECIES: EFFLUENT TOXICITY TESTS

EPA Science Inventory

Toxicity tests using standard effluent test procedures were conducted (EPA 1994) with Ceriodaphnia dubia and fathead minnows and four endangered fish species: bonytail chub (Gila elegans), Colorado squawfish (Ptychocheilus lucias ), razorback sucker (Xyrauchen texanus) and Gila t...

Single-phase dual-energy CT allows for characterization of renal masses as benign or malignant.

PubMed

Graser, Anno; Becker, Christoph R; Staehler, Michael; Clevert, Dirk A; Macari, Michael; Arndt, Niko; Nikolaou, Konstantin; Sommer, Wieland; Stief, Christian; Reiser, Maximilian F; Johnson, Thorsten R C

2010-07-01

To evaluate the diagnostic accuracy of dual-energy CT (DECT) in renal mass characterization using a single-phase acquisition. A total of 202 patients (148 males, 54 females; 63 +/- 13 years) with ultrasound-based suspicion of a renal mass underwent unenhanced single energy and nephrographic phase DECT on a dual source scanner (Siemens Somatom Definition Dual Source, n = 174; Somatom Definition Flash, n = 28). Scan parameters for DECT were: tube potential, 80/100 and 100/Sn140 kVp; exposure, 404/300 and 96/232 effective mAs; collimation, 14 x 1.2/32 x 0.6 mm. Two abdominal radiologists assessed DECT and SECT image quality and noise on a 5-point visual analogue scale. Using solely the DE acquisition including virtual nonenhanced (VNE) and color coded iodine images that enable direct visualization of iodine, masses were characterized as benign or malignant. In a second reading session after 34 to 72 (average: 55) days, the same assessment was again performed using both the true nonenhanced (TNE) and nephrographic phase scans thereby simulating conventional single-energy CT. Sensitivities, specificities, diagnostic accuracies, and interpretation times and were recorded for both reading paradigms. Dose reduction of a single-phase over a dual-phase protocol was calculated. Results were tested for statistical significance using the paired Wilcoxon signed rank test and student t test. Differences in sensitivities were tested for significance using the McNemar test. Of the 202 patients, 115 (56.9%) underwent surgical resection of renal masses. Histopathology showed malignancy in 99 and benign tumors in 18 patients, in 48 patients (23.7%), follow-up imaging showed size stability of lesions diagnosed as benign, and 37 patients (18.3%) had no mass. Based on DECT only, 95/99 (96.0%) patients with malignancy and 96/103 (93.2%) patients without malignancy were correctly identified, for an overall accuracy of 94.6%. The dual-phase approach identified 96/99 (97.0%) and 98/103 (95.1%), accuracy 96.0%, P > 0.05 for both. Mean interpretation time was 2.2 +/- 0.8 minutes for DECT, and 3.5 +/- 1.0 minutes for the dual-phase protocol, P < 0.001. Mean VNE/TNE image quality was 1.68 +/- 0.65/1.30 +/- 0.59, noise was 2.03 +/- 0.57/1.18 +/- 0.29, P < 0.001 for both. Omission of the true unenhanced phase lead to a 48.9 +/- 7.0% dose reduction. DECT allows for fast and accurate characterization of renal masses in a single-phase acquisition. Interpretation of color coded images significantly reduces interpretation time. Omission of a nonenhanced acquisition can reduce radiation exposure by almost 50%.

Anatomy of virgin and mature externae of Loxothylacus texanus, parasitic on the dark blue crab Callinectes rathbunae (Crustacea: Cirripedia: Rhizocephala: Sacculinidae).

PubMed

Alvarez, Fernando; Bortolini, José Luis; Høeg, Jens T

2010-02-01

Rhizocephalan parasites are dioecious organisms, in that one or several dwarf males are implanted into the external part of the female parasite soon after it emerges from the interior of the host animal. The structure of the female externa and its resident males is crucial for understanding both the reproductive biology and the taxonomy of these specialized parasites. We use scanning electron microscopy and histological methods to study the anatomy of juvenile and the mature externae of the rhizocephalan barnacle Loxothylacus texanus parasitizing the blue crab Callinectes rathbunae. We put emphasis on the implantation of males and the histology of the female reproductive organs. In the virgin externae, male cyprids attach around a cuticular hood covering the mantle aperture, which is partially blocked by a plug of cuticle so only trichogon larvae, not cyprids, can access the mantle cavity. This resembles the situation known from Sacculina carcini. The mature externa is characterized by a visceral mass that contains the ovary, paired colleteric glands, a single male receptacle, but paired receptacle ducts. The proximal attachment of the visceral mass is located at some distance from the basal stalk, as is characteristic for the genus Loxothylacus. The internal anatomy of the mature externa of L. texanus is in most features similar to that seen in other species of the Sacculinidae, which comprises the majority of rhizocephalan species. However, the single receptacle creates a situation where the two implanted males cannot be kept separate as in most other rhizocephalans, but pass through spermatogenesis in a common chamber. This may have unknown effects on the reproductive biology such as male-male competition.

Pulmonary Perfusion Changes as Assessed by Contrast-Enhanced Dual-Energy Computed Tomography after Endoscopic Lung Volume Reduction by Coils.

PubMed

Lador, Frédéric; Hachulla, Anne-Lise; Hohn, Olivia; Plojoux, Jérôme; Ronot, Maxime; Montet, Xavier; Soccal, Paola M

2016-01-01

Endoscopic lung volume reduction by coils (LVRC) is a recent treatment approach for severe emphysema. Furthermore, dual-energy computed tomography (DECT) now offers a combined assessment of lung morphology and pulmonary perfusion. The aim of our study was to assess the impact of LVRC on pulmonary perfusion with DECT. Seventeen patients (64.8 ± 6.7 years) underwent LVRC. DECT was performed prior to and after LVRC. For each patient, lung volumes and emphysema quantification were automatically calculated. Then, 6 regions of interest (ROIs) on the iodine perfusion map were drawn in the anterior, mid, and posterior right and left lungs at 4 defined levels. The ROI values were averaged to obtain lung perfusion as assessed by the lung's iodine concentration (CLung, μg·cm-3). The CLung values were normalized using the left atrial iodine concentration (CLA) to take into account differences between successive DECT scans. The 6-min walk distance (6MWD) improved significantly after the procedure (p = 0.0002). No lung volume changes were observed between successive DECT scans for any of the patients (p = 0.32), attesting the same suspended inspiration. After LVRC, the emphysema index was significantly reduced in the treated lung (p = 0.0014). Lung perfusion increased significantly adjacent to the treated areas (CLung/CLA from 3.4 ± 1.7 to 5.6 ± 2.2, p < 0.001) and in the ipsilateral untreated areas (from 4.1 ± 1.4 to 6.6 ± 1.7, p < 0.001), corresponding to a mean 65 and 61% increase in perfusion, respectively. No significant difference was observed in the contralateral upper and lower areas (from 4.4 ± 1.9 to 4.8 ± 2.1, p = 0.273, and from 4.9 ± 2.0 to 5.2 ± 1.7, p = 0.412, respectively). A significant correlation between increased 6MWD and increased perfusion was found (p = 0.0027, R2 = 0.3850). Quantitative analysis based on DECT acquisition revealed that LVRC results in a significant increase in perfusion in the coil-free areas adjacent to the treated ones, as well as in the ipsilateral untreated areas. This suggests a possible role for LVRC in the improvement of the ventilation/perfusion relationship. © 2016 S. Karger AG, Basel.

Dual-Energy Computed Tomography Gemstone Spectral Imaging: A Novel Technique to Determine Human Cardiac Calculus Composition.

PubMed

Cheng, Ching-Li; Chang, Hsiao-Huang; Ko, Shih-Chi; Huang, Pei-Jung; Lin, Shan-Yang

2016-01-01

Understanding the chemical composition of any calculus in different human organs is essential for choosing the best treatment strategy for patients. The purpose of this study was to assess the capability of determining the chemical composition of a human cardiac calculus using gemstone spectral imaging (GSI) mode on a single-source dual-energy computed tomography (DECT) in vitro. The cardiac calculus was directly scanned on the Discovery CT750 HD FREEdom Edition using GSI mode, in vitro. A portable fiber-optic Raman spectroscopy was also applied to verify the quantitative accuracy of the DECT measurements. The results of spectral DECT measurements indicate that effective Z values in 3 designated positions located in this calculus were 15.02 to 15.47, which are close to values of 15.74 to 15.86, corresponding to the effective Z values of calcium apatite and hydroxyapatite. The Raman spectral data were also reflected by the predominant Raman peak at 960 cm for hydroxyapatite and the minor peak at 875 cm for calcium apatite. A potential single-source DECT with GSI mode was first used to examine the morphological characteristics and chemical compositions of a giant human cardiac calculus, in vitro. The CT results were consistent with the Raman spectral data, suggesting that spectral CT imaging techniques could be accurately used to diagnose and characterize the compositional materials in the cardiac calculus.

Differentiation of low-attenuation intracranial hemorrhage and calcification using dual-energy computed tomography in a phantom system

PubMed Central

Nute, Jessica L.; Roux, Lucia Le; Chandler, Adam G.; Baladandayuthapani, Veera; Schellingerhout, Dawid; Cody, Dianna D.

2015-01-01

Objectives Calcific and hemorrhagic intracranial lesions with attenuation levels of <100 Hounsfield Units (HU) cannot currently be reliably differentiated by single-energy computed tomography (SECT). The proper differentiation of these lesion types would have a multitude of clinical applications. A phantom model was used to test the ability of dual-energy CT (DECT) to differentiate such lesions. Materials and Methods Agar gel-bound ferric oxide and hydroxyapatite were used to model hemorrhage and calcification, respectively. Gel models were scanned using SECT and DECT and organized into SECT attenuation-matched pairs at 16 attenuation levels between 0 and 100 HU. DECT data were analyzed using 3D Gaussian mixture models (GMMs), as well as a simplified threshold plane metric derived from the 3D GMM, to assign voxels to hemorrhagic or calcific categories. Accuracy was calculated by comparing predicted voxel assignments with actual voxel identities. Results We measured 6,032 voxels from each gel model, for a total of 193,024 data points (16 matched model pairs). Both the 3D GMM and its more clinically implementable threshold plane derivative yielded similar results, with >90% accuracy at matched SECT attenuation levels ≥50 HU. Conclusions Hemorrhagic and calcific lesions with attenuation levels between 50 and 100 HU were differentiable using DECT in a clinically relevant phantom system with >90% accuracy. This method warrants further testing for potential clinical applications. PMID:25162534

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dong, X; Petrongolo, M; Wang, T

Purpose: A general problem of dual-energy CT (DECT) is that the decomposition is sensitive to noise in the two sets of dual-energy projection data, resulting in severely degraded qualities of decomposed images. We have previously proposed an iterative denoising method for DECT. Using a linear decomposition function, the method does not gain the full benefits of DECT on beam-hardening correction. In this work, we expand the framework of our iterative method to include non-linear decomposition models for noise suppression in DECT. Methods: We first obtain decomposed projections, which are free of beam-hardening artifacts, using a lookup table pre-measured on amore » calibration phantom. First-pass material images with high noise are reconstructed from the decomposed projections using standard filter-backprojection reconstruction. Noise on the decomposed images is then suppressed by an iterative method, which is formulated in the form of least-square estimation with smoothness regularization. Based on the design principles of a best linear unbiased estimator, we include the inverse of the estimated variance-covariance matrix of the decomposed images as the penalty weight in the least-square term. Analytical formulae are derived to compute the variance-covariance matrix from the measured decomposition lookup table. Results: We have evaluated the proposed method via phantom studies. Using non-linear decomposition, our method effectively suppresses the streaking artifacts of beam-hardening and obtains more uniform images than our previous approach based on a linear model. The proposed method reduces the average noise standard deviation of two basis materials by one order of magnitude without sacrificing the spatial resolution. Conclusion: We propose a general framework of iterative denoising for material decomposition of DECT. Preliminary phantom studies have shown the proposed method improves the image uniformity and reduces noise level without resolution loss. In the future, we will perform more phantom studies to further validate the performance of the purposed method. This work is supported by a Varian MRA grant.« less

Evaluation of Functional Marrow Irradiation Based on Skeletal Marrow Composition Obtained Using Dual-Energy Computed Tomography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Magome, Taiki; Masonic Cancer Center, University of Minnesota, Minneapolis, Minnesota; Department of Radiology, The University of Tokyo Hospital, Tokyo

Purpose: To develop an imaging method to characterize and map marrow composition in the entire skeletal system, and to simulate differential targeted marrow irradiation based on marrow composition. Methods and Materials: Whole-body dual energy computed tomography (DECT) images of cadavers and leukemia patients were acquired, segmented to separate bone marrow components, namely, bone, red marrow (RM), and yellow marrow (YM). DECT-derived marrow fat fraction was validated using histology of lumbar vertebrae obtained from cadavers. The fractions of RM (RMF = RM/total marrow) and YMF were calculated in each skeletal region to assess the correlation of marrow composition with sites and ages. Treatmentmore » planning was simulated to target irradiation differentially at a higher dose (18 Gy) to either RM or YM and a lower dose (12 Gy) to the rest of the skeleton. Results: A significant correlation between fat fractions obtained from DECT and cadaver histology samples was observed (r=0.861, P<.0001, Pearson). The RMF decreased in the head, neck, and chest was significantly inversely correlated with age but did not show any significant age-related changes in the abdomen and pelvis regions. Conformity of radiation to targets (RM, YM) was significantly dependent on skeletal sites. The radiation exposure was significantly reduced (P<.05, t test) to organs at risk (OARs) in RM and YM irradiation compared with standard total marrow irradiation (TMI). Conclusions: Whole-body DECT offers a new imaging technique to visualize and measure skeletal-wide marrow composition. The DECT-based treatment planning offers volumetric and site-specific precise radiation dosimetry of RM and YM, which varies with aging. Our proposed method could be used as a functional compartment of TMI for further targeted radiation to specific bone marrow environment, dose escalation, reduction of doses to OARs, or a combination of these factors.« less

Application of single- and dual-energy CT brain tissue segmentation to PET monitoring of proton therapy

NASA Astrophysics Data System (ADS)

Berndt, Bianca; Landry, Guillaume; Schwarz, Florian; Tessonnier, Thomas; Kamp, Florian; Dedes, George; Thieke, Christian; Würl, Matthias; Kurz, Christopher; Ganswindt, Ute; Verhaegen, Frank; Debus, Jürgen; Belka, Claus; Sommer, Wieland; Reiser, Maximilian; Bauer, Julia; Parodi, Katia

2017-03-01

The purpose of this work was to evaluate the ability of single and dual energy computed tomography (SECT, DECT) to estimate tissue composition and density for usage in Monte Carlo (MC) simulations of irradiation induced β + activity distributions. This was done to assess the impact on positron emission tomography (PET) range verification in proton therapy. A DECT-based brain tissue segmentation method was developed for white matter (WM), grey matter (GM) and cerebrospinal fluid (CSF). The elemental composition of reference tissues was assigned to closest CT numbers in DECT space (DECTdist). The method was also applied to SECT data (SECTdist). In a validation experiment, the proton irradiation induced PET activity of three brain equivalent solutions (BES) was compared to simulations based on different tissue segmentations. Five patients scanned with a dual source DECT scanner were analyzed to compare the different segmentation methods. A single magnetic resonance (MR) scan was used for comparison with an established segmentation toolkit. Additionally, one patient with SECT and post-treatment PET scans was investigated. For BES, DECTdist and SECTdist reduced differences to the reference simulation by up to 62% when compared to the conventional stoichiometric segmentation (SECTSchneider). In comparison to MR brain segmentation, Dice similarity coefficients for WM, GM and CSF were 0.61, 0.67 and 0.66 for DECTdist and 0.54, 0.41 and 0.66 for SECTdist. MC simulations of PET treatment verification in patients showed important differences between DECTdist/SECTdist and SECTSchneider for patients with large CSF areas within the treatment field but not in WM and GM. Differences could be misinterpreted as PET derived range shifts of up to 4 mm. DECTdist and SECTdist yielded comparable activity distributions, and comparison of SECTdist to a measured patient PET scan showed improved agreement when compared to SECTSchneider. The agreement between predicted and measured PET activity distributions was improved by employing a brain specific segmentation applicable to both DECT and SECT data.

Can dual-energy CT replace perfusion CT for the functional evaluation of advanced hepatocellular carcinoma?

PubMed

Mulé, Sébastien; Pigneur, Frédéric; Quelever, Ronan; Tenenhaus, Arthur; Baranes, Laurence; Richard, Philippe; Tacher, Vania; Herin, Edouard; Pasquier, Hugo; Ronot, Maxime; Rahmouni, Alain; Vilgrain, Valérie; Luciani, Alain

2018-05-01

To determine the degree of relationship between iodine concentrations derived from dual-energy CT (DECT) and perfusion CT parameters in patients with advanced HCC under treatment. In this single-centre IRB approved study, 16 patients with advanced HCC treated with sorafenib or radioembolization who underwent concurrent dynamic perfusion CT and multiphase DECT using a single source, fast kV switching DECT scanner were included. Written informed consent was obtained for all patients. HCC late-arterial and portal iodine concentrations, blood flow (BF)-related and blood volume (BV)-related perfusion parameters maps were calculated. Mixed-effects models of the relationship between iodine concentrations and perfusion parameters were computed. An adjusted p value (Bonferroni method) < 0.05 was considered significant. Mean HCC late-arterial and portal iodine concentrations were 22.7±12.7 mg/mL and 18.7±8.3 mg/mL, respectively. Late-arterial iodine concentration was significantly related to BV (mixed-effects model F statistic (F)=28.52, p<0.0001), arterial BF (aBF, F=17.62, p<0.0001), hepatic perfusion index (F=28.24, p<0.0001), positive enhancement integral (PEI, F=66.75, p<0.0001) and mean slope of increase (F=32.96, p<0.0001), while portal-venous iodine concentration was mainly related to BV (F=29.68, p<0.0001) and PEI (F=66.75, p<0.0001). In advanced HCC lesions, DECT-derived late-arterial iodine concentration is strongly related to both aBF and BV, while portal iodine concentration mainly reflects BV, offering DECT the ability to evaluate both morphological and perfusion changes. • Late-arterial iodine concentration is highly related to arterial BF and BV. • Portal iodine concentration mainly reflects tumour blood volume. • Dual-energy CT offers significantly decreased radiation dose compared with perfusion CT.

TU-F-18A-06: Dual Energy CT Using One Full Scan and a Second Scan with Very Few Projections

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, T; Zhu, L

Purpose: The conventional dual energy CT (DECT) requires two full CT scans at different energy levels, resulting in dose increase as well as imaging errors from patient motion between the two scans. To shorten the scan time of DECT and thus overcome these drawbacks, we propose a new DECT algorithm using one full scan and a second scan with very few projections by preserving structural information. Methods: We first reconstruct a CT image on the full scan using a standard filtered-backprojection (FBP) algorithm. We then use a compressed sensing (CS) based iterative algorithm on the second scan for reconstruction frommore » very few projections. The edges extracted from the first scan are used as weights in the Objectives: function of the CS-based reconstruction to substantially improve the image quality of CT reconstruction. The basis material images are then obtained by an iterative image-domain decomposition method and an electron density map is finally calculated. The proposed method is evaluated on phantoms. Results: On the Catphan 600 phantom, the CT reconstruction mean error using the proposed method on 20 and 5 projections are 4.76% and 5.02%, respectively. Compared with conventional iterative reconstruction, the proposed edge weighting preserves object structures and achieves a better spatial resolution. With basis materials of Iodine and Teflon, our method on 20 projections obtains similar quality of decomposed material images compared with FBP on a full scan and the mean error of electron density in the selected regions of interest is 0.29%. Conclusion: We propose an effective method for reducing projections and therefore scan time in DECT. We show that a full scan plus a 20-projection scan are sufficient to provide DECT images and electron density with similar quality compared with two full scans. Our future work includes more phantom studies to validate the performance of our method.« less

Xenon-enhanced CT using subtraction CT: Basic and preliminary clinical studies for comparison of its efficacy with that of dual-energy CT and ventilation SPECT/CT to assess regional ventilation and pulmonary functional loss in smokers.

PubMed

Ohno, Yoshiharu; Yoshikawa, Takeshi; Takenaka, Daisuke; Fujisawa, Yasuko; Sugihara, Naoki; Kishida, Yuji; Seki, Shinichiro; Koyama, Hisanobu; Sugimura, Kazuro

2017-01-01

To prospectively and directly compare the capability for assessments of regional ventilation and pulmonary functional loss in smokers of xenon-ventilation CT obtained with the dual-energy CT (DE-CT) and subtraction CT (Sub-CT) MATERIALS AND METHODS: Twenty-three consecutive smokers (15 men and 8 women, mean age: 69.7±8.7years) underwent prospective unenhanced and xenon-enhanced CTs, the latter by Sub-CT and DE-CT methods, ventilation SPECT and pulmonary function tests. Sub-CT was generated from unenhanced and xenon-enhanced CT, and all co-registered SPECT/CT data were produced from SPECT and unenhanced CT data. For each method, regional ventilation was assessed by using a 11-point scoring system on a per-lobe basis. To determine the functional lung volume by each method, it was also calculated for individual sublets with a previously reported method. To determine inter-observer agreement for each method, ventilation defect assessment was evaluated by using the χ2 test with weighted kappa statistics. For evaluation of the efficacy of each method for pulmonary functional loss assessment, functional lung volume was correlated with%FEV 1 . Each inter-observer agreement was rated as substantial (Sub-CT: κ=0.69, p<0.0001; DE-CT: κ=0.64, p<0.0001; SPECT/CT: κ=0.64, p<0.0001). Functional lung volume for each method showed significant to good correlation with%FEV 1 (Sub-CT: r=0.72, p=0.0001; DE-CT: r=0.74, p<0.0001; SPECT/CT: r=0.66, p=0.0006). Xenon-enhanced CT obtained by Sub-CT can be considered at least as efficacious as that obtained by DE-CT and SPECT/CT for assessment of ventilation abnormality and pulmonary functional loss in smokers. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Material elemental decomposition in dual and multi-energy CT via a sparsity-dictionary approach for proton stopping power ratio calculation.

PubMed

Shen, Chenyang; Li, Bin; Chen, Liyuan; Yang, Ming; Lou, Yifei; Jia, Xun

2018-04-01

Accurate calculation of proton stopping power ratio (SPR) relative to water is crucial to proton therapy treatment planning, since SPR affects prediction of beam range. Current standard practice derives SPR using a single CT scan. Recent studies showed that dual-energy CT (DECT) offers advantages to accurately determine SPR. One method to further improve accuracy is to incorporate prior knowledge on human tissue composition through a dictionary approach. In addition, it is also suggested that using CT images with multiple (more than two) energy channels, i.e., multi-energy CT (MECT), can further improve accuracy. In this paper, we proposed a sparse dictionary-based method to convert CT numbers of DECT or MECT to elemental composition (EC) and relative electron density (rED) for SPR computation. A dictionary was constructed to include materials generated based on human tissues of known compositions. For a voxel with CT numbers of different energy channels, its EC and rED are determined subject to a constraint that the resulting EC is a linear non-negative combination of only a few tissues in the dictionary. We formulated this as a non-convex optimization problem. A novel algorithm was designed to solve the problem. The proposed method has a unified structure to handle both DECT and MECT with different number of channels. We tested our method in both simulation and experimental studies. Average errors of SPR in experimental studies were 0.70% in DECT, 0.53% in MECT with three energy channels, and 0.45% in MECT with four channels. We also studied the impact of parameter values and established appropriate parameter values for our method. The proposed method can accurately calculate SPR using DECT and MECT. The results suggest that using more energy channels may improve the SPR estimation accuracy. © 2018 American Association of Physicists in Medicine.

[Electromagnetic fields in the vicinity of DECT cordless telephones and mobile phones].

PubMed

Mamrot, Paweł; Mariańska, Magda; Aniołczyk, Halina; Politański, Piotr

2015-01-01

Mobile telephones belong to the most frequently used personal devices. In their surroundings they produce the electromagnetic field (EMF), in which exposure range there are not only users but also nearby bystanders. The aim of the investigations and EMF measurements in the vicinity of phones was to identify the electric field levels with regard to various working modes. Twelve sets of DECT (digital enhanced cordless telecommunications) cordless phones (12 base units and 15 handsets), 21 mobile telephones produced by different manufactures, and 16 smartphones in various applications, (including multimedia) in the conditions of daily use in living rooms were measured. Measurements were taken using the point method in predetermined distances of 0.05-1 m from the devices without the presence of users. In the vicinity of DECT cordless phone handsets, electric field strength ranged from 0.26 to 2.30 V/m in the distance of 0.05 m - 0.18-0.26 V/m (1 m). In surroundings of DECT cordless telephones base units the values of EMF were from 1.78-5.44 V/m (0.05 m) to 0.19- 0.41 V/m (1 m). In the vicinity of mobile phones working in GSM mode with voice transmission, the electric field strength ranged from 2.34-9.14 V/m (0.05 m) to 0.18-0.47 V/m (1 m) while in the vicinity of mobile phones working in WCDMA (Wideband Code Division Multiple Access) mode the electric field strength ranged from 0.22-1.83 V/m (0.05 m) to 0.18-0.20 V/m (1 m). The mean values of the electric field strength for each group of devices, mobile phones and DECT wireless phones sets do not exceed the reference value of 7 V/m, adopted as the limit for general public exposure. This work is available in Open Access model and licensed under a CC BY-NC 3.0 PL license.

Evaluating glacier movement fluctuations using remote sensing: A case study of the Baird, Patterson, LeConte, and Shakes glaciers in central Southeastern Alaska

NASA Astrophysics Data System (ADS)

Davidson, Robert Howard

Global Land Survey (GLS) data encompassing Landsat Multispectral Scanner (MSS), Landsat 5's Thematic Mapper (TM), and Landsat 7's Enhanced Thematic Mapper Plus (ETM+) were used to determine the terminus locations of Baird, Patterson, LeConte, and Shakes Glaciers in Alaska in the time period 1975-2010. The sequences of the terminuses locations were investigated to determine the movement rates of these glaciers with respect to specific physical and environmental conditions. GLS data from 1975, 1990, 2000, 2005, and 2010 in false-color composite images enhancing ice-snow differentiation and Iterative Self-Organizing (ISO) Data Cluster Unsupervised Classifications were used to 1) quantify the movement rates of Baird, Patterson, LeConte, and Shakes Glaciers; 2) analyze the movement rates for glaciers with similar terminal terrain conditions and; 3) analyze the movement rates for glaciers with dissimilar terminal terrain conditions. From the established sequence of terminus locations, movement distances were quantified between the glacier locations. Movement distances were then compared to see if any correlation existed between glaciers with similar or dissimilar terminal terrain conditions. The Global Land Ice Measurement from Space (GLIMS) data was used as a starting point from which glacier movement was measured for Baird, Patterson, and LeConte Glaciers only as the Shakes Glacier is currently not included in the GLIMS database. The National Oceanographic and Atmospheric Administration (NOAA) temperature data collected at the Petersburg, Alaska, meteorological station (from January 1, 1973 to December 31, 2009) were used to help in the understanding of the climatic condition in this area and potential impact on glaciers terminus. Results show that glaciers with similar terminal terrain conditions (Patterson and Shakes Glaciers) and glaciers with dissimilar terminal terrain conditions (Baird, Patterson, and LeConte Glaciers) did not exhibit similar movement rates. Glacier movement rates were greatest for glaciers whose terminuses were in fresh water (Patterson and Shakes Glaciers), less for those with terminuses in salt water (LeConte Glacier), and least for glaciers with terminuses on dry land (Baird Glacier).Based upon these findings, the presence of water, especially fresh water, at the terminal end of the Patterson and Shakes Glaciers had a greater effect on glacier movement than slope. Possible explanations for this effect might include a heat sink effect or tidal motions that hasten glacier disintegration in the ablation zone. In a heat sink scenario, the water bodies in which the Patterson and Shakes Glaciers terminus are located could act as a thermal energy transfer medium that increases glacier melting and subsequent retreat. On the other hand, tidal motions could act as horizontal and vertical push/pull forces, which increase the fracturing rate, calving, and subsequent retreat of glaciers terminus that are is salt water like the LeConte Glacier. Over the length of the study period, 1975 through 2010, there has been a 0.85°C increase in annual air temperatures that, although may seem low, may prove important when determining glacial mass balance rates. Further studies are necessary to test these hypotheses to determine if a heat sink effect and tidal motions significantly affected the movement rates for the glaciers in this study area. An additional significant result of this study was the creation of shapefiles delineating the positions of the Shakes Glaciers that are being submitted to the Global Land Ice Measurements from Space (GLIMS) program for inclusion in their master worldwide glacier database.

A general framework of noise suppression in material decomposition for dual-energy CT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Petrongolo, Michael; Dong, Xue; Zhu, Lei, E-mail: leizhu@gatech.edu

Purpose: As a general problem of dual-energy CT (DECT), noise amplification in material decomposition severely reduces the signal-to-noise ratio on the decomposed images compared to that on the original CT images. In this work, the authors propose a general framework of noise suppression in material decomposition for DECT. The method is based on an iterative algorithm recently developed in their group for image-domain decomposition of DECT, with an extension to include nonlinear decomposition models. The generalized framework of iterative DECT decomposition enables beam-hardening correction with simultaneous noise suppression, which improves the clinical benefits of DECT. Methods: The authors propose tomore » suppress noise on the decomposed images of DECT using convex optimization, which is formulated in the form of least-squares estimation with smoothness regularization. Based on the design principles of a best linear unbiased estimator, the authors include the inverse of the estimated variance–covariance matrix of the decomposed images as the penalty weight in the least-squares term. Analytical formulas are derived to compute the variance–covariance matrix for decomposed images with general-form numerical or analytical decomposition. As a demonstration, the authors implement the proposed algorithm on phantom data using an empirical polynomial function of decomposition measured on a calibration scan. The polynomial coefficients are determined from the projection data acquired on a wedge phantom, and the signal decomposition is performed in the projection domain. Results: On the Catphan{sup ®}600 phantom, the proposed noise suppression method reduces the average noise standard deviation of basis material images by one to two orders of magnitude, with a superior performance on spatial resolution as shown in comparisons of line-pair images and modulation transfer function measurements. On the synthesized monoenergetic CT images, the noise standard deviation is reduced by a factor of 2–3. By using nonlinear decomposition on projections, the authors’ method effectively suppresses the streaking artifacts of beam hardening and obtains more uniform images than their previous approach based on a linear model. Similar performance of noise suppression is observed in the results of an anthropomorphic head phantom and a pediatric chest phantom generated by the proposed method. With beam-hardening correction enabled by their approach, the image spatial nonuniformity on the head phantom is reduced from around 10% on the original CT images to 4.9% on the synthesized monoenergetic CT image. On the pediatric chest phantom, their method suppresses image noise standard deviation by a factor of around 7.5, and compared with linear decomposition, it reduces the estimation error of electron densities from 33.3% to 8.6%. Conclusions: The authors propose a general framework of noise suppression in material decomposition for DECT. Phantom studies have shown the proposed method improves the image uniformity and the accuracy of electron density measurements by effective beam-hardening correction and reduces noise level without noticeable resolution loss.« less

78 FR 11218 - Final Environmental Impact Statement and Record of Decision on the Edwards Aquifer Recovery...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-02-15

... fonticola) Texas blind salamander (Eurycea [=Typhlomolge] rathbuni) San Marcos gambusia (Gambusia georgei) Threatened San Marcos salamander (Eurycea nana) Non-listed Species Texas cave diving beetle (Haideoporus texanus) Texas troglobitic water slater (Lirceolus smithii) Comal Springs salamander (Eurycea sp.) Take of...

New Staphylinidae (Coleoptera) records with new collection data from New Brunswick, Canada: Scaphidiinae, Piestinae, Osorinae, and Oxytelinae

PubMed Central

Webster, Reginald P.; Sweeney, Jon D.; DeMerchant, Ian

2012-01-01

Abstract Nine species of Scaphidiinae are newly reported for New Brunswick, Canada, bringing the total number of species known from the province to 12. Scaphium castanipes Kirby, Baeocera inexspectata Löbl and Stephen, Baeocera securiforma (Cornell), Scaphisoma repandum Casey, and Toxidium gammaroides LeConte are reported for the first time from the Maritime provinces. Siagonum punctatum LeConte and Siagonum stacesmithi Hatch, and the subfamily Piestinae are reported for the first time from New Brunswick. The subfamily Osoriinae is reported for the first time from New Brunswick and the Maritime provinces based on the collection of three species: Clavilispinus prolixus (LeConte), Thoracophorus costalis (Erichson), and a Lispinodes species. The Lispinodes species is also newly recorded for Canada. Six species of Oxytelinae are newly recorded from New Brunswick, bringing the total number of species of this subfamily known to the province to 20. Apocellus sphaericollis (Say) and Platystethus americanus Erichson are new to the Maritime provinces. Additional locality and bionomic data are presented for Mitosynum vockerothi Campbell, and the male genitalia are illustrated for the first time. Collection and bionomic data are presented for all included species. PMID:22577322

Oyster Shell Dredging in Gulf of Mexico Waters, St. Mary and Terrebonne Parishes, Louisiana. Final Environmental Impact Statement and Appendixes

DTIC Science & Technology

1994-04-01

sabinae Sabine shiner x Notropis texanus weed shiner x Notropis volucellus mimic shiner X Ogeocephalus radiatus polka-dot bat fish x Oligoplites saurus ...Elope saurus ladyfish x x Erimyzon oblongus creek chubsucker x Esox americanus vermiculatus grass pickerel x Etheostoma chiorosomum, bluntnose darter

New Staphylinidae (Coleoptera) records with new collection data from New Brunswick, Canada: Omaliinae, Micropeplinae, Phloeocharinae, Olisthaerinae, and Habrocerinae

PubMed Central

Webster, Reginald P.; Sweeney, Jon D.; DeMerchant, Ian

2012-01-01

Abstract Eleven species of Omaliinae are newly recorded from New Brunswick, bringing the total number of species known from the province to 32 described species. Supporting data are presented for the New Brunswick record of Geodromicus strictus (Fauvel) reported by Majka et al. (2011). Micropeplus browni Campbell, Micropeplus laticollis Mäklin (Micropeplinae), Charyhyphus picipennis (LeConte) (Phloeocharinae), Olisthaerus substriatus (Paykull) (Olisthaerinae), Habrocerus capillaricornis (Gravenhorst), Habrocerus magnus LeConte, and Habrocerus schwarzi Horn (Habrocerinae) are also newly recorded for New Brunswick. These are the first records of the latter four subfamilies from New Brunswick. Collection and bionomic data are presented for each species and discussed. PMID:22577316

New Coleoptera records from New Brunswick, Canada: Cerambycidae.

PubMed

Webster, Reginald P; Sweeney, Jon D; Demerchant, Ian; Silk, Peter J; Mayo, Peter

2012-01-01

Five species of Cerambycidae, Acmaeops discoideus (Haldeman), Anelaphus villosus (Fabricius), Phymatodes species (CNC sp. n. #1), Sarosesthes fulminans (Fabricius), and Urgleptus signatus (LeConte) are newly recorded for New Brunswick, Canada. All but Acmaeops villosus are new to the Maritime provinces. Phymatodes testaceus (Linnaeus) is removed from the faunal list of the province as a result of mislabeled specimens, records of Phymatodes maculicollis LeConte are presented confirming the presence of this species in New Brunswick, and the first recent records ofNeospondylis upiformis (Mannerheim) are presented. Additional records are given for the recently recorded Phymatodes aereus (Newman), indicating a wider distribution in the province. Collection data, habitat data, and distribution maps are presented for each species.

Accuracy of Liver Fat Quantification With Advanced CT, MRI, and Ultrasound Techniques: Prospective Comparison With MR Spectroscopy.

PubMed

Kramer, Harald; Pickhardt, Perry J; Kliewer, Mark A; Hernando, Diego; Chen, Guang-Hong; Zagzebski, James A; Reeder, Scott B

2017-01-01

The purpose of this study was to prospectively evaluate the accuracy of proton-density fat-fraction, single- and dual-energy CT (SECT and DECT), gray-scale ultrasound (US), and US shear-wave elastography (US-SWE) in the quantification of hepatic steatosis with MR spectroscopy (MRS) as the reference standard. Fifty adults who did not have symptoms (23 men, 27 women; mean age, 57 ± 5 years; body mass index, 27 ± 5) underwent liver imaging with un-enhanced SECT, DECT, gray-scale US, US-SWE, proton-density fat-fraction MRI, and MRS for this prospective trial. MRS voxels for the reference standard were colocalized with all other modalities under investigation. For SECT (120 kVp), attenuation values were recorded. For rapid-switching DECT (80/140 kVp), monochromatic images (70-140 keV) and fat density-derived material decomposition images were reconstructed. For proton-density fat fraction MRI, a quantitative chemical shift-encoded method was used. For US, echogenicity was evaluated on a qualitative 0-3 scale. Quantitative US shear-wave velocities were also recorded. Data were analyzed by linear regression for each technique compared with MRS. There was excellent correlation between MRS and both proton-density fat-fraction MRI (r 2 = 0.992; slope, 0.974; intercept, -0.943) and SECT (r 2 = 0.856; slope, -0.559; intercept, 35.418). DECT fat attenuation had moderate correlation with MRS measurements (r 2 = 0.423; slope, 0.034; intercept, 8.459). There was good correlation between qualitative US echogenicity and MRS measurements with a weighted kappa value of 0.82. US-SWE velocity did not have reliable correlation with MRS measurements (r 2 = 0.004; slope, 0.069; intercept, 6.168). Quantitative MRI proton-density fat fraction and SECT fat attenuation have excellent linear correlation with MRS measurements and can serve as accurate noninvasive biomarkers for quantifying steatosis. Material decomposition with DECT does not improve the accuracy of fat quantification over conventional SECT attenuation. US-SWE has poor accuracy for liver fat quantification.

SU-G-TeP2-11: Initial Evaluation of a Novel Split-Filter Dual-Energy CT for Use in Radiation Oncology

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miller, J; Huang, J; Szczykutowicz, T

2016-06-15

Purpose: To perform an initial evaluation of a novel split-filter dual-energy CT (DECT) system with the goal of understanding the clinical utility and limitations of the system for radiation therapy. Methods: Several phantoms were imaged using the split-filter DECT technique on the Siemens Edge CT scanner using a range of clinically-relevant doses. The optimum-contrast reconstruction, the mixed reconstruction, and the monoenergetic reconstructions (ranging from 40 keV to 190 keV) were evaluated. Each image was analyzed for CT number accuracy, uniformity, noise, low-contrast visibility (LCV), spatial resolution and geometric distortion. For comparison purposes, all parameters were evaluated on 120 kVp single-energymore » CT (SECT) scans used for treatment planning, as well as, a sequential-scan DECT technique for corresponding doses. Results: For all DECT reconstructions no observable geometric distortion was found. Both the optimal-contrast and mixed images demonstrated slight improvements in LCV and noise when compared to the SECT, and slight reductions in CT number accuracy and spatial resolution. The CT numbers trended as expected for the monoenergetic reconstructions, with CT number accuracy within 50 HU for materials of density <2 g/cm3. Spatial resolution increased with energy, and for monoenergetic reconstructions >70 keV the spatial resolution exceeded that of the SECT. The noise in the monoenergetic reconstructions increased with decreasing energy. Thus, the image uniformity, signal-to-noise ratio and LCV were diminished at lower energies (70 keV). Applying iterative reconstruction techniques to the low-energy images reduced noise and improved LCV. The signal-to-noise ratio was stable for energies >100 keV. Conclusion: The initial commissioning of the novel split-filter DECT technology demonstrated favorable results for clinical implementation. The mixed reconstruction showed potential as a replacement for the treatment planning SECT. The image parameters for the monoenergetic reconstructions varied appropriately with energy. This work provides an initial understanding of the limitations and potential applications for monoenergetic imaging.« less

Empirical dual energy calibration (EDEC) for cone-beam computed tomography.

PubMed

Stenner, Philip; Berkus, Timo; Kachelriess, Marc

2007-09-01

Material-selective imaging using dual energy CT (DECT) relies heavily on well-calibrated material decomposition functions. These require the precise knowledge of the detected x-ray spectra, and even if they are exactly known the reliability of DECT will suffer from scattered radiation. We propose an empirical method to determine the proper decomposition function. In contrast to other decomposition algorithms our empirical dual energy calibration (EDEC) technique requires neither knowledge of the spectra nor of the attenuation coefficients. The desired material-selective raw data p1 and p2 are obtained as functions of the measured attenuation data q1 and q2 (one DECT scan = two raw data sets) by passing them through a polynomial function. The polynomial's coefficients are determined using a general least squares fit based on thresholded images of a calibration phantom. The calibration phantom's dimension should be of the same order of magnitude as the test object, but other than that no assumptions on its exact size or positioning are made. Once the decomposition coefficients are determined DECT raw data can be decomposed by simply passing them through the polynomial. To demonstrate EDEC simulations of an oval CTDI phantom, a lung phantom, a thorax phantom and a mouse phantom were carried out. The method was further verified by measuring a physical mouse phantom, a half-and-half-cylinder phantom and a Yin-Yang phantom with a dedicated in vivo dual source micro-CT scanner. The raw data were decomposed into their components, reconstructed, and the pixel values obtained were compared to the theoretical values. The determination of the calibration coefficients with EDEC is very robust and depends only slightly on the type of calibration phantom used. The images of the test phantoms (simulations and measurements) show a nearly perfect agreement with the theoretical micro values and density values. Since EDEC is an empirical technique it inherently compensates for scatter components. The empirical dual energy calibration technique is a pragmatic, simple, and reliable calibration approach that produces highly quantitative DECT images.

SU-F-J-91: Sparing Lung Function in Treatment Planning Using Dual Energy Tomography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lapointe, A; Bahig, H; Zerouali, K

2016-06-15

Purpose: To propose an alternate treatment plan that minimizes the dose to the functional lung tissues. In clinical situation, the evaluation of the lung functionality is typically derived from perfusion scintigraphy. However, such technique has spatial and temporal resolutions generally inferior to those of a CT scan. Alternatively, it is possible to evaluate pulmonary function by analysing the iodine concentration determined via contrast-enhanced dual energy CT (DECT) scan. Methods: Five lung cancer patients underwent a scintigraphy and a contrast-enhanced DECT scan (SOMATOM Definition Flash, Siemens). The iodine concentration was evaluated using the two-material decomposition method to produce a functional mapmore » of the lung. The validation of the approach is realized by comparison between the differential function computed by DECT and scintigraphy. The functional map is then used to redefine the V5 (volume of the organ that received more than 5 Gy during a radiotherapy treatment) to a novel functional parameter, the V5f. The V5f, that uses a volume weighted by its function level, can assist in evaluating optimal beam entry points for a specific treatment plan. Results: The results show that the differential functions obtained by scintigraphy and DECT are in good agreement with a mean difference of 6%. In specific cases, we are able to visually correlate low iodine concentration with abnormal pulmonary lung or cancerous tumors. The comparison between V5f and V5 has shown that some entry points can be better exploited and that new ones are now accessible, 2.34 times more in average, without increasing the V5f - thus allowing easier optimization of other planning objectives. Conclusion: In addition to the high-resolution DECT images, the iodine map provides local information used to detect potential functional heterogeneities in the 3D space. We propose that this information be used to calculate new functional dose parameters such as the V5f. The presenting author, Andreanne Lapointe, received a canadian scholarship from MITACS. Part of the funding is from the compagny Siemens.« less

Dual Energy CT (DECT) Monochromatic Imaging: Added Value of Adaptive Statistical Iterative Reconstructions (ASIR) in Portal Venography.

PubMed

Zhao, Liqin; Winklhofer, Sebastian; Jiang, Rong; Wang, Xinlian; He, Wen

2016-01-01

To investigate the effect of the adaptive statistical iterative reconstructions (ASIR) on image quality in portal venography by dual energy CT (DECT) imaging. DECT scans of 45 cirrhotic patients obtained in the portal venous phase were analyzed. Monochromatic images at 70keV were reconstructed with the following 4 ASIR percentages: 0%, 30%, 50%, and 70%. The image noise (IN) (standard deviation, SD) of portal vein (PV), the contrast-to-noise-ratio (CNR), and the subjective score for the sharpness of PV boundaries, and the diagnostic acceptability (DA) were obtained. The IN, CNR, and the subjective scores were compared among the four ASIR groups. The IN (in HU) of PV (10.05±3.14, 9.23±3.05, 8.44±2.95 and 7.83±2.90) decreased and CNR values of PV (8.04±3.32, 8.95±3.63, 9.80±4.12 and 10.74±4.73) increased with the increase in ASIR percentage (0%, 30%, 50%, and 70%, respectively), and were statistically different for the 4 ASIR groups (p<0.05). The subjective scores showed that the sharpness of portal vein boundaries (3.13±0.59, 2.82±0.44, 2.73±0.54 and 2.07±0.54) decreased with higher ASIR percentages (p<0.05). The subjective diagnostic acceptability was highest at 30% ASIR (p<0.05). 30% ASIR addition in DECT portal venography could improve the 70 keV monochromatic image quality.

Dual Energy CT (DECT) Monochromatic Imaging: Added Value of Adaptive Statistical Iterative Reconstructions (ASIR) in Portal Venography

PubMed Central

Winklhofer, Sebastian; Jiang, Rong; Wang, Xinlian; He, Wen

2016-01-01

Objective To investigate the effect of the adaptive statistical iterative reconstructions (ASIR) on image quality in portal venography by dual energy CT (DECT) imaging. Materials and Methods DECT scans of 45 cirrhotic patients obtained in the portal venous phase were analyzed. Monochromatic images at 70keV were reconstructed with the following 4 ASIR percentages: 0%, 30%, 50%, and 70%. The image noise (IN) (standard deviation, SD) of portal vein (PV), the contrast-to-noise-ratio (CNR), and the subjective score for the sharpness of PV boundaries, and the diagnostic acceptability (DA) were obtained. The IN, CNR, and the subjective scores were compared among the four ASIR groups. Results The IN (in HU) of PV (10.05±3.14, 9.23±3.05, 8.44±2.95 and 7.83±2.90) decreased and CNR values of PV (8.04±3.32, 8.95±3.63, 9.80±4.12 and 10.74±4.73) increased with the increase in ASIR percentage (0%, 30%, 50%, and 70%, respectively), and were statistically different for the 4 ASIR groups (p<0.05). The subjective scores showed that the sharpness of portal vein boundaries (3.13±0.59, 2.82±0.44, 2.73±0.54 and 2.07±0.54) decreased with higher ASIR percentages (p<0.05). The subjective diagnostic acceptability was highest at 30% ASIR (p<0.05). Conclusions 30% ASIR addition in DECT portal venography could improve the 70 keV monochromatic image quality. PMID:27315158

Usefulness of dual-energy computed tomography with and without dedicated software in identifying uric acid kidney stones.

PubMed

Salvador, R; Luque, M P; Ciudin, A; Paño, B; Buñesch, L; Sebastia, C; Nicolau, C

2016-01-01

To prospectively evaluate the usefulness of dual-energy computed tomography (DECT) with and without dedicated software in identifying uric acid kidney stones in vivo. We studied 65 kidney stones in 63 patients. All stones were analyzed in vivo by DECT and ex vivo by spectrophotometry. We evaluated the diagnostic performance in identifying uric acid stones with DECT by analyzing the radiologic densities with dedicated software and without using it (through manual measurements) as well as by analyzing the attenuation ratios of the stones in both energies with and without the dedicated software. The six uric acid stones included were correctly identified by evaluating the attenuation ratios with a cutoff of 1.21, both with the dedicated software and without it, yielding perfect diagnostic performance without false positives or false negatives. The study of the attenuations of the stones obtained the following values on the receiver operating characteristic curves in the classification of the uric acid stones: 0.92 for the measurements done with the software and 0.89 for the manual measurements; a cutoff of 538 HU yielded 84% (42/50) diagnostic accuracy for the software and 83.1% (54/65) for the manual measurements. DECT enabled the uric acid stones to be identified correctly through the calculation of the ratio of the attenuations in the two energies. The results obtained with the dedicated software were similar to those obtained manually. Copyright © 2015 SERAM. Published by Elsevier España, S.L.U. All rights reserved.

Range prediction for tissue mixtures based on dual-energy CT

NASA Astrophysics Data System (ADS)

Möhler, Christian; Wohlfahrt, Patrick; Richter, Christian; Greilich, Steffen

2016-06-01

The use of dual-energy CT (DECT) potentially decreases range uncertainties in proton and ion therapy treatment planning via determination of the involved physical target quantities. For eventual clinical application, the correct treatment of tissue mixtures and heterogeneities is an essential feature, as they naturally occur within a patient’s CT. Here, we present how existing methods for DECT-based ion-range prediction can be modified in order to incorporate proper mixing behavior on several structural levels. Our approach is based on the factorization of the stopping-power ratio into the relative electron density and the relative stopping number. The latter is confined for tissue between about 0.95 and 1.02 at a therapeutic beam energy of 200 MeV u-1 and depends on the I-value. We show that convenient mixing and averaging properties arise by relating the relative stopping number to the relative cross section obtained by DECT. From this, a maximum uncertainty of the stopping-power ratio prediction below 1% is suggested for arbitrary mixtures of human body tissues.

Role of Dual Energy Computed Tomography Imaging in the Diagnosis of Gout

PubMed Central

Sehra, Shiv T; Anand, Suneesh; Stallings, Gary W.; Danve, Abhijeet

2017-01-01

Gout is a well-known inflammatory arthritis and affects four percent of the United States population. It results from the deposition of uric acid crystals in joints, tendons, bursae, and other surrounding tissues. Prevalence of gout has increased in the recent decade. Gout is usually seen in conjunction with other chronic comorbid conditions like cardiac disease, metabolic syndrome, and renal disease. The diagnosis of this inflammatory arthritis is confirmed by visualization of monosodium urate (MSU) crystals in the synovial fluid. Though synovial fluid aspiration is the standard of care, it is often deferred because of inaccessibility of small joints, patient assessment during intercritical period, or procedural inexperience in a primary care office. Dual energy computed tomography (DECT) is a relatively new imaging modality which shows great promise in the diagnosis of gout. It is a good noninvasive alternative to synovial fluid aspiration. DECT is increasingly useful in diagnosing cases of gout where synovial fluid fails to demonstrate monosodium urate crystals. In this article, we will review the mechanism, types, advantages, and disadvantages of DECT. PMID:28229032

Accessing the inaccessible: making (successful) field observations at tidewater glacier termini

NASA Astrophysics Data System (ADS)

Kienholz, C.; Amundson, J. M.; Jackson, R. H.; Motyka, R. J.; Nash, J. D.; Sutherland, D.

2017-12-01

Glaciers terminating in ocean water (tidewater glaciers) show complex dynamic behavior driven predominantly by processes at the ice-ocean interface (sedimentation, erosion, iceberg calving, submarine melting). A quantitative understanding of these processes is required, for example, to better assess tidewater glaciers' fate in our rapidly warming environment. Lacking observations close to glacier termini, due to unpredictable risks from calving, hamper this understanding. In an effort to remedy this lack of knowledge, we initiated a large field-based effort at LeConte Glacier, southeast Alaska, in 2016. LeConte Glacier is a regional analog for many tidewater glaciers, but better accessible and observable and thus an ideal target for our multi-disciplinary effort. Our ongoing campaigns comprise measurements from novel autonomous vessels (temperature, salinity and current) in the immediate proximity of the glacier terminus and additional surveys (including multibeam bathymetry) from boats and moorings in the proglacial fjord. These measurements are complemented by iceberg and glacier velocity measurements from time lapse cameras and a portable radar interferometer situated above LeConte Bay. GPS-based velocity observations and melt measurements are conducted on the glacier. These measurements provide necessary input for process-based understanding and numerical modeling of the glacier and fjord systems. In the presentation, we discuss promising initial results and lessons learned from the campaign.

A new species of Deltaspis Audinet-Serville (Coleoptera: Cerambycidae: Cerambycinae) from Mexico.

PubMed

Eya, Bryan K

2017-03-27

As currently defined, the genus Deltaspis Audinet-Serville, 1834, contains 16 species ranging in distribution from the southwestern United States to eastern Mexico. However, the generic distinction between Deltaspis and its closely allied genera, such as Crossidius LeConte, 1851 and Muscidora Thomson, 1864, is in need of clarification. According to Audinet-Serville, Deltaspis is so named due to its distinctive triangular scutellum (i.e., Δετα, delta, ασπιζ écusson), which is actually a commonly shared character of all these genera. Members of the tribe Trachyderini Dupont (1836), which includes the above genera, also have mandibles with an emarginate-truncate apex with the edge chisel-like or bifid. This modification of mouthpart appears to be for consumption of pollen and/or petals from composite flowers visited by the adult beetles (Krenn et al., 2005; Beierl & Barchet-Beierl, 1999). Other genera from this tribe with this modification of mandibles from North America, and mostly from Mexico, include: Chemsakiella Monné, 2006, Giesbertia Chemsak & Linsley, 1984, Hoegea Bates, 1885, Neocrossidius Chemsak, 1959, Paroxoplus Chemsak, 1959, Plionoma Casey, 1912, Schizax LeConte, 1873, and Tylosis LeConte, 1850. The remainder of Trachyderini genera have unmodified or simple mandibles with apex acute.

Combined iterative reconstruction and image-domain decomposition for dual energy CT using total-variation regularization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dong, Xue; Niu, Tianye; Zhu, Lei, E-mail: leizhu@gatech.edu

2014-05-15

Purpose: Dual-energy CT (DECT) is being increasingly used for its capability of material decomposition and energy-selective imaging. A generic problem of DECT, however, is that the decomposition process is unstable in the sense that the relative magnitude of decomposed signals is reduced due to signal cancellation while the image noise is accumulating from the two CT images of independent scans. Direct image decomposition, therefore, leads to severe degradation of signal-to-noise ratio on the resultant images. Existing noise suppression techniques are typically implemented in DECT with the procedures of reconstruction and decomposition performed independently, which do not explore the statistical propertiesmore » of decomposed images during the reconstruction for noise reduction. In this work, the authors propose an iterative approach that combines the reconstruction and the signal decomposition procedures to minimize the DECT image noise without noticeable loss of resolution. Methods: The proposed algorithm is formulated as an optimization problem, which balances the data fidelity and total variation of decomposed images in one framework, and the decomposition step is carried out iteratively together with reconstruction. The noise in the CT images from the proposed algorithm becomes well correlated even though the noise of the raw projections is independent on the two CT scans. Due to this feature, the proposed algorithm avoids noise accumulation during the decomposition process. The authors evaluate the method performance on noise suppression and spatial resolution using phantom studies and compare the algorithm with conventional denoising approaches as well as combined iterative reconstruction methods with different forms of regularization. Results: On the Catphan©600 phantom, the proposed method outperforms the existing denoising methods on preserving spatial resolution at the same level of noise suppression, i.e., a reduction of noise standard deviation by one order of magnitude. This improvement is mainly attributed to the high noise correlation in the CT images reconstructed by the proposed algorithm. Iterative reconstruction using different regularization, including quadratic orq-generalized Gaussian Markov random field regularization, achieves similar noise suppression from high noise correlation. However, the proposed TV regularization obtains a better edge preserving performance. Studies of electron density measurement also show that our method reduces the average estimation error from 9.5% to 7.1%. On the anthropomorphic head phantom, the proposed method suppresses the noise standard deviation of the decomposed images by a factor of ∼14 without blurring the fine structures in the sinus area. Conclusions: The authors propose a practical method for DECT imaging reconstruction, which combines the image reconstruction and material decomposition into one optimization framework. Compared to the existing approaches, our method achieves a superior performance on DECT imaging with respect to decomposition accuracy, noise reduction, and spatial resolution.« less

Larvae and pupae of two North American darkling beetles (Coleoptera, Tenebrionidae, Stenochiinae), Glyptotus cribratus LeConte and Cibdelis blaschkei Mannerheim, with notes on ecological and behavioural similarities.

PubMed

Steiner, Warren E

2014-01-01

THIS STUDY DESCRIBES AND ILLUSTRATES THE LARVAE AND PUPAE OF TWO NORTH AMERICAN DARKLING BEETLES (COLEOPTERA: Tenebrionidae) in the subfamily Stenochiinae, Glyptotus cribratus LeConte from the southeastern United States, and Cibdelis blaschkei Mannerheim from California. Both species inhabit forested regions where adults and larvae occur in soft rotten dry wood of dead branches on living trees or in sections recently fallen from them. Species identity was confirmed by rearing of adults and pupae and the discovery of both in pupal cells with associated exuvia. Specimen label data and notes on habitats are provided. Antipredator defense structures and behaviour are noted for larvae and pupae of both species.

New Coleoptera records from New Brunswick, Canada: Cerambycidae

PubMed Central

Webster, Reginald P.; Sweeney, Jon D.; DeMerchant, Ian; Silk, Peter J.; Mayo, Peter

2012-01-01

Abstract Five species of Cerambycidae, Acmaeops discoideus (Haldeman), Anelaphus villosus (Fabricius), Phymatodes species (CNC sp. n. #1), Sarosesthes fulminans (Fabricius), and Urgleptus signatus (LeConte) are newly recorded for New Brunswick, Canada. All but Acmaeops villosus are new to the Maritime provinces. Phymatodes testaceus (Linnaeus) is removed from the faunal list of the province as a result of mislabeled specimens, records of Phymatodes maculicollis LeConte are presented confirming the presence of this species in New Brunswick, and the first recent records ofNeospondylis upiformis (Mannerheim) are presented. Additional records are given for the recently recorded Phymatodes aereus (Newman), indicating a wider distribution in the province. Collection data, habitat data, and distribution maps are presented for each species. PMID:22539899

Prediction of infarction development after endovascular stroke therapy with dual-energy computed tomography.

PubMed

Djurdjevic, Tanja; Rehwald, Rafael; Knoflach, Michael; Matosevic, Benjamin; Kiechl, Stefan; Gizewski, Elke Ruth; Glodny, Bernhard; Grams, Astrid Ellen

2017-03-01

After intraarterial recanalisation (IAR), the haemorrhage and the blood-brain barrier (BBB) disruption can be distinguished using dual-energy computed tomography (DECT). The aim of the present study was to investigate whether future infarction development can be predicted from DECT. DECT scans of 20 patients showing 45 BBB disrupted areas after IAR were assessed and compared with follow-up examinations. Receiver operator characteristic (ROC) analyses using densities from the iodine map (IM) and virtual non-contrast (VNC) were performed. Future infarction areas are denser than future non-infarction areas on IM series (23.44 ± 24.86 vs. 5.77 ± 2.77; p < 0.0001) and more hypodense on VNC series (29.71 ± 3.33 vs. 35.33 ± 3.50; p < 0.0001). ROC analyses for the IM series showed an area under the curve (AUC) of 0.99 (cut-off: <9.97 HU; p < 0.05; sensitivity 91.18 %; specificity 100.00 %; accuracy 0.93) for the prediction of future infarctions. The AUC for the prediction of haemorrhagic infarctions was 0.78 (cut-off >17.13 HU; p < 0.05; sensitivity 90.00 %; specificity 62.86 %; accuracy 0.69). The VNC series allowed prediction of infarction volume. Future infarction development after IAR can be reliably predicted with the IM series. The prediction of haemorrhages and of infarction size is less reliable. • The IM series (DECT) can predict future infarction development after IAR. • Later haemorrhages can be predicted using the IM and the BW series. • The volume of definable hypodense areas in VNC correlates with infarction volume.

Spectral multi-energy CT texture analysis with machine learning for tissue classification: an investigation using classification of benign parotid tumours as a testing paradigm.

PubMed

Al Ajmi, Eiman; Forghani, Behzad; Reinhold, Caroline; Bayat, Maryam; Forghani, Reza

2018-06-01

There is a rich amount of quantitative information in spectral datasets generated from dual-energy CT (DECT). In this study, we compare the performance of texture analysis performed on multi-energy datasets to that of virtual monochromatic images (VMIs) at 65 keV only, using classification of the two most common benign parotid neoplasms as a testing paradigm. Forty-two patients with pathologically proven Warthin tumour (n = 25) or pleomorphic adenoma (n = 17) were evaluated. Texture analysis was performed on VMIs ranging from 40 to 140 keV in 5-keV increments (multi-energy analysis) or 65-keV VMIs only, which is typically considered equivalent to single-energy CT. Random forest (RF) models were constructed for outcome prediction using separate randomly selected training and testing sets or the entire patient set. Using multi-energy texture analysis, tumour classification in the independent testing set had accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of 92%, 86%, 100%, 100%, and 83%, compared to 75%, 57%, 100%, 100%, and 63%, respectively, for single-energy analysis. Multi-energy texture analysis demonstrates superior performance compared to single-energy texture analysis of VMIs at 65 keV for classification of benign parotid tumours. • We present and validate a paradigm for texture analysis of DECT scans. • Multi-energy dataset texture analysis is superior to single-energy dataset texture analysis. • DECT texture analysis has high accura\\cy for diagnosis of benign parotid tumours. • DECT texture analysis with machine learning can enhance non-invasive diagnostic tumour evaluation.

Clinical Utility of Dual-Energy CT Analysis of Bone Marrow Edema in Acute Wrist Fractures.

PubMed

Ali, Ismail T; Wong, William D; Liang, Teresa; Khosa, Faisal; Mian, Memoona; Jalal, Sabeena; Nicolaou, Savvas

2018-04-01

The purpose of this study is to determine the utility of dual-energy CT (DECT) for assessing carpal fractures and to obtain an attenuation value cutoff (in Hounsfield units) to identify bone marrow edema due to an acute carpal fracture. In this retrospective study, 24 patients who presented with wrist fractures from September 3, 2014, through March 9, 2015, underwent imaging with DECT (80 and 140 kVp). Using the three-material decomposition algorithm specific for virtual noncalcium to construct images, two radiologists identified carpal fractures and associated bone marrow edema. Readers noted the attenuation at areas with and without bone marrow edema. The cutoff value was obtained by ROC analysis and was internally validated on 13 separate patients with suspected wrist fractures. A p < 0.05 was considered statistically significant. CT attenuation was significantly higher in areas of bone marrow edema than in areas without it (p < 0.0001, t test). A cutoff of 5.90 HU allows detection of bone marrow edema associated with acute wrist fractures with 100% sensitivity and 99.5% specificity, compared with visual DECT interpretation. In the 13 validation cases, the cutoff of 5.90 HU identified bone marrow edema with 100% accuracy, compared with visual interpretation. Kappa values were 0.83 between the two readings by reader 1, and 0.73 and 0.96 comparing the two readings of reader 1 with the reading by reader 2. DECT is a useful tool for identifying bone marrow edema in the setting of acute wrist fractures, providing an alternative to MRI. A cutoff value of 5.90 HU can be used for accurate diagnosis and exclusion of carpal fractures.

Radiofrequency electromagnetic fields emitted from base stations of DECT cordless phones and the risk of glioma and meningioma (Interphone Study Group, Germany).

PubMed

Schüz, Joachim; Böhler, Eva; Schlehofer, Brigitte; Berg, Gabriele; Schlaefer, Klaus; Hettinger, Iris; Kunna-Grass, Katharina; Wahrendorf, Jürgen; Blettner, Maria

2006-07-01

The objective of this study was to test the hypothesis that exposure to continuous low-level radiofrequency electromagnetic fields (RF EMFs) increases the risk of glioma and meningioma. Participants in a population-based case-control study in Germany on the risk of brain tumors in relation to cellular phone use were 747 incident brain tumor cases between the ages of 30 and 69 years and 1494 matched controls. The exposure measure of this analysis was the location of a base station of a DECT (Digital Enhanced Cordless Telecommunications) cordless phone close to the bed, which was used as a proxy for continuous low-level exposure to RF EMFs during the night. Estimated odds ratios were 0.82 (95% confidence interval: 0.29-2.33) for glioma and 0.83 (0.29-2.36) for meningioma. There was also no increasing risk observed with duration of exposure to DECT cordless phone base stations. Although the study was limited due to the small number of exposed subjects, it is still a first indication that residential low-level exposure to RF EMFs may not pose a higher risk of brain tumors.

Adaptive noise correction of dual-energy computed tomography images.

PubMed

Maia, Rafael Simon; Jacob, Christian; Hara, Amy K; Silva, Alvin C; Pavlicek, William; Mitchell, J Ross

2016-04-01

Noise reduction in material density images is a necessary preprocessing step for the correct interpretation of dual-energy computed tomography (DECT) images. In this paper we describe a new method based on a local adaptive processing to reduce noise in DECT images An adaptive neighborhood Wiener (ANW) filter was implemented and customized to use local characteristics of material density images. The ANW filter employs a three-level wavelet approach, combined with the application of an anisotropic diffusion filter. Material density images and virtual monochromatic images are noise corrected with two resulting noise maps. The algorithm was applied and quantitatively evaluated in a set of 36 images. From that set of images, three are shown here, and nine more are shown in the online supplementary material. Processed images had higher signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) than the raw material density images. The average improvements in SNR and CNR for the material density images were 56.5 and 54.75%, respectively. We developed a new DECT noise reduction algorithm. We demonstrate throughout a series of quantitative analyses that the algorithm improves the quality of material density images and virtual monochromatic images.

Development of a dual-energy computed tomography quality control program: Characterization of scanner response and definition of relevant parameters for a fast-kVp switching dual-energy computed tomography system.

PubMed

Nute, Jessica L; Jacobsen, Megan C; Stefan, Wolfgang; Wei, Wei; Cody, Dianna D

2018-04-01

A prototype QC phantom system and analysis process were developed to characterize the spectral capabilities of a fast kV-switching dual-energy computed tomography (DECT) scanner. This work addresses the current lack of quantitative oversight for this technology, with the goal of identifying relevant scan parameters and test metrics instrumental to the development of a dual-energy quality control (DEQC). A prototype elliptical phantom (effective diameter: 35 cm) was designed with multiple material inserts for DECT imaging. Inserts included tissue equivalent and material rods (including iodine and calcium at varying concentrations). The phantom was scanned on a fast kV-switching DECT system using 16 dual-energy acquisitions (CTDIvol range: 10.3-62 mGy) with varying pitch, rotation time, and tube current. The circular head phantom (22 cm diameter) was scanned using a similar protocol (12 acquisitions; CTDIvol range: 36.7-132.6 mGy). All acquisitions were reconstructed at 50, 70, 110, and 140 keV and using a water-iodine material basis pair. The images were evaluated for iodine quantification accuracy, stability of monoenergetic reconstruction CT number, noise, and positional constancy. Variance component analysis was used to identify technique parameters that drove deviations in test metrics. Variances were compared to thresholds derived from manufacturer tolerances to determine technique parameters that had a nominally significant effect on test metrics. Iodine quantification error was largely unaffected by any of the technique parameters investigated. Monoenergetic HU stability was found to be affected by mAs, with a threshold under which spectral separation was unsuccessful, diminishing the utility of DECT imaging. Noise was found to be affected by CTDIvol in the DEQC body phantom, and CTDIvol and mA in the DEQC head phantom. Positional constancy was found to be affected by mAs in the DEQC body phantom and mA in the DEQC head phantom. A streamlined scan protocol was developed to further investigate the effects of CTDIvol and rotation time while limiting data collection to the DEQC body phantom. Further data collection will be pursued to determine baseline values and statistically based failure thresholds for the validation of long-term DECT scanner performance. © 2018 American Association of Physicists in Medicine.

Larvae and pupae of two North American darkling beetles (Coleoptera, Tenebrionidae, Stenochiinae), Glyptotus cribratus LeConte and Cibdelis blaschkei Mannerheim, with notes on ecological and behavioural similarities

PubMed Central

Steiner, Warren E.

2014-01-01

Abstract This study describes and illustrates the larvae and pupae of two North American darkling beetles (Coleoptera: Tenebrionidae) in the subfamily Stenochiinae, Glyptotus cribratus LeConte from the southeastern United States, and Cibdelis blaschkei Mannerheim from California. Both species inhabit forested regions where adults and larvae occur in soft rotten dry wood of dead branches on living trees or in sections recently fallen from them. Species identity was confirmed by rearing of adults and pupae and the discovery of both in pupal cells with associated exuvia. Specimen label data and notes on habitats are provided. Antipredator defense structures and behaviour are noted for larvae and pupae of both species. PMID:25009432

Effects of pitfall trap preservative on collections of carabid beetles (Coleoptera: Carabidae)

USGS Publications Warehouse

McCravy, K.W.; Willand, J.E.

2007-01-01

Effects of six pitfall trap preservatives (5% acetic acid solution, distilled water, 70% ethanol, 50% ethylene glycol solution, 50% propylene glycol solution, and 10% saline solution) on collections of carabid beetles (Coleoptera: Carabidae) were studied in a west-central Illinois deciduous forest from May to October 2005. A total of 819 carabids, representing 33 species and 19 genera, were collected. Saline produced significantly fewer captures than did acetic acid, ethanol, ethylene glycol, and propylene glycol, while distilled water produced significantly fewer captures than did acetic acid. Significant associations between numbers of captures and treatment were seen in four species: Amphasia interstitialis (Say), Calathus opaculus LeConte, Chlaenius nemoralis Say, and Cyclotrachelus sodalis (LeConte). Results of this study suggest that type of preservative used can have substantial effects on abundance and species composition of carabids collected in pitfall traps.

Dose heterogeneity correction for low-energy brachytherapy sources using dual-energy CT images

NASA Astrophysics Data System (ADS)

Mashouf, S.; Lechtman, E.; Lai, P.; Keller, B. M.; Karotki, A.; Beachey, D. J.; Pignol, J. P.

2014-09-01

Permanent seed implant brachytherapy is currently used for adjuvant radiotherapy of early stage prostate and breast cancer patients. The current standard for calculation of dose around brachytherapy sources is based on the AAPM TG-43 formalism, which generates the dose in a homogeneous water medium. Recently, AAPM TG-186 emphasized the importance of accounting for tissue heterogeneities. We have previously reported on a methodology where the absorbed dose in tissue can be obtained by multiplying the dose, calculated by the TG-43 formalism, by an inhomogeneity correction factor (ICF). In this work we make use of dual energy CT (DECT) images to extract ICF parameters. The advantage of DECT over conventional CT is that it eliminates the need for tissue segmentation as well as assignment of population based atomic compositions. DECT images of a heterogeneous phantom were acquired and the dose was calculated using both TG-43 and TG-43 × \\text{ICF} formalisms. The results were compared to experimental measurements using Gafchromic films in the mid-plane of the phantom. For a seed implant configuration of 8 seeds spaced 1.5 cm apart in a cubic structure, the gamma passing score for 2%/2 mm criteria improved from 40.8% to 90.5% when ICF was applied to TG-43 dose distributions.

Quantitative image variables reflect the intratumoral pathologic heterogeneity of lung adenocarcinoma.

PubMed

Choi, E-Ryung; Lee, Ho Yun; Jeong, Ji Yun; Choi, Yoon-La; Kim, Jhingook; Bae, Jungmin; Lee, Kyung Soo; Shim, Young Mog

2016-10-11

We aimed to compare quantitative radiomic parameters from dual-energy computed tomography (DECT) of lung adenocarcinoma and pathologic complexity.A total 89 tumors with clinical stage I/II lung adenocarcinoma were prospectively included. Fifty one radiomic features were assessed both from iodine images and non-contrast images of DECT datasets. Comprehensive histologic subtyping was evaluated with all surgically resected tumors. The degree of pathologic heterogeneity was assessed using pathologic index and the number of mixture histologic subtypes in a tumor. Radiomic parameters were correlated with pathologic index. Tumors were classified as three groups according to the number of mixture histologic subtypes and radiomic parameters were compared between the three groups.Tumor density and 50th through 97.5th percentile Hounsfield units (HU) of histogram on non-contrast images showed strong correlation with the pathologic heterogeneity. Radiomic parameters including 75th and 97.5th percentile HU of histogram, entropy, and inertia on 1-, 2- and 3 voxel distance on non-contrast images showed incremental changes while homogeneity showed detrimental change according to the number of mixture histologic subtypes (all Ps < 0.05).Radiomic variables from DECT of lung adenocarcinoma reflect pathologic intratumoral heterogeneity, which may help in the prediction of intratumoral heterogeneity of the whole tumor.

Impact of low-energy CT imaging on selection of positive oral contrast media concentration.

PubMed

Patino, Manuel; Murcia, Diana J; Iamurri, Andrea Prochowski; Kambadakone, Avinash R; Hahn, Peter F; Sahani, Dushyant V

2017-05-01

To determine to what extent low-energy CT imaging affects attenuation of gastrointestinal tract (GIT) opacified with positive oral contrast media (OCM). Second, to establish optimal OCM concentrations for low-energy diagnostic CT exams. One hundred patients (38 men and 62 women; age 62 ± 11 years; BMI 26 ± 5) with positive OCM-enhanced 120-kVp single-energy CT (SECT), and follow-up 100-kVp acquisitions (group A; n = 50), or 40-70-keV reconstructions from rapid kV switching-single-source dual-energy CT (ssDECT) (group B; n = 50) were included. Luminal attenuation from different GIT segments was compared between exams. Standard dose of three OCM and diluted solutions (75%, 50%, and 25% concentrations) were introduced serially in a gastrointestinal phantom and scanned using SECT (120, 100, and 80 kVp) and DECT (80/140 kVp) acquisitions on a ssDECT scanner. Luminal attenuation was obtained on SECT and DECT images (40-70 keV), and compared to 120-kVp scans with standard OCM concentrations. Luminal attenuation was higher on 100-kVp (328 HU) and on 40-60-keV images (410-924 HU) in comparison to 120-kVp scans (298 HU) in groups A and B (p < 0.05). Phantom: There was an inverse correlation between luminal attenuation and X-ray energy, increasing up to 527 HU on low-kVp and 999 HU on low-keV images (p < 0.05). 25% and 50% diluted OCM solutions provided similar or higher attenuation than 120 kVp, at low kVp and keV, respectively. Low-energy CT imaging increases the attenuation of GIT opacified with positive OCM, permitting reduction of 25%-75% OCM concentration.

SU-F-T-270: A Technique for Modeling a Diode Array Into the TPS for Lung SBRT Patient Specific QA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Curley, C; Leventouri, T; Ouhib, Z

2016-06-15

Purpose: To accurately match the treatment planning system (TPS) with the measurement environment, where quality assurance (QA) devices are used to collect data, for lung Stereotactic Body Radiation Therapy (SBRT) patient specific QA. Incorporation of heterogeneities is also studied. Methods: Dual energy computerized tomography (DECT) and single energy computerized tomography (SECT) were used to model phantoms incorporating a 2-D diode array into the TPS. A water-equivalent and a heterogeneous phantom (simulating the thoracic region of a patient) were studied. Monte Carlo and pencil beam planar dose distributions were compared to measured distributions. Composite and individual fields were analyzed for normallymore » incident and planned gantry angle deliveries. γ- analysis was used with criteria 3% 3mm, 2% 2mm, and 1% 1mm. Results: The Monte Carlo calculations for the DECT resulted in improved agreements with the diode array for 46.4% of the fields at 3% 3mm, 85.7% at 2% 2mm, and 92.9% at 1% 1mm.For the SECT, the Monte Carlo calculations gave no agreement for the same γ-analysis criteria. Pencil beam calculations resulted in lower agreements with the diode array in the TPS. The DECT showed improvements for 14.3% of the fields at 3% 3mm and 2% 2mm, and 28.6% at 1% 1mm.In SECT comparisons, 7.1% of the fields at 3% 3mm, 10.7% at 2% 2mm, and 17.9% at 1% 1mm showed improved agreements with the diode array. Conclusion: This study demonstrates that modeling the diode array in the TPS is viable using DECT with Monte Carlo for patient specific lung SBRT QA. As recommended by task groups (e.g. TG 65, TG 101, TG 244) of the American Association of Physicists in Medicine (AAPM), pencil beam algorithms should be avoided in the presence of heterogeneous materials, including a diode array.« less

Monosodium urate crystal deposition associated with the progress of radiographic grade at the sacroiliac joint in axial SpA: a dual-energy CT study.

PubMed

Zhu, Junqing; Li, Aiwu; Jia, Ertao; Zhou, Yi; Xu, Juan; Chen, Shixian; Huang, Yinger; Xiao, Xiang; Li, Juan

2017-05-02

Previous studies have revealed that ankylosing spondylitis (AS), as the progenitor of axial spondyloarthritis (AxSpA), has been characterized by the insidiously progressive nature of sacroiliitis and spondylitis. Dual-energy computed tomography (DECT) has recently been used to analyse the deposition of monosodium urate (MSU) crystals with higher sensitivity and specificity. However, it remains unclear whether the existence of the MSU crystal deposition detected by DECT at the sacroiliac joint in patients with AxSpA also is associated with the existing structural damage. Here, we performed this study to show the DECT MSU crystal deposits in AxSpA patients without coexisting gout and to ascertain the relationship between the MSU crystal deposition and the structural joint damage of sacroiliac joints. One hundred and eighty-six AxSpA patients without coexisting gout were recruited. The plain radiographs of the sacroiliac joint were obtained, along with the DECT scans at the pelvis and the clinical variables. All statistics based on the left or right sacroiliac joint damage grading (0-4) were calculated independently. Bivariate analysis and ordinal logistic regression was performed between the clinical features and radiographic grades at the sacroiliac joint. At the pelvis, large quantities of MSU crystal deposition were found in patients with AxSpA. The average MSU crystal volume at the left sacroiliac joint, the right sacroiliac joint, and the pelvis were 0.902 ± 1.345, 1.074 ± 1.878, and 5.272 ± 9.044 cm 3 , values which were correlated with serum uric acid concentrations (r = 0.727, 0.740, 0.896; p < 0.001). In bivariate analysis, wide clinical variables were associated with the changes in sacroiliac joint damage. Further, the AxSpA duration, BASFI score, and the volume of MSU crystal at both sides of sacroiliac joint were associated with the progress of radiographic grade at the sacroiliac joints in the ordinal logistic models (left AOR = 1.180, 3.800, 1.920; right AOR = 1.190, 3.034, 1.418; p < 0.01). Large quantities of MSU crystal deposition detected by DECT were found at the pelvis in AxSpA patients without coexisting gout. In addition to AxSpA duration and BASFI score, the MSU crystal deposition at the sacroiliac joint is associated with the progress of radiographic grade at sacroiliac joints in those patients.

Impact of joint statistical dual-energy CT reconstruction of proton stopping power images: Comparison to image- and sinogram-domain material decomposition approaches.

PubMed

Zhang, Shuangyue; Han, Dong; Politte, David G; Williamson, Jeffrey F; O'Sullivan, Joseph A

2018-05-01

The purpose of this study was to assess the performance of a novel dual-energy CT (DECT) approach for proton stopping power ratio (SPR) mapping that integrates image reconstruction and material characterization using a joint statistical image reconstruction (JSIR) method based on a linear basis vector model (BVM). A systematic comparison between the JSIR-BVM method and previously described DECT image- and sinogram-domain decomposition approaches is also carried out on synthetic data. The JSIR-BVM method was implemented to estimate the electron densities and mean excitation energies (I-values) required by the Bethe equation for SPR mapping. In addition, image- and sinogram-domain DECT methods based on three available SPR models including BVM were implemented for comparison. The intrinsic SPR modeling accuracy of the three models was first validated. Synthetic DECT transmission sinograms of two 330 mm diameter phantoms each containing 17 soft and bony tissues (for a total of 34) of known composition were then generated with spectra of 90 and 140 kVp. The estimation accuracy of the reconstructed SPR images were evaluated for the seven investigated methods. The impact of phantom size and insert location on SPR estimation accuracy was also investigated. All three selected DECT-SPR models predict the SPR of all tissue types with less than 0.2% RMS errors under idealized conditions with no reconstruction uncertainties. When applied to synthetic sinograms, the JSIR-BVM method achieves the best performance with mean and RMS-average errors of less than 0.05% and 0.3%, respectively, for all noise levels, while the image- and sinogram-domain decomposition methods show increasing mean and RMS-average errors with increasing noise level. The JSIR-BVM method also reduces statistical SPR variation by sixfold compared to other methods. A 25% phantom diameter change causes up to 4% SPR differences for the image-domain decomposition approach, while the JSIR-BVM method and sinogram-domain decomposition methods are insensitive to size change. Among all the investigated methods, the JSIR-BVM method achieves the best performance for SPR estimation in our simulation phantom study. This novel method is robust with respect to sinogram noise and residual beam-hardening effects, yielding SPR estimation errors comparable to intrinsic BVM modeling error. In contrast, the achievable SPR estimation accuracy of the image- and sinogram-domain decomposition methods is dominated by the CT image intensity uncertainties introduced by the reconstruction and decomposition processes. © 2018 American Association of Physicists in Medicine.

Hazard assessment of selenium to endangered razorback suckers (Xyrauchen texanus)

USGS Publications Warehouse

Hamilton, S.J.; Holley, K.M.; Buhl, K.J.

2002-01-01

A hazard assessment was conducted based on information derived from two reproduction studies conducted with endangered razorback suckers (Xyrauchen texanus) at three sites near Grand Junction, CO, USA. Selenium contamination of the upper and lower Colorado River basin has been documented in water, sediment, and biota in studies by US Department of the Interior agencies and academia. Concern has been raised that this selenium contamination may be adversely affecting endangered fish in the upper Colorado River basin. The reproduction studies with razorback suckers revealed that adults readily accumulated selenium in various tissues including eggs, and that 4.6 μg/g of selenium in food organisms caused increased mortality of larvae. The selenium hazard assessment protocol resulted in a moderate hazard at the Horsethief site and high hazards at the Adobe Creek and North Pond sites. The selenium hazard assessment was considered conservative because an on-site toxicity test with razorback sucker larvae using 4.6 μg/g selenium in zooplankton caused nearly complete mortality, in spite of the moderate hazard at Horsethief. Using the margin of uncertainty ratio also suggested a high hazard for effects on razorback suckers from selenium exposure. Both assessment approaches suggested that selenium in the upper Colorado River basin adversely affects the reproductive success of razorback suckers.

Hazard assessment of selenium to endangered razorback suckers (Xyrauchen texanus).

PubMed

Hamilton, Steven J; Holley, Kathleen M; Buhl, Kevin J

2002-05-27

A hazard assessment was conducted based on information derived from two reproduction studies conducted with endangered razorback suckers (Xyrauchen texanus) at three sites near Grand Junction, CO, USA. Selenium contamination of the upper and lower Colorado River basin has been documented in water, sediment, and biota in studies by US Department of the Interior agencies and academia. Concern has been raised that this selenium contamination may be adversely affecting endangered fish in the upper Colorado River basin. The reproduction studies with razorback suckers revealed that adults readily accumulated selenium in various tissues including eggs, and that 4.6 microg/g of selenium in food organisms caused increased mortality of larvae. The selenium hazard assessment protocol resulted in a moderate hazard at the Horsethief site and high hazards at the Adobe Creek and North Pond sites. The selenium hazard assessment was considered conservative because an on-site toxicity test with razorback sucker larvae using 4.6 microg/g selenium in zooplankton caused nearly complete mortality, in spite of the moderate hazard at Horsethief. Using the margin of uncertainty ratio also suggested a high hazard for effects on razorback suckers from selenium exposure. Both assessment approaches suggested that selenium in the upper Colorado River basin adversely affects the reproductive success of razorback suckers.

Berkeley Lab 2nd Grader Outreach

ScienceCinema

Scoggins, Jackie; Louie, Virginia

2017-12-11

The Berkeley Lab IT Department sponsored a community outreach program aimed at teaching young children about computers and networks. Second graders from LeConte Elementary School joined Lab IT Staff for a day of in-depth exercises and fun.

Review of the Nearctic genus Lacconotus LeConte (Coleoptera, Mycteridae, Eurypinae)

PubMed Central

Pollock, Darren; Majka, Christopher G.

2012-01-01

Abstract Lacconotus LeConte, the sole Nearctic representative of the eurypine Mycteridae, is revised, based on morphological features of adults. The following syn. n. is proposed: Lacconotus pallidus Van Dyke, 1928 = Lacconotus pinicola Horn, 1879. The former is a light-colored form with a southern California distribution. A subgen. n., Alcconotus, is described for Lacconotus pinicola, producing the following comb. n.: Lacconotus (Alcconotus) pinicola (Horn). A lectotype is designated for Lacconotus pinicola. A key separating the two subgenera and species is provided, as are photographs and illustrations of salient structures of adults, and maps showing collection localities. Lacconotus punctatus is newly recorded in Alabama, Arkansas, Massachusetts, Oklahoma, Texas, and Wisconsin; Lacconotus pinicola is newly recorded in Arizona and Utah in the USA, and Baja California Norte in Mexico. Phenology information shows a north-to-south gradation in occurrence time. PMID:22303123

Three pioneers of comparative psychology in America, 1843-1890: Lewis H. Morgan, John Bascom, and Joseph LeConte.

PubMed

Johnston, Timothy D

2003-02-01

Scientific comparative psychology in America dates from the mid-1890s, but there is a body of earlier literature on the topic, written during a period of theistic debates over Darwinian evolution. The anthropologist Lewis H. Morgan rejected instinct as an explanation of animal behavior in 1843 and defended the mental similarities between animals and humans, although he was not an evolutionist. John Bascom's textbook Comparative Psychology (1878) is the earliest American work to use that title, and its theistic approach anticipates some arguments found in much later evolutionary works. Beginning in 1860, the geologist Joseph LeConte, who is well known for defending the compatibility of evolution and religion, wrote several articles in which he outlined a comparative evolutionary approach to psychological problems. However, these writers did not establish a coherent research tradition and were ignored by the "New Psychologists" of the 1880s.

An annotated catalogue of the type material of Elateroidea Leach, 1815 (Coleoptera) deposited in the Coleoptera collection of the Museum of Zoology of the University of São Paulo, Brazil.

PubMed

Ferreira, Vinicius De Souza

2015-03-25

The Museum of Zoology of the University of São Paulo (MZSP) houses one of the most important Coleoptera collections of Brazil and Neotropical Region with nearly 900,000 adult mounted material and about 1,500,000 specimens to be mounted. The superfamily Elateroidea Leach, 1815 (including Cantharoidea) comprises about 24,077 described species in 17 families. The MZSP owns type material of Brachypsectridae LeConte & Horn, 1883, Cantharidae, 1856 (1815), Cerophytidae Latreille, 1834, Elateridae Leach 1815, Eucnemidae Eschscholtz, 1829, Lampyridae Rafinesque, 1815, Lycidae Laporte, 1836, Phengodidae LeConte, 1861 and Rhinorhipidae Lawrence, 1988. This catalogue includes type material of 166 species distributed in 69 genera. Among 1,223 type specimens, are 86 holotypes, 1,133 paratypes, 2 allotypes, 1 lectotype and 1 paralectotype.

Experimental verification of stopping-power prediction from single- and dual-energy computed tomography in biological tissues

NASA Astrophysics Data System (ADS)

Möhler, Christian; Russ, Tom; Wohlfahrt, Patrick; Elter, Alina; Runz, Armin; Richter, Christian; Greilich, Steffen

2018-01-01

An experimental setup for consecutive measurement of ion and x-ray absorption in tissue or other materials is introduced. With this setup using a 3D-printed sample container, the reference stopping-power ratio (SPR) of materials can be measured with an uncertainty of below 0.1%. A total of 65 porcine and bovine tissue samples were prepared for measurement, comprising five samples each of 13 tissue types representing about 80% of the total body mass (three different muscle and fatty tissues, liver, kidney, brain, heart, blood, lung and bone). Using a standard stoichiometric calibration for single-energy CT (SECT) as well as a state-of-the-art dual-energy CT (DECT) approach, SPR was predicted for all tissues and then compared to the measured reference. With the SECT approach, the SPRs of all tissues were predicted with a mean error of (-0.84  ±  0.12)% and a mean absolute error of (1.27  ±  0.12)%. In contrast, the DECT-based SPR predictions were overall consistent with the measured reference with a mean error of (-0.02  ±  0.15)% and a mean absolute error of (0.10  ±  0.15)%. Thus, in this study, the potential of DECT to decrease range uncertainty could be confirmed in biological tissue.

A Novel Imaging Technique (X-Map) to Identify Acute Ischemic Lesions Using Noncontrast Dual-Energy Computed Tomography.

PubMed

Noguchi, Kyo; Itoh, Toshihide; Naruto, Norihito; Takashima, Shutaro; Tanaka, Kortaro; Kuroda, Satoshi

2017-01-01

We evaluated whether X-map, a novel imaging technique, can visualize ischemic lesions within 20 hours after the onset in patients with acute ischemic stroke, using noncontrast dual-energy computed tomography (DECT). Six patients with acute ischemic stroke were included in this study. Noncontrast head DECT scans were acquired with 2 X-ray tubes operated at 80 kV and Sn150 kV between 32 minutes and 20 hours after the onset. Using these DECT scans, the X-map was reconstructed based on 3-material decomposition and compared with a simulated standard (120 kV) computed tomography (CT) and diffusion-weighted imaging (DWI). The X-map showed more sensitivity to identify the lesions as an area of lower attenuation value than a simulated standard CT in all 6 patients. The lesions on the X-map correlated well with those on DWI. In 3 of 6 patients, the X-map detected a transient decrease in the attenuation value in the peri-infarct area within 1 day after the onset. The X-map is a powerful tool to supplement a simulated standard CT and characterize acute ischemic lesions. However, the X-map cannot replace a simulated standard CT to diagnose acute cerebral infarction. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Rationale and design of the dual-energy computed tomography for ischemia determination compared to "gold standard" non-invasive and invasive techniques (DECIDE-Gold): A multicenter international efficacy diagnostic study of rest-stress dual-energy computed tomography angiography with perfusion.

PubMed

Truong, Quynh A; Knaapen, Paul; Pontone, Gianluca; Andreini, Daniele; Leipsic, Jonathon; Carrascosa, Patricia; Lu, Bin; Branch, Kelley; Raman, Subha; Bloom, Stephen; Min, James K

2015-10-01

Dual-energy CT (DECT) has potential to improve myocardial perfusion for physiologic assessment of coronary artery disease (CAD). Diagnostic performance of rest-stress DECT perfusion (DECTP) is unknown. DECIDE-Gold is a prospective multicenter study to evaluate the accuracy of DECT to detect hemodynamic (HD) significant CAD, as compared to fractional flow reserve (FFR) as a reference standard. Eligible participants are subjects with symptoms of CAD referred for invasive coronary angiography (ICA). Participants will undergo DECTP, which will be performed by pharmacological stress, and participants will subsequently proceed to ICA and FFR. HD-significant CAD will be defined as FFR ≤ 0.80. In those undergoing myocardial stress imaging (MPI) by positron emission tomography (PET), single photon emission computed tomography (SPECT) or cardiac magnetic resonance (CMR) imaging, ischemia will be graded by % ischemic myocardium. Blinded core laboratory interpretation will be performed for CCTA, DECTP, MPI, ICA, and FFR. Primary endpoint is accuracy of DECTP to detect ≥1 HD-significant stenosis at the subject level when compared to FFR. Secondary and tertiary endpoints are accuracies of combinations of DECTP at the subject and vessel levels compared to FFR and MPI. DECIDE-Gold will determine the performance of DECTP for diagnosing ischemia.

Early Geologic Education in California--Berkeley and Stanford Show the Way.

ERIC Educational Resources Information Center

Norris, Robert M.

1981-01-01

Traces the early history of geological education in California universities, with emphasis upon programs at Berkeley and Stanford. Among the pioneers in the field were Joseph LeConte, Andrew C. Lawson, and John C. Branner. (WB)

Towards 3D printed multifunctional immobilization for proton therapy: Initial materials characterization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Michiels, Steven, E-mail: michiels.steven@kuleuven

Purpose: 3D printing technology is investigated for the purpose of patient immobilization during proton therapy. It potentially enables a merge of patient immobilization, bolus range shifting, and other functions into one single patient-specific structure. In this first step, a set of 3D printed materials is characterized in detail, in terms of structural and radiological properties, elemental composition, directional dependence, and structural changes induced by radiation damage. These data will serve as inputs for the design of 3D printed immobilization structure prototypes. Methods: Using four different 3D printing techniques, in total eight materials were subjected to testing. Samples with a nominalmore » dimension of 20 × 20 × 80 mm{sup 3} were 3D printed. The geometrical printing accuracy of each test sample was measured with a dial gage. To assess the mechanical response of the samples, standardized compression tests were performed to determine the Young’s modulus. To investigate the effect of radiation on the mechanical response, the mechanical tests were performed both prior and after the administration of clinically relevant dose levels (70 Gy), multiplied with a safety factor of 1.4. Dual energy computed tomography (DECT) methods were used to calculate the relative electron density to water ρ{sub e}, the effective atomic number Z{sub eff}, and the proton stopping power ratio (SPR) to water SPR. In order to validate the DECT based calculation of radiological properties, beam measurements were performed on the 3D printed samples as well. Photon irradiations were performed to measure the photon linear attenuation coefficients, while proton irradiations were performed to measure the proton range shift of the samples. The directional dependence of these properties was investigated by performing the irradiations for different orientations of the samples. Results: The printed test objects showed reduced geometric printing accuracy for 2 materials (deviation > 0.25 mm). Compression tests yielded Young’s moduli ranging from 0.6 to 2940 MPa. No deterioration in the mechanical response was observed after exposure of the samples to 100 Gy in a therapeutic MV photon beam. The DECT-based characterization yielded Z{sub eff} ranging from 5.91 to 10.43. The SPR and ρ{sub e} both ranged from 0.6 to 1.22. The measured photon attenuation coefficients at clinical energies scaled linearly with ρ{sub e}. Good agreement was seen between the DECT estimated SPR and the measured range shift, except for the higher Z{sub eff}. As opposed to the photon attenuation, the proton range shifting appeared to be printing orientation dependent for certain materials. Conclusions: In this study, the first step toward 3D printed, multifunctional immobilization was performed, by going through a candidate clinical workflow for the first time: from the material printing to DECT characterization with a verification through beam measurements. Besides a proof of concept for beam modification, the mechanical response of printed materials was also investigated to assess their capabilities for positioning functionality. For the studied set of printing techniques and materials, a wide variety of mechanical and radiological properties can be selected from for the intended purpose. Moreover the elaborated hybrid DECT methods aid in performing in-house quality assurance of 3D printed components, as these methods enable the estimation of the radiological properties relevant for use in radiation therapy.« less

Statistical image-domain multimaterial decomposition for dual-energy CT.

PubMed

Xue, Yi; Ruan, Ruoshui; Hu, Xiuhua; Kuang, Yu; Wang, Jing; Long, Yong; Niu, Tianye

2017-03-01

Dual-energy CT (DECT) enhances tissue characterization because of its basis material decomposition capability. In addition to conventional two-material decomposition from DECT measurements, multimaterial decomposition (MMD) is required in many clinical applications. To solve the ill-posed problem of reconstructing multi-material images from dual-energy measurements, additional constraints are incorporated into the formulation, including volume and mass conservation and the assumptions that there are at most three materials in each pixel and various material types among pixels. The recently proposed flexible image-domain MMD method decomposes pixels sequentially into multiple basis materials using a direct inversion scheme which leads to magnified noise in the material images. In this paper, we propose a statistical image-domain MMD method for DECT to suppress the noise. The proposed method applies penalized weighted least-square (PWLS) reconstruction with a negative log-likelihood term and edge-preserving regularization for each material. The statistical weight is determined by a data-based method accounting for the noise variance of high- and low-energy CT images. We apply the optimization transfer principles to design a serial of pixel-wise separable quadratic surrogates (PWSQS) functions which monotonically decrease the cost function. The separability in each pixel enables the simultaneous update of all pixels. The proposed method is evaluated on a digital phantom, Catphan©600 phantom and three patients (pelvis, head, and thigh). We also implement the direct inversion and low-pass filtration methods for a comparison purpose. Compared with the direct inversion method, the proposed method reduces noise standard deviation (STD) in soft tissue by 95.35% in the digital phantom study, by 88.01% in the Catphan©600 phantom study, by 92.45% in the pelvis patient study, by 60.21% in the head patient study, and by 81.22% in the thigh patient study, respectively. The overall volume fraction accuracy is improved by around 6.85%. Compared with the low-pass filtration method, the root-mean-square percentage error (RMSE(%)) of electron densities in the Catphan©600 phantom is decreased by 20.89%. As modulation transfer function (MTF) magnitude decreased to 50%, the proposed method increases the spatial resolution by an overall factor of 1.64 on the digital phantom, and 2.16 on the Catphan©600 phantom. The overall volume fraction accuracy is increased by 6.15%. We proposed a statistical image-domain MMD method using DECT measurements. The method successfully suppresses the magnified noise while faithfully retaining the quantification accuracy and anatomical structure in the decomposed material images. The proposed method is practical and promising for advanced clinical applications using DECT imaging. © 2017 American Association of Physicists in Medicine.

Dual energy CT with one full scan and a second sparse-view scan using structure preserving iterative reconstruction (SPIR)

NASA Astrophysics Data System (ADS)

Wang, Tonghe; Zhu, Lei

2016-09-01

Conventional dual-energy CT (DECT) reconstruction requires two full-size projection datasets with two different energy spectra. In this study, we propose an iterative algorithm to enable a new data acquisition scheme which requires one full scan and a second sparse-view scan for potential reduction in imaging dose and engineering cost of DECT. A bilateral filter is calculated as a similarity matrix from the first full-scan CT image to quantify the similarity between any two pixels, which is assumed unchanged on a second CT image since DECT scans are performed on the same object. The second CT image from reduced projections is reconstructed by an iterative algorithm which updates the image by minimizing the total variation of the difference between the image and its filtered image by the similarity matrix under data fidelity constraint. As the redundant structural information of the two CT images is contained in the similarity matrix for CT reconstruction, we refer to the algorithm as structure preserving iterative reconstruction (SPIR). The proposed method is evaluated on both digital and physical phantoms, and is compared with the filtered-backprojection (FBP) method, the conventional total-variation-regularization-based algorithm (TVR) and prior-image-constrained-compressed-sensing (PICCS). SPIR with a second 10-view scan reduces the image noise STD by a factor of one order of magnitude with same spatial resolution as full-view FBP image. SPIR substantially improves over TVR on the reconstruction accuracy of a 10-view scan by decreasing the reconstruction error from 6.18% to 1.33%, and outperforms TVR at 50 and 20-view scans on spatial resolution with a higher frequency at the modulation transfer function value of 10% by an average factor of 4. Compared with the 20-view scan PICCS result, the SPIR image has 7 times lower noise STD with similar spatial resolution. The electron density map obtained from the SPIR-based DECT images with a second 10-view scan has an average error of less than 1%.

In Vivo Differentiation of Uric Acid Versus Non-Uric Acid Urinary Calculi With Third-Generation Dual-Source Dual-Energy CT at Reduced Radiation Dose.

PubMed

Franken, Axelle; Gevenois, Pierre Alain; Muylem, Alain Van; Howarth, Nigel; Keyzer, Caroline

2018-02-01

The objective of our study was to evaluate in vivo urinary calculus characterization with third-generation dual-source dual-energy CT (DECT) at reduced versus standard radiation dose. One hundred fifty-three patients requiring unenhanced CT for suspected or known urolithiasis were prospectively included in our study. They underwent two acquisitions at reduced-dose CT (90 kV and 50 mAs ref ; Sn150 kV and 31 mAs ref , where Sn denotes the interposition of a tin filter in the high-energy beam) and standard-dose CT (90 kV and 50 mAs ref ; Sn150 kV and 94 mAs ref ). One radiologist interpreted the reduced-dose examinations before the standard-dose examinations during the same session. Among 103 patients (23 women, 80 men; mean age ± SD, 50 ± 15 years; age range, 18-82 years) with urolithiasis, dedicated DECT software measured the maximal diameter and CT numbers, calculated the DECT number ratio, and labeled with a color code each calculus visualized by the radiologist as uric acid (UA) or non-UA. Volume CT dose index (CTDI vol ) and dose-length product (DLP) were recorded. The radiologist visualized 279 calculi on standard-dose CT and 262 on reduced-dose CT; 17 calculi were missed on reduced-dose CT, all of which were ≤ 3 mm. Among the 262 calculi visualized at both doses, the CT number ratio was obtained with the software for 227 calculi and was not different between the doses (p = 0.093). Among these 262 calculi, 197 were labeled at both doses; 194 of the 197 labeled calculi were labeled with the same color code. Among the 65 remaining calculi, 48 and 61 (all ≤ 5 mm) were not labeled at standard-dose and reduced-dose CT (p = 0.005), respectively. At reduced-dose CT, the mean CTDI vol was 2.67 mGy and the mean DLP was 102.2 mGy × cm. With third-generation dual-source DECT, a larger proportion of calculi ≤ 5 mm are not characterized as UA or non-UA at a reduced dose.

In vivo characterization of urinary calculi on dual-energy CT: going a step ahead with sub-differentiation of calcium stones.

PubMed

Acharya, Sudeep; Goyal, Ankur; Bhalla, Ashu Seith; Sharma, Raju; Seth, Amlesh; Gupta, Arun Kumar

2015-07-01

The role of dual-energy computed tomography (DECT) in characterization of urinary calculi is evolving and literature regarding differentiation of calcium calculi is sparse and confounding. To evaluate the capability of DECT in assessing the urinary calculi composition in vivo, especially in differentiating various types of calcium calculi. One hundred and twenty patients underwent DECT for characterization of urinary calculi. Seventy patients with 114 calculi, including 93 calcium stones, were retrospectively analyzed. DE ratios and attenuation differences were compared using ANOVA and receiver-operating-characteristic (ROC) analysis was done to predict cut-off values, in particular for detecting calcium-oxalate-monohydrate (COM) stones. DE ratio ≤1.14 accurately detected uric acid calculi, ≥1.29 was definitive for calcium and intermediate values were characteristic of cystine stones. DE ratios were significantly different between group 1 (COM [n = 32]; mean 1.376 ± 0.041), group 2 ([calcium oxalate dihydrate (COD) + COM] [n = 51]; 1.416 ± 0.048), and group 3 ([carbonate apatite (CaP) + COD + COM] [n = 10]; 1.468 ± 0.038) (group 1 vs. 2, P = 0.001; 1 vs. 3, P = 0.000; 2 vs. 3, P = 0.004). More importantly, pure COM calculi (group 1) had significantly lower DE ratio compared with mixed calcium calculi (groups 2 and 3) (P = 0.000). Attenuation differences (between low and high kV images) could not distinguish between COM and mixed calculi. ROC analysis for detection of COM calculi yielded AUC of 0.770 with cut-off DE ratio 1.385 (sensitivity 65.6%, specificity 82%) and value <1.335 was seen only with COM calculi (100% specificity). DECT can be employed for in vivo differentiation of various types of calculi and for detection of relatively lithotripsy-resistant COM calculi. © The Foundation Acta Radiologica 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

Comparison of image quality and radiation dose between split-filter dual-energy images and single-energy images in single-source abdominal CT.

PubMed

Euler, André; Obmann, Markus M; Szucs-Farkas, Zsolt; Mileto, Achille; Zaehringer, Caroline; Falkowski, Anna L; Winkel, David J; Marin, Daniele; Stieltjes, Bram; Krauss, Bernhard; Schindera, Sebastian T

2018-02-19

To compare image quality and radiation dose of abdominal split-filter dual-energy CT (SF-DECT) combined with monoenergetic imaging to single-energy CT (SECT) with automatic tube voltage selection (ATVS). Two-hundred single-source abdominal CT scans were performed as SECT with ATVS (n = 100) and SF-DECT (n = 100). SF-DECT scans were reconstructed and subdivided into composed images (SF-CI) and monoenergetic images at 55 keV (SF-MI). Objective and subjective image quality were compared among single-energy images (SEI), SF-CI and SF-MI. CNR and FOM were separately calculated for the liver (e.g. CNR liv ) and the portal vein (CNR pv ). Radiation dose was compared using size-specific dose estimate (SSDE). Results of the three groups were compared using non-parametric tests. Image noise of SF-CI was 18% lower compared to SEI and 48% lower compared to SF-MI (p < 0.001). Composed images yielded higher CNR liv over single-energy images (23.4 vs. 20.9; p < 0.001), whereas CNR pv was significantly lower (3.5 vs. 5.2; p < 0.001). Monoenergetic images overcame this inferiority in CNR pv and achieved similar results compared to single-energy images (5.1 vs. 5.2; p > 0.628). Subjective sharpness was equal between single-energy and monoenergetic images and diagnostic confidence was equal between single-energy and composed images. FOM liv was highest for SF-CI. FOM pv was equal for SEI and SF-MI (p = 0.78). SSDE was significant lower for SF-DECT compared to SECT (p < 0.022). The combined use of split-filter dual-energy CT images provides comparable objective and subjective image quality at lower radiation dose compared to single-energy CT with ATVS. • Split-filter dual-energy results in 18% lower noise compared to single-energy with ATVS. • Split-filter dual-energy results in 11% lower SSDE compared to single-energy with ATVS. • Spectral shaping of split-filter dual-energy leads to an increased dose-efficiency.

Value of a noise-optimized virtual monoenergetic reconstruction technique in dual-energy CT for planning of transcatheter aortic valve replacement.

PubMed

Martin, Simon S; Albrecht, Moritz H; Wichmann, Julian L; Hüsers, Kristina; Scholtz, Jan-Erik; Booz, Christian; Bodelle, Boris; Bauer, Ralf W; Metzger, Sarah C; Vogl, Thomas J; Lehnert, Thomas

2017-02-01

To evaluate objective and subjective image quality of a noise-optimized virtual monoenergetic imaging (VMI+) reconstruction technique in dual-energy computed tomography (DECT) angiography prior to transcatheter aortic valve replacement (TAVR). Datasets of 47 patients (35 men; 64.1 ± 10.9 years) who underwent DECT angiography of heart and vascular access prior to TAVR were reconstructed with standard linear blending (F_0.5), VMI+, and traditional monoenergetic (VMI) algorithms in 10-keV intervals from 40-100 keV. Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of 564 arterial segments were evaluated. Subjective analysis was rated by three blinded observers using a Likert scale. Mean SNR and CNR were highest in 40 keV VMI+ series (SNR, 27.8 ± 13.0; CNR, 26.3 ± 12.7), significantly (all p < 0.001) superior to all VMI series, which showed highest values at 70 keV (SNR, 18.5 ± 7.6; CNR, 16.0 ± 7.4), as well as linearly-blended F_0.5 series (SNR, 16.8 ± 7.3; CNR, 13.6 ± 6.9). Highest subjective image quality scores were observed for 40, 50, and 60 keV VMI+ reconstructions (all p > 0.05), significantly superior to all VMI and standard linearly-blended images (all p < 0.01). Low-keV VMI+ reconstructions significantly increase CNR and SNR compared to VMI and standard linear-blending image reconstruction and improve subjective image quality in preprocedural DECT angiography in the context of TAVR planning. • VMI+ combines increased contrast with reduced image noise. • VMI+ shows substantially less image noise than traditional VMI. • 40-keV reconstructions show highest SNR/CNR of the aortic and iliofemoral access route. • Observers overall prefer 60 keV VMI+ images. • VMI+ DECT imaging helps improve image quality for TAVR planning.

Comparative phylogeography and population genetics within Buteo lineatus reveals evidence of distinct evolutionary lineages

USGS Publications Warehouse

Hull, J.M.; Strobel, Bradley N.; Boal, C.W.; Hull, A.C.; Dykstra, C.R.; Irish, A.M.; Fish, A.M.; Ernest, H.B.

2008-01-01

Traditional subspecies classifications may suggest phylogenetic relationships that are discordant with evolutionary history and mislead evolutionary inference. To more accurately describe evolutionary relationships and inform conservation efforts, we investigated the genetic relationships and demographic histories of Buteo lineatus subspecies in eastern and western North America using 21 nuclear microsatellite loci and 375-base pairs of mitochondrial control region sequence. Frequency based analyses of mitochondrial sequence data support significant population distinction between eastern (B. l. lineatus/alleni/texanus) and western (B. l. elegans) subspecies of B. lineatus. This distinction was further supported by frequency and Bayesian analyses of the microsatellite data. We found evidence of differing demographic histories between regions; among eastern sites, mitochondrial data suggested that rapid population expansion occurred following the end of the last glacial maximum, with B. l. texanus population expansion preceding that of B. l. lineatus/alleni. No evidence of post-glacial population expansion was detected among western samples (B. l. elegans). Rather, microsatellite data suggest that the western population has experienced a recent bottleneck, presumably associated with extensive anthropogenic habitat loss during the 19th and 20th centuries. Our data indicate that eastern and western populations of B. lineatus are genetically distinct lineages, have experienced very different demographic histories, and suggest management as separate conservation units may be warranted. ?? 2008 Elsevier Inc. All rights reserved.

Methods for assessing infestations of sunflower stem weevil (Coleoptera: Curculionidae) in sunflower stems

USDA-ARS?s Scientific Manuscript database

The sunflower stem weevil, Cylindrocopturus adspersus LeConte (Coleoptera: Curculionidae), reduces sunflower, Helianthus annuus L. (Asteraceae), yields by spreading pathogens, damaging vascular tissues, and promoting lodging of sunflower plants. To assess weevil populations for host plant resistanc...

2009 Sunflower Insect Pest Problems and Insecticide Update

USDA-ARS?s Scientific Manuscript database

Sunflowers (Helianthus annuus L.) are native to North America and a number of insect pests cause economic losses to sunflower production. Head-infesting insects include the red sunflower seed weevil, Smicronyx fulvus LeConte, banded sunflower moth, Cochylis hospes Walsingham, sunflower moth, Homoeos...

Walker's Eleodes (Coleoptera: Tenebrionidae)

USDA-ARS?s Scientific Manuscript database

The type specimens of five species of Eleodes described by Francis Walker were studied in order to establish their true identity. The synonymy of Eleodes convexicollis Walker and Eleodes conjunctus Walker with E. obscurus (Say); that of Eleodes latiusculus Walker with E. humeralis LeConte; and that ...

Influence of elevation on bark beetle (Coleoptera: Curculionidae, Scolytinae) community structure and flight periodicity in ponderosa pine forests of Arizona.

PubMed

Williams, Kelly K; McMillin, Joel D; DeGomez, Tom E; Clancy, Karen M; Miller, Andy

2008-02-01

We examined abundance and flight periodicity of five Ips and six Dendroctonus species (Coleoptera: Curculionidae, Scolytinae) among three different elevation bands in ponderosa pine (Pinus ponderosa Douglas ex. Lawson) forests of northcentral Arizona. Bark beetle populations were monitored at 10 sites in each of three elevation bands (low: 1,600-1,736 m; middle: 2,058-2,230 m; high: 2,505-2,651 m) for 3 yr (2004-2006) using pheromone-baited Lindgren funnel traps. Trap contents were collected weekly from March to December. We also studied temperature differences among the elevation bands and what role this may play in beetle flight behavior. Bark beetles, regardless of species, showed no consistent elevational trend in abundance among the three bands. The higher abundances of Ips lecontei Swaine, I. calligraphus ponderosae Swaine, Dendroctonus frontalis Zimmerman, and D. brevicomis LeConte at low and middle elevations offset the greater abundance of I. knausi Swaine, D. adjunctus Blandford, D. approximatus Dietz, and D. valens LeConte at high elevations. I. pini (Say) and I. latidens LeConte were found in similar numbers across the three bands. Flight periodicity of several species varied among elevation bands. In general, the flight period shortened as elevation increased; flight initiated later and terminated earlier in the year. The timing, number, and magnitude of peaks in flight activity also varied among the elevation bands. These results suggest that abundance and flight seasonality of several bark beetles are related to elevation and the associated temperature differences. The implications of these results are discussed in relation to bark beetle management and population dynamics.

DECT Ventilation Imaging

ClinicalTrials.gov

2018-03-21

For Oncologic Patients; Potentially Operable Lung Tumor; With a Recent (Less Than 1 Month) VQ Scan; For Lung Transplant Recipients; Single of Bilateral Lung Transplant; From 5 Months Onwards; With Recent (Less Than 1 Month) Respiratory Functional Explorations

Analysis of pulmonary pure ground-glass nodule in enhanced dual energy CT imaging for predicting invasive adenocarcinoma: comparing with conventional thin-section CT imaging

PubMed Central

Zhang, Ying; Tang, Jian; Xu, Jianrong

2017-01-01

Background To investigate the value of dual energy computed tomography (DECT) parameters (including iodine concentration and monochromatic CT numbers) for predicting pure ground-glass nodules (pGGNs) of invasive adenocarcinoma (IA). Methods A total of 55 resected pGGNs evaluated with both unenhanced thin-section CT (TSCT) and enhanced DECT scans were included. Correlations between histopathology [adenocarcinoma in situ (AIS), minimally IA (MIA), and IA] and CT scan characteristics were examined. CT scan and clinicodemographic data were investigated by univariate and multivariate analysis to identify features that helped distinguish IA from AIS or MIA. Results Both normalized iodine concentration (NIC) of IA and slope of spectral curve [slope(k)] were not significantly different between IA and AIS or MIA. Size, performance of pleural retraction and enhanced monochromatic CT attenuation values of 120–140 keV were significantly higher for IA. In multivariate regression analysis, size and enhanced monochromatic CT number of 140 keV were independent predictors for IA. Using the two parameters together, the diagnostic capacity of IA could be improved from 0.697 or 0.635 to 0.713. Conclusions DECT could help demonstrate blood supply and indicate invasion extent of pGGNs, and monochromatic CT number of higher energy (especially 140 keV) would be better for diagnosing IA than lower energies. Together with size of pGGNs, the diagnostic capacity of IA could be better. PMID:29312701

[Clinical implications of dual-energy computed tomography in the diagnosis and treatment of urolithiasis].

PubMed

Kapanadze, L B; Ternovoy, S K; Rudenko, V I; Serova, N S

2018-03-01

Urolithiasis (urolithiasis) is one of the most common urologic diseases with an estimated prevalence of no less than 3% in the population, usually affecting active working-age patients of 30-50 years. Taking into account major public health and economic significance of this problem, there is the need for the development of effective modern diagnostic techniques. Rapid medical-technological advances of the past two decades have led to the wide spread use of minimally invasive surgery the management of urolithiasis. Nevertheless, surgical intervention only removes the result of a long pathological process and does not change its course. Thus, there is a need for a detailed understanding of the etiology, epidemiology, and pathogenesis of urolithiasis. Diagnostic imaging plays a key role in the diagnosis of urolithiasis. Multislice spiral computed tomography (MSCT) is the gold standard for the diagnosis of urolithiasis. It provides information about the size, location, and density of the calculus. Over the past decade, the use of dual-energy computed tomography (DECT) in urological practice has been widely discussed in the international and domestic literature. One of the main advantages of DECT is the ability to determine the chemical composition of urinary stones. Previous studies have reported a high diagnostic value of the method, including the ability to predict treatment outcomes. However, the shortcomings of the method and the absence of standardized examination protocols leave a wide field for further research. This article reviews major distinctive features of using DECT in the diagnosis of urolithiasis.

Phenotypic changes in laboratory-reared colonies of the maize herbivore, Diabrotica virgifera virgifera

USDA-ARS?s Scientific Manuscript database

The North American and European maize pest Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae) was used to assess whether environmental conditions of the natal field, subsequent laboratory rearing, or genetic population characteristics affect phenotypic traits of fitness, activity, or...

Comparative assessment of four Steinernematidae and three Heterorhabditidae species for infectivity of larval Diabrotica virgifera virgifera

USDA-ARS?s Scientific Manuscript database

Larval Diabrotica virgifera virgifera LeConte were exposed to seven different entomopathogenic nematode species to test their potential infectivity in a laboratory setting. Known D. virgifera infecting nematode species Heterorhabditis bacteriophora Poinar, H. megidis Poinar, Jackson & Klein, Steiner...

Non-constant thermal regimes enhance overwintering success and accelerate diapause development for Smicronyx fulvus (Coleoptera: Curculionidae)

USDA-ARS?s Scientific Manuscript database

Recent populations of the red sunflower seed weevil, Smicronyx fulvus LeConte (Coleoptera: Curculionidae) have been inconsistent or declining, particularly in North Dakota. Consequently, field and laboratory research on weevil biology, including development of resistant germplasm, have been limited....

Ipsenol: An Aggregation Pheromone for Ips latidens (LeConte) (Coleoptera: Scolytidae)

Treesearch

Daniel R. Miller; John H. Borden; G.G.S. King; Keith N. Slessor

1991-01-01

Ipsenol was identified from the frass of male, but not female, Ips latidens from British Columbia, feeding in phloem tissue of lodgepole pine, Pinus contorta var. latifolia. The responses of I. latidens to sources of ipsenol and cis-verbenol were determined with multiple-...

Monogalactosyldiacylglycerols as host recognition cues for western corn rootworm larvae (Coleoptera: Chrysomelidae)

USDA-ARS?s Scientific Manuscript database

Monogalactosyldiacylglycerol (MGDG) was identified as a host recognition cue for larvae of the western corn rootworm Diabrotica virgifera virgifera LeConte. An active glycolipid fraction obtained from an extract of germinating maize roots was isolated with thin layer chromatography using a bioassay-...

Optimization of the scan protocols for CT-based material extraction in small animal PET/CT studies

NASA Astrophysics Data System (ADS)

Yang, Ching-Ching; Yu, Jhih-An; Yang, Bang-Hung; Wu, Tung-Hsin

2013-12-01

We investigated the effects of scan protocols on CT-based material extraction to minimize radiation dose while maintaining sufficient image information in small animal studies. The phantom simulation experiments were performed with the high dose (HD), medium dose (MD) and low dose (LD) protocols at 50, 70 and 80 kVp with varying mA s. The reconstructed CT images were segmented based on Hounsfield unit (HU)-physical density (ρ) calibration curves and the dual-energy CT-based (DECT) method. Compared to the (HU;ρ) method performed on CT images acquired with the 80 kVp HD protocol, a 2-fold improvement in segmentation accuracy and a 7.5-fold reduction in radiation dose were observed when the DECT method was performed on CT images acquired with the 50/80 kVp LD protocol, showing the possibility to reduce radiation dose while achieving high segmentation accuracy.

Diet improvement for western corn rootworm (Coleoptera: Chrysomelidae) larvae

USDA-ARS?s Scientific Manuscript database

The western corn rootworm (WCR), Diabrotica virgifera virgifera LeConte, is the most serious insect pest of corn (Zea mays L.) in the United States and parts of Europe, and arguably the world’s most expensive pest to control. Several diet formulations are currently used by industry and researchers t...

Synthetic feeding stimulants enhance insecticide activity against western corn rootworm larvae, Diabrotica virgifera virgifera (Coleoptera: Chrysomelidae)

USDA-ARS?s Scientific Manuscript database

In behavioral bioassays, the addition of a synthetic feeding stimulant blend improved the efficacy of the insecticide thiamethoxam against neonate western corn rootworm, Diabrotica virgifera virgifera LeConte, larvae. In 4-h bioassays, the concentration of thiamethoxam required for 50% mortality (LC...

Trap lure blend of pine volatiles and bark beetle pheromones for Monochamus spp. (Coleoptera: Cerambycidae) in pine forests of Canada and the United States.

Treesearch

Dan Miller; Kevin J. Dodds; Andy Eglitis; Chris Fettig; Richard W. Hofstetter; David W. Langor; Albert (Bud) Mayfield; A. Steven Munson; Therese M. Poland; Kenneth F. Raffa

2013-01-01

In 2007-2008, we examined the flight responses of Monochamus titillator (F.) complex [M. titillator, Monochamus carolinensis (Olivier), and any possible hybrids], Momonchamus scutellatus (Say), Monochamus clamator (LeConte), Monochamus obtusus Casey, and Monochamus...

Stridulatory mechanisms and sound production in Conotrachelus (Coleoptera: Curculionidae)

Treesearch

Lester P. Gibson

1967-01-01

The elytral stridulitra and the plectra on the sixth abdominal tergite are described and illustrated for both sexes of Conotrachelus naso LeConte, C. posticatus Boheman, and C. carinifer Casey, as is the stridulitrum of the male C. nenuphar (Herbst); the female of C. nenuphar has no...

Genome sequence of the first coleopteran iflavirus isolated from western corn rootworm, Diabrotica virgifera virgifera LeConte

USDA-ARS?s Scientific Manuscript database

Western corn rootworm (WCR), Diabrotica virgifera virgifera, adults were collected from cornfields in the United States (Iowa, Arizona, Pennsylvania), and Europe (Hungary, Croatia, Austria). Total RNA was extracted from ~100 individuals from different locations, and putative viral RNA was isolated f...

Response of different white fir geographic provenances to Trichosporium symbioticum inoculation in California

Treesearch

William J. Otrosina; Stanley J. Zarnoch

2012-01-01

We inoculated the fir engraver (Scolytus ventralis LeConte) associated fungus Trichosporium symbioticum Wright onto 56 white fir (Abies concolor (Gordon & Glend.) Lindl. ex Hildebr.) trees planted in a common garden study near Camino, California, that represented five geographic provenances of this species....

Residual efficacy of deltamethrin and ß-cyfluthrin against Trogoderma variabile and Trogoderma inclusum (Coleoptera: Dermestidae)

USDA-ARS?s Scientific Manuscript database

Trogroderma variabile Ballion, warehouse beetle, and Trogoderma inclusum LeConte, larger cabinet beetle, are dermestid pests of stored products. A series of laboratory bioassays were conducted to evaluate residual toxicity of the pyrethroids ß-cyfluthrin and deltamethrin, applied on a concrete surf...

Vertical displacement of Ips Latidens and Ips Pini

Treesearch

Daniel R. Miller

2000-01-01

The effect of semiochemical interruptants was examined for Ips latidens (LeConte) and Ips pini (Say) using artificial trees (tall-traps) consisting of an array of seven Lindgren multiple-funnel traps suspended vertically on a rope ladder. S-(+)- Ipsdienol reduced the numbers of I. latidens captured in (±)-ipsenol...

Field assessment of hybridization between Laricobius nigrinus and L. rubidus, predators of Adelgidae

Treesearch

Melissa J. Fischer; Nathan P. Havill; Carlyle C. Brewster; Gina A. Davis; Scott M. Salom; Loke T. Kok

2015-01-01

Two adelgid predators, Laricobius nigrinus Fender and Laricobius rubidus LeConte, were recently discovered to produce hybrid progeny in the eastern United States. L. rubidus is native to eastern North America where it feeds on pine bark adelgid (Pineus strobi Hartig) and L. nigrinus...

Screening for corn rootworm (Coleoptera: Chrysomelidae) resistance to transgenic Bt corn in North Dakota

USDA-ARS?s Scientific Manuscript database

Western (WCR), Diabrotica virgifera virgifera LeConte, and northern corn rootworms (NCR), D. barberi Smith & Lawrence, are major economic pests of corn in much of the U.S. Corn Belt. Western corn rootworm resistance to transgenic corn expressing Bt (Bacillus thuringiensis) endotoxins has been confi...

Dynamic precision phenotyping reveals mechanism of crop tolerance to root herbivory

USDA-ARS?s Scientific Manuscript database

The western corn rootworm, Diabrotica virgifera virgifera (LeConte) is a major pest of maize, Zea mays L. Over the years, this pest has repeatedly shown its resilience and adaptability not only to traditional crop management strategies including chemical pesticides and crop rotation, but also to de...

Sperm quality assessments for endangered razorback suckers Xyrauchen Texanus

USGS Publications Warehouse

Jenkins, Jill A.; Eilts, Bruce E.; Guitreau, Amy M.; Figiel, Chester R.; Draugelis-Dale, Rassa O.; Tiersch, Terrence R.

2011-01-01

Flow cytometry (FCM) and computer-assisted sperm motion analysis (CASA) methods were developed and validated for use with endangered razorback suckers Xyrauchen texanus collected (n=64) during the 2006 spawning season. Sperm motility could be activated within osmolality ranges noted during milt collections (here 167–343 mOsm/kg). We hypothesized that sperm quality of milt collected into isoosmotic (302 mOsm/kg) or hyperosmotic (500 mOsm/kg) Hanks' balanced salt solution would not differ. Pre-freeze viabilities were similar between osmolalities (79%±6 (S.E.M.) and 76%±7); however, post-thaw values were greater in hyperosmotic buffer (27%±3 and 12%±2; P=0.0065), as was mitochondrial membrane potential (33%±4 and 13%±2; P=0.0048). Visual estimates of pre-freeze motility correlated with total (r=0.7589; range 23–82%) and progressive motility (r=0.7449) by CASA and were associated with greater viability (r=0.5985; Pr=-0.83; P=0.0116) and mitochondrial function (r=-0.91; P=0.0016). By FCM-based assessments of DNA integrity, whereby increased fluorochrome binding indicated more fragmentation, higher levels were negatively correlated with count (r=-0.77; Pr=-0.66; P=0.0004). Fragmentation was higher in isotonic buffer (P=0.0234). To increase reproductive capacity of natural populations, the strategy and protocols developed can serve as a template for use with other imperiled fish species, biomonitoring, and genome banking.

Prevalence of monosodium urate deposits in a population of rheumatoid arthritis patients with hyperuricemia.

PubMed

Petsch, Christina; Araujo, Elizabeth G; Englbrecht, Matthias; Bayat, Sara; Cavallaro, Alexander; Hueber, Axel J; Lell, Michael; Schett, Georg; Manger, Bernhard; Rech, Juergen

2016-06-01

To investigate the prevalence of monosodium urate (MSU) crystal deposits, indicative for gout, in a population of rheumatoid arthritis (RA) patients with concomitant hyperuricemia and to analyze the clinical and disease-specific characteristics of RA patients who exhibit MSU crystal deposits. Overall, 100 consecutive patients with the diagnosis of RA and a serum urate level above 6mg/dl underwent dual energy computed tomography (DECT) of both feet and hands to search for MSU crystals in a prospective study between October 2011 and July 2013. Presence and extent of MSU crystal deposits on DECT was assessed by automated volume measurement. Demographic and disease-specific characteristics were recorded and included into two logistic regression models to test for the factors associated with MSU crystal deposits in RA. Hyperuricemic RA patients were mostly male (55%), over 60 years of age (63 ± 11 years), had established disease (8.7 ± 10.5 years) and a mean disease activity score 28 (DAS 28) of 3.2. In total, 20 out of 100 patients displayed MSU crystal deposits in DECT. Interestingly, the majority (70%) of the RA patients positive for MSU crystal deposits were seronegative RA patients. Hence, every third seronegative RA patient had MSU crystal deposits. According to logistic regression model analysis, seronegative status correlated positively with presence of urate deposits (p = 0.019). These data show that a considerable number of RA patients display periarticular MSU crystal deposits. Seronegative patients were shown to be predominantly affected with every third patient being positive for urate deposits. Copyright © 2016 Elsevier Inc. All rights reserved.

Quantification of lung perfusion blood volume (lung PBV) by dual-energy CT in patients with chronic thromboembolic pulmonary hypertension (CTEPH) before and after balloon pulmonary angioplasty (BPA): Preliminary results.

PubMed

Koike, Hirofumi; Sueyoshi, Eijun; Sakamoto, Ichiro; Uetani, Masataka; Nakata, Tomoo; Maemura, Kouji

2016-09-01

Balloon pulmonary angioplasty (BPA) is a treatment option for patients with chronic thromboembolic pulmonary hypertension (CTEPH). Its effect on pulmonary perfusion has not been quantified; we examined the clinical significance of pulmonary blood volume (PBV) using dual-energy computed tomography (DECT) in patients with CTEPH undergoing BPA. In this retrospective study of 16 BPAs in eight female patients with CTEPH, we evaluated both-lung (n=16), right- or left-lung (n=32), and three right- or left-segment (upper, middle, and lower) (n=96) PBVs before and after BPA, using DECT. We evaluated the relationships between improvement in lung PBV and pulmonary artery (PA) pressure (PAP), cardiac index (CI), pulmonary vascular resistance (PVR), and 6-min walking distance. We measured PA enhancement (PAenh) on DECT images and calculated lung PBV/PAenh to adjust timing. Pre- and post-BPA 6-segment lung PBV/PAenh were 0.067±0.021 and 0.077±0.019, respectively, in the treated segment (p<0.0001). There were significant positive correlations between pre- to post-BPA improvements in both-lung PBV/PAenh and PAP (R=0.69, p=0.005), PVR (R=0.56, p=0.03), and 6-min walking distance (R=0.67, p=0.01). Improved PBV after BPA, reflecting increased lung perfusion, was positively correlated with PAP, PVR, and 6-min walking distance. Lung PBV may be an indicator of BPA treatment effect. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Development of optimized segmentation map in dual energy computed tomography

NASA Astrophysics Data System (ADS)

Yamakawa, Keisuke; Ueki, Hironori

2012-03-01

Dual energy computed tomography (DECT) has been widely used in clinical practice and has been particularly effective for tissue diagnosis. In DECT the difference of two attenuation coefficients acquired by two kinds of X-ray energy enables tissue segmentation. One problem in conventional DECT is that the segmentation deteriorates in some cases, such as bone removal. This is due to two reasons. Firstly, the segmentation map is optimized without considering the Xray condition (tube voltage and current). If we consider the tube voltage, it is possible to create an optimized map, but unfortunately we cannot consider the tube current. Secondly, the X-ray condition is not optimized. The condition can be set empirically, but this means that the optimized condition is not used correctly. To solve these problems, we have developed methods for optimizing the map (Method-1) and the condition (Method-2). In Method-1, the map is optimized to minimize segmentation errors. The distribution of the attenuation coefficient is modeled by considering the tube current. In Method-2, the optimized condition is decided to minimize segmentation errors depending on tube voltagecurrent combinations while keeping the total exposure constant. We evaluated the effectiveness of Method-1 by performing a phantom experiment under the fixed condition and of Method-2 by performing a phantom experiment under different combinations calculated from the total exposure constant. When Method-1 was followed with Method-2, the segmentation error was reduced from 37.8 to 13.5 %. These results demonstrate that our developed methods can achieve highly accurate segmentation while keeping the total exposure constant.

Image quality improvements using adaptive statistical iterative reconstruction for evaluating chronic myocardial infarction using iodine density images with spectral CT.

PubMed

Kishimoto, Junichi; Ohta, Yasutoshi; Kitao, Shinichiro; Watanabe, Tomomi; Ogawa, Toshihide

2018-04-01

Single-source dual-energy CT (ssDECT) allows the reconstruction of iodine density images (IDIs) from projection based computing. We hypothesized that adding adaptive statistical iterative reconstruction (ASiR) could improve image quality. The aim of our study was to evaluate the effect and determine the optimal blend percentages of ASiR for IDI of myocardial late iodine enhancement (LIE) in the evaluation of chronic myocardial infarction using ssDECT. A total of 28 patients underwent cardiac LIE using a ssDECT scanner. IDIs between 0 and 100% of ASiR contributions in 10% increments were reconstructed. The signal-to-noise ratio (SNR) of remote myocardia and the contrast-to-noise ratio (CNR) of infarcted myocardia were measured. Transmural extent of infarction was graded using a 5-point scale. The SNR, CNR, and transmural extent were assessed for each ASiR contribution ratio. The transmural extents were compared with MRI as a reference standard. Compared to 0% ASiR, the use of 20-100% ASiR resulted in a reduction of image noise (p < 0.01) without significant differences in the signal. Compared with 0% ASiR images, reconstruction with 100% ASiR image showed the highest improvement in SNR (229%; p < 0.001) and CNR (199%; p < 0.001). ASiR above 80% showed the highest ratio (73.7%) of accurate transmural extent classification. In conclusion, ASiR intensity of 80-100% in IDIs can improve image quality without changes in signal and maximizes the accuracy of transmural extent in infarcted myocardium.

Learning-Based Object Identification and Segmentation Using Dual-Energy CT Images for Security.

PubMed

Martin, Limor; Tuysuzoglu, Ahmet; Karl, W Clem; Ishwar, Prakash

2015-11-01

In recent years, baggage screening at airports has included the use of dual-energy X-ray computed tomography (DECT), an advanced technology for nondestructive evaluation. The main challenge remains to reliably find and identify threat objects in the bag from DECT data. This task is particularly hard due to the wide variety of objects, the high clutter, and the presence of metal, which causes streaks and shading in the scanner images. Image noise and artifacts are generally much more severe than in medical CT and can lead to splitting of objects and inaccurate object labeling. The conventional approach performs object segmentation and material identification in two decoupled processes. Dual-energy information is typically not used for the segmentation, and object localization is not explicitly used to stabilize the material parameter estimates. We propose a novel learning-based framework for joint segmentation and identification of objects directly from volumetric DECT images, which is robust to streaks, noise and variability due to clutter. We focus on segmenting and identifying a small set of objects of interest with characteristics that are learned from training images, and consider everything else as background. We include data weighting to mitigate metal artifacts and incorporate an object boundary field to reduce object splitting. The overall formulation is posed as a multilabel discrete optimization problem and solved using an efficient graph-cut algorithm. We test the method on real data and show its potential for producing accurate labels of the objects of interest without splits in the presence of metal and clutter.

Susceptibility of Nebraska Western Corn Rootworm (Coleoptera: Chrysomelidae) Populations to Bt Corn Events

USDA-ARS?s Scientific Manuscript database

Transgenic plants have been widely adopted by growers to manage the western corn rootworm, Diabrotica virgifera virgifera LeConte, in field corn. Because of reduced efficacy in some Nebraska fields after repeated use of Cry3Bb1 expressing hybrids, single plant bioassays were conducted in 2012 and 20...

Toxic and behavioral effects of free fatty acids on western corn rootworm (Coleoptera: Chrysomelidae) larvae

USDA-ARS?s Scientific Manuscript database

Feeding behavior, feeding intensity and staying behavior of neonate western corn rootworm (Diabrotica virgifera virgifera LeConte) larvae were evaluated in response to synthetic feeding stimulant blends. All of the treatments contained a 3-sugar blend (glucose:fructose:sucrose, 30:4:4 mg per ml) an...

Verbenone: Dose-Dependent Interruption of Pheromone-Based Attraction of Three Sympatric Species of Pine Bark Beetles (Coleoptera: Scolytidae)

Treesearch

Daniel R. Miller; John H. Borden; B. Staffan Lindgren

1995-01-01

Verbenone significantly reduced catches of Ips latidens (LeConte), I. pini (Say), and Dendroctonus ponderosae Hopkins in multiple-funnel traps, baited with aggregation pheromones, in stands of lodgepole pine in southern British Columbia. Interruption of attraction was dose dependent for all three species. There...

Evaluation of multiple funnel traps and stand characteristics for estimating western pine beetle-caused tree mortality

Treesearch

C.J. Hayes; C.J. Fettig; L.D. Merrill

2009-01-01

The western pine beetle, Dendroctonus brevicomis LeConte (Coleoptera: Curculionidae: Scolytinae), is a major cause of ponderosa pine, Pinus ponderosa Dougl. ex Laws., mortality in much of western North America. This study was designed to quantify relationships between western pine beetle trap catches [including those of its...

Western Pine Beetle

Treesearch

Clarence J. Jr. DeMars; Bruce H. Roettgering

1982-01-01

The western pine beetle, Dendroctonus brevicomis LeConte, can aggressively attack and kill ponderosa and Coulter pine trees of all ages and vigor classes that are 6 inches (15 cm) or larger in diameter, including apparently healthy trees. Group killing of trees is common in dense, overstocked stands of pure, even-aged, young sawtimber (fig. 1), but also occurs among...

Hybridization between a native and introduced predator of Adelgidae: An unintended result of classical biological control

Treesearch

N.P. Havill; Gina Davis; David Mausel; Joanne Klein; Richard McDonald; Cera Jones; Melissa Fischer; Scott Salom; Adelgisa Caccone

2012-01-01

Hybridization between introduced biological control agents and native species has the potential to impact native biodiversity and pest control efforts. This study reports progress towards predicting the outcome of hybridization between two beetle species, the introduced Laricobius nigrinus Fender and the native L. rubidus LeConte...

Protandry of western corn rootworm (Coleoptera: Chrysomelidae) beetle emergence partially due to earlier egg hatch of males

USDA-ARS?s Scientific Manuscript database

The western corn rootworm, Diabrotica virgifera virgifera LeConte, exhibits protandry. The contribution of pre-hatch development to protandry in western corn rootworm was previously investigated with a small set of data from one population. To verify the contribution of pre-hatch development to prot...

Direct control of western pine beetle (Dendroctonus brevicomis LeConte): review and assessment

Treesearch

Richard H. Smith

1990-01-01

Nearly 70 years of research and application are reviewed and assessed. Results of direct control projects can be characterized as generally effective, temporary, quite variable, and unpredictable in reducing subsequent tree mortality. Some causes of this characterization are variable and difficult stand conditions and logistics, lack of good beetle population...

Attraction of Pissodes affinis and P. fasciatus (Coleoptera: Curculionidae) to pityol and a-pinene in a Coastal Stand of Western White Pine and Douglas-fir

Treesearch

Daniel R. Miller; Don Heppner

1999-01-01

Lindgren multiple-funnel traps, baited with (-)-a-pinene and (±)-pityol, captured significant numbers of the weevils, Pissodes affinis Randall and P. fasciatus LeConte, in a coastal stand of Douglas-fir and western white pine.

Resistance in Cultivated Sunflower Germplasm to the Red Sunflower Seed Weevil (Coleoptera: Curculionidae) in the Northern Great Plains

USDA-ARS?s Scientific Manuscript database

A 6-year field study evaluated 52 sunflower, Helianthus annuus L., accessions, 20 breeding lines, and 9 interspecific crosses for resistance to infestation by naturally occurring populations of the red sunflower seed weevil, Smicronyx fulvus LeConte (Coleoptera: Curculionidae). Germplasm with potent...

Efficacy of verbenone for protecting ponderosa pine stands from western pine beetle (Coleoptera: Curculionidae, Scolytinae) attack in California

Treesearch

C.J. Fettig; S.R. McKelvey; R.R. Borys; C.P Dabney; S.M. Hamud; L.J. Nelson; S.J. Seybold

2009-01-01

The western pine beetle, Dendroctonus brevicomis LeConte (Coleoptera: Curculionidae: Scolytinae), is a major cause of ponderosa pine, Pinus ponderosa Dougl. ex Laws., mortality in much of western North America. Currently, techniques for managing D. brevicomis infestations are limited. Verbenone (4,6,6-...

Seasonal abundance, arrival and emergence patterns of predaceous hister beetles (Coleoptera: Histeridae) associated with Ips engraver beetles (Coleoptera: Scolytidae) in Louisiana

Treesearch

William P. Shepherd; Richard A. Goyer

2003-01-01

The most common predaceious hister beetles (Coleoptera: Histeridae) found associated with Ips engraver beetles (Coleoptera: Scolytidae) in southern Louisiana were Platysoma attenuata LeConte, P. cylindrica (Paykull), P. parallelum (Say), and Plegaderus transversus (Say). The seasonal abundance of...

Electrophysiological and behavioral responses of Dendroctonus valens to non-host volatiles

Treesearch

Long-wa Zhang; Nancy E. Gillette; Jiang-hua Sun

2007-01-01

Non-host volatiles (NHVs) that are often reported as being disruptive to coniferophagous bark beetles were tested for both electrophysiological and behavioral effects on the red turpentine beetle, Dendroctonus valens LeConte (Coleoptera: Curculionidae: Scolytinae), which was accidentally introduced into China in the mid-1980's. All NHVs tested...

The effect of western corn rootworm (Coleoptera: Chrysomelidae) and water deficit on maize performance under controlled conditions

USDA-ARS?s Scientific Manuscript database

A series of greenhouse experiments using three infestation levels of the western corn rootworm, Diabrotica virgifera virgifera LeConte, under well-watered, moderately dry, and very dry soil moisture levels were conducted to quantify the interaction of western corn rootworm and soil water deficit on ...

A core set of microsatellite markers for Western Corn Rootworm (Coleoptera: Chrysomelidae) population genetics studies

EPA Science Inventory

Interest in the ecological and population genetics of the western corn rootworm, Diabrotica virgifera virgifera LeConte, has grown rapidly in the last few years in North America and Europe. This interest is a result of a number of converging issues related to increasing difficult...

The eastern larch beetle in Alaska.

Treesearch

Richard A. Werner

1986-01-01

The eastern larch beetle (Dendroctonus simplex LeConte) exists throughout the range of tamarack (Larix laricina (Du Roi) K. Koch) in interior Alaska where it has a 1-year life cycle. Beetles overwinter as adults in the bark of the trunk below snowline in infested trees. Tamarack trees that are slow growing because of repeated...

Relationship of stand characteristics to drought-induced mortality in three Southwestern pinyon-juniper woodlands

Treesearch

M. Lisa Floyd; Michael Clifford; Neil S. Cob; Dustin Hanna; Robert Delph; Paulette Ford; Dave Turner

2009-01-01

Extreme drought conditions accompanied by rising temperatures have characterized the American Southwest during the past decade, causing widespread tree mortality in pinon-juniper woodlands. Pinon pine (Pinus edulis Engelm.) mortality is linked primarily to outbreaks of the pinyon ips (Ips confusus (Leconte)) precipitated by drought conditions. Although we searched...

Response of western pine beetle, Dendroctonus brevicomis LeConte (Coleoptera: Curculionidae), to different release rates of nonhost angiosperm volatiles and verbenone

Treesearch

C.J. Fettig; S.R. McKelvey; C.P. Dabney; R.R. Borys; D.P.W. Huber

2009-01-01

A blend of eight nonhost angiosperm volatiles (benzyl alcohol, benzaldehyde, guaiacol, nonanal, salicylaldehyde, (E)-2-hexenal, (E)-2-hexen-1-ol and (Z)-2-hexen-1-ol) without [NAV] and with [NAVV] (–)-verbenone (4,6,6-trimethylbicyclo[3...

crw1- A novel maize mutant highly susceptible to foliar damage by the Western corn rootworm beetle

USDA-ARS?s Scientific Manuscript database

Western corn rootworm (WCR), Diabrotica virgifera virgifera Leconte (Coleoptera: Chrysomelidae), is the most destructive insect pest of corn (Zea mays L) in the United States. The adult WCR beetles derive their nourishment from multiple sources including corn pollen and silks as well as the pollen o...

4-allylanisole as an inhibitor of bark beetle (Coleoptera: Scolytidae) aggregation

Treesearch

Jane L. Hayes; Brian L. Strom

1994-01-01

To assess the extent of inhibitory activity of the host compound 4-allylanisole, we conducted field studies with three scolytid species.These species are geographically widespread and economically important.Trials were completed with Dendroctonus brevicomis LeConte (California), D. ponderosae Hopkins (Oregon), and Ips pini (Say) (Wisconsin) by using multiple-funnel...

Field-based assessment of resistance to Bt Corn by Western Corn Rootworm (Coleoptera: Chrysomelidae)

USDA-ARS?s Scientific Manuscript database

Western corn rootworm, Diabrotica virgifera virgifera LeConte, is a serious pest of corn and is managed with Bt corn that produce insecticidal toxins derived from the bacterium Bacillus thuringiensis (Bt). Beginning in 2009, severe injury to Bt corn producing Cry3Bb1 was observed in some cornfields ...

Dendroctonus brevicomis responses in behavioral assays: Implication to development of a semiochemical-based tool for tree protection

Treesearch

Christopher J. Fettig; Stephen R. McKelvey; Christopher P. Dabney; Dezene P.W. Huber

2012-01-01

Currently, techniques for managing western pine beetle, Dendroctonus brevicomis LeConte (Coleoptera: Curculionidae, Scolytinae), infestations are limited to tree removals (thinning) that reduce stand density and presumably host susceptibility, and/or the use of insecticides to protect individual trees. There continues to be significant interest in...

The Hydraenidae of Cuba (Insecta: Coleoptera) II: Morphology of preimaginal stages of six species and notes on their biology.

PubMed

Deler-Hernández, Albert; Delgado, Juan A

2017-03-06

Preimaginal stages of the six species of Hydraenidae presently known from Cuba were obtained by rearing adults in the laboratory. Eggs of Hydraena perkinsi Spangler, 1980, H. decui Spangler, 1980 and H. franklyni Deler-Hernández & Delgado, 2012 are described and illustrated for the first time. The first instar larva of Gymnochthebius fossatus (LeConte, 1855) is redescribed, adding some new remarkable morphological characters including what could be the first abdominal egg-burster reported for this family. All larval instars of H. perkinsi, H. guadelupensis Orchymont, 1923 and Ochthebius attritus LeConte, 1878 are described and illustrated for the first time, with a special emphasis on their chaetotaxy. The second instar larva of G. fossatus along with first and third instar larvae of H. decui and H. franklyni are also studied for the first time. The pupal morphology and vestiture of a species belonging to the genus Hydraena are described for the first time, based on the pupa of H. perkinsi. Biological notes for several preimaginal stages of the studied species are also given.

Evaluation of low-dose dual energy computed tomography for in vivo assessment of renal/ureteric calculus composition.

PubMed

Mahalingam, Harshavardhan; Lal, Anupam; Mandal, Arup K; Singh, Shrawan Kumar; Bhattacharyya, Shalmoli; Khandelwal, Niranjan

2015-08-01

This study aimed to assess the accuracy of low-dose dual-energy computed tomography (DECT) in predicting the composition of urinary calculi. A total of 52 patients with urinary calculi were scanned with a 128-slice dual-source DECT scanner by use of a low-dose protocol. Dual-energy (DE) ratio, weighted average Hounsfield unit (HU) of calculi, radiation dose, and image noise levels were recorded. Two radiologists independently rated study quality. Stone composition was assessed after extraction by Fourier transform infrared spectroscopy (FTIRS). Analysis of variance was used to determine if the differences in HU values and DE ratios between the various calculus groups were significant. Threshold cutoff values to classify the calculi into separate groups were identified by receiver operating characteristic curve analysis. A total of 137 calculi were detected. FTIRS analysis differentiated the calculi into five groups: uric acid (n=17), struvite (n=3), calcium oxalate monohydrate and dihydrate (COM-COD, n=84), calcium oxalate monohydrate (COM, n=28), and carbonate apatite (n=5). The HU value could differentiate only uric acid calculi from calcified calculi (p<0.001). The DE ratio could confidently differentiate uric acid, struvite, calcium oxalate, and carbonate apatite calculi (p<0.001) with cutoff values of 1.12, 1.34, and 1.66, respectively, giving >80% sensitivity and specificity to differentiate them. The DE ratio could not differentiate COM from COM-COD calculi. No study was rated poor in quality by either of the observers. The mean radiation dose was 1.8 mSv. Low-dose DECT accurately predicts urinary calculus composition in vivo while simultaneously reducing radiation exposure without compromising study quality.

Making the invisible visible: improving conspicuity of noncalcified gallstones using dual-energy CT.

PubMed

Uyeda, Jennifer W; Richardson, Ian J; Sodickson, Aaron D

2017-12-01

To determine whether virtual monochromatic imaging (VMI) increases detectability of noncalcified gallstones on dual-energy CT (DECT) compared with conventional CT imaging. This retrospective IRB-approved, HIPAA-compliant study included consecutive patients who underwent DECT of the abdomen in the Emergency Department during a 30-month period (July 1, 2013-December 31, 2015), with a comparison US or MR within 1-year. 51 patients (36F, 15M; mean age 52 years) fulfilled the inclusion criteria. All DECT were acquired on a dual-source 128 × 2 slice scanner using either 80/Sn140 or 100/Sn140 kVp pairs. Source images at high and low kVp were used for DE post-processing with VMI. Within 3 mm reconstructed images, regions of interest of 0.5 cm 2 were placed on noncalcified gallstones and bile to record hounsfield units (HU) at VMI energy levels ranging between 40 and 190 keV. Noncalcified gallstones uniformly demonstrated lowest HU at 40 keV and increase at higher keV; the HU of bile varied at higher keV. Few of the noncalcified stones are visible at 70 keV (simulating a conventional 120 kVp scan), with measured contrast (bile-stone HU difference) <10 HU in 78%, 10-20 HU in 20%, and >20 HU in 2%. Contrast was maximal at 40 keV, where 100% demonstrated >20 HU difference from surrounding bile, 75% >44 HU difference, and 50% >60 HU difference. A paired t test demonstrated a significant difference (p < 0.0001) between this stone-bile contrast at 40 vs. 70 keV and 70 vs. 190 keV. Low keV virtual monochromatic imaging increased conspicuity of noncalcified gallstones, improving their detectability.

Predictive value of low tube voltage and dual-energy CT for successful shock wave lithotripsy: an in vitro study.

PubMed

Largo, Remo; Stolzmann, Paul; Fankhauser, Christian D; Poyet, Cédric; Wolfsgruber, Pirmin; Sulser, Tullio; Alkadhi, Hatem; Winklhofer, Sebastian

2016-06-01

This study investigates the capabilities of low tube voltage computed tomography (CT) and dual-energy CT (DECT) for predicting successful shock wave lithotripsy (SWL) of urinary stones in vitro. A total of 33 urinary calculi (six different chemical compositions; mean size 6 ± 3 mm) were scanned using a dual-source CT machine with single- (120 kVp) and dual-energy settings (80/150, 100/150 Sn kVp) resulting in six different datasets. The attenuation (Hounsfield Units) of calculi was measured on single-energy CT images and the dual-energy indices (DEIs) were calculated from DECT acquisitions. Calculi underwent SWL and the number of shock waves for successful disintegration was recorded. The prediction of required shock waves regarding stone attenuation/DEI was calculated using regression analysis (adjusted for stone size and composition) and the correlation between CT attenuation/DEI and the number of shock waves was assessed for all datasets. The median number of shock waves for successful stone disintegration was 72 (interquartile range 30-361). CT attenuation/DEI of stones was a significant, independent predictor (P < 0.01) for the number of required shock waves with the best prediction at 80 kVp (β estimate 0.576) (P < 0.05). Correlation coefficients between attenuation/DEI and the number of required shock waves ranged between ρ = 0.31 and 0.68 showing the best correlation at 80 kVp (P < 0.001). The attenuation of urinary stones at low tube voltage CT is the best predictor for successful stone disintegration, being independent of stone composition and size. DECT shows no added value for predicting the success of SWL.

Influence of Telecommunication Modality, Internet Transmission Quality, and Accessories on Speech Perception in Cochlear Implant Users

PubMed Central

Koller, Roger; Guignard, Jérémie; Caversaccio, Marco; Kompis, Martin; Senn, Pascal

2017-01-01

Background Telecommunication is limited or even impossible for more than one-thirds of all cochlear implant (CI) users. Objective We sought therefore to study the impact of voice quality on speech perception with voice over Internet protocol (VoIP) under real and adverse network conditions. Methods Telephone speech perception was assessed in 19 CI users (15-69 years, average 42 years), using the German HSM (Hochmair-Schulz-Moser) sentence test comparing Skype and conventional telephone (public switched telephone networks, PSTN) transmission using a personal computer (PC) and a digital enhanced cordless telecommunications (DECT) telephone dual device. Five different Internet transmission quality modes and four accessories (PC speakers, headphones, 3.5 mm jack audio cable, and induction loop) were compared. As a secondary outcome, the subjective perceived voice quality was assessed using the mean opinion score (MOS). Results Speech telephone perception was significantly better (median 91.6%, P<.001) with Skype compared with PSTN (median 42.5%) under optimal conditions. Skype calls under adverse network conditions (data packet loss > 15%) were not superior to conventional telephony. In addition, there were no significant differences between the tested accessories (P>.05) using a PC. Coupling a Skype DECT phone device with an audio cable to the CI, however, resulted in higher speech perception (median 65%) and subjective MOS scores (3.2) than using PSTN (median 7.5%, P<.001). Conclusions Skype calls significantly improve speech perception for CI users compared with conventional telephony under real network conditions. Listening accessories do not further improve listening experience. Current Skype DECT telephone devices do not fully offer technical advantages in voice quality. PMID:28438727

Dual-energy computed tomography in patients with cutaneous malignant melanoma: Comparison of noise-optimized and traditional virtual monoenergetic imaging.

PubMed

Martin, Simon S; Wichmann, Julian L; Weyer, Hendrik; Albrecht, Moritz H; D'Angelo, Tommaso; Leithner, Doris; Lenga, Lukas; Booz, Christian; Scholtz, Jan-Erik; Bodelle, Boris; Vogl, Thomas J; Hammerstingl, Renate

2017-10-01

The aim of this study was to investigate the impact of noise-optimized virtual monoenergetic imaging (VMI+) reconstructions on quantitative and qualitative image parameters in patients with cutaneous malignant melanoma at thoracoabdominal dual-energy computed tomography (DECT). Seventy-six patients (48 men; 66.6±13.8years) with metastatic cutaneous malignant melanoma underwent DECT of the thorax and abdomen. Images were post-processed with standard linear blending (M_0.6), traditional virtual monoenergetic (VMI), and VMI+ technique. VMI and VMI+ images were reconstructed in 10-keV intervals from 40 to 100keV. Attenuation measurements were performed in cutaneous melanoma lesions, as well as in regional lymph node, subcutaneous and in-transit metastases to calculate objective signal-to-noise (SNR) and contrast-to-noise (CNR) ratios. Five-point scales were used to evaluate overall image quality and lesion delineation by three radiologists with different levels of experience. Objective indices SNR and CNR were highest at 40-keV VMI+ series (5.6±2.6 and 12.4±3.4), significantly superior to all other reconstructions (all P<0.001). Qualitative image parameters showed highest values for 50-keV and 60-keV VMI+ reconstructions (median 5, respectively; P≤0.019) regarding overall image quality. Moreover, qualitative assessment of lesion delineation peaked in 40-keV VMI+ (median 5) and 50-keV VMI+ (median 4; P=0.055), significantly superior to all other reconstructions (all P<0.001). Low-keV noise-optimized VMI+ reconstructions substantially increase quantitative and qualitative image parameters, as well as subjective lesion delineation compared to standard image reconstruction and traditional VMI in patients with cutaneous malignant melanoma at thoracoabdominal DECT. Copyright © 2017 Elsevier B.V. All rights reserved.

Evaluation of low-dose dual energy computed tomography for in vivo assessment of renal/ureteric calculus composition

PubMed Central

Mahalingam, Harshavardhan; Mandal, Arup K; Singh, Shrawan Kumar; Bhattacharyya, Shalmoli; Khandelwal, Niranjan

2015-01-01

Purpose This study aimed to assess the accuracy of low-dose dual-energy computed tomography (DECT) in predicting the composition of urinary calculi. Materials and Methods A total of 52 patients with urinary calculi were scanned with a 128-slice dual-source DECT scanner by use of a low-dose protocol. Dual-energy (DE) ratio, weighted average Hounsfield unit (HU) of calculi, radiation dose, and image noise levels were recorded. Two radiologists independently rated study quality. Stone composition was assessed after extraction by Fourier transform infrared spectroscopy (FTIRS). Analysis of variance was used to determine if the differences in HU values and DE ratios between the various calculus groups were significant. Threshold cutoff values to classify the calculi into separate groups were identified by receiver operating characteristic curve analysis. Results A total of 137 calculi were detected. FTIRS analysis differentiated the calculi into five groups: uric acid (n=17), struvite (n=3), calcium oxalate monohydrate and dihydrate (COM-COD, n=84), calcium oxalate monohydrate (COM, n=28), and carbonate apatite (n=5). The HU value could differentiate only uric acid calculi from calcified calculi (p<0.001). The DE ratio could confidently differentiate uric acid, struvite, calcium oxalate, and carbonate apatite calculi (p<0.001) with cutoff values of 1.12, 1.34, and 1.66, respectively, giving >80% sensitivity and specificity to differentiate them. The DE ratio could not differentiate COM from COM-COD calculi. No study was rated poor in quality by either of the observers. The mean radiation dose was 1.8 mSv. Conclusions Low-dose DECT accurately predicts urinary calculus composition in vivo while simultaneously reducing radiation exposure without compromising study quality. PMID:26279828

Effect of a Noise-Optimized Second-Generation Monoenergetic Algorithm on Image Noise and Conspicuity of Hypervascular Liver Tumors: An In Vitro and In Vivo Study.

PubMed

Marin, Daniele; Ramirez-Giraldo, Juan Carlos; Gupta, Sonia; Fu, Wanyi; Stinnett, Sandra S; Mileto, Achille; Bellini, Davide; Patel, Bhavik; Samei, Ehsan; Nelson, Rendon C

2016-06-01

The purpose of this study is to investigate whether the reduction in noise using a second-generation monoenergetic algorithm can improve the conspicuity of hypervascular liver tumors on dual-energy CT (DECT) images of the liver. An anthropomorphic liver phantom in three body sizes and iodine-containing inserts simulating hypervascular lesions was imaged with DECT and single-energy CT at various energy levels (80-140 kV). In addition, a retrospective clinical study was performed in 31 patients with 66 hypervascular liver tumors who underwent DECT during the late hepatic arterial phase. Datasets at energy levels ranging from 40 to 80 keV were reconstructed using first- and second-generation monoenergetic algorithms. Noise, tumor-to-liver contrast-to-noise ratio (CNR), and CNR with a noise constraint (CNRNC) set with a maximum noise increase of 50% were calculated and compared among the different reconstructed datasets. The maximum CNR for the second-generation monoenergetic algorithm, which was attained at 40 keV in both phantom and clinical datasets, was statistically significantly higher than the maximum CNR for the first-generation monoenergetic algorithm (p < 0.001) or single-energy CT acquisitions across a wide range of kilovoltage values. With the second-generation monoenergetic algorithm, the optimal CNRNC occurred at 55 keV, corresponding to lower energy levels compared with first-generation algorithm (predominantly at 70 keV). Patient body size did not substantially affect the selection of the optimal energy level to attain maximal CNR and CNRNC using the second-generation monoenergetic algorithm. A noise-optimized second-generation monoenergetic algorithm significantly improves the conspicuity of hypervascular liver tumors.

Metal artefact reduction in gemstone spectral imaging dual-energy CT with and without metal artefact reduction software.

PubMed

Lee, Young Han; Park, Kwan Kyu; Song, Ho-Taek; Kim, Sungjun; Suh, Jin-Suck

2012-06-01

To assess the usefulness of gemstone spectral imaging (GSI) dual-energy CT (DECT) with/without metal artefact reduction software (MARs). The DECTs were performed using fast kV-switching GSI between 80 and 140 kV. The CT data were retro-reconstructed with/without MARs, by different displayed fields-of-view (DFOV), and with synthesised monochromatic energy in the range 40-140 keV. A phantom study of size and CT numbers was performed in a titanium plate and a stainless steel plate. A clinical study was performed in 26 patients with metallic hardware. All images were retrospectively reviewed in terms of the visualisation of periprosthetic regions and the severity of beam-hardening artefacts by using a five-point scale. The GSI-MARs reconstruction can markedly reduce the metal-related artefacts, and the image quality was affected by the prosthesis composition and DFOV. The spectral CT numbers of the prosthesis and periprosthetic regions showed different patterns on stainless steel and titanium plates. Dual-energy CT with GSI-MARs can reduce metal-related artefacts and improve the delineation of the prosthesis and periprosthetic region. We should be cautious when using GSI-MARs because the image quality was affected by the prosthesis composition, energy (in keV) and DFOV. The metallic composition and size should be considered in metallic imaging with GSI-MARs reconstruction. • Metal-related artefacts can be troublesome on musculoskeletal computed tomography (CT). • Gemstone spectral imaging (GSI) with dual-energy CT (DECT) offers a novel solution • GSI and metallic artefact reduction software (GSI-MAR) can markedly reduce these artefacts. • However image quality is influenced by the prosthesis composition and other parameters. • We should be aware about potential overcorrection when using GSI-MARs.

Influence of Telecommunication Modality, Internet Transmission Quality, and Accessories on Speech Perception in Cochlear Implant Users.

PubMed

Mantokoudis, Georgios; Koller, Roger; Guignard, Jérémie; Caversaccio, Marco; Kompis, Martin; Senn, Pascal

2017-04-24

Telecommunication is limited or even impossible for more than one-thirds of all cochlear implant (CI) users. We sought therefore to study the impact of voice quality on speech perception with voice over Internet protocol (VoIP) under real and adverse network conditions. Telephone speech perception was assessed in 19 CI users (15-69 years, average 42 years), using the German HSM (Hochmair-Schulz-Moser) sentence test comparing Skype and conventional telephone (public switched telephone networks, PSTN) transmission using a personal computer (PC) and a digital enhanced cordless telecommunications (DECT) telephone dual device. Five different Internet transmission quality modes and four accessories (PC speakers, headphones, 3.5 mm jack audio cable, and induction loop) were compared. As a secondary outcome, the subjective perceived voice quality was assessed using the mean opinion score (MOS). Speech telephone perception was significantly better (median 91.6%, P<.001) with Skype compared with PSTN (median 42.5%) under optimal conditions. Skype calls under adverse network conditions (data packet loss > 15%) were not superior to conventional telephony. In addition, there were no significant differences between the tested accessories (P>.05) using a PC. Coupling a Skype DECT phone device with an audio cable to the CI, however, resulted in higher speech perception (median 65%) and subjective MOS scores (3.2) than using PSTN (median 7.5%, P<.001). Skype calls significantly improve speech perception for CI users compared with conventional telephony under real network conditions. Listening accessories do not further improve listening experience. Current Skype DECT telephone devices do not fully offer technical advantages in voice quality. ©Georgios Mantokoudis, Roger Koller, Jérémie Guignard, Marco Caversaccio, Martin Kompis, Pascal Senn. Originally published in the Journal of Medical Internet Research (http://www.jmir.org), 24.04.2017.

Lung perfusion characteristics in pulmonary arterial hypertension (PAH) and peripheral forms of chronic thromboembolic pulmonary hypertension (pCTEPH): Dual-energy CT experience in 31 patients.

PubMed

Giordano, Jessica; Khung, Suonita; Duhamel, Alain; Hossein-Foucher, Claude; Bellèvre, Dimitri; Lamblin, Nicolas; Remy, Jacques; Remy-Jardin, Martine

2017-04-01

To compare lung perfusion in PAH and pCTEPH on dual-energy CT (DECT) examinations. Thirty-one patients with PAH (group 1; n = 19) and pCTEPH (group 2; n = 12) underwent a dual-energy chest CTA with reconstruction of diagnostic and perfusion images. Perfusion alterations were analysed at a segmental level. V/Q scintigraphy was available in 22 patients (group 1: 13/19; group 2: 9/12). CT perfusion was abnormal in 52.6 % of group 1 patients and in 100 % of group 2 patients (p = 0.0051). The patterns of perfusion alteration significantly differed between the two groups (p < 0.0001): (1) in group 1, 96.6 % of segments with abnormal perfusion showed patchy defects; (2) in group 2, the most frequent abnormalities consisted of patchy (58.5 %) and PE-type (37.5 %) defects. Paired comparison of CT perfusion and scintigraphy showed concordant findings in 76.9 % of group 1 (10/13) and 100 % of group 2 (9/9) patients, with a predominant or an exclusive patchy pattern in group 1 and a mixed pattern of abnormalities in group 2. Lung perfusion alterations at DECT are less frequent and more homogeneous in PAH than in pCTEPH, with a high level of concordant findings with V/Q scintigraphy. • Depiction of chronic pulmonary embolism exclusively located on peripheral arteries is difficult. • The main differential diagnosis of pCTEPH is PAH. • The pattern of DECT perfusion changes can help differentiate PAH and pCETPH. • In PAH, almost all segments with abnormal perfusion showed patchy defects. • In pCTEPH, patchy and PE-type defects were the most frequent abnormalities.

Immune responses of a wall lizard to whole-body exposure to radiofrequency electromagnetic radiation.

PubMed

Mina, Despoina; Sagonas, Kostas; Fragopoulou, Adamantia F; Pafilis, Panayiotis; Skouroliakou, Aikaterini; Margaritis, Lukas H; Tsitsilonis, Ourania E; Valakos, Efstratios D

2016-01-01

During the last three decades, the number of devices that emit non-ionizing electromagnetic radiation (EMR) at the wireless communication spectrum has rapidly increased and possible effects on living organisms have become a major concern. The purpose of this study was to investigate the effects of radiofrequency EMR emitted by a widely used wireless communication device, namely the Digital Enhanced Communication Telephony (DECT) base, on the immune responses of the Aegean wall lizard (Podarcis erhardii). Adult male lizards were exposed 24 h/day for 8 weeks to 1880-1900 MHz DECT base radiation at average electric field intensity of 3.2 V/m. Immune reactivity was assessed using the phytohemagglutinin (PHA) skin swelling and mixed lymphocyte reaction (MLR) tests. Our results revealed a noticeable suppression (approximately 45%) of inflammatory responses in EMR-exposed lizards compared to sham-exposed animals. T cell-mediated responses were marginally affected. Daily radiofrequency EMR exposure seems to affect, at least partially, the immunocompetence of the Aegean wall lizard.

System-independent characterization of materials using dual-energy computed tomography

DOE PAGES

Azevedo, Stephen G.; Martz, Jr., Harry E.; Aufderheide, III, Maurice B.; ...

2016-02-01

In this study, we present a new decomposition approach for dual-energy computed tomography (DECT) called SIRZ that provides precise and accurate material description, independent of the scanner, over diagnostic energy ranges (30 to 200 keV). System independence is achieved by explicitly including a scanner-specific spectral description in the decomposition method, and a new X-ray-relevant feature space. The feature space consists of electron density, ρ e, and a new effective atomic number, Z e, which is based on published X-ray cross sections. Reference materials are used in conjunction with the system spectral response so that additional beam-hardening correction is not necessary.more » The technique is tested against other methods on DECT data of known specimens scanned by diverse spectra and systems. Uncertainties in accuracy and precision are less than 3% and 2% respectively for the (ρ e, Z e) results compared to prior methods that are inaccurate and imprecise (over 9%).« less

Geographic variation in bacterial communities associated with the red turpentine beetle (Coleoptera: Curculionidae)

Treesearch

Aaron S. Adams; Sandye M. Adams; Cameron R. Currie; Nancy E. Gillette; Kenneth F. Raffa

2010-01-01

Bacterial communities are known to play important roles in insect life histories, yet their consistency or variation across populations is poorly understood. Bacteria associated with the bark beetle Dendroctonus valens LeConte from eight populations, ranging from Wisconsin to Oregon, were evaluated and compared. We used the culture-independent technique of denaturing...

Red turpentine beetle: Innocuous native becomes invasive tree killer in China

Treesearch

Jianghua Sun; Min Lu; Nancy E. Gillette; Michael J. Wingfield

2012-01-01

The red turpentine beetle (RTB), Dendroctonus valens LeConte (Coleoptera: Curculionidae: Scolytinae), is a secondary pest of pines in its native range in North and Central America. Outbreaks and tree mortality attributed to RTB alone are rare in its native range. RTB was introduced into China in the early 1980s and spread rapidly from Shanxi...

Fir Engraver (FIDL)

Treesearch

George T. Ferrell

1986-01-01

The fir engraver, Scolytus ventralis LeConte, belongs to the family of insects called bark beetles, which live between the bark and wood of host trees. A wide-ranging, native beetle, the fir engraver attacks most species of fir in the Western United States. Epidemics can cause severe tree mortality. From 1977 to 1978, for example, the fir engraver killed an estimated 1...

Effects on eastern larch beetle of its natural attractant and synthetic pheromones in Alaska.

Treesearch

Richard A. Werner; Malcom M. Furniss; Thomas. Ward

1981-01-01

Traps baited with Seudenol + a-pinene caught 87 percent more eastern larch beetles, Dendroctonus simplex LeConte, than did tamarack logs infested with females. Male beetles responded to the synthetic attractant in greater numbers than females. Male beetles were not attracted to frontalin, a principal attractant of the closely related Douglas-fir...

Mating success, longevity, and fertility of Diabrotica virgifera virgifera LeConte (Chrysomelidae: Coleoptera) in relation to body size and Cry3Bb1 resistant and susceptible genotypes

USDA-ARS?s Scientific Manuscript database

Insect resistance to population control methodologies is a widespread problem, with the development of effective resistance management programs often dependent on detailed knowledge regarding the biology of individual species and changes in that biology associated with resistance evolution. This stu...

Isolation of transcripts from Diabrotica virgifera virgifera LeConte responsive to the Bacillus thuringiensis toxin Cry3Bb1

EPA Science Inventory

Crystal proteins derived from Bacillus thuringiensis (Bt) have been widely used as a method of insect pest management for several decades. In recent years, a transgenic corn expressing the Cry3Bb1 toxin has been successfully used for protection against corn rootworm larvae (Genus...

Natural enemies of adelgids in North America: Their prospect for biological control of Adelges tsugae (Homoptera: Adelgidae)

Treesearch

Michael E. Montgomery; Suzanne M. Lyon

1995-01-01

On eastern hemlock, we found two resident beetles preying on Adelges tsugae Annand. One is a coccinellid native to Europe, Scymnus suturalis Thunberg, that also feeds on Pineus sp. that attack pines. The other is a native derodontid beetle, Laricobius rubidus LeConte. The seasonal life history...

Response of maize hybrids with and without rootworm-and drought-tolerance to rootworm infestation under well-watered and drought conditions

USDA-ARS?s Scientific Manuscript database

Anecdotal data have suggested that the effect of the western corn rootworm, Diabrotica virgifera virgifera LeConte, is greater under drought and the effect of drought is greater under rootworm infestations, but few experiments have controlled both moisture and rootworm levels. Field studies were con...

A new artificial diet for western corn rootworm larvae is compatible with and detects resistance to all current Bt toxins

USDA-ARS?s Scientific Manuscript database

Insect resistance to transgenic crops expressing one or more genes from Bacillus thuringiensis Berliner (Bt) is a growing concern for farmers, regulatory agencies, the seed industry, and researchers alike. Western corn rootworm (Diabrotica virgifera virgifera LeConte) is a pest of corn (Zea mays L.)...

Pinyon Needle Scale (FIDL)

Treesearch

William F. McCambridge

1994-01-01

The pinyon needle scale (Matsucoccus acalyptus Herbert) is a native sap-sucking insect found in the Southwest. Feeding by scales weakens trees by killing needles older than 1 year. Sometimes small trees are killed by repeated feeding and large trees weakened to such an extent that they fall victims to attack by the bark beetle Ips confusus (LeConte). Scale infestations...

Acetophenone superior to verbenone for reducing attraction of western pine beetle Dendroctonus brevicomis to its aggregation pheromone

Treesearch

Nadir Erbilgin; Nancy E. Gillette; Donald R. Owen; Sylvia R. Mori; Andrew S. Nelson; Fabian C.C. Uzoh; David L. Wood

2008-01-01

The western pine beetle Dendroctonus brevicomis LeConte (Coleoptera: Scolytidae) is one of the most damaging insect pests of ponderosa pines Pinus ponderosa Douglas ex P. & C. Lawson in Western U.S.A. We compared the effect of verbenone, a well known bark beetle anti-aggregation pheromone, with that...

Susceptibility of Trogoderma granarium Everts and Trogoderma inclusum LeConte (Coleoptera: Dermestidae) to residual contact insecticides

USDA-ARS?s Scientific Manuscript database

Two pyrethroid insecticides were evaluated on concrete arenas for their efficacy against Trogoderma granarium and T. inclusum larvae. Ten larvae of either species were exposed to treated arenas for 1, 2, 3, and 7 d then transferred into 175 ml cups with diet for 30 d to evaluate delayed mortality. I...

Pallidus beetle, Delphastus pallidus LeConte (Insecta: Coleoptera: Coccinellidae), a native predatory beetle of whitefly species in Florida

USDA-ARS?s Scientific Manuscript database

Beetles in the genus Delphastus Casey are small whitefly-specific predatory ladybird beetles belonging to the coccinellid tribe Serangiini. They feed on all immature stages of whitefly and are reared and sold commercially all over the world for this purpose. They are compatible with the application ...

Effect of transgenic corn hybrids and a soil insecticide on corn rootworm (Coleoptera: Chrysomelidae) beetle emergence in North Dakota

USDA-ARS?s Scientific Manuscript database

Northern, Diabrotica barberi Smith & Lawrence, and western corn rootworms, D. virgifera virgifera LeConte, are economic pests of corn, Zea mays L. (Poaceae) in North Dakota. Many area corn growers rely on transgenic Bt (Bacillus thuringiensis) corn hybrids to manage corn rootworms. Our objective was...

Larval mortality and development for rotation-resistant and rotation-susceptible populations of the western corn rootworm on Bt corn

USDA-ARS?s Scientific Manuscript database

The western corn rootworm, Diabrotica virgifera virgifera LeConte, is one of the most economically important insect pests threatening the production of corn, Zea mays (L.), in the United States. Throughout its history, this insect has displayed considerable adaptability by overcoming a variety of pe...

Responses of Dendroctonus brevicomis (Coleoptera: Curculionidae) in behavioral assays: Implications to development of a semiochemical-based tool for tree protection

Treesearch

Christopher J. Fettig; Stephen R. McKelvey; Christopher P. Dabney; Dezene P.W. Huber

2012-01-01

Currently, techniques for managing western pine beetle, Dendroctonus brevicomis LeConte (Coleoptera: Curculionidae, Scolytinae), infestations are limited to tree removals (thinning) that reduce stand density and presumably host susceptibility, and/or the use of insecticides to protect individual trees. There continues to be significant interest in...

Dual energy exposure control (DEEC) for computed tomography: algorithm and simulation study.

PubMed

Stenner, Philip; Kachelriess, Marc

2008-11-01

DECT means acquiring the same object at two different energies, respectively two different tube voltages U1 and U2. The raw data q1 and q2 undergo a decomposition process of type p = p(q1,q2). The raw data p are reconstructed to obtain monochromatic images of the attenuation mu, of the object density rho, or of a specific material distribution. Recent advances in DECT focus on noise reduction techniques [S. Richard and J. H. Siewerdsen, Med. Phys. 35(2), 586-600 (2008)] and enable high performance DECT such as lung nodule detection [Shkumat et al., Med. Phys. 35(2), 629-632 (2008)]. Given p and a raw data-based projection-wise patient dose estimation D(alpha) the authors determine the optimal tube current curves I1(alpha) and I2(alpha), with alpha being the view angle, which minimizes image noise for a given patient dose level. DEEC can perform online; I1(alpha) and I2(alpha) can be determined during the scan. Simulation studies using semianthropomorphic phantom data were carried out. In particular, functions p that generate mu-images and density images were evaluated. Image quality was compared to standard scans at U0=120 kV (clinical CT) and U0=45 kV (micro-CT) that were taken at the same dose level (D0=D1 + D2) and identical spatial resolution. Appropriate choice of p(q1, q2) allows to obtain mu-images that show fewer artifacts and yield image noise levels comparable to the noise of the standard scan. The authors compared the standard scan to mu-images at 70 keV, which is the effective energy used in clinical CT, and found optimal results with mu-images at 25 keV for micro-CT. Nonoptimal choice of the decomposition function will, however, significantly increase image noise. In particular mu-images at 511 keV, as needed for PET/CT attenuation correction, exhibit more than twice as much image noise as the standard scan. With DEEC, which guarantees best dose usage possible, monochromatic images are generated with only slightly increased noise levels at the same dose compared to a standard scan. The benefit of significantly decreased artifacts appears to allow using DEEC-generated monochromatic images in daily routine. Furthermore, DEEC is not restricted to DECT and the inherent tube current modulation algorithm may also be applied to single energy CT.

Dual energy exposure control (DEEC) for computed tomography: Algorithm and simulation study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stenner, Philip; Kachelriess, Marc

2008-11-15

DECT means acquiring the same object at two different energies, respectively two different tube voltages U{sub 1} and U{sub 2}. The raw data q{sub 1} and q{sub 2} undergo a decomposition process of type p=p(q{sub 1},q{sub 2}). The raw data p are reconstructed to obtain monochromatic images of the attenuation {mu}, of the object density {rho}, or of a specific material distribution. Recent advances in DECT focus on noise reduction techniques [S. Richard and J. H. Siewerdsen, Med. Phys. 35(2), 586-600 (2008)] and enable high performance DECT such as lung nodule detection [Shkumat et al., Med. Phys. 35(2), 629-632 (2008)].more » Given p and a raw data-based projection-wise patient dose estimation D({alpha}) the authors determine the optimal tube current curves I{sub 1}({alpha}) and I{sub 2}({alpha}), with {alpha} being the view angle, which minimizes image noise for a given patient dose level. DEEC can perform online; I{sub 1}({alpha}) and I{sub 2}({alpha}) can be determined during the scan. Simulation studies using semianthropomorphic phantom data were carried out. In particular, functions p that generate {mu}-images and density images were evaluated. Image quality was compared to standard scans at U{sub 0}=120 kV (clinical CT) and U{sub 0}=45 kV (micro-CT) that were taken at the same dose level (D{sub 0}=D{sub 1}+D{sub 2}) and identical spatial resolution. Appropriate choice of p(q{sub 1},q{sub 2}) allows to obtain {mu}-images that show fewer artifacts and yield image noise levels comparable to the noise of the standard scan. The authors compared the standard scan to {mu}-images at 70 keV, which is the effective energy used in clinical CT, and found optimal results with {mu}-images at 25 keV for micro-CT. Nonoptimal choice of the decomposition function will, however, significantly increase image noise. In particular {mu}-images at 511 keV, as needed for PET/CT attenuation correction, exhibit more than twice as much image noise as the standard scan. With DEEC, which guarantees best dose usage possible, monochromatic images are generated with only slightly increased noise levels at the same dose compared to a standard scan. The benefit of significantly decreased artifacts appears to allow using DEEC-generated monochromatic images in daily routine. Furthermore, DEEC is not restricted to DECT and the inherent tube current modulation algorithm may also be applied to single energy CT.« less

Collection of an adult gizzard shad (Dorosoma cepedianum) from the San Juan River, Utah

USGS Publications Warehouse

Mueller, G.A.; Brooks, J.L.

2004-01-01

We collected an adult gizzard shad (Dorosoma cepedianum) from the San Juan River just upstream of Lake Powell, Utah, on 6 June 2000. This represents the first documented occurrence of the species in the Colorado River or its tributaries. The adult male (35 cm TL, 470 g) was taken by trammel net from a small (0.5 ha), shallow (<2 m) backwater along with several other fish that included 3 endangered razorback sucker (Xyrauchen texanus). The specimen is stored at the Museum of Southwestern Biology, University of New Mexico, Albuquerque (curation number 49122).

Optimization of dual-energy xenon-computed tomography for quantitative assessment of regional pulmonary ventilation.

PubMed

Fuld, Matthew K; Halaweish, Ahmed F; Newell, John D; Krauss, Bernhard; Hoffman, Eric A

2013-09-01

Dual-energy x-ray computed tomography (DECT) offers visualization of the airways and quantitation of regional pulmonary ventilation using a single breath of inhaled xenon gas. In this study, we sought to optimize scanning protocols for DECT xenon gas ventilation imaging of the airways and lung parenchyma and to characterize the quantitative nature of the developed protocols through a series of test-object and animal studies. The Institutional Animal Care and Use Committee approved all animal studies reported here. A range of xenon/oxygen gas mixtures (0%, 20%, 25%, 33%, 50%, 66%, 100%; balance oxygen) were scanned in syringes and balloon test-objects to optimize the delivered gas mixture for assessment of regional ventilation while allowing for the development of improved 3-material decomposition calibration parameters. In addition, to alleviate gravitational effects on xenon gas distribution, we replaced a portion of the oxygen in the xenon/oxygen gas mixture with helium and compared gas distributions in a rapid-prototyped human central-airway test-object. Additional syringe tests were performed to determine if the introduction of helium had any effect on xenon quantitation. Xenon gas mixtures were delivered to anesthetized swine to assess airway and lung parenchymal opacification while evaluating various DECT scan acquisition settings. Attenuation curves for xenon were obtained from the syringe test-objects and were used to develop improved 3-material decomposition parameters (Hounsfield unit enhancement per percentage xenon: within the chest phantom, 2.25 at 80 kVp, 1.7 at 100 kVp, and 0.76 at 140 kVp with tin filtration; in open air, 2.5 at 80 kVp, 1.95 at 100 kVp, and 0.81 at 140 kVp with tin filtration). The addition of helium improved the distribution of xenon gas to the gravitationally nondependent portion of the airway tree test-object, while not affecting the quantitation of xenon in the 3-material decomposition DECT. The mixture 40% Xe/40% He/20% O2 provided good signal-to-noise ratio (SNR), greater than the Rose criterion (SNR > 5), while avoiding gravitational effects of similar concentrations of xenon in a 60% O2 mixture. Compared with 100/140 Sn kVp, 80/140 Sn kVp (Sn = tin filtered) provided improved SNR in a swine with an equivalent thoracic transverse density to a human subject with a body mass index of 33 kg/m. Airways were brighter in the 80/140 Sn kVp scan (80/140 Sn, 31.6%; 100/140 Sn, 25.1%) with considerably lower noise (80/140 Sn, coefficient of variation of 0.140; 100/140 Sn, coefficient of variation of 0.216). To provide a truly quantitative measure of regional lung function with xenon-DECT, the basic protocols and parameter calibrations need to be better understood and quantified. It is critically important to understand the fundamentals of new techniques to allow for proper implementation and interpretation of their results before widespread usage. With the use of an in-house derived xenon calibration curve for 3-material decomposition rather than the scanner supplied calibration and a xenon/helium/oxygen mixture, we demonstrate highly accurate quantitation of xenon gas volumes and avoid gravitational effects on gas distribution. This study provides a foundation for other researchers to use and test these methods with the goal of clinical translation.

Optimization of Dual-Energy Xenon-CT for Quantitative Assessment of Regional Pulmonary Ventilation

PubMed Central

Fuld, Matthew K.; Halaweish, Ahmed; Newell, John D.; Krauss, Bernhard; Hoffman, Eric A.

2013-01-01

Objective Dual-energy X-ray computed tomography (DECT) offers visualization of the airways and quantitation of regional pulmonary ventilation using a single breath of inhaled xenon gas. In this study we seek to optimize scanning protocols for DECT xenon gas ventilation imaging of the airways and lung parenchyma and to characterize the quantitative nature of the developed protocols through a series of test-object and animal studies. Materials and Methods The Institutional Animal Care and Use Committee approved all animal studies reported here. A range of xenon-oxygen gas mixtures (0, 20, 25, 33, 50, 66, 100%; balance oxygen) were scanned in syringes and balloon test-objects to optimize the delivered gas mixture for assessment of regional ventilation while allowing for the development of improved three-material decomposition calibration parameters. Additionally, to alleviate gravitational effects on xenon gas distribution, we replaced a portion of the oxygen in the xenon/oxygen gas mixture with helium and compared gas distributions in a rapid-prototyped human central-airway test-object. Additional syringe tests were performed to determine if the introduction of helium had any effect on xenon quantitation. Xenon gas mixtures were delivered to anesthetized swine in order to assess airway and lung parenchymal opacification while evaluating various DECT scan acquisition settings. Results Attenuation curves for xenon were obtained from the syringe test objects and were used to develop improved three-material decomposition parameters (HU enhancement per percent xenon: Within the chest phantom: 2.25 at 80kVp, 1.7 at 100 kVp, and 0.76 at 140 kVp with tin filtration; In open air: 2.5 at 80kVp, 1.95 at 100 kVp, and 0.81 at 140 kVp with tin filtration). The addition of helium improved the distribution of xenon gas to the gravitationally non-dependent portion of the airway tree test-object, while not affecting quantitation of xenon in the three-material decomposition DECT. 40%Xe/40%He/20%O2 provided good signal-to-noise, greater than the Rose Criterion (SNR > 5), while avoiding gravitational effects of similar concentrations of xenon in a 60%O2 mixture. 80/140-kVp (tin-filtered) provided improved SNR compared with 100/140-kVp in a swine with an equivalent thoracic transverse density to a human subject with body mass index of 33. Airways were brighter in the 80/140 kVp scan (80/140Sn, 31.6%; 100/140Sn, 25.1%) with considerably lower noise (80/140Sn, CV of 0.140; 100/140Sn, CV of 0.216). Conclusion In order to provide a truly quantitative measure of regional lung function with xenon-DECT, the basic protocols and parameter calibrations needed to be better understood and quantified. It is critically important to understand the fundamentals of new techniques in order to allow for proper implementation and interpretation of their results prior to wide spread usage. With the use of an in house derived xenon calibration curve for three-material decomposition rather than the scanner supplied calibration and a xenon/helium/oxygen mixture we demonstrate highly accurate quantitation of xenon gas volumes and avoid gravitational effects on gas distribution. This study provides a foundation for other researchers to use and test these methods with the goal of clinical translation. PMID:23571834

Minnesota field population of western corn rootworm (Coleoptera: Chrysomelidae) shows incomplete resistance to Cry34Ab1/Cry35Ab1 and Cry3Bb1

USDA-ARS?s Scientific Manuscript database

The western corn rootworm, Diabrotica virgifera virgifera LeConte, is commonly managed with corn (Zea mays L.) expressing insecticidal proteins from the bacteria Bacillus thuringiensis (Bt). Under laboratory conditions, populations of western corn rootworm have been selected for resistance to each c...

Dose-Dependent Pheromone Responses of Ips pini, Orthotomicus latiden (Coleoptera: Scolytidae), and associates in stands of lodgepole pine

Treesearch

Daniel R. Miller; John H. Borden; B. Staffan Lidgren

2005-01-01

We conducted four behavioral choice tests in stands of mature lodgepole pine in British Columbia, from 1988 to 1991, to determine the dose-dependent responses of Orthotomicus latidens (LeConte) and Ips pini (Say) to their respective pheromones. Dose-dependent responses were exhibited by I. pini to (±)-ipsdienol and lanierone, with...

Bugs in the system: development of tools to minimize ponderosa pine losses from western pine beetle infestations

Treesearch

Christopher J. Fettig

2005-01-01

The western pine beetle, Dendroctonus brevicomis LeConte, is a major cause of ponderosa pine, Pinus ponderosa Dougl. Ex Laws., mortality in the western USA and particularly in California. Under certain conditions, the beetle can aggressively attack and kill apparently healthy trees of all ages and size classes. The average loss is...

Efficacy of “Verbenone Plus” for protecting ponderosa pine trees and stands from Dendroctonus brevicomis (Coleoptera: Curculionidae) attack in British Columbia and California

Treesearch

Christopher J. Fettig; Stephen R. McKelvey; Christopher P. Dabney; Dezene P.W. Huber; Cameron C. Lait; Donald L Fowler; John H. Borden

2012-01-01

The western pine beetle, Dendroctonus brevicomis LeConte (Coleoptera: Curculionidae, Scolytinae), is a major cause of ponderosa pine, Pinus ponderosa Douglas ex Lawson, mortality in much of western North America. We review several years of research that led to the identification of Verbenone Plus, a novel four-component...

Chemosterilants to control bark beetles...tepa shows promise in preliminary test

Treesearch

Robert L. Lyon; Patrick J. Shea

1967-01-01

In a preliminary study, two chemosterilants-tepa and hempa-were tested for their effects on the fertility of adult bark beetles (Ips confusus [LeConte). Hempa was Ineffective. Tepa proved 97 percent effective in reducing egg hatch, when applied at 10 µg./10 mg. body weight to both parents. The possibility of using a chemosterilant and the...

Neonate larvae of the specialist herbivore Diabrotica virgifera virgifera do not exploit the defensive volatile (E)-ß-caryophyllene in locating maize roots

USDA-ARS?s Scientific Manuscript database

The behavior of the neonate larvae of Diabrotica virgifera virgifera LeConte (western corn rootworm, WCR) was assessed in presence of maize root constitutively emitting (E)-ß-caryophylene (EßC). This root volatile has been shown to attract both second instar WCR and insect-killing nematodes, offerin...

Evidence of field-evolved resistance to bifenthrin in western corn rootworm (Diabrotica virgifera virgifera LeConte) populations in western Nebraska and Kansas

USDA-ARS?s Scientific Manuscript database

Pyrethroid insecticides are widely used to control larvae or adult western corn rootworm, a key pest of corn in the United States. In response to reports of reduced efficacy of pyrethroids in WCR management programs in southwestern areas of Nebraska and Kansas the present research was designed to es...

Development and characterization of MIR604 resistance in a western corn rootworm population (Coleoptera: Chrysomelidae)

USDA-ARS?s Scientific Manuscript database

mCry3A is one of only four proteins licensed for commercial use in Diabrotica control. Utilizing a colony of western corn rootworm, Diabrotica virgifera virgifera LeConte, selected for resistance to mCry3A, we evaluated how mCry3A resistance was inherited and whether fitness costs were associated wi...

Acetophenone as an anti-attractant for the western pine beetle, Dendroctonus brevicomis LeConte (Coleoptera: Scolytidae)

Treesearch

N. Erbilgin; N.E. Gillette; S.R. Mori; J.D Stein; D.R. Owen; D.L. Wood

2007-01-01

Abstract Host location and colonization by bark beetles is dependent upon the relative and absolute amounts of attractant and antiattractant compounds available. Many investigations have lead to use of antiattractants for the management of these pests and have been especially focused on verbenone. However, recent studies have identified new antiattractants for several...

Green leaf volatiles disrupt responses by the spruce beetle, Dendroctonus rufipennis, and the western pine beetle, Dendroctonus brevicomis (Coleoptera: Scolytidae) to attractant-baited traps

Treesearch

Therese M. Poland; J. H. Borden; A. J. Stock; L. J. Chong

1998-01-01

We tested the hypothesis that green leaf volatiles (GLVs) disrupt the response of spruce beetles, Dendroctonus rufipennis Kirby, and western pine beetles, Dendroctonus brevicomis LeConte, to attraetant-baited traps. Two green leaf aldehydes, hexanal and (E)-2-hexenal, reduced the number of spruce beetles captured...

Further contributions to the Coleoptera fauna of New Brunswick with an addition to the fauna of Nova Scotia, Canada

PubMed Central

Webster, Reginald P.; Webster, Vincent L.; Alderson, Chantelle A.; Hughes, Cory C.; Sweeney, Jon D.

2016-01-01

Abstract This paper treats 134 new records of Coleoptera for the province of New Brunswick, Canada from the following 41 families: Gyrinidae, Carabidae, Dytiscidae, Histeridae, Leiodidae, Scarabaeidae, Scirtidae, Buprestidae, Elmidae, Limnichidae, Heteroceridae, Ptilodactylidae, Eucnemidae, Throscidae, Elateridae, Lampyridae, Cantharidae, Dermestidae, Bostrichidae, Ptinidae, Cleridae, Melyridae, Monotomidae, Cryptophagidae, Silvanidae, Laemophloeidae, Nitidulidae, Endomychidae, Coccinellidae, Corylophidae, Latridiidae, Tetratomidae, Melandryidae, Mordellidae, Tenebrionidae, Mycteridae, Pyrochroidae, Aderidae, Scraptiidae, Megalopodidae, and Chrysomelidae. Among these, the following four species are newly recorded from Canada: Dirrhagofarsus ernae Otto, Muona & McClarin (Eucnemidae), Athous equestris (LeConte) (Elateridae), Ernobius opicus Fall (Ptinidae), and Stelidota coenosa Erichson (Nitidulidae). The Family Limnichidae is newly reported for New Brunswick, and one species is added to the fauna of Nova Scotia. Stephostethus productus Rosenhauer (Latridiidae), Tetratoma (Abstrulia) variegata Casey (Tetratomidae), and Chauliognathus marginatus (Fabricius) (Cantharidae) are removed from the faunal list of New Brunswick, and additional records of Lacconotus punctatus LeConte (Mycteridae) are presented and discussed. Lindgren funnel traps provided specimens for 104 (78%) of the species and were the sole source of specimens for 89 (66%) of the species reported here, suggesting they are a very useful tool for sampling Coleoptera fauna in the forests of New Brunswick. PMID:27110171

New Staphylinidae (Coleoptera) records with new collection data from New Brunswick, Canada: Pselaphinae

PubMed Central

Webster, Reginald P.; Chandler, Donald S.; Sweeney, Jon D.; DeMerchant, Ian

2012-01-01

Abstract Twenty species of Pselaphinae are newly recorded from New Brunswick, Canada. This brings the total number of species known from the province to 36. Thirteen of these species are newly recorded for the Maritime provinces of Canada. Dalmosella tenuis Casey and Brachygluta luniger (LeConte) are newly recorded for Canada. Collection and habitat data are presented for these species. PMID:22577317

The response of Dendroctonus valens (Coleoptera: Scolytidae) and Temnochila chlorodia (Coleoptera: Trogossitidae) to Ips paraconfusus (Coleoptera: Scolytidae) pheromone components and verbenone

Treesearch

Christopher J. Fettig; Stepehen R. McKelvey; Christopher P. Dabney; Robert R. Borys

2007-01-01

The red turpentine beetle, Dendroctonus valens LeConte, 1860 (Coleoptera: Curculionidae, Scolytinae), is a common bark beetle species found throughout much of North America and China. In 2004, we observed that California fivespined ips, Ips paraconfusus Lanier, 1970 (Coleoptera: Curculionidae, Scolytinae), attack densities in logging debris were inversely related to D...

The current status of the distribution range of the western pine beetle, Dendroctonus brevicomis (Curculionidae: Solytinae) in northern Mexico

Treesearch

O. Valerio-Mendoza; F. Armendariz-Toledano; G. Cuellar-Rodriguez; Jose F. Negron; G. Zuniga

2017-01-01

The distribution range of the western pine beetle Dendroctonus brevicomis LeConte (Coleoptera: Curculionidae) is supported only by scattered records in the northern parts of Mexico, suggesting that its populations may be marginal and rare in this region. In this study, we review the geographical distribution of D. brevicomis in northern Mexico and perform a geometric...

Quantitative trait loci mapping of western corn rootworm (Coleoptera: Chrysomelidae) host plant resistance in two populations of doubled haploid lines in maize (Zea mays L.)

USDA-ARS?s Scientific Manuscript database

Over the last 70 years, more than 12,000 maize accessions have been screened for their level of resistance to western corn rootworm, Diabrotica virgifera virgifera LeConte, larval feeding. Less than 1% of this germplasm was selected for initiating recurrent selection or other breeding programs. Sele...

Evidence of resistance to Cry34/35Ab1 corn by western corn rootworm: root injury in the field and larval survival in plant-based bioassays

USDA-ARS?s Scientific Manuscript database

Western corn rootworm, Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae), is a serious pest of corn in the United States and recent management of western corn rootworm has included planting of Bt corn. Beginning in 2009, western corn rootworm populations with resistance to Cry3Bb1 c...

Virtual monochromatic imaging in dual-source and dual-energy CT for visualization of acute ischemic stroke

NASA Astrophysics Data System (ADS)

Hara, Hidetake; Muraishi, Hiroshi; Matsuzawa, Hiroki; Inoue, Toshiyuki; Nakajima, Yasuo; Satoh, Hitoshi; Abe, Shinji

2015-07-01

We have recently developed a phantom that simulates acute ischemic stroke. We attempted to visualize an acute-stage cerebral infarction by using dual-energy Computed tomography (DECT) to obtain virtual monochromatic images of this phantom. Virtual monochromatic images were created by using DECT voltages from 40 to 100 keV in steps of 10 keV and from 60 to 80 keV in steps of 1 keV, under three conditions of the tube voltage with thin (Sn) filters. Calculation of the CNR values allowed us to evaluate the visualization of acute-stage cerebral infarction. The CNR value of a virtual monochromatic image was the highest at 68 keV under 80 kV / Sn 140 kV, at 72 keV under 100 kV / Sn 140 kV, and at 67 keV under 140 kV / 80 kV. The CNR values of virtual monochromatic images at voltages between 65 and 75 keV were significantly higher than those obtained for all other created images. Therefore, the optimal conditions for visualizing acute ischemic stroke were achievable.

TU-AB-BRC-03: Accurate Tissue Characterization for Monte Carlo Dose Calculation Using Dual-and Multi-Energy CT Data

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lalonde, A; Bouchard, H

Purpose: To develop a general method for human tissue characterization with dual-and multi-energy CT and evaluate its performance in determining elemental compositions and the associated proton stopping power relative to water (SPR) and photon mass absorption coefficients (EAC). Methods: Principal component analysis is used to extract an optimal basis of virtual materials from a reference dataset of tissues. These principal components (PC) are used to perform two-material decomposition using simulated DECT data. The elemental mass fraction and the electron density in each tissue is retrieved by measuring the fraction of each PC. A stoichiometric calibration method is adapted to themore » technique to make it suitable for clinical use. The present approach is compared with two others: parametrization and three-material decomposition using the water-lipid-protein (WLP) triplet. Results: Monte Carlo simulations using TOPAS for four reference tissues shows that characterizing them with only two PC is enough to get a submillimetric precision on proton range prediction. Based on the simulated DECT data of 43 references tissues, the proposed method is in agreement with theoretical values of protons SPR and low-kV EAC with a RMS error of 0.11% and 0.35%, respectively. In comparison, parametrization and WLP respectively yield RMS errors of 0.13% and 0.29% on SPR, and 2.72% and 2.19% on EAC. Furthermore, the proposed approach shows potential applications for spectral CT. Using five PC and five energy bins reduces the SPR RMS error to 0.03%. Conclusion: The proposed method shows good performance in determining elemental compositions from DECT data and physical quantities relevant to radiotherapy dose calculation and generally shows better accuracy and unbiased results compared to reference methods. The proposed method is particularly suitable for Monte Carlo calculations and shows promise in using more than two energies to characterize human tissue with CT.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Niu, T; Dong, X; Petrongolo, M

Purpose: Dual energy CT (DECT) imaging plays an important role in advanced imaging applications due to its material decomposition capability. Direct decomposition via matrix inversion suffers from significant degradation of image signal-to-noise ratios, which reduces clinical value. Existing de-noising algorithms achieve suboptimal performance since they suppress image noise either before or after the decomposition and do not fully explore the noise statistical properties of the decomposition process. We propose an iterative image-domain decomposition method for noise suppression in DECT, using the full variance-covariance matrix of the decomposed images. Methods: The proposed algorithm is formulated in the form of least-square estimationmore » with smoothness regularization. It includes the inverse of the estimated variance-covariance matrix of the decomposed images as the penalty weight in the least-square term. Performance is evaluated using an evaluation phantom (Catphan 600) and an anthropomorphic head phantom. Results are compared to those generated using direct matrix inversion with no noise suppression, a de-noising method applied on the decomposed images, and an existing algorithm with similar formulation but with an edge-preserving regularization term. Results: On the Catphan phantom, our method retains the same spatial resolution as the CT images before decomposition while reducing the noise standard deviation of decomposed images by over 98%. The other methods either degrade spatial resolution or achieve less low-contrast detectability. Also, our method yields lower electron density measurement error than direct matrix inversion and reduces error variation by over 97%. On the head phantom, it reduces the noise standard deviation of decomposed images by over 97% without blurring the sinus structures. Conclusion: We propose an iterative image-domain decomposition method for DECT. The method combines noise suppression and material decomposition into an iterative process and achieves both goals simultaneously. The proposed algorithm shows superior performance on noise suppression with high image spatial resolution and low-contrast detectability. This work is supported by a Varian MRA grant.« less

Accuracy of iodine quantification using dual energy CT in latest generation dual source and dual layer CT.

PubMed

Pelgrim, Gert Jan; van Hamersvelt, Robbert W; Willemink, Martin J; Schmidt, Bernhard T; Flohr, Thomas; Schilham, Arnold; Milles, Julien; Oudkerk, Matthijs; Leiner, Tim; Vliegenthart, Rozemarijn

2017-09-01

To determine the accuracy of iodine quantification with dual energy computed tomography (DECT) in two high-end CT systems with different spectral imaging techniques. Five tubes with different iodine concentrations (0, 5, 10, 15, 20 mg/ml) were analysed in an anthropomorphic thoracic phantom. Adding two phantom rings simulated increased patient size. For third-generation dual source CT (DSCT), tube voltage combinations of 150Sn and 70, 80, 90, 100 kVp were analysed. For dual layer CT (DLCT), 120 and 140 kVp were used. Scans were repeated three times. Median normalized values and interquartile ranges (IQRs) were calculated for all kVp settings and phantom sizes. Correlation between measured and known iodine concentrations was excellent for both systems (R = 0.999-1.000, p < 0.0001). For DSCT, median measurement errors ranged from -0.5% (IQR -2.0, 2.0%) at 150Sn/70 kVp and -2.3% (IQR -4.0, -0.1%) at 150Sn/80 kVp to -4.0% (IQR -6.0, -2.8%) at 150Sn/90 kVp. For DLCT, median measurement errors ranged from -3.3% (IQR -4.9, -1.5%) at 140 kVp to -4.6% (IQR -6.0, -3.6%) at 120 kVp. Larger phantom sizes increased variability of iodine measurements (p < 0.05). Iodine concentration can be accurately quantified with state-of-the-art DECT systems from two vendors. The lowest absolute errors were found for DSCT using the 150Sn/70 kVp or 150Sn/80 kVp combinations, which was slightly more accurate than 140 kVp in DLCT. • High-end CT scanners allow accurate iodine quantification using different DECT techniques. • Lowest measurement error was found in scans with largest photon energy separation. • Dual-source CT quantified iodine slightly more accurately than dual layer CT.

Dual-energy X-ray micro-CT imaging of hybrid Ni/Al open-cell foam

NASA Astrophysics Data System (ADS)

Fíla, T.; Kumpová, I.; Koudelka, P.; Zlámal, P.; Vavřík, D.; Jiroušek, O.; Jung, A.

2016-01-01

In this paper, we employ dual-energy X-ray microfocus tomography (DECT) measurement to develop high-resolution finite element (FE) models that can be used for the numerical assessment of the deformation behaviour of hybrid Ni/Al foam subjected to both quasi-static and dynamic compressive loading. Cubic samples of hybrid Ni/Al open-cell foam with an edge length of [15]mm were investigated by the DECT measurement. The material was prepared using AlSi7Mg0.3 aluminium foam with a mean pore size of [0.85]mm, coated with nanocrystalline nickel (crystallite size of approx. [50]nm) to form a surface layer with a theoretical thickness of [0.075]mm. CT imaging was carried out using state-of-the-art DSCT/DECT X-ray scanner developed at Centre of Excellence Telč. The device consists of a modular orthogonal assembly of two tube-detector imaging pairs, with an independent geometry setting and shared rotational stage mounted on a complex 16-axis CNC positioning system to enable unprecedented measurement variability for highly-detailed tomographical measurements. A sample of the metal foam was simultaneously irradiated using an XWT-240-SE reflection type X-ray tube and an XWT-160-TCHR transmission type X-ray tube. An enhanced dual-source sampling strategy was used for data acquisition. X-ray images were taken using XRD1622 large area GOS scintillator flat panel detectors with an active area of [410 × 410]mm and resolution [2048 × 2048]pixels. Tomographic scanning was performed in 1,200 projections with a 0.3 degree angular step to improve the accuracy of the generated models due to the very complex microstructure and high attenuation of the investigated material. Reconstructed data was processed using a dual-energy algorithm, and was used for the development of a 3D model and voxel model of the foam. The selected parameters of the models were compared with nominal parameters of the actual foam and showed good correlation.

Methodological accuracy of image-based electron density assessment using dual-energy computed tomography.

PubMed

Möhler, Christian; Wohlfahrt, Patrick; Richter, Christian; Greilich, Steffen

2017-06-01

Electron density is the most important tissue property influencing photon and ion dose distributions in radiotherapy patients. Dual-energy computed tomography (DECT) enables the determination of electron density by combining the information on photon attenuation obtained at two different effective x-ray energy spectra. Most algorithms suggested so far use the CT numbers provided after image reconstruction as input parameters, i.e., are imaged-based. To explore the accuracy that can be achieved with these approaches, we quantify the intrinsic methodological and calibration uncertainty of the seemingly simplest approach. In the studied approach, electron density is calculated with a one-parametric linear superposition ('alpha blending') of the two DECT images, which is shown to be equivalent to an affine relation between the photon attenuation cross sections of the two x-ray energy spectra. We propose to use the latter relation for empirical calibration of the spectrum-dependent blending parameter. For a conclusive assessment of the electron density uncertainty, we chose to isolate the purely methodological uncertainty component from CT-related effects such as noise and beam hardening. Analyzing calculated spectrally weighted attenuation coefficients, we find universal applicability of the investigated approach to arbitrary mixtures of human tissue with an upper limit of the methodological uncertainty component of 0.2%, excluding high-Z elements such as iodine. The proposed calibration procedure is bias-free and straightforward to perform using standard equipment. Testing the calibration on five published data sets, we obtain very small differences in the calibration result in spite of different experimental setups and CT protocols used. Employing a general calibration per scanner type and voltage combination is thus conceivable. Given the high suitability for clinical application of the alpha-blending approach in combination with a very small methodological uncertainty, we conclude that further refinement of image-based DECT-algorithms for electron density assessment is not advisable. © 2017 American Association of Physicists in Medicine.

TU-A-12A-08: Computing Longitudinal Material Changes in Bone Metastases Using Dual Energy Computed Tomography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schmidtlein, CR; Hwang, S; Veeraraghavan, H

Purpose: This study demonstrates a methodology for tracking changes in metastatic bone disease using trajectories in material basis space in serial dual energy computed tomography (DECT) studies. Methods: This study includes patients with bone metastases from breast cancer that had clinical surveillance CT scans using a General Electric CT750HD in dual energy mode. A radiologist defined regions-of-interested (ROI) for bone metastasis, normal bone, and marrow across the serial DECT scans. Our approach employs a Radon transform to forward-projection the basis images, namely, water and iodine, into sinogram space. This data is then repartitioned into fat/bone and effective density/Z image pairsmore » using assumed energy spectrums for the x-ray energies. This approach both helps remove negative material densities and avoids adding spectrum-hardening artifacts. These new basis data sets were then reconstructed via filtered back-projection to create new material basis pair images. The trajectories of these pairs were then plotted in the new basis space providing a means to both visualize and quantitatively measure changes in the material properties of the tumors. Results: ROI containing radiologist defined metastatic bone disease showed well-defined trajectories in both fat/bone and effective density/Z space. ROI that contained radiologist defined normal bone and marrow did not exhibit any discernible trajectories and were stable from scan to scan. Conclusions: The preliminary results show that changes in material composition and effective density/Z image pairs were seen primarily in metastasis and not in normal tissue. This study indicates that by using routine clinical DECT it may be possible to monitor therapy response of bone metastases because healing or worsening bone metastases change material composition of bone. Additional studies are needed to further validate these results and to test for their correlation with outcome.« less

Xenon-Enhanced Dual-Energy CT Imaging in Combined Pulmonary Fibrosis and Emphysema

PubMed Central

Kobayashi, Masahiro; Nakamura, Yasuhiko; Gocho, Kyoko; Ishida, Fumiaki; Isobe, Kazutoshi; Shiraga, Nobuyuki; Homma, Sakae

2017-01-01

Background Little has been reported on the feasibility of xenon-enhanced dual-energy computed tomography (Xe-DECT) in the visual and quantitative analysis of combined pulmonary fibrosis and emphysema (CPFE). Objectives We compared CPFE with idiopathic pulmonary fibrosis (IPF) and chronic obstructive pulmonary disease (COPD), as well as correlation with parameters of pulmonary function tests (PFTs). Methods Studied in 3 groups were 25 patients with CPFE, 25 with IPF without emphysema (IPF alone), 30 with COPD. Xe-DECT of the patients’ entire thorax was taken from apex to base after a patient’s single deep inspiration of 35% stable nonradioactive xenon. The differences in several parameters of PFTs and percentage of areas enhanced by xenon between 3 groups were compared and analyzed retrospectively. Results The percentage of areas enhanced by xenon in both lungs were calculated as CPFE/IPF alone/COPD = 72.2 ± 15.1% / 82.2 ± 14.7% /45.2 ± 23.2%, respectively. In the entire patients, the percentage of areas enhanced by xenon showed significantly a positive correlation with FEV1/FVC (R = 0.558, P < 0.0001) and %FEV1, (R = 0.528, P < 0.0001) and a negative correlation with %RV (R = -0.594, P < 0.0001) and RV/TLC (R = -0.579, P < 0.0001). The percentage of areas enhanced by xenon in patients with CPFE showed significantly a negative correlation with RV/TLC (R = -0.529, P = 0.007). Xenon enhancement of CPFE indicated 3 different patterns such as upper predominant, diffuse, and multifocal defect. The percentage of areas enhanced by xenon in upper predominant defect pattern was significantly higher than that in diffuse defect and multifocal defect pattern among these 3 different patterns in CPFE. Conclusion The percentage of areas enhanced by xenon demonstrated strong correlations with obstructive ventilation impairment. Therefore, we conclude that Xe-DECT may be useful for distinguishing emphysema lesion from fibrotic lesion in CPFE. PMID:28107411

Xenon-Enhanced Dual-Energy CT Imaging in Combined Pulmonary Fibrosis and Emphysema.

PubMed

Sugino, Keishi; Kobayashi, Masahiro; Nakamura, Yasuhiko; Gocho, Kyoko; Ishida, Fumiaki; Isobe, Kazutoshi; Shiraga, Nobuyuki; Homma, Sakae

2017-01-01

Little has been reported on the feasibility of xenon-enhanced dual-energy computed tomography (Xe-DECT) in the visual and quantitative analysis of combined pulmonary fibrosis and emphysema (CPFE). We compared CPFE with idiopathic pulmonary fibrosis (IPF) and chronic obstructive pulmonary disease (COPD), as well as correlation with parameters of pulmonary function tests (PFTs). Studied in 3 groups were 25 patients with CPFE, 25 with IPF without emphysema (IPF alone), 30 with COPD. Xe-DECT of the patients' entire thorax was taken from apex to base after a patient's single deep inspiration of 35% stable nonradioactive xenon. The differences in several parameters of PFTs and percentage of areas enhanced by xenon between 3 groups were compared and analyzed retrospectively. The percentage of areas enhanced by xenon in both lungs were calculated as CPFE/IPF alone/COPD = 72.2 ± 15.1% / 82.2 ± 14.7% /45.2 ± 23.2%, respectively. In the entire patients, the percentage of areas enhanced by xenon showed significantly a positive correlation with FEV1/FVC (R = 0.558, P < 0.0001) and %FEV1, (R = 0.528, P < 0.0001) and a negative correlation with %RV (R = -0.594, P < 0.0001) and RV/TLC (R = -0.579, P < 0.0001). The percentage of areas enhanced by xenon in patients with CPFE showed significantly a negative correlation with RV/TLC (R = -0.529, P = 0.007). Xenon enhancement of CPFE indicated 3 different patterns such as upper predominant, diffuse, and multifocal defect. The percentage of areas enhanced by xenon in upper predominant defect pattern was significantly higher than that in diffuse defect and multifocal defect pattern among these 3 different patterns in CPFE. The percentage of areas enhanced by xenon demonstrated strong correlations with obstructive ventilation impairment. Therefore, we conclude that Xe-DECT may be useful for distinguishing emphysema lesion from fibrotic lesion in CPFE.

ELF exposure from mobile and cordless phones for the epidemiological MOBI-Kids study.

PubMed

Calderón, Carolina; Ichikawa, Hiroki; Taki, Masao; Wake, Kanako; Addison, Darren; Mee, Terry; Maslanyj, Myron; Kromhout, Hans; Lee, Ae-Kyoung; Sim, Malcolm R; Wiart, Joe; Cardis, Elisabeth

2017-04-01

This paper describes measurements and computational modelling carried out in the MOBI-Kids case-control study to assess the extremely low frequency (ELF) exposure of the brain from use of mobile and cordless phones. Four different communication systems were investigated: Global System for Mobile (GSM), Universal Mobile Telecommunications System (UMTS), Digital Enhanced Cordless Telecommunications (DECT) and Wi-Fi Voice over Internet Protocol (VoIP). The magnetic fields produced by the phones during transmission were measured under controlled laboratory conditions, and an equivalent loop was fitted to the data to produce three-dimensional extrapolations of the field. Computational modelling was then used to calculate the induced current density and electric field strength in the brain resulting from exposure to these magnetic fields. Human voxel phantoms of four different ages were used: 8, 11, 14 and adult. The results indicate that the current densities induced in the brain during DECT calls are likely to be an order of magnitude lower than those generated during GSM calls but over twice that during UMTS calls. The average current density during Wi-Fi VoIP calls was found to be lower than for UMTS by 30%, but the variability across the samples investigated was high. Spectral contributions were important to consider in relation to current density, particularly for DECT phones. This study suggests that the spatial distribution of the ELF induced current densities in brain tissues is determined by the physical characteristics of the phone (in particular battery position) while the amplitude is mainly dependent on communication system, thus providing a feasible basis for assessing ELF exposure in the epidemiological study. The number of phantoms was not large enough to provide definitive evidence of an increase of induced current density with age, but the data that are available suggest that, if present, the effect is likely to be very small. Copyright © 2017 Elsevier Ltd. All rights reserved.

Response to host volatiles by native and introduced populations of Dendroctonus valens (Coleoptera: Curculionidae, Scolytinae) in North America and China.  Journal of Chemical Ecology 33: 131-146.

Treesearch

N. Erbilgin; S.R. Mori; J.H. Sun; J.D. Stein; D.R. Owen; L.D. Merrill; R. Campos Bolande; os; K.F. Raffa; T. Mendez Montiel; D.L. Wood; N.E.  Gillette

2007-01-01

Bark beetles (Coleoptera: Curculionidae, Scolytinae) have specialized feeding habits, and commonly colonize only one or a few closely related host genera in their geographical ranges. The red turpentine beetle, Dendroctonus valens LeConte, has a broad geographic distribution in North America and exploits volatile cues from a wide variety of pines...

Fitness Costs Related To Selection for Resistance to the Cry3Bb1 Protein in a Genetically Diverse Population of Non-diapausing Western Corn Rootworm

USDA-ARS?s Scientific Manuscript database

The western corn rootworm (Diabrotica virgifera virgifera LeConte) is an important pest of maize in North America. Since approved for commercial use in 2003, the acreage planted to maize (Zea mays L.) expressing the Bt derived Cry3Bb1 protein has significantly increased each year in the United State...

Verbenone interrupts attraction to host volatiles and reduces attack on Pinus tabuliformis (Pinaceae) by Dendroctonus valens (Coleoptera: Scolytidae) in the People's Republic of China

Treesearch

Jianghua Sun; Nancy Gillette; Zhengwan Miao; Zhongning Zhang Le Kang; Donald R. Owen; John D Stein

2003-01-01

The introduced red turpentine beetle, Dendroctonus valens LeConte, is one of the most economically important forest pests in the People's Republic of China, having killed more than 6 million pines in recent years. There is an urgent need to develop effective behavioral chemicals to monitor and control D. valens in the People...

Relationships among pest flour beetles of the genus Tribolium (Tenebrionidae) inferred from multiple molecular markers

PubMed Central

Angelini, David R.; Jockusch, Elizabeth L.

2008-01-01

Model species often provide initial hypotheses and tools for studies of development, genetics, and molecular evolution in closely related species. Flour beetles of the genus Tribolium MacLeay (1825) are one group with potential for such comparative studies. Tribolium castaneum (Herbst 1797) is an increasingly useful developmental genetic system. The convenience with which congeneric and other species of tenebrionid flour beetles can be reared in the laboratory makes this group attractive for comparative studies on a small phylogenetic scale. Here we present the results of phylogenetic analyses of relationships among the major pest species of Tribolium based on two mitochondrial and three nuclear markers (cytochrome oxidase 1, 16S ribosomal DNA, wingless, 28S ribosomal DNA, histone H3). The utility of partitioning the dataset in a manner informed by biological structure and function is demonstrated by comparing various partitioning strategies. In parsimony and partitioned Bayesian analyses of the combined dataset, the castaneum and confusum species groups are supported as monophyletic and as each other’s closest relatives. However, a sister group relationship between this clade and Tribolium brevicornis (Leconte 1859) is not supported. Therefore, we suggest transferring brevicornis group species to the genus Aphanotus Leconte (1862). The inferred phylogeny provides an evolutionary framework for comparative studies using flour beetles. PMID:18024090

World reclassification of the Cardiophorinae (Coleoptera, Elateridae), based on phylogenetic analyses of morphological characters

PubMed Central

Douglas, Hume B.

2017-01-01

Abstract The prior genus-level classification of Cardiophorinae had never been assessed phylogenetically, and not revised since 1906. A phylogeny for Cardiophorinae and Negastriinae is inferred by Bayesian analyses of 163 adult morphological characters to revise the generic classification. Parsimony analysis is also performed to assess the sensitivity of the Bayesian results to the choice of optimality criterion. Bayesian hypothesis testing rejected monophyly for: Negastriinae; Cardiophorinae (but monophyletic after addition of four taxa); Cardiophorini; cardiophorine genera Aphricus LeConte, 1853; Aptopus Eschscholtz, 1829; Cardiophorus Eschscholtz, 1829; Cardiotarsus Eschscholtz, 1836; Paracardiophorus Schwarz, 1895; Phorocardius Fleutiaux, 1931; Dicronychus sensu Platia, 1994; Dicronychus sensu Méquignon, 1931; Craspedostethus sensu Schwarz, 1906 (i.e., including Tropidiplus Fleutiaux, 1903); Paracardiophorus sensu Cobos, 1970, although well-supported alternative classifications were available for only some. Based on taxonomic interpretation of phylogenetic results: Nyctorini is syn. n. of Cardiophorini; Globothorax Fleutiaux, 1891 (Physodactylinae), Margogastrius Schwarz, 1903 (Physodactylinae), and Pachyelater Lesne, 1897 (Dendrometrinae) are transferred to Cardiophorinae. The following changes are proposed for cardiophorine genera: Aptopus Eschscholtz, 1829 is redefined to exclude Horistonotus-like species; Coptostethus Wollaston, 1854 is subgenus of Cardiophorus; Dicronychus Brullé, 1832 and Diocarphus Fleutiaux, 1947, Metacardiophorus Gurjeva, 1966, Platynychus Motschulsky, 1858, and Zygocardiophorus Iablokoff-Khnzorian and Mardjanian, 1981 are placed at genus rank; Paracardiophorus Schwarz, 1895 is redefined based on North American and Eurasian species only; Horistonotus Candèze, 1860 redefined to include species with multiple apices on each side of their tarsal claws; Patriciella Van Zwaluwenburg, 1953 is syn. n. of Aphricus LeConte, 1853; Teslasena Fleutiaux, 1892 (Physodactylinae) is syn. n. of Globothorax Fleutiaux, 1891. The following new genera are described: Austrocardiophorus (type species: Cardiophorus humeralis Fairmaire and Germain, 1860); Chileaphricus (type species: Aphricus chilensis Fleutiaux, 1940); Floridelater (type species: Coptostethus americanus Horn, 1871, transferred from Negastriinae to Cardiophorinae). Paradicronychus (nomen nudum), is syn. n. of Cardiophorus Eschscholtz, 1829. Generic reassignments to make Cardiodontulus, Cardiophorus, Cardiotarsus, Paracardiophorus consistent with phylogenetically revised genus concepts resulted in 84 new combinations. Lectotypes are designated for 29 type species to fix generic concepts: Anelastes femoralis Lucas, 1857; Aphricus chilensis Fleutiaux, 1940; Athous argentatus Abeille de Perrin, 1894; Cardiophorus adjutor Candèze, 1875; Cardiophorus florentini Fleutiaux, 1895; Cardiophorus inflatus Candèze, 1882; Cardiophorus luridipes Candèze, 1860; Cardiophorus mirabilis Candèze, 1860; Cardiophorus musculus Erichson, 1840; Cardiotarsus capensis Candèze, 1860; Cardiotarsus vitalisi Fleutiaux, 1918; Craspedostethus rufiventris Schwarz, 1898; Elater cinereus Herbst, 1784; Elater minutissimus Germar, 1817; Elater sputator Linnaeus, 1758; Elater thoracicus Fabricius, 1801; Eniconyx pullatus Horn, 1884; Esthesopus castaneus Eschscholtz, 1829; Gastrimargus schneideri Schwarz, 1902; Globothorax chevrolati Fleutiaux, 1891; Horistonotus flavidus Candèze, 1860; Horistonotus simplex LeConte, 1863; Lesnelater madagascariensis Fleutiaux, 1935; Oedostethus femoralis LeConte, 1853; Phorocardius solitarius Fleutiaux, 1931; Platynychus indicus Motschulsky, 1858; Platynychus mixtus Fleutiaux, 1931; Triplonychus acuminatus Candèze, 1860; Tropidiplus tellinii Fleutiaux, 1903. A key to genera and diagnoses are provided for all genera and subgenera. A bibliographic synonymy includes references for all taxonomic changes to genera and new species through 2015. PMID:28331397

World reclassification of the Cardiophorinae (Coleoptera, Elateridae), based on phylogenetic analyses of morphological characters.

PubMed

Douglas, Hume B

2017-01-01

The prior genus-level classification of Cardiophorinae had never been assessed phylogenetically, and not revised since 1906. A phylogeny for Cardiophorinae and Negastriinae is inferred by Bayesian analyses of 163 adult morphological characters to revise the generic classification. Parsimony analysis is also performed to assess the sensitivity of the Bayesian results to the choice of optimality criterion. Bayesian hypothesis testing rejected monophyly for: Negastriinae; Cardiophorinae (but monophyletic after addition of four taxa); Cardiophorini; cardiophorine genera Aphricus LeConte, 1853; Aptopus Eschscholtz, 1829; Cardiophorus Eschscholtz, 1829; Cardiotarsus Eschscholtz, 1836; Paracardiophorus Schwarz, 1895; Phorocardius Fleutiaux, 1931; Dicronychus sensu Platia, 1994; Dicronychus sensu Méquignon, 1931; Craspedostethus sensu Schwarz, 1906 (i.e., including Tropidiplus Fleutiaux, 1903); Paracardiophorus sensu Cobos, 1970, although well-supported alternative classifications were available for only some. Based on taxonomic interpretation of phylogenetic results: Nyctorini is syn. n. of Cardiophorini; Globothorax Fleutiaux, 1891 (Physodactylinae), Margogastrius Schwarz, 1903 (Physodactylinae), and Pachyelater Lesne, 1897 (Dendrometrinae) are transferred to Cardiophorinae. The following changes are proposed for cardiophorine genera: Aptopus Eschscholtz, 1829 is redefined to exclude Horistonotus -like species; Coptostethus Wollaston, 1854 is subgenus of Cardiophorus ; Dicronychus Brullé, 1832 and Diocarphus Fleutiaux, 1947, Metacardiophorus Gurjeva, 1966, Platynychus Motschulsky, 1858, and Zygocardiophorus Iablokoff-Khnzorian and Mardjanian, 1981 are placed at genus rank; Paracardiophorus Schwarz, 1895 is redefined based on North American and Eurasian species only; Horistonotus Candèze, 1860 redefined to include species with multiple apices on each side of their tarsal claws; Patriciella Van Zwaluwenburg, 1953 is syn. n. of Aphricus LeConte, 1853; Teslasena Fleutiaux, 1892 (Physodactylinae) is syn. n. of Globothorax Fleutiaux, 1891. The following new genera are described: Austrocardiophorus (type species: Cardiophorus humeralis Fairmaire and Germain, 1860); Chileaphricus (type species: Aphricus chilensis Fleutiaux, 1940); Floridelater (type species: Coptostethus americanus Horn, 1871, transferred from Negastriinae to Cardiophorinae). Paradicronychus ( nomen nudum ), is syn. n. of Cardiophorus Eschscholtz, 1829. Generic reassignments to make Cardiodontulus , Cardiophorus , Cardiotarsus , Paracardiophorus consistent with phylogenetically revised genus concepts resulted in 84 new combinations. Lectotypes are designated for 29 type species to fix generic concepts: Anelastes femoralis Lucas, 1857; Aphricus chilensis Fleutiaux, 1940; Athous argentatus Abeille de Perrin, 1894; Cardiophorus adjutor Candèze, 1875; Cardiophorus florentini Fleutiaux, 1895; Cardiophorus inflatus Candèze, 1882; Cardiophorus luridipes Candèze, 1860; Cardiophorus mirabilis Candèze, 1860; Cardiophorus musculus Erichson, 1840; Cardiotarsus capensis Candèze, 1860; Cardiotarsus vitalisi Fleutiaux, 1918; Craspedostethus rufiventris Schwarz, 1898; Elater cinereus Herbst, 1784; Elater minutissimus Germar, 1817; Elater sputator Linnaeus, 1758; Elater thoracicus Fabricius, 1801; Eniconyx pullatus Horn, 1884; Esthesopus castaneus Eschscholtz, 1829; Gastrimargus schneideri Schwarz, 1902; Globothorax chevrolati Fleutiaux, 1891; Horistonotus flavidus Candèze, 1860; Horistonotus simplex LeConte, 1863; Lesnelater madagascariensis Fleutiaux, 1935; Oedostethus femoralis LeConte, 1853; Phorocardius solitarius Fleutiaux, 1931; Platynychus indicus Motschulsky, 1858; Platynychus mixtus Fleutiaux, 1931; Triplonychus acuminatus Candèze, 1860; Tropidiplus tellinii Fleutiaux, 1903. A key to genera and diagnoses are provided for all genera and subgenera. A bibliographic synonymy includes references for all taxonomic changes to genera and new species through 2015.

Public Exposure from Indoor Radiofrequency Radiation in the City of Hebron, West Bank-Palestine.

PubMed

Lahham, Adnan; Sharabati, Afefeh; ALMasri, Hussien

2015-08-01

This work presents the results of measured indoor exposure levels to radiofrequency (RF) radiation emitting sources in one of the major cities in the West Bank-the city of Hebron. Investigated RF emitters include FM, TV broadcasting stations, mobile telephony base stations, cordless phones [Digital Enhanced Cordless Telecommunications (DECT)], and wireless local area networks (WLAN). Measurements of power density were conducted in 343 locations representing different site categories in the city. The maximum total power density found at any location was about 2.3 × 10 W m with a corresponding exposure quotient of about 0.01. This value is well below unity, indicating compliance with the guidelines of the International Commission on Non-ionizing Radiation Protection (ICNIRP). The average total exposure from all RF sources was 0.08 × 10 W m. The relative contributions from different sources to the total exposure in terms of exposure quotient were evaluated and found to be 46% from FM radio, 26% from GSM900, 15% from DECT phones, 9% from WLAN, 3% from unknown sources, and 1% from TV broadcasting. RF sources located outdoors contribute about 73% to the population exposure indoors.

A linear, separable two-parameter model for dual energy CT imaging of proton stopping power computation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Han, Dong, E-mail: radon.han@gmail.com; Williamson, Jeffrey F.; Siebers, Jeffrey V.

2016-01-15

Purpose: To evaluate the accuracy and robustness of a simple, linear, separable, two-parameter model (basis vector model, BVM) in mapping proton stopping powers via dual energy computed tomography (DECT) imaging. Methods: The BVM assumes that photon cross sections (attenuation coefficients) of unknown materials are linear combinations of the corresponding radiological quantities of dissimilar basis substances (i.e., polystyrene, CaCl{sub 2} aqueous solution, and water). The authors have extended this approach to the estimation of electron density and mean excitation energy, which are required parameters for computing proton stopping powers via the Bethe–Bloch equation. The authors compared the stopping power estimation accuracymore » of the BVM with that of a nonlinear, nonseparable photon cross section Torikoshi parametric fit model (VCU tPFM) as implemented by the authors and by Yang et al. [“Theoretical variance analysis of single- and dual-energy computed tomography methods for calculating proton stopping power ratios of biological tissues,” Phys. Med. Biol. 55, 1343–1362 (2010)]. Using an idealized monoenergetic DECT imaging model, proton ranges estimated by the BVM, VCU tPFM, and Yang tPFM were compared to International Commission on Radiation Units and Measurements (ICRU) published reference values. The robustness of the stopping power prediction accuracy of tissue composition variations was assessed for both of the BVM and VCU tPFM. The sensitivity of accuracy to CT image uncertainty was also evaluated. Results: Based on the authors’ idealized, error-free DECT imaging model, the root-mean-square error of BVM proton stopping power estimation for 175 MeV protons relative to ICRU reference values for 34 ICRU standard tissues is 0.20%, compared to 0.23% and 0.68% for the Yang and VCU tPFM models, respectively. The range estimation errors were less than 1 mm for the BVM and Yang tPFM models, respectively. The BVM estimation accuracy is not dependent on tissue type and proton energy range. The BVM is slightly more vulnerable to CT image intensity uncertainties than the tPFM models. Both the BVM and tPFM prediction accuracies were robust to uncertainties of tissue composition and independent of the choice of reference values. This reported accuracy does not include the impacts of I-value uncertainties and imaging artifacts and may not be achievable on current clinical CT scanners. Conclusions: The proton stopping power estimation accuracy of the proposed linear, separable BVM model is comparable to or better than that of the nonseparable tPFM models proposed by other groups. In contrast to the tPFM, the BVM does not require an iterative solving for effective atomic number and electron density at every voxel; this improves the computational efficiency of DECT imaging when iterative, model-based image reconstruction algorithms are used to minimize noise and systematic imaging artifacts of CT images.« less

A Western Corn Rootworm Cadherin-like Protein is not Involved in the Binding and Toxicity of Cry34/35Ab1 and Cry3Aa Bacillus Thuringiensis Proteins

USDA-ARS?s Scientific Manuscript database

The western corn rootworm (WCR) Diabrotica virgifera virgifera LeConte is an important insect pest of corn. Bacillus thuringiensis (Bt) insecticidal proteins Cry3Aa (as mCry3A) and Cry34Ab1/Cry35Ab1 have been expressed in transgenic corn and are used to control the insect in the U.S. To date, there ...

Habitat Value of Man-Made Coastal Marshes in Florida

DTIC Science & Technology

1991-09-01

extraneous material as possible, and preserved in plastic bags. All cores were taken directly over a culm of Spartina that had been clipped at ground...spoonbill Ajaia ajaja x Wood stork Mycteri.a .ne:-. ana X Mottled duck Anas tulvigula x Black rail Lateral/us jamaici-,A,. X Clapper rail Rat/us...erythrophthalmus X X LeConte’s or sharp-tailed sparrow Ammodramus spp. X X Seaside sparrow Ammodramus maritimus X X Red- winged blackbird Agelaius

Quantitative variation and biosynthesis of hindgut volatiles associated with the red turpentine beetle, Dendroctonus valens LeConte, at different attack phases.

PubMed

Shi, Z-H; Sun, J-H

2010-06-01

The red turpentine beetle (RTB), Dendroctonus valens LeConte, is a destructive invasive forest pest in China. For such tree-killing species, how to initiate a volatile-mediated mass attack is of great importance during the course of establishment. To understand the hindgut volatile production mechanism underlying mass attack initiated by RTB, coupled gas chromatography-mass spectrometry and 13C-labelled precursors were applied to explore the quantitative variation and biosynthesis of volatiles associated with RTB at different attack phases. Five previously described volatiles, trans-verbenol, myrtenol, cis-verbenol, myrtenal and verbenone, were identified and quantified from extracts of female and male hindguts, with the first two compounds as the major components and the latter three as minor constituents. In newly emerged females and males, only minute amounts of these compounds were detected. The quantity of volatiles from female adults significantly increased after they fed on bolts. Male adults also yielded larger quantities of volatiles after they joined females in galleries, which suggested that RTB males could accelerate the mass colonization on host trees. We also confirmed that RTB produced the five volatiles through oxidizing the major host monoterpene, alpha-pinene, but not synthesized de novo since products were labeled without 13C. The implication of this study in understanding the successful invasion of RTB is discussed.

Traps and attractants for wood-boring insects in ponderosa pine stands in the Black Hills, South Dakota.

PubMed

Costello, Sheryl L; Negrón, José F; Jacobi, William R

2008-04-01

Recent large-scale wildfires have increased populations of wood-boring insects in the Black Hills of South Dakota. Because little is known about possible impacts of wood-boring insects in the Black Hills, land managers are interested in developing monitoring techniques such as flight trapping with semiochemical baits. Two trap designs and four semiochemical attractants were tested in a recently burned ponderosa pine, Pinus ponderosa Dougl. ex Laws., forest in the Black Hills. Modified panel and funnel traps were tested in combination with the attractants, which included a woodborer standard (ethanol and alpha-pinene), standard plus 3-carene, standard plus ipsenol, and standard plus ipsdienol. We found that funnel traps were equally efficient or more efficient in capturing wood-boring insects than modified panel traps. Trap catches of cerambycids increased when we added the Ips spp. pheromone components (ipsenol or ipsdienol) or the host monoterpene (3-carene) to the woodborer standard. During the summers of 2003 and 2004, 18 cerambycid, 14 buprestid, and five siricid species were collected. One species of cerambycid, Monochamus clamator (LeConte), composed 49 and 40% of the 2003 and 2004 trap catches, respectively. Two other cerambycids, Acanthocinus obliquus (LeConte) and Acmaeops proteus (Kirby), also were frequently collected. Flight trap data indicated that some species were present throughout the summer, whereas others were caught only at the beginning or end of the summer.

Modeling Failure and Reliability in New-Generation Devices

DTIC Science & Technology

1990-07-15

them to point of per- manen da=age. An airaft enploying GaAs MMIC rIar DU] reccivr can expet to have the receiveis damaged by a Dects cko= appoach to...znergUy. usng tannielwg electron spxtrIDopy, an 8. Julie E. Lawr=,-e Vic~tcr A. J. van Lintk and Jamnes P. th = au usn ba bandC~ dopulses In Pw Of Raymcmd

MO-FG-204-01: Improved Noise Suppression for Dual-Energy CT Through Entropy Minimization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Petrongolo, M; Zhu, L

2015-06-15

Purpose: In dual energy CT (DECT), noise amplification during signal decomposition significantly limits the utility of basis material images. Since clinically relevant objects contain a limited number of materials, we propose to suppress noise for DECT based on image entropy minimization. An adaptive weighting scheme is employed during noise suppression to improve decomposition accuracy with limited effect on spatial resolution and image texture preservation. Methods: From decomposed images, we first generate a 2D plot of scattered data points, using basis material densities as coordinates. Data points representing the same material generate a highly asymmetric cluster. We orient an axis bymore » minimizing the entropy in a 1D histogram of these points projected onto the axis. To suppress noise, we replace pixel values of decomposed images with center-of-mass values in the direction perpendicular to the optimal axis. To limit errors due to cluster overlap, we weight each data point’s contribution based on its high and low energy CT values and location within the image. The proposed method’s performance is assessed on physical phantom studies. Electron density is used as the quality metric for decomposition accuracy. Our results are compared to those without noise suppression and with a recently developed iterative method. Results: The proposed method reduces noise standard deviations of the decomposed images by at least one order of magnitude. On the Catphan phantom, this method greatly preserves the spatial resolution and texture of the CT images and limits induced error in measured electron density to below 1.2%. In the head phantom study, the proposed method performs the best in retaining fine, intricate structures. Conclusion: The entropy minimization based algorithm with adaptive weighting substantially reduces DECT noise while preserving image spatial resolution and texture. Future investigations will include extensive investigations on material decomposition accuracy that go beyond the current electron density calculations. This work was supported in part by the National Institutes of Health (NIH) under Grant Number R21 EB012700.« less

New Coleoptera records from New Brunswick, Canada: Geotrupidae and Scarabaeidae

PubMed Central

Webster, Reginald P.; Sweeney, Jon D.; DeMerchant, Ian

2012-01-01

Abstract Two species of Geotrupidae, Geotrupes splendidus splendidus (Fabricius) and Odonteus liebecki (Wallis), are newly reported for New Brunswick, Canada. Twelve species of Scarabaeidae are added to the faunal list of the province, including Aegialia criddlei Brown, Caelius humeralis (Brown), Dialytellus dialytoides (Fall), Diapterna omissa (LeConte), Diapterna pinguis (Haldeman), Planolinoides aenictus (Cooper and Gordon), Stenotothorax badipes (Melsheimer), and Ataenius strigatus (Say), which are also newly recorded for the Maritime provinces. Collection data, habitat data, and distribution maps are presented for each species. PMID:22539883

Projection decomposition algorithm for dual-energy computed tomography via deep neural network.

PubMed

Xu, Yifu; Yan, Bin; Chen, Jian; Zeng, Lei; Li, Lei

2018-03-15

Dual-energy computed tomography (DECT) has been widely used to improve identification of substances from different spectral information. Decomposition of the mixed test samples into two materials relies on a well-calibrated material decomposition function. This work aims to establish and validate a data-driven algorithm for estimation of the decomposition function. A deep neural network (DNN) consisting of two sub-nets is proposed to solve the projection decomposition problem. The compressing sub-net, substantially a stack auto-encoder (SAE), learns a compact representation of energy spectrum. The decomposing sub-net with a two-layer structure fits the nonlinear transform between energy projection and basic material thickness. The proposed DNN not only delivers image with lower standard deviation and higher quality in both simulated and real data, and also yields the best performance in cases mixed with photon noise. Moreover, DNN costs only 0.4 s to generate a decomposition solution of 360 × 512 size scale, which is about 200 times faster than the competing algorithms. The DNN model is applicable to the decomposition tasks with different dual energies. Experimental results demonstrated the strong function fitting ability of DNN. Thus, the Deep learning paradigm provides a promising approach to solve the nonlinear problem in DECT.

Synergism between Enantiomers Creates Species-Specific Pheromone Blends and Minimizes Cross-Attraction for Two Species of Cerambycid Beetles.

PubMed

Meier, Linnea R; Zou, Yunfan; Millar, Jocelyn G; Mongold-Diers, Judith A; Hanks, Lawrence M

2016-11-01

Research over the last decade has revealed extensive parsimony among pheromones within the large insect family Cerambycidae, with males of many species producing the same, or very similar aggregation pheromones. Among some species in the subfamily Cerambycinae, interspecific attraction is minimized by temporal segregation, and/or by minor pheromone components that synergize attraction of conspecifics or inhibit attraction of heterospecifics. Less is known about pheromone-based mechanisms of reproductive isolation among species in the largest subfamily, the Lamiinae. Here, we present evidence that the pheromone systems of two sympatric lamiine species consist of synergistic blends of enantiomers of (E)-6,10-dimethyl-5,9-undecadien-2-ol (fuscumol) and the structurally related (E)-6,10-dimethyl-5,9-undecadien-2-yl acetate (fuscumol acetate), as a mechanism by which species-specific blends of pheromone components can minimize interspecific attraction. Male Astylidius parvus (LeConte) were found to produce (R)- and (S)-fuscumol + (R)-fuscumol acetate + geranylacetone, whereas males of Lepturges angulatus (LeConte) produced (R)- and (S)-fuscumol acetate + geranylacetone. Field experiments confirmed that adult beetles were attracted only by their species-specific blend of the enantiomers of fuscumol and fuscumol acetate, respectively, and not to the individual enantiomers. Because other lamiine species are known to produce single enantiomers or blends of enantiomers of fuscumol and/or fuscumol acetate, synergism between enantiomers, or inhibition by enantiomers, may be a widespread mechanism for forming species-specific pheromone blends in this subfamily.

Information Assurance Technical Framework (IATF). Release 3.1

DTIC Science & Technology

2002-09-01

used in the United States and Europe for both cordless phones and wireless PBXs. In addition to DECT, some cordless telephones use other signaling...1.544 Mbps. Europe and Japan use a different standard for primary rate service. Government equipment is being designed for N-ISDN. This device was...There are three main components of a polymorphic virus: a scrambled virus body, a decryption routine, and a mutation engine. In a polymorphic virus, the

A simple formulation for deriving effective atomic numbers via electron density calibration from dual-energy CT data in the human body.

PubMed

Saito, Masatoshi; Sagara, Shota

2017-06-01

The main objective of this study is to propose a simple formulation (which we called DEEDZ) for deriving effective atomic numbers (Z eff ) via electron density (ρ e ) calibration from dual-energy (DE) CT data. We carried out numerical analysis of this DEEDZ method for a large variety of materials with known elemental compositions and mass densities using an available photon cross sections database. The new conversion approach was also applied to previously published experimental DECT data to validate its practical feasibility. We performed numerical analysis of the DEEDZ conversion method for tissue surrogates that have the same chemical compositions and mass densities as a commercial tissue-characterization phantom in order to determine the parameters necessary for the ρ e and Z eff calibrations in the DEEDZ conversion. These parameters were then applied to the human-body-equivalent tissues of ICRU Report 46 as objects of interest with unknown ρ e and Z eff . The attenuation coefficients of these materials were calculated using the XCOM photon cross sections database. We also applied the DEEDZ conversion to experimental DECT data available in the literature, which was measured for two commercial phantoms of different shapes and sizes using a dual-source CT scanner at 80 kV and 140 kV/Sn. The simulated Z eff 's were in excellent agreement with the reference values for almost all of the ICRU-46 human tissues over the Z eff range from 5.83 (gallstones-cholesterol) to 16.11 (bone mineral-hydroxyapatite). The relative deviations from the reference Z eff were within ± 0.3% for all materials, except for one outlier that presented a -3.1% deviation, namely, the thyroid. The reason for this discrepancy is that the thyroid contains a small amount of iodine, an element with a large atomic number (Z = 53). In the experimental case, we confirmed that the simple formulation with less fit parameters enable to calibrate Z eff as accurately as the existing calibration procedure. The DEEDZ conversion method based on the simple formulation proposed could facilitate the construction of ρ e and Z eff images from acquired DECT data. © 2017 American Association of Physicists in Medicine.

A full-spectral Bayesian reconstruction approach based on the material decomposition model applied in dual-energy computed tomography.

PubMed

Cai, C; Rodet, T; Legoupil, S; Mohammad-Djafari, A

2013-11-01

Dual-energy computed tomography (DECT) makes it possible to get two fractions of basis materials without segmentation. One is the soft-tissue equivalent water fraction and the other is the hard-matter equivalent bone fraction. Practical DECT measurements are usually obtained with polychromatic x-ray beams. Existing reconstruction approaches based on linear forward models without counting the beam polychromaticity fail to estimate the correct decomposition fractions and result in beam-hardening artifacts (BHA). The existing BHA correction approaches either need to refer to calibration measurements or suffer from the noise amplification caused by the negative-log preprocessing and the ill-conditioned water and bone separation problem. To overcome these problems, statistical DECT reconstruction approaches based on nonlinear forward models counting the beam polychromaticity show great potential for giving accurate fraction images. This work proposes a full-spectral Bayesian reconstruction approach which allows the reconstruction of high quality fraction images from ordinary polychromatic measurements. This approach is based on a Gaussian noise model with unknown variance assigned directly to the projections without taking negative-log. Referring to Bayesian inferences, the decomposition fractions and observation variance are estimated by using the joint maximum a posteriori (MAP) estimation method. Subject to an adaptive prior model assigned to the variance, the joint estimation problem is then simplified into a single estimation problem. It transforms the joint MAP estimation problem into a minimization problem with a nonquadratic cost function. To solve it, the use of a monotone conjugate gradient algorithm with suboptimal descent steps is proposed. The performance of the proposed approach is analyzed with both simulated and experimental data. The results show that the proposed Bayesian approach is robust to noise and materials. It is also necessary to have the accurate spectrum information about the source-detector system. When dealing with experimental data, the spectrum can be predicted by a Monte Carlo simulator. For the materials between water and bone, less than 5% separation errors are observed on the estimated decomposition fractions. The proposed approach is a statistical reconstruction approach based on a nonlinear forward model counting the full beam polychromaticity and applied directly to the projections without taking negative-log. Compared to the approaches based on linear forward models and the BHA correction approaches, it has advantages in noise robustness and reconstruction accuracy.

New Coleoptera records from New Brunswick, Canada: Buprestidae

PubMed Central

Webster, Reginald P.; DeMerchant, Ian

2012-01-01

Abstract Nine species of Buprestidae; Agrilus bilineatus (Weber), Agrilus crinicornis Horn, Agrilus obsoletoguttatus Gory, Agrilus putillus putillus Say, Brachys ovatus (Weber), Buprestis sulcicollis (LeConte), Chalcophora liberta (Germar), Phaenops aeneola (Melsheimer), and Taphrocerus gracilis (Say) are newly recorded for New Brunswick, Canada. Agrilus bilineatus, A. crinicornis, A. obsoletoguttatus,and B. ovatus are also newly reported for the Maritime provinces. Lindgren 12-funnel traps do not appear to be an effective tool for sampling the Bupresidae. Collection, habitat notes, and distribution maps are presented for each species. PMID:22539885

Quantitative data standardization of X-ray based densitometry methods

NASA Astrophysics Data System (ADS)

Sergunova, K. A.; Petraikin, A. V.; Petrjajkin, F. A.; Akhmad, K. S.; Semenov, D. S.; Potrakhov, N. N.

2018-02-01

In the present work is proposed the design of special liquid phantom for assessing the accuracy of quantitative densitometric data. Also are represented the dependencies between the measured bone mineral density values and the given values for different X-ray based densitometry techniques. Shown linear graphs make it possible to introduce correction factors to increase the accuracy of BMD measurement by QCT, DXA and DECT methods, and to use them for standardization and comparison of measurements.

Differentiation of uric acid versus non-uric acid kidney stones in the presence of iodine using dual-energy CT

NASA Astrophysics Data System (ADS)

Wang, J.; Qu, M.; Leng, S.; McCollough, C. H.

2010-04-01

In this study, the feasibility of differentiating uric acid from non-uric acid kidney stones in the presence of iodinated contrast material was evaluated using dual-energy CT (DECT). Iodine subtraction was accomplished with a commercial three material decomposition algorithm to create a virtual non-contrast (VNC) image set. VNC images were then used to segment stone regions from tissue background. The DE ratio of each stone was calculated using the CT images acquired at two different energies with DECT using the stone map generated from the VNC images. The performance of DE ratio-based stone differentiation was evaluated at five different iodine concentrations (21, 42, 63, 84 and 105 mg/ml). The DE ratio of stones in iodine solution was found larger than those obtained in non-iodine cases. This is mainly caused by the partial volume effect around the boundary between the stone and iodine solution. The overestimation of the DE ratio leads to substantial overlap between different stone types. To address the partial volume effect, an expectation-maximization (EM) approach was implemented to estimate the contribution of iodine and stone within each image pixel in their mixture area. The DE ratio of each stone was corrected to maximally remove the influence of iodine solutions. The separation of uric-acid and non-uric-acid stone was improved in the presence of iodine solution.

Pulmonary embolism detection using localized vessel-based features in dual energy CT

NASA Astrophysics Data System (ADS)

Dicente Cid, Yashin; Depeursinge, Adrien; Foncubierta Rodríguez, Antonio; Platon, Alexandra; Poletti, Pierre-Alexandre; Müller, Henning

2015-03-01

Pulmonary embolism (PE) affects up to 600,000 patients and contributes to at least 100,000 deaths every year in the United States alone. Diagnosis of PE can be difficult as most symptoms are unspecific and early diagnosis is essential for successful treatment. Computed Tomography (CT) images can show morphological anomalies that suggest the existence of PE. Various image-based procedures have been proposed for improving computer-aided diagnosis of PE. We propose a novel method for detecting PE based on localized vessel-based features computed in Dual Energy CT (DECT) images. DECT provides 4D data indexed by the three spatial coordinates and the energy level. The proposed features encode the variation of the Hounsfield Units across the different levels and the CT attenuation related to the amount of iodine contrast in each vessel. A local classification of the vessels is obtained through the classification of these features. Moreover, the localization of the vessel in the lung provides better comparison between patients. Results show that the simple features designed are able to classify pulmonary embolism patients with an AUC (area under the receiver operating curve) of 0.71 on a lobe basis. Prior segmentation of the lung lobes is not necessary because an automatic atlas-based segmentation obtains similar AUC levels (0.65) for the same dataset. The automatic atlas reaches 0.80 AUC in a larger dataset with more control cases.

Iterative image-domain decomposition for dual-energy CT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Niu, Tianye; Dong, Xue; Petrongolo, Michael

2014-04-15

Purpose: Dual energy CT (DECT) imaging plays an important role in advanced imaging applications due to its capability of material decomposition. Direct decomposition via matrix inversion suffers from significant degradation of image signal-to-noise ratios, which reduces clinical values of DECT. Existing denoising algorithms achieve suboptimal performance since they suppress image noise either before or after the decomposition and do not fully explore the noise statistical properties of the decomposition process. In this work, the authors propose an iterative image-domain decomposition method for noise suppression in DECT, using the full variance-covariance matrix of the decomposed images. Methods: The proposed algorithm ismore » formulated in the form of least-square estimation with smoothness regularization. Based on the design principles of a best linear unbiased estimator, the authors include the inverse of the estimated variance-covariance matrix of the decomposed images as the penalty weight in the least-square term. The regularization term enforces the image smoothness by calculating the square sum of neighboring pixel value differences. To retain the boundary sharpness of the decomposed images, the authors detect the edges in the CT images before decomposition. These edge pixels have small weights in the calculation of the regularization term. Distinct from the existing denoising algorithms applied on the images before or after decomposition, the method has an iterative process for noise suppression, with decomposition performed in each iteration. The authors implement the proposed algorithm using a standard conjugate gradient algorithm. The method performance is evaluated using an evaluation phantom (Catphan©600) and an anthropomorphic head phantom. The results are compared with those generated using direct matrix inversion with no noise suppression, a denoising method applied on the decomposed images, and an existing algorithm with similar formulation as the proposed method but with an edge-preserving regularization term. Results: On the Catphan phantom, the method maintains the same spatial resolution on the decomposed images as that of the CT images before decomposition (8 pairs/cm) while significantly reducing their noise standard deviation. Compared to that obtained by the direct matrix inversion, the noise standard deviation in the images decomposed by the proposed algorithm is reduced by over 98%. Without considering the noise correlation properties in the formulation, the denoising scheme degrades the spatial resolution to 6 pairs/cm for the same level of noise suppression. Compared to the edge-preserving algorithm, the method achieves better low-contrast detectability. A quantitative study is performed on the contrast-rod slice of Catphan phantom. The proposed method achieves lower electron density measurement error as compared to that by the direct matrix inversion, and significantly reduces the error variation by over 97%. On the head phantom, the method reduces the noise standard deviation of decomposed images by over 97% without blurring the sinus structures. Conclusions: The authors propose an iterative image-domain decomposition method for DECT. The method combines noise suppression and material decomposition into an iterative process and achieves both goals simultaneously. By exploring the full variance-covariance properties of the decomposed images and utilizing the edge predetection, the proposed algorithm shows superior performance on noise suppression with high image spatial resolution and low-contrast detectability.« less

Dual-Energy Computed Tomography for the Characterization of Intracranial Hemorrhage and Calcification: A Systematic Approach in a Phantom System.

PubMed

Nute, Jessica L; Jacobsen, Megan C; Chandler, Adam; Cody, Dianna D; Schellingerhout, Dawid

2017-01-01

The aim of this study was to develop a diagnostic framework for distinguishing calcific from hemorrhagic cerebral lesions using dual-energy computed tomography (DECT) in an anthropomorphic phantom system. An anthropomorphic phantom was designed to mimic the CT imaging characteristics of the human head. Cylindrical lesion models containing either calcium or iron, mimicking calcification or hemorrhage, respectively, were developed to exhibit matching, and therefore indistinguishable, single-energy CT (SECT) attenuation values from 40 to 100 HU. These lesion models were fabricated at 0.5, 1, and 1.5 cm in diameter and positioned in simulated cerebrum and skull base locations within the anthropomorphic phantom. All lesion sizes were modeled in the cerebrum, while only 1.5-cm lesions were modeled in the skull base. Images were acquired using a GE 750HD CT scanner and an expansive dual-energy protocol that covered variations in dose (36.7-132.6 mGy CTDIvol, n = 12), image thickness (0.625-5 mm, n = 4), and reconstruction filter (soft, standard, detail, n = 3) for a total of 144 unique technique combinations. Images representing each technique combination were reconstructed into water and calcium material density images, as well as a monoenergetic image chosen to mimic the attenuation of a 120-kVp SECT scan. A true single-energy routine brain protocol was also included for verification of lesion SECT attenuation. Points representing the 3 dual-energy reconstructions were plotted into a 3-dimensional space (water [milligram/milliliter], calcium [milligram/milliliter], monoenergetic Hounsfield unit as x, y, and z axes, respectively), and the distribution of points analyzed using 2 approaches: support vector machines and a simple geometric bisector (GB). Each analysis yielded a plane of optimal differentiation between the calcification and hemorrhage lesion model distributions. By comparing the predicted lesion composition to the known lesion composition, we identified the optimal combination of CTDIvol, image thickness, and reconstruction filter to maximize differentiation between the lesion model types. To validate these results, a new set of hemorrhage and calcification lesion models were created, scanned in a blinded fashion, and prospectively classified using the planes of differentiation derived from support vector machine and GB methods. Accuracy of differentiation improved with increasing dose (CTDIvol) and image thickness. Reconstruction filter had no effect on the accuracy of differentiation. Using an optimized protocol consisting of the maximum CTDIvol of 132.6 mGy, 5-mm-thick images, and a standard filter, hemorrhagic and calcific lesion models with equal SECT attenuation (Hounsfield unit) were differentiated with over 90% accuracy down to 70 HU for skull base lesions of 1.5 cm, and down to 100 HU, 60 HU, and 60 HU for cerebrum lesions of 0.5, 1.0, and 1.5 cm, respectively. The analytic method that yielded the best results was a simple GB plane through the 3-dimensional DECT space. In the validation study, 96% of unknown lesions were correctly classified across all lesion sizes and locations investigated. We define the optimal scan parameters and expected limitations for the accurate classification of hemorrhagic versus calcific cerebral lesions in an anthropomorphic phantom with DECT. Although our proposed DECT protocol represents an increase in dose compared with routine brain CT, this method is intended as a specialized evaluation of potential brain hemorrhage and is thus counterbalanced by increased diagnostic benefit. This work provides justification for the application of this technique in human clinical trials.

Directly measuring melt at a vertical face tidewater glacier: is it possible?

NASA Astrophysics Data System (ADS)

Sutherland, D.; Amundson, J. M.; Duncan, D.; Jackson, R. H.; Kienholz, C.; Motyka, R. J.; Nash, J. D.

2017-12-01

Direct observations of melt on the underwater portion of tidewater glaciers have proved elusive, mostly due to the inherent dangers of making measurements next to a calving ice front. Additionally, the melting process itself is often masked by large ice speeds, variable calving across the glacier front, and enhanced melting due to rising subglacial discharge plumes. Here, we use repeat multibeam sonar images of LeConte Glacier to assess the possibility of measuring terminus melt in situ. LeConte Glacier is a fast-moving tidewater system in southeast Alaska with ice speeds of 25 m d-1 and previously estimated submarine melting that accounts for 50% of ice loss at the front. In August 2016, May 2017, and September 2017, we conducted intensive fieldwork at the 1.5 km long, 250 m deep glacier front, collecting dozens of repeat multibeam images of the underwater terminus. Combined with coincident time-lapse photography and surface radar measurements, we attempt to disentangle the ambient melt at the glacier face from ice motion and calving. We use a suite of oceanographic observations of the emerging subglacial discharge plume to separate portions of the glacier front that show evidence of enhanced melting versus portions outside of the affected plume areas. We find a complex, time-varying geometry, with regions of undercutting, overcutting, and large discharge channels. Measurements like these are critical to i) improving numerical model parameterizations of coupled glacier-ocean interactions and ii) developing a process-based understanding of how the literal ice-ocean boundary evolves in time and space.

Pine Sawyers (Coleoptera: Cerambycidae) Attracted to α-Pinene, Monochamol, and Ipsenol in North America.

PubMed

Miller, D R; Allison, J D; Crowe, C M; Dickinson, D M; Eglitis, A; Hofstetter, R W; Munson, A S; Poland, T M; Reid, L S; Steed, B E; Sweeney, J D

2016-04-22

Detection tools are needed for Monochamus species (Coleoptera: Cerambycidae) because they are known to introduce pine wilt disease by vectoring nematodes in Asia, Europe, and North America. In 2012-2014, we examined the effects of the semiochemicals monochamol and ipsenol on the flight responses of the sawyer beetles Monochamus carolinensis (Olivier), Monochamus clamator (LeConte), Monochamus mutator LeConte, Monochamus notatus (Drury), Monochamus obtusus Casey, Monochamus scutellatus (Say), and Monochamus titillator (F.) complex (Coleoptera: Cerambycidae) to traps baited with α-pinene. Experiments were set in pine forests in New Brunswick and Ontario (Canada), and Arizona, Georgia, Michigan, Montana, Oregon, South Carolina, Utah, and Washington (United States). In brief, 40 traps were placed in 10 blocks of 4 traps per block per location. Traps were baited with: 1) α-pinene; 2) α-pinene + monochamol; 3) α-pinene + ipsenol; and 4) α-pinene + monochamol + ipsenol. Monochamol increased catches of six species and one species complex of Monochamus with an additive effect of ipsenol for five species and one species complex. There was no evidence of synergy between monochamol and ipsenol on beetle catches. Monochamol had no effect on catches of other Cerambycidae or on any associated species of bark beetles, weevils, or bark beetle predators. We present a robust data set suggesting that the combination of α-pinene, ipsenol, and monochamol may be a useful lure for detecting Monochamus species. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

P53 Gene Mutagenesis in Breast Cancer

DTIC Science & Technology

2005-03-01

the wild type T peak. 12 Table 1. Sonic ntations dected by SINtA Individual Cell Sequence Amino Acid Species Conservation 3 ID’ ID Change2 Change... differences in the content of toxic substances in the diet (Biggs et al., 1993; Blaszyk et al., 1996). The development of this p53 mutation load...Changes in the P53 Gene in Single Cells Individual Sequence Amino acid Species conservation ’ ID’ Cell ID change’ change Monkey Mouse Rat Chicken

Behaviors of southwestern native fishes in response to introduced catfish predators

USGS Publications Warehouse

Ward, David L.; Figiel, Chester R.

2013-01-01

Native fishes reared in hatcheries typically suffer high predation mortality when stocked into natural environments. We evaluated the behavior of juvenile bonytail Gila elegans, roundtail chub Gila robusta, razorback sucker Xyrauchen texanus, and Sonora sucker Catostomus insignis in response to introduced channel catfish Ictalurus punctatus and flathead catfish Pylodictis olivaris. Our laboratory tests indicate these species did not inherently recognize catfish as a threat, but they can quickly (within 12 h) change their behavior in response to a novel predator paired with the sight and scent of a dead conspecific. Chubs appear to avoid predation by swimming away from the threat, whereas suckers reduced movement. Effects of antipredator conditioning on survival of fish reared in hatcheries is unknown; however, our results suggest some native fish can be conditioned to recognize introduced predators, which could increase poststocking survival.

A stoichiometric calibration method for dual energy computed tomography

NASA Astrophysics Data System (ADS)

Bourque, Alexandra E.; Carrier, Jean-François; Bouchard, Hugo

2014-04-01

The accuracy of radiotherapy dose calculation relies crucially on patient composition data. The computed tomography (CT) calibration methods based on the stoichiometric calibration of Schneider et al (1996 Phys. Med. Biol. 41 111-24) are the most reliable to determine electron density (ED) with commercial single energy CT scanners. Along with the recent developments in dual energy CT (DECT) commercial scanners, several methods were published to determine ED and the effective atomic number (EAN) for polyenergetic beams without the need for CT calibration curves. This paper intends to show that with a rigorous definition of the EAN, the stoichiometric calibration method can be successfully adapted to DECT with significant accuracy improvements with respect to the literature without the need for spectrum measurements or empirical beam hardening corrections. Using a theoretical framework of ICRP human tissue compositions and the XCOM photon cross sections database, the revised stoichiometric calibration method yields Hounsfield unit (HU) predictions within less than ±1.3 HU of the theoretical HU calculated from XCOM data averaged over the spectra used (e.g., 80 kVp, 100 kVp, 140 kVp and 140/Sn kVp). A fit of mean excitation energy (I-value) data as a function of EAN is provided in order to determine the ion stopping power of human tissues from ED-EAN measurements. Analysis of the calibration phantom measurements with the Siemens SOMATOM Definition Flash dual source CT scanner shows that the present formalism yields mean absolute errors of (0.3 ± 0.4)% and (1.6 ± 2.0)% on ED and EAN, respectively. For ion therapy, the mean absolute errors for calibrated I-values and proton stopping powers (216 MeV) are (4.1 ± 2.7)% and (0.5 ± 0.4)%, respectively. In all clinical situations studied, the uncertainties in ion ranges in water for therapeutic energies are found to be less than 1.3 mm, 0.7 mm and 0.5 mm for protons, helium and carbon ions respectively, using a generic reconstruction algorithm (filtered back projection). With a more advanced method (sinogram affirmed iterative technique), the values become 1.0 mm, 0.5 mm and 0.4 mm for protons, helium and carbon ions, respectively. These results allow one to conclude that the present adaptation of the stoichiometric calibration yields a highly accurate method for characterizing tissue with DECT for ion beam therapy and potentially for photon beam therapy.

Immunocompetence of the red turpentine beetle, Dendroctonus valens LeConte (Coleoptera: Curculionidae, Scolytinae): variation between developmental stages and sexes in populations in China.

PubMed

Shi, Zhang-Hong; Sun, Jiang-Hua

2010-11-01

Immune defense imposes fitness costs as well as benefits, so organisms should optimize, not maximize, their immune function through their life cycle. We investigated this issue in the red turpentine beetle, Dendroctonus valens LeConte (Coleoptera: Curculionidae, Scolytinae), which is a pine-killing invasive beetle in China, though it is usually considered as a secondary pest in its native range of North America. We hypothesized that pathogen pressure may affect these beetles differently throughout their life history. We measured the insect's immunocompetence throughout life, determining encapsulation ability and phenoloxidase activity in larval stages, pupae and adults. Pupae had the highest encapsulation ability, but encapsulation was not different between final instar larvae and adults. Phenoloxidase (PO) activity was highest in final instar larvae and pupae, followed by the second instar larvae and adults. Total phenoloxidase activity increased significantly from the second instar larval stage to pupae, and then decreased in adults. Although the second instar larvae had the lowest phenoloxidase activity, more than 90% of total PO existed in the hemolymph in the form of the active enzyme, as compared with pupae, in which over 60% of PO occurred as a proenzyme. Both active PO and total PO were much higher in females than in males, though no significant differences were detected between the encapsulation ability of male and female adults. This result suggests the existence of a sexual dimorphism of immunocompetence in D. valens adults. Variations in immunocompetence across developmental stages suggest that D. valens adopts diverse investment strategies in immunocompetence during different stages. Potential reasons for variation in immunocompetence among developmental stages and between the sexes of D. valens are discussed. Copyright 2010 Elsevier Ltd. All rights reserved.

Dual-energy computed tomography of the head: a phantom study assessing axial dose distribution, eye lens dose, and image noise level

NASA Astrophysics Data System (ADS)

Matsubara, Kosuke; Kawashima, Hiroki; Hamaguchi, Takashi; Takata, Tadanori; Kobayashi, Masanao; Ichikawa, Katsuhiro; Koshida, Kichiro

2016-03-01

The aim of this study was to propose a calibration method for small dosimeters to measure absorbed doses during dual- source dual-energy computed tomography (DECT) and to compare the axial dose distribution, eye lens dose, and image noise level between DE and standard, single-energy (SE) head CT angiography. Three DE (100/Sn140 kVp 80/Sn140 kVp, and 140/80 kVp) and one SE (120 kVp) acquisitions were performed using a second-generation dual-source CT device and a female head phantom, with an equivalent volumetric CT dose index. The axial absorbed dose distribution at the orbital level and the absorbed doses for the eye lens were measured using radiophotoluminescent glass dosimeters. CT attenuation numbers were obtained in the DE composite images and the SE images of the phantom at the orbital level. The doses absorbed at the orbital level and in the eye lens were lower and standard deviations for the CT attenuation numbers were slightly higher in the DE acquisitions than those in the SE acquisition. The anterior surface dose was especially higher in the SE acquisition than that in the DE acquisitions. Thus, DE head CT angiography can be performed with a radiation dose lower than that required for a standard SE head CT angiography, with a slight increase in the image noise level. The 100/Sn140 kVp acquisition revealed the most balanced axial dose distribution. In addition, our proposed method was effective for calibrating small dosimeters to measure absorbed doses in DECT.

Dual-energy bone removal computed tomography (BRCT): preliminary report of efficacy of acute intracranial hemorrhage detection.

PubMed

Naruto, Norihito; Tannai, Hidenori; Nishikawa, Kazuma; Yamagishi, Kentaro; Hashimoto, Masahiko; Kawabe, Hideto; Kamisaki, Yuichi; Sumiya, Hisashi; Kuroda, Satoshi; Noguchi, Kyo

2018-02-01

One of the major applications of dual-energy computed tomography (DECT) is automated bone removal (BR). We hypothesized that the visualization of acute intracranial hemorrhage could be improved on BRCT by removing bone as it has the highest density tissue in the head. This preliminary study evaluated the efficacy of a DE BR algorithm for the head CT of trauma patients. Sixteen patients with acute intracranial hemorrhage within 1 day after head trauma were enrolled in this study. All CT examinations were performed on a dual-source dual-energy CT scanner. BRCT images were generated using the Bone Removal Application. Simulated standard CT and BRCT images were visually reviewed in terms of detectability (presence or absence) of acute hemorrhagic lesions. DECT depicted 28 epidural/subdural hemorrhages, 17 contusional hemorrhages, and 7 subarachnoid hemorrhages. In detecting epidural/subdural hemorrhage, BRCT [28/28 (100%)] was significantly superior to simulated standard CT [17/28 (61%)] (p = .001). In detecting contusional hemorrhage, BRCT [17/17 (100%)] was also significantly superior to simulated standard CT [11/17 (65%)] (p = .0092). BRCT was superior to simulated standard CT in detecting acute intracranial hemorrhage. BRCT could improve the detection of small intracranial hemorrhages, particularly those adjacent to bone, by removing bone that can interfere with the visualization of small acute hemorrhage. In an emergency such as head trauma, BRCT can be used as support imaging in combination with simulated standard CT and bone scale CT, although BRCT cannot replace a simulated standard CT.

Dual-energy CT for the characterization of urinary calculi: In vitro and in vivo evaluation of a low-dose scanning protocol.

PubMed

Thomas, C; Patschan, O; Ketelsen, D; Tsiflikas, I; Reimann, A; Brodoefel, H; Buchgeister, M; Nagele, U; Stenzl, A; Claussen, C; Kopp, A; Heuschmid, M; Schlemmer, H-P

2009-06-01

The efficiency and radiation dose of a low-dose dual-energy (DE) CT protocol for the evaluation of urinary calculus disease were evaluated. A low-dose dual-source DE-CT renal calculi protocol (140 kV, 46 mAs; 80 kV, 210 mAs) was derived from the single-energy (SE) CT protocol used in our institution for the detection of renal calculi (120 kV, 75 mAs). An Alderson-Rando phantom was equipped with thermoluminescence dosimeters and examined by CT with both protocols. The effective doses were calculated. Fifty-one patients with suspected or known urinary calculus disease underwent DE-CT. DE analysis was performed if calculi were detected using a dedicated software tool. Results were compared to chemical analysis after invasive calculus extraction. An effective dose of 3.43 mSv (male) and 5.30 mSv (female) was measured in the phantom for the DE protocol (vs. 3.17/4.57 mSv for the SE protocol). Urinary calculi were found in 34 patients; in 28 patients, calculi were removed and analyzed (23 patients with calcified calculi, three with uric acid calculi, one with 2,8-dihyxdroxyadenine-calculi, one patient with a mixed struvite calculus). DE analysis was able to distinguish between calcified and non-calcified calculi in all cases. In conclusion, dual-energy urinary calculus analysis is effective also with a low-dose protocol. The protocol tested in this study reliably identified calcified urinary calculi in vivo.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vinke, R; Peng, H; Xing, L

Purpose: In searching for a robust, efficient and cost-effective dual energy cone beam CT (DECBCT) solution for various radiation oncology applications, in particularly for improved proton dose planning/replanning accuracy and DE-CBCT guided radiation therapy, we investigate a novel energy modulation scheme using a beam modifier placed between the source and patient and optimize its geometric configuration for routine clinical use. Methods: The study was performed using a Hitachi CBCT scanner and the tube voltage was set at 125 kVp. The higher energy beam was obtained by filtering the incident utilizing a beam modulation layer (material: copper, thickness: 1.8 mm). Tomore » avoid the need for double scans (one with and one without the energy modulator), the modulation layer was configured to cover only the half of the X-ray beam so that two sets of sinograms corresponding low and high energies were collected after a single gantry rotation of 360 deg. The average high energy and low energy HU numbers (HUhigh and HUlow) were derived for pixels in a defined region-of-interest, respectively. Results: The beam modifier increased the threshold of the energy spectrum from ∼20 keV up to ∼50 keV. Two complete sets of images were obtained with good alignment between the high energy and low-energy cases without any artifact observed (Fig. 2). The HUlow/HUhigh is ∼0/0 (water), ∼394/238 (brain), ∼1283/1085 (cortical bone) and ∼3000/1800 (titanium). Conclusion: The feasibility of the proposed DECT implementation using a beam modifier has been demonstrated. Compared to the existing DECT solutions, the proposed scheme is much more cost-effective and requires minimum hardware modification. The work lays foundation for us to study the quantification of HU values to derive material density images and atomic number (and electron density) of substances.« less

Survey of electromagnetic field exposure in bedrooms of residences in lower Austria.

PubMed

Tomitsch, Johannes; Dechant, Engelbert; Frank, Wilhelm

2010-04-01

Previous investigations of exposure to electric, magnetic, or electromagnetic fields (EMF) in households were either about electricity supply EMFs or radio frequency EMFs (RF-EMFs). We report results from spot measurements at the bedside that comprise electrostatic fields, extremely low-frequency electric fields (ELF-EFs), extremely low-frequency magnetic fields (ELF-MFs), and RF-EMFs. Measurements were taken in 226 households throughout Lower Austria. In addition, effects of simple reduction measures (e.g., removal of clock radios or increasing their distance from the bed, turning off Digital Enhanced Cordless Telecommunication (DECT) telephone base stations) were assessed. All measurements were well below International Commission on Non-Ionizing Radiation Protection (ICNIRP) guideline levels. Average night-time ELF-MFs (long-term measurement from 10 pm to 6 am, geometric mean over households) above 100 nT were obtained in 2.3%, and RF-EMFs above 1000 microW/m(2) in 7.1% of households. Highest ELF-EFs were primarily due to lamps beside the bed (max = 166 V/m), and highest ELF-MFs because of transformers of devices (max = 1030 nT) or high current of power lines (max = 380 nT). The highest values of RF-EMFs were caused by DECT telephone base stations (max = 28979 microW/m(2)) and mobile phone base stations (max = 4872 microW/m(2)). Simple reduction measures resulted in an average decrease of 23 nT for ELF-MFs, 23 V/m for ELF-EFs, and 246 microW/m(2) for RF-EMFs. A small but statistically significant correlation between ELF-MF exposure and overall RF-EMF levels of R = 0.16 (P = 0.008) was computed that was independent of type (flat, single family) and location (urban, rural) of houses. (c) 2009 Wiley-Liss, Inc.

Bone erosions in patients with chronic gouty arthropathy are associated with tophi but not bone oedema or synovitis: new insights from a 3 T MRI study.

PubMed

McQueen, Fiona M; Doyle, Anthony; Reeves, Quentin; Gao, Angela; Tsai, Amy; Gamble, Greg D; Curteis, Barbara; Williams, Megan; Dalbeth, Nicola

2014-01-01

Bone erosion has been linked with tophus deposition in gout but the roles of osteitis (MRI bone oedema) and synovitis remain uncertain. Our aims in this prospective 3 T MRI study were to investigate the frequency of these features in gout and determine their relation to one another. 3 T MRI scans of the wrist were obtained in 40 gout patients. Scans were scored independently by two radiologists for bone oedema, erosions, tophi and synovitis. Dual-energy CT (DECT) scans were scored for tophi in a subgroup of 10 patients. Interreader reliability was high for erosions and tophi [intraclass correlation coefficients (ICCs) 0.77 (95% CI 0.71, 0.87) and 0.71 (95% CI 0.52, 0.83)] and moderate for bone oedema [ICC = 0.60 (95% CI 0.36, 0.77)]. Compared with DECT, MRI had a specificity of 0.98 (95% CI 0.93, 0.99) and sensitivity of 0.63 (95% CI 0.48, 0.76) for tophi. Erosions were detected in 63% of patients and were strongly associated with tophi [odds ratio (OR) = 13.0 (95% CI 1.5, 113)]. In contrast, no association was found between erosions and bone oedema. Using concordant data, bone oedema was scored at 6/548 (1%) sites in 5/40 patients (12.5%) and was very mild (median carpal score = 1, maximum = 45). In logistic regression analysis across all joints nested within individuals, tophus, but not synovitis, was independently associated with erosion [OR = 156.5 (21.2, >999.9), P < 0.0001]. Erosions were strongly associated with tophi but not bone oedema or synovitis. MRI bone oedema was relatively uncommon and low grade. These findings highlight the unique nature of the osteopathology of gout.

Gene Regulation and Targeted Therapy in Gastric Cancer Peritoneal Metastasis: Radiological Findings from Dual Energy CT and PET/CT.

PubMed

Shi, Bowen; Lin, Huimin; Zhang, Miao; Lu, Wei; Qu, Ying; Zhang, Huan

2018-01-22

Gastric cancer remains fourth in cancer incidence worldwide with a five-year survival of only 20%-30%. Peritoneal metastasis is the most frequent type of metastasis that accompanies unresectable gastric cancer and is a definitive determinant of prognosis. Preventing and controlling the development of peritoneal metastasis could play a role in helping to prolong the survival of gastric cancer patients. A non-invasive and efficient imaging technique will help us to identify the invasion and metastasis process of peritoneal metastasis and to monitor the changes in tumor nodules in response to treatments. This will enable us to obtain an accurate description of the development process and molecular mechanisms of gastric cancer. We have recently described experiment using dual energy CT (DECT) and positron emission tomography/computed tomography (PET/CT) platforms for the detection and monitoring of gastric tumor metastasis in nude mice models. We have shown that weekly continuous monitoring with DECT and PET/CT can identify dynamic changes in peritoneal metastasis. The sFRP1-overexpression in gastric cancer mice models showed positive radiological performance, a higher FDG uptake and increasing enhancement, and the SUVmax (standardized uptake value) of nodules demonstrated an obvious alteration trend in response to targeted therapy of TGF-β1 inhibitor. In this article, we described the detailed non-invasive imaging procedures to conduct more complex research on gastric cancer peritoneal metastasis using animal models and provided representative imaging results. The use of non-invasive imaging techniques should enable us to better understand the mechanisms of tumorigenesis, monitor tumor growth, and evaluate the effect of therapeutic interventions for gastric cancer.

Application of dual-energy CT to suppression of metal artefact caused by pedicle screw fixation in radiotherapy: a feasibility study using original phantom

NASA Astrophysics Data System (ADS)

Wang, Tianyuan; Ishihara, Takeaki; Kono, Atsushi; Yoshida, Naoki; Akasaka, Hiroaki; Mukumoto, Naritoshi; Yada, Ryuichi; Ejima, Yasuo; Yoshida, Kenji; Miyawaki, Daisuke; Kakutani, Kenichiro; Nishida, Kotaro; Negi, Noriyuki; Minami, Toshiaki; Aoyama, Yuuichi; Takahashi, Satoru; Sasaki, Ryohei

2017-08-01

The objective of the present study was the determination of the potential dosimetric benefits of using metal-artefact-suppressed dual-energy computed tomography (DECT) images for cases involving pedicle screw implants in spinal sites. A heterogeneous spinal phantom was designed for the investigation of the dosimetric effect of the pedicle-screw-related artefacts. The dosimetric comparisons were first performed using a conventional two-directional opposed (AP-PA) plan, and then a volumetric modulated arc therapy (VMAT) plan, which are both used for the treatment of spinal metastases in our institution. The results of Acuros® XB dose-to-medium (Dm) and dose-to-water (Dw) calculations using different imaging options were compared with experimental measurements including the chamber and film dosimetries in the spinal phantom. A dual-energy composition image with a weight factor of  -0.2 and a dual-energy monochromatic image (DEMI) with an energy level of 180 keV were found to have superior abilities for artefact suppression. The Dm calculations revealed greater dosimetric effects of the pedicle screw-related artefacts compared to the Dw calculations. The results of conventional single-energy computed tomography showed that, although the pedicle screws were made from low-Z titanium alloy, the metal artefacts still have dosimetric effects, namely, an average (maximum) Dm error of 4.4% (5.6%) inside the spinal cord for a complex VMAT treatment plan. Our findings indicate that metal-artefact suppression using the proposed DECT (DEMI) approach is promising for improving the dosimetric accuracy near the implants and inside the spinal cord (average (maximum) Dm error of 1.1% (2.0%)).

Virtual non-contrast in second-generation, dual-energy computed tomography: reliability of attenuation values.

PubMed

Toepker, Michael; Moritz, Thomas; Krauss, Bernhard; Weber, Michael; Euller, Gordon; Mang, Thomas; Wolf, Florian; Herold, Christian J; Ringl, Helmut

2012-03-01

To evaluate the reliability of attenuation values in virtual non-contrast images (VNC) reconstructed from contrast-enhanced, dual-energy scans performed on a second-generation dual-energy CT scanner, compared to single-energy, non-contrast images (TNC). Sixteen phantoms containing a mixture of contrast agent and water at different attenuations (0-1400 HU) were investigated on a Definition Flash-CT scanner using a single-energy scan at 120 kV and a DE-CT protocol (100 kV/SN140 kV). For clinical assessment, 86 patients who received a dual-phase CT, containing an unenhanced single-energy scan at 120 kV and a contrast enhanced (110 ml Iomeron 400 mg/ml; 4 ml/s) DE-CT (100 kV/SN140 kV) in an arterial (n=43) or a venous phase, were retrospectively analyzed. Mean attenuation was measured within regions of interest of the phantoms and in different tissue types of the patients within the corresponding VNC and TNC images. Paired t-tests and Pearson correlation were used for statistical analysis. For all phantoms, mean attenuation in VNC was 5.3±18.4 HU, with respect to water. In 86 patients overall, 2637 regions were measured in TNC and VNC images, with a mean difference between TNC and VNC of -3.6±8.3 HU. In 91.5% (n=2412) of all cases, absolute differences between TNC and VNC were under 15HU, and, in 75.3% (n=1986), differences were under 10 HU. Second-generation dual-energy CT based VNC images provide attenuation values close to those of TNC. To avoid possible outliers multiple measurements are recommended especially for measurements in the spleen, the mesenteric fat, and the aorta. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Mobile phone radiation causes brain tumors and should be classified as a probable human carcinogen (2A) (review).

PubMed

Morgan, L Lloyd; Miller, Anthony B; Sasco, Annie; Davis, Devra Lee

2015-05-01

Quickly changing technologies and intensive uses of radiofrequency electromagnetic field (RF-EMF)‑emitting phones pose a challenge to public health. Mobile phone users and uses and exposures to other wireless transmitting devices (WTDs) have increased in the past few years. We consider that CERENAT, a French national study, provides an important addition to the literature evaluating the use of mobile phones and risk of brain tumors. The CERENAT finding of increased risk of glioma is consistent with studies that evaluated use of mobile phones for a decade or longer and corroborate those that have shown a risk of meningioma from mobile phone use. In CERENAT, exposure to RF‑EMF from digitally enhanced cordless telephones (DECTs), used by over half the population of France during the period of this study, was not evaluated. If exposures to DECT phones could have been taken into account, the risks of glioma from mobile phone use in CERENAT are likely to be higher than published. We conclude that radiofrequency fields should be classified as a Group 2A ̔probable̓ human carcinogen under the criteria used by the International Agency for Research on Cancer (Lyon, France). Additional data should be gathered on exposures to mobile and cordless phones, other WTDs, mobile phone base stations and Wi‑Fi routers to evaluate their impact on public health. We advise that the as low as reasonable achievable (ALARA) principle be adopted for uses of this technology, while a major cross‑disciplinary effort is generated to train researchers in bioelectromagnetics and provide monitoring of potential health impacts of RF‑EMF.

Dual-energy CT in patients with abdominal malignant lymphoma: impact of noise-optimised virtual monoenergetic imaging on objective and subjective image quality.

PubMed

Lenga, L; Czwikla, R; Wichmann, J L; Leithner, D; Albrecht, M H; D'Angelo, T; Arendt, C T; Booz, C; Hammerstingl, R; Vogl, T J; Martin, S S

2018-06-05

To investigate the impact of noise-optimised virtual monoenergetic imaging (VMI+) reconstructions on quantitative and qualitative image parameters in patients with malignant lymphoma at dual-energy computed tomography (DECT) examinations of the abdomen. Thirty-five consecutive patients (mean age, 53.8±18.6 years; range, 21-82 years) with histologically proven malignant lymphoma of the abdomen were included retrospectively. Images were post-processed with standard linear blending (M_0.6), traditional VMI, and VMI+ technique at energy levels ranging from 40 to 100 keV in 10 keV increments. Signal-to-noise (SNR) and contrast-to-noise ratios (CNR) were objectively measured in lymphoma lesions. Image quality, lesion delineation, and image noise were rated subjectively by three blinded observers using five-point Likert scales. Quantitative image quality parameters peaked at 40-keV VMI+ (SNR, 15.77±7.74; CNR, 18.27±8.04) with significant differences compared to standard linearly blended M_0.6 (SNR, 7.96±3.26; CNR, 13.55±3.47) and all traditional VMI series (p<0.001). Qualitative image quality assessment revealed significantly superior ratings for image quality at 60-keV VMI+ (median, 5) in comparison with all other image series (p<0.001). Assessment of lesion delineation showed the highest rating scores for 40-keV VMI+ series (median, 5), while lowest subjective image noise was found for 100-keV VMI+ reconstructions (median, 5). Low-keV VMI+ reconstructions led to improved image quality and lesion delineation of malignant lymphoma lesions compared to standard image reconstruction and traditional VMI at abdominal DECT examinations. Copyright © 2018 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

Fused monochromatic imaging acquired by single source dual energy CT in hepatocellular carcinoma during arterial phase: an initial experience.

PubMed

Gao, Shun-Yu; Zhang, Xiao-Peng; Cui, Yong; Sun, Ying-Shi; Tang, Lei; Li, Xiao-Ting; Zhang, Xiao-Yan; Shan, Jun

2014-08-01

To explore whether single and fused monochromatic images can improve liver tumor detection and delineation by single source dual energy CT (ssDECT) in patients with hepatocellular carcinoma (HCC) during arterial phase. Fifty-seven patients with HCC who underwent ssDECT scanning at Beijing Cancer Hospital were enrolled retrospectively. Twenty-one sets of monochromatic images from 40 to 140 keV were reconstructed at 5 keV intervals in arterial phase. The optimal contrast-noise ratio (CNR) monochromatic images of the liver tumor and the lowest-noise monochromatic images were selected for image fusion. We evaluated the image quality of the optimal-CNR monochromatic images, the lowest-noise monochromatic images and the fused monochromatic images, respectively. The evaluation indicators included the spatial resolution of the anatomical structure, the noise level, the contrast and CNR of the tumor. In arterial phase, the anatomical structure of the liver can be displayed most clearly in the 65-keV monochromatic images, with the lowest image noise. The optimal-CNR monochromatic images of HCC tumor were 50-keV monochromatic images in which the internal structural features of the liver tumors were displayed most clearly and meticulously. For tumor detection, the fused monochromatic images and the 50-keV monochromatic images had similar performances, and were more sensitive than 65-keV monochromatic images. We achieved good arterial phase images by fusing the optimal-CNR monochromatic images of the HCC tumor and the lowest-noise monochromatic images. The fused images displayed liver tumors and anatomical structures more clearly, which is potentially helpful for identifying more and smaller HCC tumors.

Distribution of MCA-coated grits in maize fields after high wheel tractor application for disrupting orientation of Diabrotica virgifera virgifera LeConte.

PubMed

Wennemann, Ludger; Hummel, Hans E

2002-01-01

High wheel tractor applications of 4-methoxycinnamaldehyde (MCA)-coated corn granules ('grits') were conducted in Ruski Krstur (Serbia) in summer 2001 in a 5 ha corn field. Grits are a by-product after corn is harvested and separated from the cob and used as a carrier medium to disseminate MCA into the corn field. MCA is a kairomone mimic derived form Cucurbita maxima (Duchesne) used to disrupt orientation of Diabrotica virgifera virgifera LeConte towards different MCA and pheromone baited traps. The ultimate goal is to investigate the use of MCA as a mating disruptant. MCA was dissolved in an organic solvent and mixed in a cement machine with the grits. Grits were applied at rates of 17.39, 17.1 and 12.45 kg/ha on July 4th, July 19th and August 3rd. Before the impact of MCA as a disruptant can be addressed, the distribution patterns of MCA coated grits have to be thoroughly investigated. They were evaluated by counting girts deposited in 16 or 20 plastic dishes of 30-cm diameter positioned along 2 rows through the field directly after the grit application by tractor. Additionally, grits deposited on corn plant surface such as leaves, leaf axils and corn cobs were counted. Total number of grits collected in plastic dishes revealed even application rates at the first and second application but not on the third application date. Number of grits collected on plant surfaces were significantly different from each other regarding each application date. Altogether, grit distribution in the dishes as well as on the plant surface was variable. However, distribution patterns achieved so far hold promise to disseminate MCA coated grits into corn fields for orientation disruption or mating disruption of D. virgifera virgifera.

The turbulent life of juvenile icebergs: Observations from an array of high-rate time-lapse cameras in LeConte Bay, Alaska

NASA Astrophysics Data System (ADS)

Kienholz, C.; Amundson, J. M.; Jackson, R. H.; Motyka, R. J.; Nash, J. D.; Sutherland, D.

2017-12-01

Tidewater glacier behavior is driven by poorly understood processes occurring at the ice-ocean interface, including sedimentation and erosion, iceberg calving, and submarine melting. These processes are inherently difficult to observe, calling for innovative field techniques and numerical models. As part of a multi-year field effort to constrain ocean-glacier heat and mass exchange, we deployed an array of high-rate time-lapse cameras (sampling intervals between 15 seconds and 2 minutes) to monitor the terminus of LeConte Glacier and its proglacial fjord. The camera array has operated continuously for more than a year. Our high sampling rates enable tracking of iceberg motion with optical flow algorithms, which have been used widely in computer vision but less so in glaciology and oceanography. Such algorithms track individual features (e.g., corners of icebergs), which is ideal for iceberg-rich fjords, where motion can vary substantially over short temporal and spatial scales (e.g., due to complex surface currents or different iceberg sizes). We process our data to quantify subdaily to seasonal patterns in surface currents and relate them to forcing from tides, wind, and glacier runoff. Flow is most variable close to the glacier terminus due to frequent calving events and turbulent plume dynamics. Farther down fjord, more consistent patterns emerge, driven by tides, wind, and runoff and altered by fjord geometry. Our tracking results compare favorably to and complement our Acoustic Doppler Current Profiler measurements from boats and moorings. Given their high spatial and temporal resolution, our observations will place important surface constraints on forthcoming hydrodynamic modeling efforts. The deployment of the cameras in a harsh environment and the corresponding image processing provided an opportunity to test hardware and software thoroughly, which will prove useful for similar systems at other glaciers.

Determination of selenium in fish from designated critical habitat in the Gunnison River, Colorado, March through October, 2012

USGS Publications Warehouse

May, Thomas W.; Walther, Michael J.

2013-01-01

This report presents results for the summer 2012 sam-pling of muscle plugs from common carp (Cyprinus carpio), bonytail chub (Gila elegans), Colorado pikeminnow (Ptycho-cheilus lucius), and razorback suckers (Xyrauchen texanus) inhabiting critical habitat in the Gunnison River in western Colorado. Total selenium in fish muscle plugs was determinedby instrumental neutron activation analysis. Total selenium concentrations (range and mean ± standard deviation) in micrograms per gram dry weight were 6.0 to 10.7, 8.8 ± 1.3 for common carp; 2.9 to 8.7, 5.6 ± 2.4 for Colorado pikemin-now; and 1.4 to 7.3, 3.4 ± 2.7 for razorback sucker. The selenium concentration for one bonytail chub sample was 0.8 micrograms per gram dry weight. Selenium concentrations in muscle plugs from 1 Colorado pikeminnow and 12 common carp exceeded the 8 micrograms per gram dry weight toxicity guideline for selenium in fish muscle tissue.

A review of the genus Berosus Leach of Cuba (Coleoptera, Hydrophilidae)

PubMed Central

Deler-Hernández, Albert; Fikáček, Martin; Cala-Riquelme, Franklyn

2013-01-01

Abstract The Cuban fauna of the genus Berosus Leach, 1817 is reviewed based on newly collected material as well as historical and type specimens. Nine species are recognized, including three recorded from Cuba for the first time: Berosus infuscatus LeConte, 1855, Berosus interstitialis Knisch, 1924 (= Berosus stribalus Orchymont, 1946 syn. n.) and Berosus metalliceps Sharp, 1882. Only one of the nine Cuban species, Berosus chevrolati, remains endemic to Cuba, as two other species previously considered as endemic to Cuba are recorded from elsewhere: Berosus quadridens from Mexico and Central America and Berosus trilobus from the Dominican Republic. Notes on biology and Cuban distribution are provided for all nine species. Berosus quadridens Chevrolat, 1863, stat. restit. is removed from synonym with Berosus truncatipennis and considered a valid species. PMID:23794806

New Staphylinidae (Coleoptera) records with new collection data from New Brunswick and an addition to the fauna of Quebec: Staphylininae

PubMed Central

Webster, Reginald P.; Smetana, Aleš; Sweeney, Jon D.; DeMerchant, Ian

2012-01-01

Abstract Forty-four species of Staphylininae are newly reported from New Brunswick, bringing the total number of species known from the province to 126. Quedius criddlei (Casey) is reported for the first time from Quebec. Bisnius cephalotes (Gravenhorst) is removed from the faunal list of New Brunswick due to a lack of supporting voucher specimens. Additional locality data are presented for seven species either recently recorded from the province or with few previous records and little habitat data. We provide the first documented records of Atrecus americanus (Casey), Quedius erythrogaster Mannerheim, Quedius labradorensis labradorensis Smetana, Quedius plagiatus (Mannerheim), and Neobisnius terminalis (LeConte) from New Brunswick. Collection and habitat data are presented and discussed for all species. PMID:22577325

New Coleoptera records from New Brunswick, Canada: Anthribidae, Brentidae, Dryophthoridae, Brachyceridae, and Curculionidae, with additions to the fauna of Quebec, Nova Scotia and Prince Edward Island

PubMed Central

Webster, Reginald P.; Anderson, Robert S.; Sweeney, Jon D.; DeMerchant, Ian

2012-01-01

Abstract We report 63 species of Curculionoidea that are new to New Brunswick (three species of Anthribidae, four species of Brentidae, three species of Dryophthoridae, three species of Brachyceridae, 50 species of Curculionidae). Among these are 27 species (two Anthribidae, two Brenthidae, one Brachyceridae, 22 Curculionidae) that are also newly recorded for the Maritime provinces, and one species, Plesiobaris disjuncta Casey (Curculionidae) that is newly recorded for Canada from New Brunswick and Quebec. Bagous planatus LeConte is reinstated to the faunal list of New Brunswick. Two species of Curculionidae are newly recorded from Nova Scotia and the Maritime provinces, and two others are reported for the first time for Prince Edward Island. PMID:22539901

SU-G-IeP3-04: Effective Dose Measurements in Fast Kvp Switch Dual Energy Computed Tomography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Raudabaugh, J; Moore, B; Nguyen, G

2016-06-15

Purpose: The objective of this study was two-fold: (a) to test a new approach to approximating organ dose by using the effective energy of the combined 80kV/140kV beam in dual-energy (DE) computed tomography (CT), and (b) to derive the effective dose (ED) in the abdomen-pelvis protocol in DECT. Methods: A commercial dual energy CT scanner was employed using a fast-kV switch abdomen/pelvis protocol alternating between 80 kV and 140 kV. MOSFET detectors were used for organ dose measurements. First, an experimental validation of the dose equivalency between MOSFET and ion chamber (as a gold standard) was performed using a CTDImore » phantom. Second, the ED of DECT scans was measured using MOSFET detectors and an anthropomorphic phantom. For ED calculations, an abdomen/pelvis scan was used using ICRP 103 tissue weighting factors; ED was also computed using the AAPM Dose Length Product (DLP) method and compared to the MOSFET value. Results: The effective energy was determined as 42.9 kV under the combined beam from half-value layer (HVL) measurement. ED for the dual-energy scan was calculated as 16.49 ± 0.04 mSv by the MOSFET method and 14.62 mSv by the DLP method. Conclusion: Tissue dose in the center of the CTDI body phantom was 1.71 ± 0.01 cGy (ion chamber) and 1.71 ± 0.06 (MOSFET) respectively; this validated the use of effective energy method for organ dose estimation. ED from the abdomen-pelvis scan was calculated as 16.49 ± 0.04 mSv by MOSFET and 14.62 mSv by the DLP method; this suggests that the DLP method provides a reasonable approximation to the ED.« less

Rapid kV-switching single-source dual-energy CT ex vivo renal calculi characterization using a multiparametric approach: refining parameters on an expanded dataset.

PubMed

Kriegshauser, J Scott; Paden, Robert G; He, Miao; Humphreys, Mitchell R; Zell, Steven I; Fu, Yinlin; Wu, Teresa; Sugi, Mark D; Silva, Alvin C

2018-06-01

We aimed to determine the best algorithms for renal stone composition characterization using rapid kV-switching single-source dual-energy computed tomography (rsDECT) and a multiparametric approach after dataset expansion and refinement of variables. rsDECT scans (80 and 140 kVp) were performed on 38 ex vivo 5- to 10-mm renal stones composed of uric acid (UA; n = 21), struvite (STR; n = 5), cystine (CYS; n = 5), and calcium oxalate monohydrate (COM; n = 7). Measurements were obtained for 17 variables: mean Hounsfield units (HU) at 11 monochromatic keV levels, effective Z, 2 iodine-water material basis pairs, and 3 mean monochromatic keV ratios (40/140, 70/120, 70/140). Analysis included using 5 multiparametric algorithms: Support Vector Machine, RandomTree, Artificial Neural Network, Naïve Bayes Tree, and Decision Tree (C4.5). Separating UA from non-UA stones was 100% accurate using multiple methods. For non-UA stones, using a 70-keV mean cutoff value of 694 HU had 100% accuracy for distinguishing COM from non-COM (CYS, STR) stones. The best result for distinguishing all 3 non-UA subtypes was obtained using RandomTree (15/17, 88%). For stones 5 mm or larger, multiple methods can distinguish UA from non-UA and COM from non-COM stones with 100% accuracy. Thus, the choice for analysis is per the user's preference. The best model for separating all three non-UA subtypes was 88% accurate, although with considerable individual overlap between CYS and STR stones. Larger, more diverse datasets, including in vivo data and technical improvements in material separation, may offer more guidance in distinguishing non-UA stone subtypes in the clinical setting.

Detection of different kidney stone types: an ex vivo comparison of ultrashort echo time MRI to reference standard CT.

PubMed

Ibrahim, El-Sayed H; Cernigliaro, Joseph G; Pooley, Robert A; Bridges, Mellena D; Giesbrandt, Jamie G; Williams, James C; Haley, William E

2016-01-01

With the development of ultrashort echo time (UTE) sequences, it may now be possible to detect kidney stones by using magnetic resonance imaging (MRI). In this study, kidney stones of varying composition and sizes were imaged using both UTE MRI as well as the reference standard of computed tomography (CT), with different surrounding materials and scan setups. One hundred and fourteen kidney stones were inserted into agarose and urine phantoms and imaged both on a dual-energy CT (DECT) scanner using a standard renal stone imaging protocol and on an MRI scanner using the UTE sequence with both head and body surface coils. A subset of the stones representing all composition types and sizes was then inserted into the collecting system of porcine kidneys and imaged in vitro with both CT and MRI. All of the stones were visible on both CT and MRI imaging. DECT was capable of differentiating between uric acid and nonuric acid stones. In MRI imaging, the choice of coil and large field of view (FOV) did not affect stone detection or image quality. The MRI images showed good visualization of the stones' shapes, and the stones' dimensions measured from MRI were in good agreement with the actual values (R(2)=0.886, 0.895, and 0.81 in the agarose phantom, urine phantom, and pig kidneys, respectively). The measured T2 relaxation times ranged from 4.2 to 7.5ms, but did not show significant differences among different stone composition types. UTE MRI compared favorably with the reference standard CT for imaging stones of different composition types and sizes using body surface coil and large FOV, which suggests potential usefulness of UTE MRI in imaging kidney stones in vivo. Copyright © 2015 Elsevier Inc. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sorensen, J; Duran, C; Stingo, F

Purpose: To characterize the effect of virtual monochromatic reconstructions on several commonly used texture analysis features in DECT of the chest. Further, to assess the effect of monochromatic energy levels on the ability of these textural features to identify tissue types. Methods: 20 consecutive patients underwent chest CTs for evaluation of lung nodules using Siemens Somatom Definition Flash DECT. Virtual monochromatic images were constructed at 10keV intervals from 40–190keV. For each patient, an ROI delineated the lesion under investigation, and cylindrical ROI’s were placed within 5 different healthy tissues (blood, fat, muscle, lung, and liver). Several histogram- and Grey Levelmore » Cooccurrence Matrix (GLCM)-based texture features were then evaluated in each ROI at each energy level. As a means of validation, these feature values were then used in a random forest classifier to attempt to identify the tissue types present within each ROI. Their predictive accuracy at each energy level was recorded. Results: All textural features changed considerably with virtual monochromatic energy, particularly below 70keV. Most features exhibited a global minimum or maximum around 80keV, and while feature values changed with energy above this, patient ranking was generally unaffected. As expected, blood demonstrated the lowest inter-patient variability, for all features, while lung lesions (encompassing many different pathologies) exhibited the highest. The accuracy of these features in identifying tissues (76% accuracy) was highest at 80keV, but no clear relationship between energy and classification accuracy was found. Two common misclassifications (blood vs liver and muscle vs fat) accounted for the majority (24 of the 28) errors observed. Conclusion: All textural features were highly dependent on virtual monochromatic energy level, especially below 80keV, and were more stable above this energy. However, in a random forest model, these commonly used features were able to reliably differentiate between most tissues types regardless of energy level. Dr Godoy has received a dual-energy CT research grant from Siemens Healthcare. That grant did not directly fund this research.« less

Carotid dual-energy CT angiography: Evaluation of low keV calculated monoenergetic datasets by means of a frequency-split approach for noise reduction at low keV levels.

PubMed

Riffel, Philipp; Haubenreisser, Holger; Meyer, Mathias; Sudarski, Sonja; Morelli, John N; Schmidt, Bernhard; Schoenberg, Stefan O; Henzler, Thomas

2016-04-01

Calculated monoenergetic ultra-low keV datasets did not lead to improved contrast-to-noise ratio (CNR) due to the dramatic increase in image noise. The aim of the present study was to evaluate the objective image quality of ultra-low keV monoenergetic images (MEIs) calculated from carotid DECT angiography data with a new monoenergetic imaging algorithm using a frequency-split technique. 20 patients (12 male; mean age 53±17 years) were retrospectively analyzed. MEIs from 40 to 120 keV were reconstructed using the monoenergetic split frequency approach (MFSA). Additionally MEIs were reconstructed for 40 and 50 keV using a conventional monoenergetic (CM) software application. Signal intensity, noise, signal-to-noise ratio (SNR) and CNR were assessed in the basilar, common, internal carotid arteries. Ultra-low keV MEIs at 40 keV and 50 keV demonstrated highest vessel attenuation, significantly greater than those of the polyenergetic images (PEI) (all p-values <0.05). The highest SNR level and CNR level was found at 40 keV and 50 keV (all p-values <0.05). MEIs with MFSA showed significantly lower noise levels than those processed with CM (all p-values <0.05) and no significant differences in vessel attenuation (p>0.05). Thus MEIs with MFSA showed significantly higher SNR and CNR compared to MEIs with CM. Combining the lower spatial frequency stack for contrast at low keV levels with the high spatial frequency stack for noise at high keV levels (frequency-split technique) leads to improved image quality of ultra-low keV monoenergetic DECT datasets when compared to previous monoenergetic reconstruction techniques without the frequency-split technique. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Technical Note: Improved CT number stability across patient size using dual-energy CT virtual monoenergetic imaging

DOE Office of Scientific and Technical Information (OSTI.GOV)

Michalak, Gregory; Grimes, Joshua; Fletcher, Joel

2016-01-15

Purpose: The purpose of this study was to evaluate, over a wide range of phantom sizes, CT number stability achieved using two techniques for generating dual-energy computed tomography (DECT) virtual monoenergetic images. Methods: Water phantoms ranging in lateral diameter from 15 to 50 cm and containing a CT number test object were scanned on a DSCT scanner using both single-energy (SE) and dual-energy (DE) techniques. The SE tube potentials were 70, 80, 90, 100, 110, 120, 130, 140, and 150 kV; the DE tube potential pairs were 80/140, 70/150Sn, 80/150Sn, 90/150Sn, and 100/150Sn kV (Sn denotes that the 150 kVmore » beam was filtered with a 0.6 mm tin filter). Virtual monoenergetic images at energies ranging from 40 to 140 keV were produced from the DECT data using two algorithms, monoenergetic (mono) and monoenergetic plus (mono+). Particularly in large phantoms, water CT number errors and/or artifacts were observed; thus, datasets with water CT numbers outside ±10 HU or with noticeable artifacts were excluded from the study. CT numbers were measured to determine CT number stability across all phantom sizes. Results: Data exclusions were generally limited to cases when a SE or DE technique with a tube potential of less than 90 kV was used to scan a phantom larger than 30 cm. The 90/150Sn DE technique provided the most accurate water background over the large range of phantom sizes evaluated. Mono and mono+ provided equally improved CT number stability as a function of phantom size compared to SE; the average deviation in CT number was only 1.4% using 40 keV and 1.8% using 70 keV, while SE had an average deviation of 11.8%. Conclusions: The authors’ report demonstrates, across all phantom sizes, the improvement in CT number stability achieved with mono and mono+ relative to SE.« less

Optimization of window settings for standard and advanced virtual monoenergetic imaging in abdominal dual-energy CT angiography.

PubMed

Caruso, Damiano; Parinella, Ashley H; Schoepf, U Joseph; Stroebel, Maxwell H; Mangold, Stefanie; Wichmann, Julian L; Varga-Szemes, Akos; Ball, B Devon; De Santis, Domenico; Laghi, Andrea; De Cecco, Carlo N

2017-03-01

To determine the optimal window setting for displaying virtual monoenergetic reconstructions of third generation dual-source, dual-energy CT (DECT) angiography of the abdomen. Forty-five patients were evaluated with DECT angiography (90/150 kV, 180/90 ref. mAs). Three datasets were reconstructed: standard linear blending (M_0.6), 70 keV traditional virtual monoenergetic (M70), and 40 keV advanced noise-optimized virtual monoenergetic (M40+). The best window setting (width and level, W/L) was assessed by two blinded observers and was correlated with aortic attenuation to obtain the Optimized W/L setting (O-W/L). Subjective image quality was assessed, and vessel diameters were measured to determine any possible influences between different W/L settings. Repeated measures of variance were used to evaluate comparison of W/L values, image quality, and vessel sizing between M_0.6, M70, and M40+. The Best W/L (B-W/L) for M70 and M40+ was 880/280 and 1410/450, respectively. Results from regression analysis inferred an O-W/L of 850/270 for M70 and 1350/430 for M40+. Significant differences for W and L were found between the Best and the Optimized W/L for M40+, and between M70 and M40+ for both the Best and Optimized W/L. No significant differences for vessel measurements were found using the O-W/L for M40+ compared to the standard M_0.6 (p ≥ 0.16), and significant differences were observed when using the B-W/L with M40+ compared to M_0.6 (p ≤ 0.04). In order to optimize virtual monoenergetic imaging with both traditional M70 and advanced M40+, adjusting the W/L settings is necessary. Our results suggest a W/L setting of 850/270 for M70 and 1350/430 for M40+.

Technical Note: Improved CT number stability across patient size using dual-energy CT virtual monoenergetic imaging.

PubMed

Michalak, Gregory; Grimes, Joshua; Fletcher, Joel; Halaweish, Ahmed; Yu, Lifeng; Leng, Shuai; McCollough, Cynthia

2016-01-01

The purpose of this study was to evaluate, over a wide range of phantom sizes, CT number stability achieved using two techniques for generating dual-energy computed tomography (DECT) virtual monoenergetic images. Water phantoms ranging in lateral diameter from 15 to 50 cm and containing a CT number test object were scanned on a DSCT scanner using both single-energy (SE) and dual-energy (DE) techniques. The SE tube potentials were 70, 80, 90, 100, 110, 120, 130, 140, and 150 kV; the DE tube potential pairs were 80/140, 70/150Sn, 80/150Sn, 90/150Sn, and 100/150Sn kV (Sn denotes that the 150 kV beam was filtered with a 0.6 mm tin filter). Virtual monoenergetic images at energies ranging from 40 to 140 keV were produced from the DECT data using two algorithms, monoenergetic (mono) and monoenergetic plus (mono+). Particularly in large phantoms, water CT number errors and/or artifacts were observed; thus, datasets with water CT numbers outside ±10 HU or with noticeable artifacts were excluded from the study. CT numbers were measured to determine CT number stability across all phantom sizes. Data exclusions were generally limited to cases when a SE or DE technique with a tube potential of less than 90 kV was used to scan a phantom larger than 30 cm. The 90/150Sn DE technique provided the most accurate water background over the large range of phantom sizes evaluated. Mono and mono+ provided equally improved CT number stability as a function of phantom size compared to SE; the average deviation in CT number was only 1.4% using 40 keV and 1.8% using 70 keV, while SE had an average deviation of 11.8%. The authors' report demonstrates, across all phantom sizes, the improvement in CT number stability achieved with mono and mono+ relative to SE.

Wetlands Research Program Bulletin. Volume 5. Number 1

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gilbert, M.C.; Stutheit, R.G.; Davis, M.

1995-03-01

The city of Lincoln, Neb., was founded in the mid-18OOs along Salt Creek. During the last century, the saline marshes suffered extensive degradation through commercial and residential development, road construction, and agriculture. Today, Nebraska`s eastern saline wetlands are considered to be among the most restricted and imperiled ecosystems. Eastern Nebraska saline wetlands are regionally unique, located in floodplain swales and depressions within the Salt Creek and Rock Creek watersheds in Lancaster and southern Saunders counties. Water sources are a combination of discharge from the Dakota sandstone formation aquifer, precipitation, and overbank flooding. Salts are concentrated in the soil during drymore » periods. Vegetation in these wetlands is characterized by halophytes including spearscale (Atriplex subspicata), inland saltgrass (Distichlis spicata var. stricta), saltwort (Sa1icornia rubra), prairie bulrush (Scirpus mantimus var. paludosus), sea blite (Suaeda depressa), and narrow-leaved cattail (Typha angustifolia). Four plant species considered rare in Nebraska are saltmarsh aster (Aster subulatus var. ligulatus), seaside heliotrope (Heliotropium curassavicurn), saltwort, and Texas dropseed (Sporobolus texanus) can be found in the marshes along Salt Creek.« less

Commentary: selenium study on endangered razorback sucker is flawed

USGS Publications Warehouse

Hamilton, Steven J.

2005-01-01

The razorback sucker (Xyrauchen texanus) is listed as federally endangered throughout its range. A massive recovery effort by the Recovery Implementation Program for Endangered Fish Species in the Upper Colorado River Basin has focused its efforts in the upper Colorado River. The upper Colorado River basin also has two locations that have been identified by the National Irrigation Water Quality Program as having substantial selenium contamination. Selenium is toxic to fishes, affecting reproductive success. Thus, there is concern about potential effects of selenium on the endangered razorback sucker. Two sets of studies have investigated the effects of selenium on razorback suckers, but study results are conflicting. This commentary evaluates studies that claim selenium is not a problem for razorback sucker. We find that study bias was so pervasive that purported conclusions were unwarranted. Contaminated control water, older life stages of fish tested, lack of methodology for analysis of selenium in water, diet, or fish, use of rotifer food, low feeding rates, low growth rates of fish, and improper storage of site waters resulted in an apparent erroneous linkage of high selenium in whole-body residues with no adverse effects.

Histone and ribosomal RNA repetitive gene clusters of the boll weevil are linked in a tandem array.

PubMed

Roehrdanz, R; Heilmann, L; Senechal, P; Sears, S; Evenson, P

2010-08-01

Histones are the major protein component of chromatin structure. The histone family is made up of a quintet of proteins, four core histones (H2A, H2B, H3 & H4) and the linker histones (H1). Spacers are found between the coding regions. Among insects this quintet of genes is usually clustered and the clusters are tandemly repeated. Ribosomal DNA contains a cluster of the rRNA sequences 18S, 5.8S and 28S. The rRNA genes are separated by the spacers ITS1, ITS2 and IGS. This cluster is also tandemly repeated. We found that the ribosomal RNA repeat unit of at least two species of Anthonomine weevils, Anthonomus grandis and Anthonomus texanus (Coleoptera: Curculionidae), is interspersed with a block containing the histone gene quintet. The histone genes are situated between the rRNA 18S and 28S genes in what is known as the intergenic spacer region (IGS). The complete reiterated Anthonomus grandis histone-ribosomal sequence is 16,248 bp.

Distribution and host associations of ixodid ticks collected from wildlife in Florida, USA.

PubMed

Hertz, Jeffrey C; Ferree Clemons, Bambi C; Lord, Cynthia C; Allan, Sandra A; Kaufman, Phillip E

2017-10-01

A tick survey was conducted to document tick-host associations with Florida (USA) wildlife, and to determine the relative abundance and distribution of ixodid ticks throughout the state. The survey was conducted using collection kits distributed to licensed Florida hunters as well as the examination of archived specimens from ongoing state wildlife research programs. Collected tick samples were obtained from 66% of Florida counties and were collected from nine wildlife hosts, including black bear, bobcat, coyote, deer, gray fox, Florida panther, raccoon, swine, and wild turkey. In total, 4176 ticks were identified, of which 75% were Amblyomma americanum, 14% Ixodes scapularis, 8% A. maculatum, 3% Dermacentor variabilis, and < 1% were I. affinis and I. texanus. americanum, D. variabilis, and I. scapularis had the broadest host range, while A. maculatum, D. variabilis, and I. scapularis had the widest geographic distribution. While the survey data contribute to an understanding of tick-host associations in Florida, they also provide insight into the seasonal and geographic distribution of several important vector species in the southeastern USA.

DECT evaluation of noncalcified coronary artery plaque

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ravanfar Haghighi, Rezvan; Chatterjee, S.; Tabin, Milo

2015-10-15

Purpose: Composition of the coronary artery plaque is known to have critical role in heart attack. While calcified plaque can easily be diagnosed by conventional CT, it fails to distinguish between fibrous and lipid rich plaques. In the present paper, the authors discuss the experimental techniques and obtain a numerical algorithm by which the electron density (ρ{sub e}) and the effective atomic number (Z{sub eff}) can be obtained from the dual energy computed tomography (DECT) data. The idea is to use this inversion method to characterize and distinguish between the lipid and fibrous coronary artery plaques. Methods: For the purposemore » of calibration of the CT machine, the authors prepare aqueous samples whose calculated values of (ρ{sub e}, Z{sub eff}) lie in the range of (2.65 × 10{sup 23} ≤ ρ{sub e} ≤ 3.64 × 10{sup 23}/cm{sup 3}) and (6.80 ≤ Z{sub eff} ≤ 8.90). The authors fill the phantom with these known samples and experimentally determine HU(V{sub 1}) and HU(V{sub 2}), with V{sub 1},V{sub 2} = 100 and 140 kVp, for the same pixels and thus determine the coefficients of inversion that allow us to determine (ρ{sub e}, Z{sub eff}) from the DECT data. The HU(100) and HU(140) for the coronary artery plaque are obtained by filling the channel of the coronary artery with a viscous solution of methyl cellulose in water, containing 2% contrast. These (ρ{sub e}, Z{sub eff}) values of the coronary artery plaque are used for their characterization on the basis of theoretical models of atomic compositions of the plaque materials. These results are compared with histopathological report. Results: The authors find that the calibration gives ρ{sub e} with an accuracy of ±3.5% while Z{sub eff} is found within ±1% of the actual value, the confidence being 95%. The HU(100) and HU(140) are found to be considerably different for the same plaque at the same position and there is a linear trend between these two HU values. It is noted that pure lipid type plaques are practically nonexistent, and microcalcification, as observed in histopathology, has to be taken into account to explain the nature of the observed (ρ{sub e}, Z{sub eff}) data. This also enables us to judge the composition of the plaque in terms of basic model which considers the plaque to be composed of fibres, lipids, and microcalcification. Conclusions: This simple and reliable method has the potential as an effective modality to investigate the composition of noncalcified coronary artery plaques and thus help in their characterization. In this inversion method, (ρ{sub e}, Z{sub eff}) of the scanned sample can be found by eliminating the effects of the CT machine and also by ensuring that the determination of the two unknowns (ρ{sub e}, Z{sub eff}) does not interfere with each other and the nature of the plaque can be identified in terms of a three component model.« less

Experiences with population dynamics of Diabrotica virgifera virgifera LeConte in the Swiss canton of Ticino up to 2007.

PubMed

Bertossa, M; Hummel, Hans E

2008-01-01

The Western corn rootworm (WCR) Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae) is a vexing alien invasive insect pest. It occupies the attention of entomologists in most countries of Europe and beyond. In spite of numerous research advances (e.g., Diabrotica symposium at Engelberg, Switzerland 2004) its behavior is still incompletely understood and cannot be predicted for a specific growing season with any degree of certainty. Nonetheless, by comparing several years in sequence a somewhat consistent and coherent picture is emerging that is subject of this contribution. The Ticino province received first beetles from the major infestation in Lombardy in 2000 across the geographically open border at Chiasso. The rapid advance of WCR in northerly direction along the river valleys of Ticino and Misox posed a threat to cantons north of the mountain chain of the Alps and beyond, a scenario outlined by Bertossa (2004), Wudtke et al. (2005) and subsequent papers. Following the Swiss Federal rule of crop rotation obligation around infested regions introduced in 2001, the rapid increase in population density leveled off. Careful monitoring by both Metcalf type pheromone and kairomone baited sticky traps and Hungarian traps provided a reliable tool for judging the success of any quarantine measures taken up until 2007. (1) Trends in population development of 2006 were confirmed. (2) However, for reasons not well understood, the overall population encountered in 2007 was significantly smaller in Ticino and neighboring areas of Lombardy, Italy, but also in other areas south of the Alps. This may be a consequence of the rather mild winter 2006-2007. (3) At the mountain pass of Monte Ceneri (some 600 m above sea level) no beetles were trapped in 2007, while 3 WCR were seen in 2006. (4) No new WCR were encountered in Swiss cantons north of the main chain of the Alps. (5) Metcalf sticky traps proved to be 4-5 times as sensitive as Hungarian traps used for comparison. By and large, mandatory crop rotation was beneficial in reducing WCR populations in Ticino and avoided or delayed northbound spread of WCR.

Noise suppression for dual-energy CT via penalized weighted least-square optimization with similarity-based regularization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Harms, Joseph; Wang, Tonghe; Petrongolo, Michael

Purpose: Dual-energy CT (DECT) expands applications of CT imaging in its capability to decompose CT images into material images. However, decomposition via direct matrix inversion leads to large noise amplification and limits quantitative use of DECT. Their group has previously developed a noise suppression algorithm via penalized weighted least-square optimization with edge-preservation regularization (PWLS-EPR). In this paper, the authors improve method performance using the same framework of penalized weighted least-square optimization but with similarity-based regularization (PWLS-SBR), which substantially enhances the quality of decomposed images by retaining a more uniform noise power spectrum (NPS). Methods: The design of PWLS-SBR is basedmore » on the fact that averaging pixels of similar materials gives a low-noise image. For each pixel, the authors calculate the similarity to other pixels in its neighborhood by comparing CT values. Using an empirical Gaussian model, the authors assign high/low similarity value to one neighboring pixel if its CT value is close/far to the CT value of the pixel of interest. These similarity values are organized in matrix form, such that multiplication of the similarity matrix to the image vector reduces image noise. The similarity matrices are calculated on both high- and low-energy CT images and averaged. In PWLS-SBR, the authors include a regularization term to minimize the L-2 norm of the difference between the images without and with noise suppression via similarity matrix multiplication. By using all pixel information of the initial CT images rather than just those lying on or near edges, PWLS-SBR is superior to the previously developed PWLS-EPR, as supported by comparison studies on phantoms and a head-and-neck patient. Results: On the line-pair slice of the Catphan{sup ©}600 phantom, PWLS-SBR outperforms PWLS-EPR and retains spatial resolution of 8 lp/cm, comparable to the original CT images, even at 90% reduction in noise standard deviation (STD). Similar performance on spatial resolution is observed on an anthropomorphic head phantom. In addition, results of PWLS-SBR show substantially improved image quality due to preservation of image NPS. On the Catphan{sup ©}600 phantom, NPS using PWLS-SBR has a correlation of 93% with that via direct matrix inversion, while the correlation drops to −52% for PWLS-EPR. Electron density measurement studies indicate high accuracy of PWLS-SBR. On seven different materials, the measured electron densities calculated from the decomposed material images using PWLS-SBR have a root-mean-square error (RMSE) of 1.20%, while the results of PWLS-EPR have a RMSE of 2.21%. In the study on a head-and-neck patient, PWLS-SBR is shown to reduce noise STD by a factor of 3 on material images with image qualities comparable to CT images, whereas fine structures are lost in the PWLS-EPR result. Additionally, PWLS-SBR better preserves low contrast on the tissue image. Conclusions: The authors propose improvements to the regularization term of an optimization framework which performs iterative image-domain decomposition for DECT with noise suppression. The regularization term avoids calculation of image gradient and is based on pixel similarity. The proposed method not only achieves a high decomposition accuracy, but also improves over the previous algorithm on NPS as well as spatial resolution.« less

Noise suppression for dual-energy CT via penalized weighted least-square optimization with similarity-based regularization

PubMed Central

Harms, Joseph; Wang, Tonghe; Petrongolo, Michael; Niu, Tianye; Zhu, Lei

2016-01-01

Purpose: Dual-energy CT (DECT) expands applications of CT imaging in its capability to decompose CT images into material images. However, decomposition via direct matrix inversion leads to large noise amplification and limits quantitative use of DECT. Their group has previously developed a noise suppression algorithm via penalized weighted least-square optimization with edge-preservation regularization (PWLS-EPR). In this paper, the authors improve method performance using the same framework of penalized weighted least-square optimization but with similarity-based regularization (PWLS-SBR), which substantially enhances the quality of decomposed images by retaining a more uniform noise power spectrum (NPS). Methods: The design of PWLS-SBR is based on the fact that averaging pixels of similar materials gives a low-noise image. For each pixel, the authors calculate the similarity to other pixels in its neighborhood by comparing CT values. Using an empirical Gaussian model, the authors assign high/low similarity value to one neighboring pixel if its CT value is close/far to the CT value of the pixel of interest. These similarity values are organized in matrix form, such that multiplication of the similarity matrix to the image vector reduces image noise. The similarity matrices are calculated on both high- and low-energy CT images and averaged. In PWLS-SBR, the authors include a regularization term to minimize the L-2 norm of the difference between the images without and with noise suppression via similarity matrix multiplication. By using all pixel information of the initial CT images rather than just those lying on or near edges, PWLS-SBR is superior to the previously developed PWLS-EPR, as supported by comparison studies on phantoms and a head-and-neck patient. Results: On the line-pair slice of the Catphan©600 phantom, PWLS-SBR outperforms PWLS-EPR and retains spatial resolution of 8 lp/cm, comparable to the original CT images, even at 90% reduction in noise standard deviation (STD). Similar performance on spatial resolution is observed on an anthropomorphic head phantom. In addition, results of PWLS-SBR show substantially improved image quality due to preservation of image NPS. On the Catphan©600 phantom, NPS using PWLS-SBR has a correlation of 93% with that via direct matrix inversion, while the correlation drops to −52% for PWLS-EPR. Electron density measurement studies indicate high accuracy of PWLS-SBR. On seven different materials, the measured electron densities calculated from the decomposed material images using PWLS-SBR have a root-mean-square error (RMSE) of 1.20%, while the results of PWLS-EPR have a RMSE of 2.21%. In the study on a head-and-neck patient, PWLS-SBR is shown to reduce noise STD by a factor of 3 on material images with image qualities comparable to CT images, whereas fine structures are lost in the PWLS-EPR result. Additionally, PWLS-SBR better preserves low contrast on the tissue image. Conclusions: The authors propose improvements to the regularization term of an optimization framework which performs iterative image-domain decomposition for DECT with noise suppression. The regularization term avoids calculation of image gradient and is based on pixel similarity. The proposed method not only achieves a high decomposition accuracy, but also improves over the previous algorithm on NPS as well as spatial resolution. PMID:27147376

Red turpentine beetle: innocuous native becomes invasive tree killer in China.

PubMed

Sun, Jianghua; Lu, Min; Gillette, Nancy E; Wingfield, Michael J

2013-01-01

The red turpentine beetle (RTB), Dendroctonus valens LeConte (Coleoptera: Curculionidae: Scolytinae), is a secondary pest of pines in its native range in North and Central America. Outbreaks and tree mortality attributed to RTB alone are rare in its native range. RTB was introduced into China in the early 1980s and spread rapidly from Shanxi Province to four adjacent provinces; it has infested over 500,000 ha of pine forest and has caused extensive tree mortality since 1999. We provide a historical background on RTB outbreaks, explanations for its invasive success, management options, and economic impacts of RTB in China. Genetic variation in RTB fungal associates, interactions between RTB and its associated fungi, behavioral differences in Chinese RTB, and other factors favoring RTB outbreaks are considered in an effort to explain the invasiveness of RTB in China. The promise of semiochemicals as a management tool is also discussed.

New Coleoptera records from New Brunswick, Canada: Trogossitidae, Cleridae, and Melyridae, with an addition to the fauna of Nova Scotia

PubMed Central

Webster, Reginald P.; Sweeney, Jon D.; DeMerchant, Ian

2012-01-01

Abstract Grynocharis quadrilineata (Melsheimer) and Tenebroides corticalis (Melsheimer) of the family Trogossitidae are newly recorded for New Brunswick, Canada. Additional records of the recently reported Calitys scabra (Thunberg)and Ostoma fraterna (Randall) are presented for the province. The record of Ostoma fraterna is the first recent record of this species from New Brunswick. Additional New Brunswick records of the thaneroclerine, Zenodosus sanguineus (Say), are given, indicting that this species is common and widespread in the province. One species of Cleridae, Cymatodera bicolor (Say),is newly reported from New Brunswick, and the adventive Thanasimus formicarius Linnaeus is newly recorded from Nova Scotia and the Maritime provinces. Attalus morulus (LeConte) and Dolichosoma foveicolle (Kirby), family Melyridae, are reported for the first time for New Brunswick and the Maritime provinces. Collection, habitat data, and distribution maps are presented for these species. PMID:22539891

Razorback sucker movements and habitat use in the San Juan River inflow, Lake Powell, Utah, 1995-1997

USGS Publications Warehouse

Karp, C.A.; Mueller, G.

2002-01-01

Seventeen subadult, hatchery-reared razorback suckers (Xyrauchen texanus; (x̄ = 456 mm total length) were implanted with sonic transmitters and tracked for 23 months in the lower 89.6 km of the San Juan River (San Juan arm of Lake Powell, Utah). Fish were released at 2 sites, and 9 made extensive up-and downstream movements (x = 47.8 km; contact was lost with 4, and 4 others presumably died or lost their transmitters). The San Juan arm is primarily inundated canyon; however, most fish contacts occurred in shallow coves and shoreline with thick stands of flooded salt cedar in the upper inflow area. Eight fish frequented the Piute Farms river/lake mixing zone, and at least 4 moved upstream into the San Juan River. Seven fish were found in 2 aggregations in spring (3 fish in Neskahi Bay in 1996 and 4 fish just downstream of Piute Farms in 1997), and these may have been associated with spawning activity. Continued presence of razorback suckers in the Piute Farms area and lower San Juan River suggests the San Juan inflow to Lake Powell could be used as an alternate stocking site for reintroduction efforts.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dharmarajan, Guha; Beasley, James C.; Beatty, William S.

Many aspects of parasite biology critically depend on their hosts, and understanding how host-parasite populations are co-structured can help improve our understanding of the ecology of parasites, their hosts, and host-parasite interactions. Here, this study utilized genetic data collected from raccoons (Procyon lotor), and a specialist parasite, the raccoon tick (Ixodes texanus), to test for genetic co-structuring of host-parasite populations at both landscape and host scales. At the landscape scale, our analyses revealed a significant correlation between genetic and geographic distance matrices (i.e., isolation by distance) in ticks, but not their hosts. While there are several mechanisms that could leadmore » to a stronger pattern of isolation by distance in tick vs. raccoon datasets, our analyses suggest that at least one reason for the above pattern is the substantial increase in statistical power (due to the ≈8-fold increase in sample size) afforded by sampling parasites. Host-scale analyses indicated higher relatedness between ticks sampled from related vs. unrelated raccoons trapped within the same habitat patch, a pattern likely driven by increased contact rates between related hosts. Lastly, by utilizing fine-scale genetic data from both parasites and hosts, our analyses help improve our understanding of epidemiology and host ecology.« less

Comparative habitat ecology of Texas and masked bobwhites

USGS Publications Warehouse

Guthery, F.S.; King, N.M.; Nolte, K.R.; Kuvlesky, W.P.; DeStefano, S.; Gall, S.A.; Silvy, N.J.

2000-01-01

The habitat ecology of masked bobwhites (Colinus virginianus ridgwayi) is poorly understood, which hampers recovery efforts for this endangered bird. During 1994-96, we analyzed the habitat ecology of masked bobwhites in Sonora, Mexico, and Arizona, and compared these findings with the habitat ecology of Texas bobwhites (C. v. texanus) in southern Texas. Mean values for the quantity of low screening cover (<50 cm aboveground), operative temperature (??C), and exposure to aerial predators were relatively constant across regions (CV <14.2%), indicating these variables are important in adaptive habitat-use decisions by bobwhites. Bobwhites exhibited preference in all regions for higher canopy coverage of woody vegetation, lower exposure to aerial predators, and lower operative temperatures in comparison with randomly available conditions. The major habitat deficiencies for masked bobwhites were lack of woody and herbaceous cover, which led to high exposure to aerial predators in Sonora and Arizona. High operative temperatures at quail level were associated with the loss of ???24% of potential habitat space-time in Texas, Sonora, and Arizona. Management to improve habitat for masked bobwhites includes any practice that increases canopy coverage of woody vegetation, and height and coverage of herbaceous vegetation.

Small nonnative fishes as predators of larval razorback suckers

USGS Publications Warehouse

Carpenter, J.; Mueller, G.A.

2008-01-01

The razorback sucker (Xyrauchen texanus), an endangered big-river fish of the Colorado River basin, has demonstrated no sustainable recruitment in 4 decades, despite presence of spawning adults and larvae. Lack of adequate recruitment has been attributed to several factors, including predation by nonnative fishes. Substantial funding and effort has been expended on mechanically removing nonnative game fishes, typically targeting large predators. As a result, abundance of larger predators has declined, but the abundance of small nonnative fishes has increased in some areas. We conducted laboratory experiments to determine if small nonnative fishes would consume larval razorback suckers. We tested adults of three small species (threadfin shad, Dorosoma petenense; red shiner, Cyprinella lutrensis; fathead minnow, Pimephales promelas) and juveniles of six larger species (common carp, Cyprinus carpio; yellow bullhead, Ameiurus natalis; channel catfish, Ictalurus punctatus; rainbow trout, Oncorhynchus mykiss; green sunfish, Lepomis cyanellus; bluegill, L. macrochirus). These nonnative fishes span a broad ecological range and are abundant within the historical range of the razorback sucker. All nine species fed on larval razorback suckers (total length, 9-16 mm). Our results suggest that predation by small nonnative fishes could be responsible for limiting recovery of this endangered species.

Communication using eye roll reflective signalling

USGS Publications Warehouse

Flamarique, I.N.; Mueller, G.A.; Cheng, C.L.; Figiel, C.R.

2007-01-01

Body reflections in the ultraviolet (UV) are a common occurrence in nature. Despite the abundance of such signals and the presence of UV cones in the retinas of many vertebrates, the function of UV cones in the majority of taxa remains unclear. Here, we report on an unusual communication system in the razorback sucker, Xyrauchen texanus, that involves flash signals produced by quick eye rolls. Behavioural experiments and field observations indicate that this form of communication is used to signal territorial presence between males. The flash signal shows highest contrast in the UV region of fhe visual spectrum (??max???380 nm), corresponding to the maximum wavelength of absorption of the UV cone mechanism in suckers. Furthermore, these cones are restricted to the dorsal retina of the animal and the upwelling light background is such that their relative sensitivity would be enhanced by chromatic adaptation of the other cone mechanisms. Thus, the UV cones in the sucker have optimal characteristics (both in terms of absorbance and retinal topography) to constitute the main detectors of the flash signal. Our findings provide the first ecological evidence for restricted distribution of UV cones in the retina of a vertebrate. ?? 2007 The Royal Society.

Standard weight (Ws) equations for four rare desert fishes

USGS Publications Warehouse

Didenko, A.V.; Bonar, Scott A.; Matter, W.J.

2004-01-01

Standard weight (Ws) equations have been used extensively to examine body condition in sport fishes. However, development of these equations for nongame fishes has only recently been emphasized. We used the regression-line-percentile technique to develop standard weight equations for four rare desert fishes: flannelmouth sucker Catostomus latipinnis, razorback sucker Xyrauchen texanus, roundtail chub Gila robusta, and humpback chub G. cypha. The Ws equation for flannelmouth suckers of 100-690 mm total length (TL) was developed from 17 populations: log10Ws = -5.180 + 3.068 log10TL. The Ws equation for razorback suckers of 110-885 mm TL was developed from 12 populations: log 10Ws = -4.886 + 2.985 log10TL. The W s equation for roundtail chub of 100-525 mm TL was developed from 20 populations: log10Ws = -5.065 + 3.015 log10TL. The Ws equation for humpback chub of 120-495 mm TL was developed from 9 populations: log10Ws = -5.278 + 3.096 log 10TL. These equations meet criteria for acceptable standard weight indexes and can be used to calculate relative weight, an index of body condition.

SU-F-207-07: Dual-Energy Computed Tomography Detection Limit of Various Radiopaque Contrast Agents That Can Be Infused Within Absorbable Inferior Vena Cava Filters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Melancon, A; Jacobsen, M; Salatan, F

Purpose: Absorbable IVC filters are shown to be safe and efficacious in preventing pulmonary embolism. These absorbable filters disappear from the body after their required duration, alleviating costly removal procedures and downstream complications. Monitoring the positioning and integrity of absorbable devices using dual-energy computed tomography (DECT) would improve treatment efficacy. The purpose of this study is to determine the limit of detection and the energy dependence of DECT for various contrast agents that may be infused within the IVC filters including gold nanoparticles (AuNP) having diameters of 2 and 4 nm. Methods: All imaging studies were performed on a GEmore » Discovery CT750 system in Gemstone Spectral Imaging (GSI) mode. Plastic vials containing the contrast agent solutions of water and blood were placed in a water bath, and images were acquired with the GSI-5 preset. The images were reformatted into the coronal plane and 5mm diameter ROIs were placed within each solution on a GE Advantage Workstation. Monoenergetic reconstructions were generated from 40 – 140 keV. Results: Mass attenuation (contrast per unit density) for AuNPs was greater than iron, but less than barium and iodine. Contrast was 10.2 (± 3.6) HU for 4 nm AuNP at 0.72 mg/ml and 12.1 (± 4.2) for 2 nm AuNP at 0.31 mg/ml at 70 keV suggesting reasonable chance of visualization at these concentrations for 70 keV reconstruction. The contrast as a function of CT energy is similar in both water and blood. Iodine is most dependent, followed closely by barium and iron, and trailed by a large margin by the AuNP. This was unexpected given Au’s large atomic number and the predominance of photoelectric effect at low energy. Conclusion: Infusion of IVC filters with AuNP is feasible. Discrimination of AuNP-infused IVC filters from surrounding anatomy warrants further investigation.« less

Optimal Adaptive Statistical Iterative Reconstruction Percentage in Dual-energy Monochromatic CT Portal Venography.

PubMed

Zhao, Liqin; Winklhofer, Sebastian; Yang, Zhenghan; Wang, Keyang; He, Wen

2016-03-01

The aim of this article was to study the influence of different adaptive statistical iterative reconstruction (ASIR) percentages on the image quality of dual-energy computed tomography (DECT) portal venography in portal hypertension patients. DECT scans of 40 patients with cirrhosis (mean age, 56 years) at the portal venous phase were retrospectively analyzed. Monochromatic images at 60 and 70 keV were reconstructed with four ASIR percentages: 0%, 30%, 50%, and 70%. Computed tomography (CT) numbers of the portal veins (PVs), liver parenchyma, and subcutaneous fat tissue in the abdomen were measured. The standard deviation from the region of interest of the liver parenchyma was interpreted as the objective image noise (IN). The contrast-noise ratio (CNR) between PV and liver parenchyma was calculated. The diagnostic acceptability (DA) and sharpness of PV margins were obtained using a 5-point score. The IN, CNR, DA, and sharpness of PV were compared among the eight groups with different keV + ASIR level combinations. The IN, CNR, DA, and sharpness of PV of different keV + ASIR groups were all statistically different (P < 0.05). In the eight groups, the best and worst CNR were obtained in the 60 keV + 70% ASIR and 70 keV + 0% ASIR (filtered back-projection [FBP]) combination, respectively, whereas the largest and smallest objective IN were obtained in the 60 keV + 0% ASIR (FBP) and 70 keV + 70% combination. The highest DA and sharpness values of PV were obtained at 50% ASIR for 60 keV. An optimal ASIR percentage (50%) combined with an appropriate monochromatic energy level (60 keV) provides the highest DA in portal venography imaging, whereas for the higher monochromatic energy (70 keV) images, 30% ASIR provides the highest image quality, with less IN than 60 keV with 50% ASIR. Copyright © 2015 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.

Chronic toxicity of un-ionized ammonia to early life-stages of endangered Colorado pikeminnow (Ptychocheilus lucius) and razorback sucker (Xyrauchen texanus) compared to the surrogate fathead minnow (Pimephales promelas)

USGS Publications Warehouse

Fairchild, J.F.; Allert, A.L.; Sappington, L.C.; Waddell, B.

2005-01-01

Ammonia-contaminated groundwater enters the Upper Colorado River from beneath the abandoned Moab Uranium Mill Tailings Pile near Moab, Utah. This reach of the Upper Colorado River was designated as critical habitat for four endangered fish species because it is one of the few existing areas with known spawning and rearing habitats. Un-ionized ammonia (NH3) concentrations frequently exceed 1.00 mg/L in backwaters adjacent to the tailings pile, which exceeds the Utah 30-d average chronic water quality criterion for un-ionized ammonia (0.07 mg/L NH3; temperature 20??C; pH 8.2) by a factor of more than 10. However, there is little published information regarding the sensitivity of endangered fishes to ammonia. We conducted 28-d static renewal studies with post-swim-up larvae to determine the relative sensitivity of Colorado pikeminnow (Ptychocheilus lucius), razorback sucker (Xyrauchen texanus), and the standard surrogate fathead minnow (Pimephales promelas) to NH3. Chronic values (ChVs) for mortality and growth were determined as the geometric mean of the no observed effect concentration and the lowest observed effect concentration based on analysis of variance. The ChVs for growth of fathead minnow, Colorado pikeminnow, and razorback sucker were 0.43, 0.40, and 0.67 mg/L NH3, respectively. The ChVs for mortality of fathead minnow, Colorado pikeminnow, and razorback sucker were 0.43, 0.70, and 0.67 mg/L NH3, respectively. Therefore, the ChVs for mortality and growth were similar for fathead minnow and razorback sucker; however, the ChV for growth was lower than the ChV for mortality for Colorado pikeminnow. Maximum likelihood regression was used to calculate 28-d lethal concentrations (LCx) for each species. The 28-d LC50, LC20, and LC1 values for fathead minnow were 0.69, 0.42, and 0.13 mg/L NH3, respectively. The 28-d LC50, LC20, and LC1 values for Colorado pikeminnow were 0.76, 0.61, and 0.38 mg/L NH3, respectively. The 28-d LC50, LC20, and LC1 values for razorback sucker were 0.54, 0.38, and 0.25 mg/L NH3, respectively. The fathead minnow, Colorado pikeminnow, and razorback sucker are relatively similar in sensitivity and rank at the 35th, 49th, and 31st percentiles, respectively, of the theoretical chronic fish sensitivity distributions for NH3. The existing water quality criteria for NH3, if met by remediation activities at the Moab site, would be protective of these endangered fishes even if fish sensitivity is based on the conservative LC1 value. ?? 2005 Springer Science+Business Media, Inc.

Recent Advances in Cardiac Computed Tomography: Dual Energy, Spectral and Molecular CT Imaging

PubMed Central

Danad, Ibrahim; Fayad, Zahi A.; Willemink, Martin J.; Min, James K.

2015-01-01

Computed tomography (CT) evolved into a powerful diagnostic tool and it is impossible to imagine current clinical practice without CT imaging. Due to its widespread availability, ease of clinical application, superb sensitivity for detection of CAD, and non-invasive nature, CT has become a valuable tool within the armamentarium of the cardiologist. In the last few years, numerous technological advances in CT have occurred—including dual energy CT (DECT), spectral CT and CT-based molecular imaging. By harnessing the advances in technology, cardiac CT has advanced beyond the mere evaluation of coronary stenosis to an imaging modality tool that permits accurate plaque characterization, assessment of myocardial perfusion and even probing of molecular processes that are involved in coronary atherosclerosis. Novel innovations in CT contrast agents and pre-clinical spectral CT devices have paved the way for CT-based molecular imaging. PMID:26068288

Modems for emerging digital cellular-mobile radio system

NASA Technical Reports Server (NTRS)

Feher, Kamilo

1991-01-01

Digital modem techniques for emerging digital cellular telecommunications-mobile radio system applications are described and analyzed. In particular, theoretical performance, experimental results, principles of operation, and various architectures of pi/4-QPSK (pi/4-shifted coherent or differential QPSK) modems for second-generation US digital cellular radio system applications are presented. The spectral/power efficiency and performance of the pi/4-QPSK modems (American and Japanese digital cellular emerging standards) are studied and briefly compared to GMSK (Gaussian minimum-shift keying) modems (proposed for European DECT and GSM cellular standards). Improved filtering strategies and digital pilot-aided (digital channel sounding) techniques are also considered for pi/4-QPSK and other digital modems. These techniques could significantly improve the performance of digital cellular and other digital land mobile and satellite mobile radio systems. More spectrally efficient modem trends for future cellular/mobile (land mobile) and satellite communication systems applications are also highlighted.

The Current Status of the Distribution Range of the Western Pine Beetle, Dendroctonus brevicomis (Curculionidae: Scolytinae) in Northern Mexico

PubMed Central

Valerio-Mendoza, O; Armendáriz-Toledano, F; Cuéllar-Rodríguez, G; Negrón, José F

2017-01-01

Abstract The distribution range of the western pine beetle Dendroctonus brevicomis LeConte (Coleoptera: Curculionidae) is supported only by scattered records in the northern parts of Mexico, suggesting that its populations may be marginal and rare in this region. In this study, we review the geographical distribution of D. brevicomis in northern Mexico and perform a geometric morphometric analysis of seminal rod shape to evaluate its reliability for identifying this species with respect to other members of the Dendroctonus frontalis Zimmermann (Coleoptera: Curculionidae) complex. Our results provide 30 new records, with 26 distributed in the Sierra Madre Occidental and 4 in the Sierra Madre Oriental. These records extend the known distribution range of D. brevicomis to Durango and Tamaulipas states in northern Mexico. Furthermore, we find high geographic variation in size and shape of the seminal rod, with conspicous differences among individuals from different geographical regions, namely west and east of the Great Basin and between mountain systems in Mexico. PMID:28922899

Taxonomy of 'Euconnus complex'. Part XII. Synonymy circle of Psomophus, Spanioconnus, Scydmaenites and Xestophus (Coleoptera, Staphylinidae, Scydmaeninae).

PubMed

Jałoszyński, Paweł

2017-05-31

Status of subgenera established for Euconnus Thomson with three-segmented antennal club is clarified. Examination of the type species of Psomophus Casey, Spanioconnus Ganglbauer, Scydmaenites Croissandeau and Xestophus Casey led to the conclusion that differences in morphological structures between all these taxa are minor and represent character variability within one subgenus. Consequently, Spanioconnus is maintained as a junior synonym of Psomophus; Scydmaenites is synonymized with Psomophus; and Xestophus, already placed as a junior synonym of Psomophus by Franz and later resurrected by O'Keefe, is again synonymized with Psomophus. Based on small morphological differences (visible only in the antennal structure), it is suggested that in future Psomophus may be placed as a junior synonym of Euconnus s. str. An emended diagnosis of Psomophus is given, and lectotypes are designated for Euconnus callidus Casey, Euconnus kraatzi Reitter and Scydmaenus salinator LeConte.

Review of the genera of Conoderinae (Coleoptera, Curculionidae) from North America, Central America, and the Caribbean

PubMed Central

Anzaldo, Salvatore S.

2017-01-01

Abstract The thirty-nine extant genera of Conoderinae known to occur in North America, Central America, and the Caribbean are reviewed based on external morphology. An identification key is provided along with diagnoses, distributions, species counts, and natural history information, when known, for each genus. Morphological character systems of importance for weevil classification are surveyed, potential relationships among the tribes and genera are discussed, and groups most in need of taxonomic and phylogenetic attention are identified. The following genera are transferred to new tribes: Acoptus LeConte, 1876 from the Lechriopini to the Othippiini (new placement) and the South American genus Hedycera Pascoe, 1870 from the Lechriopini to the Piazurini (new placement). Philides Champion, 1906 and Philinna Champion, 1906 are transferred from the Lechriopini to Conoderinae incertae sedis (new placement) although their placement as conoderines is uncertain. The species Copturomimus cinereus Heller, 1895 is designated as the type species of the genus Copturomimus Heller, 1895. PMID:28769729

Ground beetles (Coleoptera, Carabidae) of the Hanford Nuclear Site in south-central Washington State.

PubMed

Looney, Chris; Zack, Richard S; Labonte, James R

2014-01-01

Carabidae) collected from the Hanford Nuclear Reservation and Hanford National Monument (together the Hanford Site), which is located in south-central Washington State. The Site is a relatively undisturbed relict of the shrub-steppe habitat present throughout much of the western Columbia Basin before the westward expansion of the United States. Species, localities, months of capture, and capture method are reported for field work conducted between 1994 and 2002. Most species were collected using pitfall traps, although other capture methods were employed. Trapping results indicate the Hanford Site supports a diverse ground beetle community, with over 90% of the 92 species captured native to North America. Four species collected during the study period are newly recorded for Washington State: Bembidion diligens Casey, Calosoma obsoletum Say, Pseudaptinus rufulus (LeConte), and Stenolophus lineola (Fabricius). Based on these data, the Site maintains a diverse ground beetle fauna and, due to its size and diversity of habitats, is an important repository of shrub-steppe biodiversity.

Variation in diel activity of ground beetles (Coleoptera: Carabidae) associated with a soybean field and coal mine remnant

USGS Publications Warehouse

Willand, J.E.; McCravy, K.W.

2006-01-01

Diel activities of carabids (Coleoptera: Carabidae) associated with a coal mine remnant and surrounding soybean field were studied in west-central Illinois from June through October 2002. A total of 1,402 carabids, representing 29 species and 17 genera, were collected using pitfall traps. Poecilus chalcites (Say) demonstrated roughly equal diurnal and nocturnal activity in June, but greater diurnal activity thereafter. Pterostichus permundus (Say), Cyclotrachelus seximpressus (LeConte), Amara obesa (Say), and Scarites quadriceps Chaudoir showed significant nocturnal activity. Associations between habitat and diel activity were found for three species: P. chalcites associated with the remnant and edge habitats showed greater diurnal activity than those associated with the soybean field; C. seximpressus was most active diurnally in the remnant, and Harpalus pensylvanicus (DeGeer) showed the greatest nocturnal activity in the remnant and edge habitats. We found significant temporal and habitat-related variation in diel activity among carabid species inhabiting agricultural areas in west-central Illinois.

The complete mitochondrial genome of the desert darkling beetle Asbolus verrucosus (Coleoptera, Tenebrionidae).

PubMed

Rider, Stanley Dean

2016-07-01

The complete mitochondrial genome of the desert darkling beetle Asbolus verrucosus (LeConte, 1851) was sequenced using paired-end technology to an average depth of 42,111× and assembled using De Bruijn graph-based methods. The genome is 15,828 bp in length and conforms to the basal arthropod mitochondrial gene composition with the same gene orders and orientations as other darkling beetle mitochondria. This arrangement includes a control region, 22 tRNA genes, 2 rRNA genes and 13 protein-coding genes. The main coding strand is probably replicated as the lagging strand (GC skew of -0.36 and AT skew of +0.19). Phylogenomics analyses are consistent with taxonomic classifications and indicate that Tenebrio molitor is the closest relative that has a completely sequenced mitochondrial genome available for analysis. This is the first fully assembled mitogenome sequence for a darkling beetle in the subfamily Pimeliinae and will be useful for population studies on members of this ecologically important group of beetles.

The subtribes and genera of the tribe Listroderini (Coleoptera, Curculionidae, Cyclominae): Phylogenetic analysis with systematic and biogeographical accounts

PubMed Central

Morrone, Juan J.

2013-01-01

Abstract The phylogenetic relationships of the genera of Listroderini LeConte, 1876 are analyzed based on 58 morphological characters. The genera are grouped in four clades, which are given subtribal status: Macrostyphlina new subtribe (Adioristidius, Amathynetoides, Andesianellus, Macrostyphlus, Nacodius and Puranius), Palaechthina Brinck, 1948 (Anorthorhinus, Gunodes, Haversiella, Inaccodes, Listronotus, Neopachytychius, Palaechthus, Palaechtodes, Steriphus and Tristanodes), Falklandiina new subtribe (Falklandiellus, Falklandiopsis, Falklandius, Gromilus, Lanteriella, Liparogetus, Nestrius and Telurus), and Listroderina (Acroriellus, Acrorius, Acrostomus, Antarctobius, Germainiellus, Hyperoides, Lamiarhinus, Listroderes, Methypora, Philippius, Rupanius and Trachodema). The subtribes are characterized and keys to identify them and their genera are provided. Listroderini have four main biogeographical patterns: Andean (Macrostyphlina), Andean-New Zealand (Falklandiina), Andean-Neotropical-Australian (Listroderina) and Andean-Neotropical-Australian-New Zealand-Nearctic-Tristan da Cunha-Gough islands (Palaechthina). Geographical paralogy, particularly evident in the Subantarctic subregion of the Andean region, suggests that Listroderini are an ancient Gondwanic group, in which several extinction events might have obscured relationships among the areas. PMID:23794805

A taxonomic monograph of Nearctic Scolytus Geoffroy (Coleoptera, Curculionidae, Scolytinae).

PubMed

Smith, Sarah M; Cognato, Anthony I

2014-01-01

The Nearctic bark beetle genus Scolytus Geoffroy was revised based in part on a molecular and morphological phylogeny. Monophyly of the native species was tested using mitochondrial (COI) and nuclear (28S, CAD, ArgK) genes and 43 morphological characters in parsimony and Bayesian phylogenetic analyses. Parsimony analyses of molecular and combined datasets provided mixed results while Bayesian analysis recovered most nodes with posterior probabilities >90%. Native hardwood- and conifer-feeding Scolytus species were recovered as paraphyletic. Native Nearctic species were recovered as paraphyletic with hardwood-feeding species sister to Palearctic hardwood-feeding species rather than to native conifer-feeding species. The Nearctic conifer-feeding species were monophyletic. Twenty-five species were recognized. Four new synonyms were discovered: Scolytuspraeceps LeConte, 1868 (= Scolytusabietis Blackman, 1934; = Scolytusopacus Blackman, 1934), Scolytusreflexus Blackman, 1934 (= Scolytusvirgatus Bright, 1972; = Scolytuswickhami Blackman, 1934). Two species were reinstated: Scolytusfiskei Blackman, 1934 and Scolytussilvaticus Bright, 1972. A diagnosis, description, distribution, host records and images were provided for each species and a key is presented to all species.

Hazard assessment of inorganics to three endangered fish in the Green River, Utah

USGS Publications Warehouse

Hamilton, S.J.

1995-01-01

Acute toxicity tests were conducted with three life stages of Colorado squawfish (Ptychocheilus lucius), razorback sucker (Xyrauchen texanus), and bonytail (Gila elegans) in a reconstituted water quality simulating the middle part of the Green River of Utah. Tests were conducted with boron, lithium, selenate, selenite, uranium, vanadium, and zinc. The overall rank order of toxicity to all species and life stages combined from most to least toxic was vanadium = zinc > selenite > lithium = uranium > selenate > boron. There was no difference between the three species in their sensitivity to the seven inorganics based on a rank-order evaluation at the species level. Colorado squawfish were 2-5 times more sensitive to selenate and selenite at the swimup life stage than older stages, whereas razorback suckers displayed equal sensitivity among life stages. Bonytail exhibited equal sensitivity to selenite, but were five times more sensitive to selenate at the swimup life stage than the older stages. Comparison of 96-hr LC50 values with a limited number of environmental water concentrations in Ashley Creek, Utah, which receives irrigation drainwater, revealed moderate hazard ratios for boron, selenate, selenite, and zinc, low hazard ratios for uranium and vanadium, but unknown ratios for lithium. These inorganic contaminants in drainwaters may adversely affect endangered fish in the Green River.

Biostratigraphy and petrography of upper Paleozoic rocks of Sierra Las Pintas, northern Baja California

NASA Astrophysics Data System (ADS)

Navas-Parejo, Pilar; Lara-Peña, R. Aaron; Torres-Martínez, Miguel Angel; Martini, Michelangelo

2018-07-01

A transported crinoid fauna is herein described for the first time in the Paleozoic succession cropping out in the Sierra Las Pintas, northern Baja California, northwestern Mexico. The fossil association includes Heterostelechus texanus Moore and Jeffords, Preptopremnum laeve? Moore and Jeffords, and Mooreanteris perforatus Moore and Jeffords, which indicates a Middle Pennsylvanian-early Permian time-averaged age. The studied area corresponds with the northernmost outcrop of definitely late Paleozoic deep-water facies in northwestern Mexico and the southern United States. Petrographic analyses indicate that the studied metasandstones were primarily derived from high-grade metamorphic rocks and from a shallow-water platform environment dominated by crinoid meadows. These results allow the correlation of the studied metasedimentary rocks with the Carboniferous Rancho Nuevo Formation of the Sonora allochthon, which crops out in central Sonora. The Sonora allochthon includes an Early Ordovician-Late Pennsylvanian sedimentary succession that was deposited in the oceanic basin located south of the Laurentian craton. Therefore, upper Paleozoic metasedimentary rocks of the Sierra Las Pintas were deposited along the same continental margin of Laurentia as those rocks in the Sonora allochthon, and were mostly derived from metamorphic rocks of the continental craton and by the typical Carboniferous encrinites, which characterize the shallow-water rocks of central and northern Sonora.

Genetic co-structuring in host-parasite systems: Empirical data from raccoons and raccoon ticks

DOE PAGES

Dharmarajan, Guha; Beasley, James C.; Beatty, William S.; ...

2016-03-31

Many aspects of parasite biology critically depend on their hosts, and understanding how host-parasite populations are co-structured can help improve our understanding of the ecology of parasites, their hosts, and host-parasite interactions. Here, this study utilized genetic data collected from raccoons (Procyon lotor), and a specialist parasite, the raccoon tick (Ixodes texanus), to test for genetic co-structuring of host-parasite populations at both landscape and host scales. At the landscape scale, our analyses revealed a significant correlation between genetic and geographic distance matrices (i.e., isolation by distance) in ticks, but not their hosts. While there are several mechanisms that could leadmore » to a stronger pattern of isolation by distance in tick vs. raccoon datasets, our analyses suggest that at least one reason for the above pattern is the substantial increase in statistical power (due to the ≈8-fold increase in sample size) afforded by sampling parasites. Host-scale analyses indicated higher relatedness between ticks sampled from related vs. unrelated raccoons trapped within the same habitat patch, a pattern likely driven by increased contact rates between related hosts. Lastly, by utilizing fine-scale genetic data from both parasites and hosts, our analyses help improve our understanding of epidemiology and host ecology.« less

Selenium impacts on razorback sucker, Colorado River, Colorado II. Eggs.

PubMed

Hamilton, Steven J; Holley, Kathy M; Buhl, Kevin J; Bullard, Fern A

2005-05-01

Effects on hatching and development of fertilized eggs in adult razorback sucker (Xyrauchen texanus) exposed to selenium in flooded bottomland sites near Grand Junction, Colorado, were determined. After 9 months exposure, fish were collected and induced to spawn and eggs collected for inorganic element analyses. A 9-day egg study was conducted with five spawns from Horsethief ponds, six spawns from Adobe Creek channel, and four spawns from North Pond using a reference water and site waters. Selenium concentrations in eggs were 6.5 microg/g from Horsethief, 46 microg/g from Adobe Creek, 38 microg/g from North Pond, and 6.0 microg/g from brood stock. Eggs from young adults had a smaller diameter and higher moisture content than brood stock. There were no differences among the four sources in viability, survival, hatch, hatchability, or mortality of deformed embryos or larvae. Adobe Creek larvae had more deformed embryos in eggs held in site water than held in reference water. There were significant negative correlations between selenium concentrations in adult muscle plugs and percent hatch, egg diameter, and deformities in embryos. Results from this study suggest that selenium contamination in parts of the upper basin of the Colorado River should be a major concern to recovery efforts for endangered fish.

Selenium impacts on razorback sucker, Colorado River, Colorado: II. Eggs

USGS Publications Warehouse

Hamilton, S.J.; Holley, K.M.; Buhl, K.J.; Bullard, F.A.

2005-01-01

Effects on hatching and development of fertilized eggs in adult razorback sucker (Xyrauchen texanus) exposed to selenium in flooded bottomland sites near Grand Junction, Colorado, were determined. After 9 months exposure, fish were collected and induced to spawn and eggs collected for inorganic element analyses. A 9-day egg study was conducted with five spawns from Horsethief ponds, six spawns from Adobe Creek channel, and four spawns from North Pond using a reference water and site waters. Selenium concentrations in eggs were 6.5 μg/g from Horsethief, 46 μg/g from Adobe Creek, 38 μg/g from North Pond, and 6.0 μg/g from brood stock. Eggs from young adults had a smaller diameter and higher moisture content than brood stock. There were no differences among the four sources in viability, survival, hatch, hatchability, or mortality of deformed embryos or larvae. Adobe Creek larvae had more deformed embryos in eggs held in site water than held in reference water. There were significant negative correlations between selenium concentrations in adult muscle plugs and percent hatch, egg diameter, and deformities in embryos. Results from this study suggest that selenium contamination in parts of the upper basin of the Colorado River should be a major concern to recovery efforts for endangered fish.

Cry3Bb1-Resistant Western Corn Rootworm, Diabrotica virgifera virgifera (LeConte) Does Not Exhibit Cross-Resistance to DvSnf7 dsRNA.

PubMed

Moar, William; Khajuria, Chitvan; Pleau, Michael; Ilagan, Oliver; Chen, Mao; Jiang, Changjian; Price, Paula; McNulty, Brian; Clark, Thomas; Head, Graham

2017-01-01

There is a continuing need to express new insect control compounds in transgenic maize against western corn rootworm, Diabrotica virgifera virgifera (LeConte) (WCR). In this study three experiments were conducted to determine cross-resistance between the new insecticidal DvSnf7 dsRNA, and Bacillus thuringiensis (Bt) Cry3Bb1; used to control WCR since 2003, with field-evolved resistance being reported. Laboratory susceptible and Cry3Bb1-resistant WCR were evaluated against DvSnf7 dsRNA in larval diet-incorporation bioassays. Additionally, the susceptibility of seven field and one field-derived WCR populations to DvSnf7 (and Cry3Bb1) was assessed in larval diet-overlay bioassays. Finally, beetle emergence of laboratory susceptible and Cry3Bb1-resistant WCR was evaluated with maize plants in the greenhouse expressing Cry3Bb1, Cry34Ab1/Cry35Ab1, or DvSnf7 dsRNA singly, or in combination. The Cry3Bb1-resistant colony had slight but significantly (2.7-fold; P<0.05) decreased susceptibility to DvSnf7 compared to the susceptible colony, but when repeated using a field-derived WCR population selected for reduced Cry3Bb1 susceptibility, there was no significant difference (P<0.05) in DvSnf7 susceptibility compared to that same susceptible population. Additionally, this 2.7-fold difference in susceptibility falls within the range of DvSnf7 susceptibility among the seven field populations tested. Additionally, there was no correlation between susceptibility to DvSnf7 and Cry3Bb1 for all populations evaluated. In greenhouse studies, there were no significant differences (P<0.05) between beetle emergence of susceptible and Cry3Bb1-resistant colonies on DvSnf7 and Cry34Ab1/Cry35Ab1, and between DvSnf7 and MON 87411 (DvSnf7 + Cry3Bb1) for the Cry3Bb1-resistant colony. These results demonstrate no cross-resistance between DvSnf7 and Cry3Bb1 against WCR. Therefore, pyramiding DvSnf7 with Bt proteins such as Cry3Bb1 and Cry34Ab1/Cry35Ab1 will provide a valuable IRM tool against WCR that will increase the durability of these Bt proteins. These results also illustrate the importance of using appropriate bioassay methods when characterizing field-evolved resistant WCR populations.

Cry3Bb1-Resistant Western Corn Rootworm, Diabrotica virgifera virgifera (LeConte) Does Not Exhibit Cross-Resistance to DvSnf7 dsRNA

PubMed Central

Khajuria, Chitvan; Pleau, Michael; Ilagan, Oliver; Chen, Mao; Jiang, Changjian; Price, Paula; McNulty, Brian; Clark, Thomas; Head, Graham

2017-01-01

Background and Methodology There is a continuing need to express new insect control compounds in transgenic maize against western corn rootworm, Diabrotica virgifera virgifera (LeConte) (WCR). In this study three experiments were conducted to determine cross-resistance between the new insecticidal DvSnf7 dsRNA, and Bacillus thuringiensis (Bt) Cry3Bb1; used to control WCR since 2003, with field-evolved resistance being reported. Laboratory susceptible and Cry3Bb1-resistant WCR were evaluated against DvSnf7 dsRNA in larval diet-incorporation bioassays. Additionally, the susceptibility of seven field and one field-derived WCR populations to DvSnf7 (and Cry3Bb1) was assessed in larval diet-overlay bioassays. Finally, beetle emergence of laboratory susceptible and Cry3Bb1-resistant WCR was evaluated with maize plants in the greenhouse expressing Cry3Bb1, Cry34Ab1/Cry35Ab1, or DvSnf7 dsRNA singly, or in combination. Principal Findings and Conclusions The Cry3Bb1-resistant colony had slight but significantly (2.7-fold; P<0.05) decreased susceptibility to DvSnf7 compared to the susceptible colony, but when repeated using a field-derived WCR population selected for reduced Cry3Bb1 susceptibility, there was no significant difference (P<0.05) in DvSnf7 susceptibility compared to that same susceptible population. Additionally, this 2.7-fold difference in susceptibility falls within the range of DvSnf7 susceptibility among the seven field populations tested. Additionally, there was no correlation between susceptibility to DvSnf7 and Cry3Bb1 for all populations evaluated. In greenhouse studies, there were no significant differences (P<0.05) between beetle emergence of susceptible and Cry3Bb1-resistant colonies on DvSnf7 and Cry34Ab1/Cry35Ab1, and between DvSnf7 and MON 87411 (DvSnf7 + Cry3Bb1) for the Cry3Bb1-resistant colony. These results demonstrate no cross-resistance between DvSnf7 and Cry3Bb1 against WCR. Therefore, pyramiding DvSnf7 with Bt proteins such as Cry3Bb1 and Cry34Ab1/Cry35Ab1 will provide a valuable IRM tool against WCR that will increase the durability of these Bt proteins. These results also illustrate the importance of using appropriate bioassay methods when characterizing field-evolved resistant WCR populations. PMID:28060922

Summary of fluvial sediment collected at selected sites on the Gunnison River in Colorado and the Green and Duchesne Rivers in Utah, Water Years 2005-2008

USGS Publications Warehouse

Williams, Cory A.; Gerner, Steven J.; Elliott, John G.

2009-01-01

The Colorado River Basin provides habitat for 14 native fish, including four endangered species protected under the Federal Endangered Species Act of 1973 - Colorado pikeminnow (Ptychocheilus lucius), razorback sucker (Xyrauchen texanus), bonytail (Gila elegans), and humpback chub (Gila cypha). These endangered fish species once thrived in the Colorado River system, but water-resource development, including the building of numerous diversion dams and several large reservoirs, and the introduction of nonnative fish, resulted in large reductions in the numbers and range of the four species. Knowledge of sediment dynamics in river reaches important to specifc life-stages of the endangered fishes is critical to understanding the effects of flow regimes on endangered fish habitats. The U.S. Geological Survey, in cooperation with the Upper Colorado River Endangered Fish Recovery Program, Bureau of Reclamation, U.S. Fish and Wildlife Service, and Wyoming State Engineer's Office, implemented daily sediment sampling at three locations in critical habitat reaches in the Upper Colorado River Basin. This report presents a summary of data collected at these sites, including water and suspended-sediment discharge, streambed compositions, and channel and flood-plain topography. The locations are at U.S. Geological Survey streamflow-gaging stations 09152500, Gunnison River near Grand Junction, Colorado; 09261000, Green River near Jensen, Utah; and 09302000, Duchesne River near Randlett, Utah.

Factors influencing poststocking dispersal of razorback sucker

USGS Publications Warehouse

Mueller, G.A.; Marsh, P.C.; Foster, D.; Ulibarri, M.; Burke, T.

2003-01-01

Efforts to reintroduce razorback suckers Xyrauchen texanus to specific river reaches have been plagued by downstream drift and poor survival, which have been attributed to stress, disorientation, predation, and poor conditioning. Poststocking dispersal of eight test groups (15 fish each) of razorback suckers was examined for 28 d with telemetry equipment. Fish were released in three different locations in the Colorado River basin of Utah, Arizona, and Nevada: (1) a 65,000-ha reservoir, (2) a small (<1-ha) backwater, and (3) a large (30-ha) backwater on the mainstem river. At each location, subgroups were released immediately (reference) or held to acclimate them to the site (3–7 d) before release. Two of four subgroups for the large-backwater test were preconditioned to flow. Dispersal from the stocking sites was rapid and declined with time for all tests, as fish appeared to seek and find cover. Downstream drift was most pronounced (x = 69.5 km) from the small backwater and significantly (Kruskal–Wallis test, P < 0.01) greater than either the reservoir (x = 3.7 km) or large-backwater sites (x = 7.7 km). Site-acclimation tests were inconclusive, but downstream movement was significantly (Wilcoxon two-sample test, Z = −2.298, P < 0.01) less for fish preconditioned to flow (x = 1.9 km) compared with pond-reared fish (x = 7.7 km). We concluded that poststocking dispersal may decrease if razorback suckers are preconditioned to flow.

Spatial and temporal use of a spawning site in the middle green river by wild and hatchery-reared razorback suckers

USGS Publications Warehouse

Modde, T.; Bowen, Z.H.; Kitcheyan, D.C.

2005-01-01

The population of endangered razorback suckers Xyrauchen texanus in the middle Green River (upper Colorado River basin) has declined during the last 40 years. The apparent cause for this decline is a lack of successful recruitment. This study used radiotelemetry to evaluate the ability of hatchery-reared razorback suckers to locate spawning areas where wild fish congregate during the ascending hydrographic limb of the snowmelt runoff. Hatchery-reared razorback suckers appeared to show similar reproductive behavior to wild fish. Both wild and hatchery-reared fish were found near the middle Green River spawning area between 1 and 25 May 2000. Hatchery fish occupied the same areas on the spawning site as wild fish, and remained on the spawning site during both nocturnal and diurnal hours. Males were more abundant on the spawning area than females, but the few females captured tended to stage away from the primary spawning area. The results from this study suggest hatchery-reared fish are capable of responding to natural cues that prompt spawning aggregations and are successful in locating existing spawning aggregations of wild fish. Given attention to stocking criteria, including genetic diversity and the size and time of stocking, the challenges of recovering razorback suckers will center on those factors that led to the population declines, particularly the survival of early life stages in off-channel habitats. ?? American Fisheries Society 2005.

Selenium impacts on razorback sucker, Colorado: Colorado River III. Larvae.

PubMed

Hamilton, Steven J; Holley, Kathy M; Buhl, Kevin J; Bullard, Fern A

2005-06-01

Razorback sucker (Xyrauchen texanus) larvae from adults exposed to selenium at three sites near Grand Junction, Colorado, for 9 months were used in a 30-day waterborne and dietary selenium study. Selenium concentrations in water averaged <1.6 microg/L from 24-Road, 0.9 microg/L from Horsethief, 5.5 microg/L from Adobe Creek, and 10.7 microg/L from the North Pond. Selenium in dietary items averaged 2.7 microg/g in brine shrimp, 5.6 microg/g in zooplankton from Horsethief east wetland, 20 microg/g in zooplankton from Adobe Creek, and 39 microg/g in zooplankton from North Pond. The lowest survival occurred in larvae fed zooplankton rather than brine shrimp. Survival of larvae at Adobe Creek and North Pond was lower in site water than in reference water. Survival of brood stock larvae was higher than Horsethief larvae even though they received the same water and dietary treatments. Arsenic concentrations in brine shrimp may have resulted in an antagonistic interaction with selenium and reduced adverse effects in larvae. Deformities in larvae from North Pond were similar to those reported for selenium-induced teratogenic deformities in other fish species. Selenium concentrations of 4.6 microg/g in food resulted in rapid mortality of larvae from Horsethief, Adobe Creek, and North Pond, and suggested that selenium toxicity in the Colorado River could limit recovery of this endangered fish.

Factors affecting reproductive performance of white-tailed deer subjected to fixed-time artificial insemination or natural mating.

PubMed

Mellado, Miguel; Orta, Claudia G; Lozano, Eloy A; García, Jose E; Veliz, Francisco G; de Santiago, Angeles

2013-01-01

The objectives of this study were to examine the effects of several factors affecting fawning rate, litter size, litter weight and neonatal fawn mortality in white-tailed deer inseminated either transcervically or by means of laparoscopy. Oestrus synchronisation with a controlled internal drug release (CIDR)-based protocol and fixed-time artificial insemination (FTAI) was conducted in 130 white-tailed deer (Odocoileus virginianus texanus) during three reproductive seasons (2007-2009; 271 services) in a game-hunting ranch in a hot-arid environment (26°4' N, 101°25' W). Ninety additional non-treated does were exposed to bucks for natural mating. Fawning rate did not differ between AI methods (40.0 vs 45.0% for transcervical and laparoscopic AI, respectively). Overall fawning rate (proportion of all does fawning after FTAI and a subsequent period of buck exposure) did not differ between transcervical (89.5%), laparoscopic (80.3%) or natural (88.9%) insemination. Litter size per fawning doe was higher (P<0.05) in naturally-served does (1.65±0.48) than in transcervically-inseminated does (1.40±0.51) or in laparoscopically-inseminated does (1.48±0.50). The main conclusion was that no enhancement of fawning rate or litter size occurred as a result of intrauterine deposition of semen by laparoscopy compared with the transcervical insemination technique.

Ants can be used as bio-indicators to reveal biological effects of electromagnetic waves from some wireless apparatus.

PubMed

Cammaerts, Marie-Claire; Johansson, Olle

2014-12-01

Society is confronted with an increasing number of applications making use of wireless communication. We also notice an increasing awareness about potentially harmful effects of the related electromagnetic fields on living organisms. At present, it is not realistic to expect that wireless communication will decrease or disappear within the near future. That is why we currently are investigating the mechanisms behind these effects and the effectiveness of possible solutions. In order to be efficient and effective, we designed and validated a fast and easy test on ants - these insects being used as a biological model - for revealing the effect of wireless equipments like mobile phones, smartphones, digital enhanced cordless telephone (DECT) phones, WiFi routers and so on. This test includes quantification of ants' locomotion under natural conditions, then in the vicinity of such wireless equipments. Observations, numerical results and statistical results allow detecting any effect of a radiating source on these living organisms.

Response of Caenorhabditis elegans to wireless devices radiation exposure.

PubMed

Fasseas, Michael K; Fragopoulou, Adamantia F; Manta, Areti K; Skouroliakou, Aikaterini; Vekrellis, Konstantinos; Margaritis, Lukas H; Syntichaki, Popi

2015-03-01

To examine the impact of electromagnetic radiation, produced by GSM (Global System for Mobile communications) mobile phones, Wi-Fi (Wireless-Fidelity) routers and wireless DECT (Digital Enhanced Cordless Telecommunications) phones, on the nematode Caenorhabditis elegans. We exposed synchronized populations, of different developmental stages, to these wireless devices at E-field levels below ICNIRP's (International Commission on Non-Ionizing Radiation Protection) guidelines for various lengths of time. WT (wild-type) and aging- or stress-sensitive mutant worms were examined for changes in growth, fertility, lifespan, chemotaxis, short-term memory, increased ROS (Reactive Oxygen Species) production and apoptosis by using fluorescent marker genes or qRT-PCR (quantitative Reverse Transcription-Polymerase Chain Reaction). No statistically significant differences were found between the exposed and the sham/control animals in any of the experiments concerning lifespan, fertility, growth, memory, ROS, apoptosis or gene expression. The worm appears to be robust to this form of (pulsed) radiation, at least under the exposure conditions used.

Ground beetles (Coleoptera, Carabidae) of the Hanford Nuclear Site in south-central Washington State

PubMed Central

Looney, Chris; Zack, Richard S.; LaBonte, James R.

2014-01-01

Abstract In this paper we report on ground beetles (Coleoptera: Carabidae) collected from the Hanford Nuclear Reservation and Hanford National Monument (together the Hanford Site), which is located in south-central Washington State. The Site is a relatively undisturbed relict of the shrub-steppe habitat present throughout much of the western Columbia Basin before the westward expansion of the United States. Species, localities, months of capture, and capture method are reported for field work conducted between 1994 and 2002. Most species were collected using pitfall traps, although other capture methods were employed. Trapping results indicate the Hanford Site supports a diverse ground beetle community, with over 90% of the 92 species captured native to North America. Four species collected during the study period are newly recorded for Washington State: Bembidion diligens Casey, Calosoma obsoletum Say, Pseudaptinus rufulus (LeConte), and Stenolophus lineola (Fabricius). Based on these data, the Site maintains a diverse ground beetle fauna and, due to its size and diversity of habitats, is an important repository of shrub-steppe biodiversity. PMID:24715791

Revision of Hemiquedius Casey (Staphylinidae, Staphylininae) and a review of beetles dependent on beavers and muskrats in North America

PubMed Central

Brunke, Adam; Smetana, Aleš; Carruthers-Lay, Duncan; Buffam, Joel

2017-01-01

Abstract Based on newly discovered characters on the male genitalia, external morphology and an accumulation of ecological data, we revise the single member of the genus Hemiquedius. Two new species, H. infinitus Brunke & Smetana, sp. n. and H. castoris Brunke & Smetana, sp. n., from eastern North America are described, and H. ferox (LeConte), restricted to peninsular Florida, is re-described. Hemiquedius castoris is strongly associated with the microhabitats provided by nest materials of the North American beaver and muskrat. A key to the three species of Hemiquedius is provided and diagnostic characters are illustrated. We also review the beetles known to be obligate associates of beavers and muskrats, and discuss the potential role of these keystone vertebrates in beetle evolution and distribution. Based on nest-associated beetles and their closest living relatives, beaver and muskrat lodges may extend distributions northward by moderating winters, promote sympatric speciation and act as refugia against extinction of lineages on a broader timescale. Further research into these potential impacts by ecologists and evolutionary biologists is encouraged. PMID:29118599

Revision of Hemiquedius Casey (Staphylinidae, Staphylininae) and a review of beetles dependent on beavers and muskrats in North America.

PubMed

Brunke, Adam; Smetana, Aleš; Carruthers-Lay, Duncan; Buffam, Joel

2017-01-01

Based on newly discovered characters on the male genitalia, external morphology and an accumulation of ecological data, we revise the single member of the genus Hemiquedius . Two new species, H. infinitus Brunke & Smetana, sp. n. and H. castoris Brunke & Smetana, sp. n. , from eastern North America are described, and H. ferox (LeConte), restricted to peninsular Florida, is re-described. Hemiquedius castoris is strongly associated with the microhabitats provided by nest materials of the North American beaver and muskrat. A key to the three species of Hemiquedius is provided and diagnostic characters are illustrated. We also review the beetles known to be obligate associates of beavers and muskrats, and discuss the potential role of these keystone vertebrates in beetle evolution and distribution. Based on nest-associated beetles and their closest living relatives, beaver and muskrat lodges may extend distributions northward by moderating winters, promote sympatric speciation and act as refugia against extinction of lineages on a broader timescale. Further research into these potential impacts by ecologists and evolutionary biologists is encouraged.

A taxonomic monograph of Nearctic Scolytus Geoffroy (Coleoptera, Curculionidae, Scolytinae)

PubMed Central

Smith, Sarah M.; Cognato, Anthony I.

2014-01-01

Abstract The Nearctic bark beetle genus Scolytus Geoffroy was revised based in part on a molecular and morphological phylogeny. Monophyly of the native species was tested using mitochondrial (COI) and nuclear (28S, CAD, ArgK) genes and 43 morphological characters in parsimony and Bayesian phylogenetic analyses. Parsimony analyses of molecular and combined datasets provided mixed results while Bayesian analysis recovered most nodes with posterior probabilities >90%. Native hardwood- and conifer-feeding Scolytus species were recovered as paraphyletic. Native Nearctic species were recovered as paraphyletic with hardwood-feeding species sister to Palearctic hardwood-feeding species rather than to native conifer-feeding species. The Nearctic conifer-feeding species were monophyletic. Twenty-five species were recognized. Four new synonyms were discovered: Scolytus praeceps LeConte, 1868 (= Scolytus abietis Blackman, 1934; = Scolytus opacus Blackman, 1934), Scolytus reflexus Blackman, 1934 (= Scolytus virgatus Bright, 1972; = Scolytus wickhami Blackman, 1934). Two species were reinstated: Scolytus fiskei Blackman, 1934 and Scolytus silvaticus Bright, 1972. A diagnosis, description, distribution, host records and images were provided for each species and a key is presented to all species. PMID:25408617

The Current Status of the Distribution Range of the Western Pine Beetle, Dendroctonus brevicomis (Curculionidae: Solytinae) in Northern Mexico.

PubMed

Valerio-Mendoza, O; Armendáriz-Toledano, F; Cuéllar-Rodríguez, G; Negrón, José F; Zúñiga, G

2017-09-01

The distribution range of the western pine beetle Dendroctonus brevicomis LeConte (Coleoptera: Curculionidae) is supported only by scattered records in the northern parts of Mexico, suggesting that its populations may be marginal and rare in this region. In this study, we review the geographical distribution of D. brevicomis in northern Mexico and perform a geometric morphometric analysis of seminal rod shape to evaluate its reliability for identifying this species with respect to other members of the Dendroctonus frontalis Zimmermann (Coleoptera: Curculionidae) complex. Our results provide 30 new records, with 26 distributed in the Sierra Madre Occidental and 4 in the Sierra Madre Oriental. These records extend the known distribution range of D. brevicomis to Durango and Tamaulipas states in northern Mexico. Furthermore, we find high geographic variation in size and shape of the seminal rod, with conspicous differences among individuals from different geographical regions, namely west and east of the Great Basin and between mountain systems in Mexico. © The Author 2017. Published by Oxford University Press on behalf of Entomological Society of America.

Qualitative and quantitative evaluation of rigid and deformable motion correction algorithms using dual-energy CT images in view of application to CT perfusion measurements in abdominal organs affected by breathing motion

PubMed Central

Skornitzke, S; Fritz, F; Klauss, M; Pahn, G; Hansen, J; Hirsch, J; Grenacher, L; Kauczor, H-U

2015-01-01

Objective: To compare six different scenarios for correcting for breathing motion in abdominal dual-energy CT (DECT) perfusion measurements. Methods: Rigid [RRComm(80 kVp)] and non-rigid [NRComm(80 kVp)] registration of commercially available CT perfusion software, custom non-rigid registration [NRCustom(80 kVp], demons algorithm) and a control group [CG(80 kVp)] without motion correction were evaluated using 80 kVp images. Additionally, NRCustom was applied to dual-energy (DE)-blended [NRCustom(DE)] and virtual non-contrast [NRCustom(VNC)] images, yielding six evaluated scenarios. After motion correction, perfusion maps were calculated using a combined maximum slope/Patlak model. For qualitative evaluation, three blinded radiologists independently rated motion correction quality and resulting perfusion maps on a four-point scale (4 = best, 1 = worst). For quantitative evaluation, relative changes in metric values, R2 and residuals of perfusion model fits were calculated. Results: For motion-corrected images, mean ratings differed significantly [NRCustom(80 kVp) and NRCustom(DE), 3.3; NRComm(80 kVp), 3.1; NRCustom(VNC), 2.9; RRComm(80 kVp), 2.7; CG(80 kVp), 2.7; all p < 0.05], except when comparing NRCustom(80 kVp) with NRCustom(DE) and RRComm(80 kVp) with CG(80 kVp). NRCustom(80 kVp) and NRCustom(DE) achieved the highest reduction in metric values [NRCustom(80 kVp), 48.5%; NRCustom(DE), 45.6%; NRComm(80 kVp), 29.2%; NRCustom(VNC), 22.8%; RRComm(80 kVp), 0.6%; CG(80 kVp), 0%]. Regarding perfusion maps, NRCustom(80 kVp) and NRCustom(DE) were rated highest [NRCustom(80 kVp), 3.1; NRCustom(DE), 3.0; NRComm(80 kVp), 2.8; NRCustom(VNC), 2.6; CG(80 kVp), 2.5; RRComm(80 kVp), 2.4] and had significantly higher R2 and lower residuals. Correlation between qualitative and quantitative evaluation was low to moderate. Conclusion: Non-rigid motion correction improves spatial alignment of the target region and fit of CT perfusion models. Using DE-blended and DE-VNC images for deformable registration offers no significant improvement. Advances in knowledge: Non-rigid algorithms improve the quality of abdominal CT perfusion measurements but do not benefit from DECT post processing. PMID:25465353

Toxicity of inorganic contaminants, individually and in environmental mixtures, to three endangered fishes (Colorado squawfish, bonytail, and razorback sucker)

USGS Publications Warehouse

Buhl, Kevin J.; Hamilton, S.J.

1996-01-01

Two life stages of three federally-listed endangered fishes, Colorado squawfish (Ptychocheilus lucius), bonytail (Gila elegans), and razorback sucker (Xyrauchen texanus) were exposed to copper, selenate, selenite, and zinc individually, and to mixtures of nine inorganics in a reconstituted water that simulated the water quality of the middle Green River, Utah. The mixtures simulated environmental ratios of arsenate, boron, copper, molybdenum, selenate, selenite, uranium, vanadium, and zinc in two tributaries, Ashley Creek and Stewart Lake outlet, of the middle Green River. The rank order of toxicity of the individual inorganics, from most to least toxic, was: copper > zinc > selenite > selenate. Colorado squawfish larvae were more sensitive to all four inorganics and the two mixtures than the juveniles, whereas there was no consistent response between the two life stages for the other two species. There was no consistent difference in sensitivity to the inorganics among the three endangered fishes. Both mixtures exhibited either additive or greater than additive toxicity to these fishes. The primary toxic components in the mixtures, based on toxic units, were copper and zinc. Acute toxicity values were compared to measured environmental concentrations in the two tributaries to derive margins of uncertainty. Margins of uncertainty were low for both mixtures (9–22 for the Stewart Lake outlet mixture, and 12–32 for the Ashley Creek mixture), indicating that mixtures of inorganics derived from irrigation activities may pose a hazard to endangered fishes in the Green River.

Selenium impacts on razorback sucker, Colorado: Colorado River: III. Larvae

USGS Publications Warehouse

Hamilton, Steven J.; Holley, Kathy M.; Buhl, Kevin J.; Bullard, Fern A.

2005-01-01

Razorback sucker (Xyrauchen texanus) larvae from adults exposed to selenium at three sites near Grand Junction, Colorado, for 9 months were used in a 30-day waterborne and dietary selenium study. Selenium concentrations in water averaged <1.6 μg/L from 24-Road, 0.9 μg/L from Horsethief, 5.5 μg/L from Adobe Creek, and 10.7 μg/L from the North Pond. Selenium in dietary items averaged 2.7 μg/g in brine shrimp, 5.6 μg/g in zooplankton from Horsethief east wetland, 20 μg/g in zooplankton from Adobe Creek, and 39 μg/g in zooplankton from North Pond. The lowest survival occurred in larvae fed zooplankton rather than brine shrimp. Survival of larvae at Adobe Creek and North Pond was lower in site water than in reference water. Survival of brood stock larvae was higher than Horsethief larvae even though they received the same water and dietary treatments. Arsenic concentrations in brine shrimp may have resulted in an antagonistic interaction with selenium and reduced adverse effects in larvae. Deformities in larvae from North Pond were similar to those reported for selenium-induced teratogenic deformities in other fish species. Selenium concentrations of ⩾4.6 μg/g in food resulted in rapid mortality of larvae from Horsethief, Adobe Creek, and North Pond, and suggested that selenium toxicity in the Colorado River could limit recovery of this endangered fish.

Gut bacteria facilitate adaptation to crop rotation in the western corn rootworm

PubMed Central

Chu, Chia-Ching; Spencer, Joseph L.; Curzi, Matías J.; Zavala, Jorge A.; Seufferheld, Manfredo J.

2013-01-01

Insects are constantly adapting to human-driven landscape changes; however, the roles of their gut microbiota in these processes remain largely unknown. The western corn rootworm (WCR, Diabrotica virgifera virgifera LeConte) (Coleoptera: Chrysomelidae) is a major corn pest that has been controlled via annual rotation between corn (Zea mays) and nonhost soybean (Glycine max) in the United States. This practice selected for a “rotation-resistant” variant (RR-WCR) with reduced ovipositional fidelity to cornfields. When in soybean fields, RR-WCRs also exhibit an elevated tolerance of antiherbivory defenses (i.e., cysteine protease inhibitors) expressed in soybean foliage. Here we show that gut bacterial microbiota is an important factor facilitating this corn specialist’s (WCR's) physiological adaptation to brief soybean herbivory. Comparisons of gut microbiota between RR- and wild-type WCR (WT-WCR) revealed concomitant shifts in bacterial community structure with host adaptation to soybean diets. Antibiotic suppression of gut bacteria significantly reduced RR-WCR tolerance of soybean herbivory to the level of WT-WCR, whereas WT-WCR were unaffected. Our findings demonstrate that gut bacteria help to facilitate rapid adaptation of insects in managed ecosystems. PMID:23798396

Selection for Cry3Bb1 resistance in a genetically diverse population of nondiapausing western corn rootworm (Coleoptera: Chrysomelidae).

PubMed

Oswald, Kenneth J; French, B Wade; Nielson, Chad; Bagley, Mark

2011-06-01

Five short-diapause laboratory lines of western corn rootworm, Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae), were selected for resistance to MON863, a variety of corn genetically modified with the Bacillus thuringiensis Berliner (Bt) transgene that expresses the Cry3Bb1 delta-endotoxin. Three of the selected lines were developed by incremental increase in the duration of exposure to MON863 over 11 generations (moderate selected lines). Two selected lines were developed from a control group by constant exposure to MON863 for at least 14 d posthatch over seven generations (intense selected lines). At the end of the experiment, survivorship, as measured by adult emergence, was approximately 4 times higher in each of the selected lines reared on MON863 compared with control lines. Estimates of realized heritabilities (h2) were 0.16 and 0.15 for the moderate and intense selected lines, respectively, and are consistent with h2 estimates reported previously from a variety of pest insects. These lines provide data necessary for evaluating the potential for Bt resistance within diabroticite beetles and will be useful for developing improved insect resistance management strategies.

A Simple and Sensitive Plant-Based Western Corn Rootworm Bioassay Method for Resistance Determination and Event Selection.

PubMed

Wen, Zhimou; Chen, Jeng Shong

2018-05-26

We report here a simple and sensitive plant-based western corn rootworm, Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae), bioassay method that allows for examination of multiple parameters for both plants and insects in a single experimental setup within a short duration. For plants, injury to roots can be visually examined, fresh root weight can be measured, and expression of trait protein in plant roots can be analyzed. For insects, in addition to survival, larval growth and development can be evaluated in several aspects including body weight gain, body length, and head capsule width. We demonstrated using the method that eCry3.1Ab-expressing 5307 corn was very effective against western corn rootworm by eliciting high mortality and significantly inhibiting larval growth and development. We also validated that the method allowed determination of resistance in an eCry3.1Ab-resistant western corn rootworm strain. While data presented in this paper demonstrate the usefulness of the method for selection of events of protein traits and for determination of resistance in laboratory populations, we envision that the method can be applied in much broader applications.

2,3-Hexanediols as Sex Attractants and a Female-produced Sex Pheromone for Cerambycid Beetles in the Prionine Genus Tragosoma

PubMed Central

Barbour, James D.; McElfresh, J. Steven; Moreira, Jardel A.; Swift, Ian; Wright, Ian M.; Žunič, Alenka; Mitchell, Robert F.; Graham, Elizabeth E.; Alten, Ronald L.; Millar, Jocelyn G.; Hanks, Lawrence M.

2013-01-01

Recent work suggests that closely related cerambycid species often share pheromone components, or even produce pheromone blends of identical composition. However, little is known of the pheromones of species in the subfamily Prioninae. During field bioassays in California, males of three species in the prionine genus Tragosoma were attracted to 2,3-hexanediols, common components of male-produced aggregation pheromones of beetles in the subfamily Cerambycinae. We report here that the female-produced sex pheromone of Tragosoma depsarium “sp. nov. Laplante” is (2R,3R)-2,3-hex-anediol, and provide evidence from field bioassays and electro-antennography that the female-produced pheromone of both Tragosoma pilosicorne Casey and T depsarium “harrisi” LeConte may be (2S,3R)-2,3-hexanediol. Sexual dimorphism in the sculpting of the prothorax suggests that the pheromone glands are located in the prothorax of females. This is the second sex attractant pheromone structure identified from the subfamily Prioninae, and our results provide further evidence of pheromonal parsimony within the Cerambycidae, in this case extending across both subfamily and gender lines. PMID:22923142

Quantitative Comparison of Virtual Monochromatic Images of Dual Energy Computed Tomography Systems: Beam Hardening Artifact Correction and Variance in Computed Tomography Numbers: A Phantom Study.

PubMed

Wu, Rongli; Watanabe, Yoshiyuki; Satoh, Kazuhiko; Liao, Yen-Peng; Takahashi, Hiroto; Tanaka, Hisashi; Tomiyama, Noriyuki

2018-05-21

The aim of this study was to quantitatively compare the reduction in beam hardening artifact (BHA) and variance in computed tomography (CT) numbers of virtual monochromatic energy (VME) images obtained with 3 dual-energy computed tomography (DECT) systems at a given radiation dose. Five different iodine concentrations were scanned using dual-energy and single-energy (120 kVp) modes. The BHA and CT number variance were evaluated. For higher iodine concentrations, 40 and 80 mgI/mL, BHA on VME imaging was significantly decreased when the energy was higher than 50 keV (P = 0.003) and 60 keV (P < 0.001) for GE, higher than 80 keV (P < 0.001) and 70 keV (P = 0.002) for Siemens, and higher than 40 keV (P < 0.001) and 60 keV (P < 0.001) for Toshiba, compared with single-energy CT imaging. Virtual monochromatic energy imaging can decrease BHA and improve CT number accuracy in different dual-energy computed tomography systems, depending on energy levels and iodine concentrations.

Public health implications of wireless technologies.

PubMed

Sage, Cindy; Carpenter, David O

2009-08-01

Global exposures to emerging wireless technologies from applications including mobile phones, cordless phones, DECT phones, WI-FI, WLAN, WiMAX, wireless internet, baby monitors, and others may present serious public health consequences. Evidence supporting a public health risk is documented in the BioInitiative Report. New, biologically based public exposure standards for chronic exposure to low-intensity exposures are warranted. Existing safety standards are obsolete because they are based solely on thermal effects from acute exposures. The rapidly expanding development of new wireless technologies and the long latency for the development of such serious diseases as brain cancers means that failure to take immediate action to reduce risks may result in an epidemic of potentially fatal diseases in the future. Regardless of whether or not the associations are causal, the strengths of the associations are sufficiently strong that in the opinion of the authors, taking action to reduce exposures is imperative, especially for the fetus and children. Such action is fully compatible with the precautionary principle, as enunciated by the Rio Declaration, the European Constitution Principle on Health (Section 3.1) and the European Union Treaties Article 174.

Effects of ultraviolet-B radiation on fish: Histologic comparison of a UVB-sensitive and a UVB-tolerant species

USGS Publications Warehouse

Blazer, V.S.; Fabacher, D.L.; Little, E.E.; Ewing, M.S.; Kocan, K.M.

1997-01-01

Lahontan cutthroat trout Oncorhynchus clarki henshawi were sensitive to simulated solar ultraviolet-B radiation (UVB) and exhibited grossly visible signs of sunburn upon exposure. Razorback suckers Xyrauchen texanus, however, were tolerant to simulated solar UVB and showed no grossly visible signs of exposure. Cutthroat trout also had considerably less of an unidentified, possibly photoprotective, substance in the skin than did razorback suckers. In all attempt to characterize the cellular response to simulated solar UVB exposure in the skin of these two species, we examined sections from UVB-exposed fish by light and electron microscopy. Cutthroat trout showed grossly visible signs of sunburn by 48 h. Histologic observations included a sloughing of the mucous cells, necrosis and edema in the epidermis and dermis, and, in some cases, secondary fungal infections. Razorback suckers did not show any visible signs of sunburn during 72 h of experimental exposure. Histologic analyses revealed that cell necrosis had occurred, but the severe necrosis and sloughing noted in cutthroat trout was not observed. An increase in epidermal thickness, apparently due to hypertrophy and hyperplasia of large PAS-negative cells, occurred in the razorback suckers. These cells contained a large central region of low electron density and appeared to be club cells. In some, extensive interdigitation of the electron-lucent cytoplasm with adjacent epithelial cell margins occurred. Near the surface of the epidermis these cells were larger and the interface with epithelial cells lacked complex interdigitation. These cells may contain the substance that appears to protect razorback suckers against UV-B radiation.

Epizootiologic studies on filarioids of the raccoon

USGS Publications Warehouse

Herman, C.M.; Price, D.L.

1965-01-01

Filarioid worms (Dirofilaria immitis, D. tenuis, Dipetalonema procyonis, and D. llewellyni) were discovered in raccoons (Procyon lotar) in Maryland. Raccoons were trapped in lowland, upland, and agricultural-residential areas, which were further classified as stream borders, poorly drained, and well drained. Data on incidence of D. llewellyni were analyzed on basis of host distribution within these areas to indicate type of habitat in which one might seek the vector. It was concluded that exposure takes place in the spring of the year. The arthropod found associated most often with the raccoon in spring was Ixodes texanus. Larvae of this tick which were fed on infected raccoons presented no evidence of development of the microfilariae. Feeding experiments were also conducted with mosquitoes: Aedes aegypti, A. canadensis, A. sollicitans, A. triseriatus, A. vexans, Culex pipiens, Anopheles punctipennis, and A. quadrimaculatus. Although microfilariae remained alive and active in the gut contents of all these mosquitoes for 2 days, only in Aedes aegypti did they enter the hemocele, but no developmental changes were noted and all microfilariae were dead by the eighth day. Although the intermediate host of D. llewellyni was not determined, evaluation of the accumulated data provides criteria for seeking the vector. It appeared unlikely that exposure of the raccoons took place in the den or that the filarioids were transmitted by an ectoparasite commonly found in raccoon dens. The data suggest that the vector is available only early in spring, although there are infected raccoons throughout the year. Prevalence in juveniles was 21 percent; in subadults, 64 percent; in adults, 87 percent.

Effects of capture by trammel net on Colorado River native fishes

USGS Publications Warehouse

Hunt, Teresa A.; Ward, David L.; Propper, Catherine R.; Gibb, Alice C.

2012-01-01

Trammel nets are commonly used to sample rare fishes; however, little research has assessed delayed mortality associated with this capture technique. We conducted laboratory experiments to evaluate the effects of capture by trammel net on bonytail Gila elegans, razorback sucker Xyrauchen texanus, and roundtail chub Gila robusta, at 15, 20, and 25uC. Fish (139–288 mm total length) were entangled in a trammel net for 2 h or captured by seine net and then monitored for mortality for at least 14 d. Blood samples were collected immediately after capture, and plasma cortisol levels were quantified as an index of capture-related stress. The cortisol response varied by species, but mean cortisol levels were higher for fish captured by trammel netting (295.9 ng/mL) relative to fish captured by seine netting (215.8 ng/mL). Only one fish (of 550) died during capture and handling, but 42% of the trammel-netted fish and 11% of the seine-netted fish died within 14 d after capture. In general, mortality after capture by trammel net increased with increased water temperature and at 25uC was 88% for bonytail, 94% for razorback sucker, and 25% for roundtail chub. Delayed mortality of wild-caught fish captured by trammel net has the potential to be high, at least under some circumstances. We suggest that sampling frequency, timing of sampling (relative to reproductive cycles), and water temperature all be considered carefully when using trammel nets to sample diminished populations of imperiled native fishes.

Identifying Preservation and Restoration Priority Areas for Desert Fishes in an Increasingly Invaded World

NASA Astrophysics Data System (ADS)

Pool, Thomas K.; Strecker, Angela L.; Olden, Julian D.

2013-03-01

A commonly overlooked aspect of conservation planning assessments is that wildlife managers are increasingly focused on habitats that contain non-native species. We examine this management challenge in the Gila River basin (150,730 km2), and present a new planning strategy for fish conservation. By applying a hierarchical prioritization algorithm to >850,000 fish records in 27,181 sub-watersheds we first identified high priority areas (PAs) termed "preservation PAs" with high native fish richness and low non-native richness; these represent traditional conservation targets. Second, we identified "restoration PAs" with high native fish richness that also contained high numbers of non-native species; these represent less traditional conservation targets. The top 10 % of preservation and restoration PAs contained common native species (e.g., Catostomus clarkii, desert sucker; Catostomus insignis, Sonora sucker) in addition to native species with limited distributions (i.e., Xyrauchen texanus, razorback sucker; Oncorhynchus gilae apache, Apache trout). The top preservation and restoration PAs overlapped by 42 %, indicating areas with high native fish richness range from minimally to highly invaded. Areas exclusively identified as restoration PAs also encompassed a greater percentage of native species ranges than would be expected by the random addition of an equivalent basin area. Restoration PAs identified an additional 19.0 and 26.6 % of the total ranges of two federally endangered species— Meda fulgida (spikedace) and Gila intermedia (Gila chub), respectively, compared to top preservation PAs alone—despite adding only 5.8 % of basin area. We contend that in addition to preservation PAs, restoration PAs are well suited for complementary management activities benefiting native fishes.

Selenium impacts on razorback sucker, Colorado River, Colorado I. Adults.

PubMed

Hamilton, Steven J; Holley, Kathy M; Buhl, Kevin J; Bullard, Fern A; Ken Weston, L; McDonald, Susan F

2005-05-01

Adult razorback sucker (Xyrauchen texanus) were exposed to various selenium concentrations in ponds and isolated river channels of the Colorado River near Grand Junction, CO, to determine effects on their growth and residue accumulation over an 11-month period. Adults at Horsethief ponds were fed a commercial diet, whereas fish at Adobe Creek channel and North Pond foraged on natural food items. Selenium concentrations at Horsethief were 2.2 microg/L in water, 0.1-1.4 microg/g in sediment, and 2.3-3.1 microg/g in food organisms (1.1 microg/g in commercial fish food), at Adobe Creek were 3.8 microg/L in water, 0.5-2.1 microg/g in sediment, and 4-56 microg/g in food organisms, and at North Pond were 9.5 microg/L in water, 7-55 microg/g in sediment, and 20-81 microg/g in food organisms. The selenium concentrations in muscle plugs from adults at Adobe Creek (11.7 microg/g, SD = 0.4, n = 6) and North Pond (16.6 microg/g, SD = 1.0, n = 6) were greater than at Horsethief (4.5 microg/g, SD = 0.2, n = 6). During a depuration period adults from Adobe Creek and North Pond lost 1-2% of their selenium burden in 32 days and 14-19% in 66 days. Selenium accumulated in razorback sucker above toxic thresholds reported in other studies, yet those residues were less than those reported in muscle plugs of 40% of wild razorback sucker caught in the Green River, Utah.

Selenium concentrations in the razorback sucker (Xyrauchen texanus): Substitution of non-lethal muscle plugs for muscle tissue in contaminant assessment

USGS Publications Warehouse

Waddell, B.; May, T.

1995-01-01

A single muscle plug was collected from each of 25 live razorback suckers inhabiting the Colorado River basin and analyzed for selenium by instrumental neutron activation. Eight fish from Ashley Creek and three from Razorback Bar exhibited selenium concentrations exceeding 8 μg/g, a level associated with reproductive failure in fish. Concentrations of selenium in eggs and milt were significantly correlated with selenium concentrations in muscle plugs and together indicate a possible explanation for the decline of this species in the Colorado River basin. Muscle plugs (<50mg) and muscle tissue (20 g) were collected from dorsal, anterior, and posterior areas of common carp, flannelmouth sucker, and an archived razorback sucker and analyzed for selenium. Concentrations of selenium in muscle plugs were significantly correlated with selenium concentrations in muscle tissue from the same location and fish (r=0.97). Coefficients of variation for selenium concentrations in each fish were <6.5% for muscle tissue, but ranged from 1.5 to 32.4% for muscle plugs. Increased variation in muscle plugs was attributed to lower selenium concentrations found in the anterior muscle plugs of flannelmouth suckers. Mean selenium concentrations in muscle plugs and tissue from dorsal and posterior areas and muscle tissue from the anterior area were not significantly different. The non-lethal collection of a muscle plug from dorsal and posterior areas of the razorback sucker and other fish species may provide an accurate assessment of selenium concentrations that exist in adjacent muscle tissue.

Temperature variability is a key component in accurately forecasting the effects of climate change on pest phenology.

PubMed

Merrill, Scott C; Peairs, Frank B

2017-02-01

Models describing the effects of climate change on arthropod pest ecology are needed to help mitigate and adapt to forthcoming changes. Challenges arise because climate data are at resolutions that do not readily synchronize with arthropod biology. Here we explain how multiple sources of climate and weather data can be synthesized to quantify the effects of climate change on pest phenology. Predictions of phenological events differ substantially between models that incorporate scale-appropriate temperature variability and models that do not. As an illustrative example, we predicted adult emergence of a pest of sunflower, the sunflower stem weevil Cylindrocopturus adspersus (LeConte). Predictions of the timing of phenological events differed by an average of 11 days between models with different temperature variability inputs. Moreover, as temperature variability increases, developmental rates accelerate. Our work details a phenological modeling approach intended to help develop tools to plan for and mitigate the effects of climate change. Results show that selection of scale-appropriate temperature data is of more importance than selecting a climate change emission scenario. Predictions derived without appropriate temperature variability inputs will likely result in substantial phenological event miscalculations. Additionally, results suggest that increased temperature instability will lead to accelerated pest development. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Seasonal Flight Activity of the Sugarcane Beetle (Coleoptera: Scarabaeidae) in North Carolina Using Black Light Traps.

PubMed

Billeisen, T L; Brandenburg, R L

2016-04-01

Seasonal flight activity, adult beetle sex count, and egg production were examined in sugarcane beetles Euetheola rugiceps (LeConte) caught in light traps in North Carolina from the fall of 2009 through the summer of 2014. A regression model using variable environmental conditions as predictive parameters was developed to examine the impact of these conditions on flight activity. Depending on flight trap location and sampling years, beetles exhibited an inconsistent flight pattern, with the majority of adults flying in the spring (April-June) and intermittently in the fall (September-October). Our model indicated that larger numbers of adults collected from traps coincided with an increase in average soil temperature. Sugarcane beetles also exhibit a synchronous emergence during both periods of flight activity. Eggs were detected in females collected from light traps every week throughout the entire sampling period. The majority of females produced 7-12 eggs, with most egg production occurring between 15 May and 1 August. The findings of this research provide adult sugarcane beetle emergence and flight behavior information necessary to determine optimal pesticide application timing. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Further contributions to the staphylinid fauna of New Brunswick, Canada, and the USA, with descriptions of two new Proteinus species (Coleoptera, Staphylinidae).

PubMed

Webster, Reginald P; Davies, Anthony E; Klimaszewski, Jan; Bourdon, Caroline

2016-01-01

This paper treats the discovery of new species and new records of Staphylinidae from the subfamilies Omaliinae, Proteininae, Tachyporinae, Oxytelinae, Scydmaeninae, Steninae, Euaesthetinae, Pseudopsinae, Paederinae, and Staphylininae for the province of New Brunswick and other provinces of Canada, and the USA. We report here two species new to science, three new North American records, nine new Canadian records, two new USA records, and 50 new provincial records. The following are the species new to science: Proteinus hughesi Webster & Davies, sp. n. and Proteinus sweeneyi Webster & Klimaszewski, sp. n. (Proteininae). Sepedophilus immaculatus (Stephens) and Carpelimus erichsoni (Sharp), Carpelimus mundus (Sharp) are newly recorded from North America. New Canadian records are as follows: Carpelimus difficilis (Casey), Carpelimus gracilis (Mannerheim), Carpelimus lacustris (Notman), Carpelimus probus (Casey), Carpelimus pusillus (Gravenhorst), Carpelimus rivularis (Motschulsky), Carpelimus spretus (Casey), Carpelimus weissi (Notman) (Oxytelinae), and Edaphus lederi Eppelsheim (Euaesthetinae). This is the first record of the genus Edaphus for Canada. Bledius basalis LeConte and Carpelimus obesus (Kiesenwetter) (Oxytelinae) are removed from the faunal list of New Brunswick. Proteinus acadiensis Klimaszewski and Proteinus pseudothomasi Klimaszewski are newly recorded from the USA and several provinces of Canada. Habitat data from New Brunswick are provided for most of the species treated in this contribution.

Further contributions to the staphylinid fauna of New Brunswick, Canada, and the USA, with descriptions of two new Proteinus species (Coleoptera, Staphylinidae)

PubMed Central

Webster, Reginald P.; Davies, Anthony E.; Klimaszewski, Jan; Bourdon, Caroline

2016-01-01

Abstract This paper treats the discovery of new species and new records of Staphylinidae from the subfamilies Omaliinae, Proteininae, Tachyporinae, Oxytelinae, Scydmaeninae, Steninae, Euaesthetinae, Pseudopsinae, Paederinae, and Staphylininae for the province of New Brunswick and other provinces of Canada, and the USA. We report here two species new to science, three new North American records, nine new Canadian records, two new USA records, and 50 new provincial records. The following are the species new to science: Proteinus hughesi Webster & Davies, sp. n. and Proteinus sweeneyi Webster & Klimaszewski, sp. n. (Proteininae). Sepedophilus immaculatus (Stephens) and Carpelimus erichsoni (Sharp), Carpelimus mundus (Sharp) are newly recorded from North America. New Canadian records are as follows: Carpelimus difficilis (Casey), Carpelimus gracilis (Mannerheim), Carpelimus lacustris (Notman), Carpelimus probus (Casey), Carpelimus pusillus (Gravenhorst), Carpelimus rivularis (Motschulsky), Carpelimus spretus (Casey), Carpelimus weissi (Notman) (Oxytelinae), and Edaphus lederi Eppelsheim (Euaesthetinae). This is the first record of the genus Edaphus for Canada. Bledius basalis LeConte and Carpelimus obesus (Kiesenwetter) (Oxytelinae) are removed from the faunal list of New Brunswick. Proteinus acadiensis Klimaszewski and Proteinus pseudothomasi Klimaszewski are newly recorded from the USA and several provinces of Canada. Habitat data from New Brunswick are provided for most of the species treated in this contribution. PMID:27110167

Investigating plume dynamics at the ocean-glacier interface with turbulence profiling and autonomous vessels

NASA Astrophysics Data System (ADS)

Jackson, R. H.; Nash, J. D.; Sutherland, D. A.; Amundson, J. M.; Kienholz, C.; Skyllingstad, E. D.; Motyka, R. J.

2017-12-01

The exchanges of heat and freshwater at tidewater glacier termini are modulated by small-scale turbulent processes. However, few observations have been obtained near the ocean-glacier interface, limiting our ability to quantify turbulent fluxes or test melt parameterizations in ocean-glacier models. Here, we explore the turbulent plume dynamics at LeConte Glacier, Alaska with three extensive field campaigns in May, August and September (2016-17). Two autonomous vessels collected repeat transects of velocity and water properties near the glacier, often within 20 m of the terminus. Concurrent shipboard surveying measured turbulence with a vertical microstructure profiler, along with water properties and velocity. These high-resolution surveys provide a 3D view of the circulation and allow us to quantify turbulent fluxes in the near-glacier region. We observe two regimes at the terminus: an energetic upwelling plume driven by subglacial discharge at a persistent location, and submarine melt-driven convection along other parts of the terminus. We trace the evolution of the subglacial discharge plume as it flows away from the glacier, from an initial stage of vigorous mixing to a more quiescent outflow downstream. Resolving these spatial patterns of upwelling and mixing near glaciers is a key step towards understanding submarine melt rates and glacial fjord circulation.

Relationship between carrot weevil infestation and parsley yield.

PubMed

Torres, Angel N; Hoy, Casey W

2005-08-01

The relationship between numbers of carrot weevil, Listronotus oregonensis (LeConte), oviposition scars and parsley fresh weight and plant mortality was measured in research plots during 1999 and 2000. Fresh weight was measured in one to two cuttings of parsley planted on two planting dates. The average weight declined with increasing numbers of oviposition scars in the later planting in 1999. Compensatory growth in surviving plants may reduce this effect. Plant mortality increased as number of oviposition scars per plant increased in the second planting in both years and in the first cutting of the first planting in 2000. One oviposition scar per plant is sufficient to result in significant reduction in fresh weight per plant. In commercial parsley fields, the relationship between fresh weight of parsley per 30-cm row section of parsley was best described as a linear function of the proportion of plants with root feeding. Economic damage to parsley that is equivalent to the cost of controlling carrot weevil was estimated to result from approximately 1% of plants with root damage. Based upon this estimated economic injury level, we suggest an action threshold of 1% of plants containing carrot weevil oviposition scars earlier in the growing season when controls could be applied to prevent the damage.

Systematic implementation of spectral CT with a photon counting detector for liquid security inspection

NASA Astrophysics Data System (ADS)

Xu, Xiaofei; Xing, Yuxiang; Wang, Sen; Zhang, Li

2018-06-01

X-ray liquid security inspection system plays an important role in homeland security, while the conventional dual-energy CT (DECT) system may have a big deviation in extracting the atomic number and the electron density of materials in various conditions. Photon counting detectors (PCDs) have the capability of discriminating the incident photons of different energy. The technique becomes more and more mature in nowadays. In this work, we explore the performance of a multi-energy CT imaging system with a PCD for liquid security inspection in material discrimination. We used a maximum-likelihood (ML) decomposition method with scatter correction based on a cross-energy response model (CERM) for PCDs so that to improve the accuracy of atomic number and electronic density imaging. Experimental study was carried to examine the effectiveness and robustness of the proposed system. Our results show that the concentration of different solutions in physical phantoms can be reconstructed accurately, which could improve the material identification compared to current available dual-energy liquid security inspection systems. The CERM-base decomposition and reconstruction method can be easily used to different applications such as medical diagnosis.

Satellite Observations of Glacier Surface Velocities in Southeast Alaska

NASA Astrophysics Data System (ADS)

Elliott, J.; Melkonian, A. K.; Pritchard, M. E.

2012-12-01

Glaciers in southeast Alaska are undergoing rapid changes and are significant contributors to sea level rise. A key to understanding the ice dynamics is knowledge of the surface velocities, which can be used with ice thickness measurements to derive mass flux rates. For many glaciers in Alaska, surface velocity estimates either do not exist or are based on data that are at least a decade old. Here we present updated maps of glacier surface velocities in southeast Alaska produced through a pixel tracking technique using synthetic aperture radar data and high-resolution optical imagery. For glaciers with previous velocity estimates, we will compare the results and discuss possible implications for ice dynamics. We focus on Glacier Bay and the Stikine Icefield, which contain a number of fast-flowing tidewater glaciers including LeConte, Johns Hopkins, and La Perouse. For the Johns Hopkins, we will also examine the influence a massive landslide in June 2012 had on flow dynamics. Our velocity maps show that within Glacier Bay, the highest surface velocities occur on the tidewater glaciers. La Perouse, the only Glacier Bay glacier to calve directly into the Pacific Ocean, has maximum velocities of 3.5 - 4 m/day. Johns Hopkins Glacier shows 4 m/day velocities at both its terminus and in its upper reaches, with lower velocities of ~1-3 m/day in between those two regions. Further north, the Margerie Glacier has a maximum velocity of ~ 4.5 m/day in its upper reaches and a velocity of ~ 2 m/day at its terminus. Along the Grand Pacific terminus, the western terminus fed by the Ferris Glacier displays velocities of about 1 m/day while the eastern terminus has lower velocities of < 0.5 m/day. The lake terminating glaciers along the Pacific coast have overall lower surface velocities, but they display complex flow patterns. The Alsek Glacier displays maximum velocities of 2.5 m/day above where it divides into two branches. Velocities at the terminus of the northern branch reach 1 m/day while the terminus of the southern branch moves about 2 m/day. Grand Plateau Glacier also divides into two main branches, with a northern branch displaying peak velocities of 1.5 m/day and a southern branch flowing at a rate of 1 m/day. The Stikine Icefield contains a number of large tidewater glaciers showing maximum velocities near their termini. At the terminus of the South Sawyer Glacier, velocities reach a peak of about 2 m/day. Along the terminus of the Dawes Glacier, velocities reach 3.5 m/day. The Baird Glacier displays lower velocities of 1-1.5 m/day. LeConte Glacier has 2-3 m/day velocities in its upper regions with higher velocities near its terminus. In contrast to the pattern shown by the surrounding glaciers, the Great Glacier has a peak velocity of 2 m/day in the upper portion of the glacier and a velocity of only 0.5 m/day near its terminus.

Numerical observer for atherosclerotic plaque classification in spectral computed tomography

PubMed Central

Lorsakul, Auranuch; Fakhri, Georges El; Worstell, William; Ouyang, Jinsong; Rakvongthai, Yothin; Laine, Andrew F.; Li, Quanzheng

2016-01-01

Abstract. Spectral computed tomography (SCT) generates better image quality than conventional computed tomography (CT). It has overcome several limitations for imaging atherosclerotic plaque. However, the literature evaluating the performance of SCT based on objective image assessment is very limited for the task of discriminating plaques. We developed a numerical-observer method and used it to assess performance on discrimination vulnerable-plaque features and compared the performance among multienergy CT (MECT), dual-energy CT (DECT), and conventional CT methods. Our numerical observer was designed to incorporate all spectral information and comprised two-processing stages. First, each energy-window domain was preprocessed by a set of localized channelized Hotelling observers (CHO). In this step, the spectral image in each energy bin was decorrelated using localized prewhitening and matched filtering with a set of Laguerre–Gaussian channel functions. Second, the series of the intermediate scores computed from all the CHOs were integrated by a Hotelling observer with an additional prewhitening and matched filter. The overall signal-to-noise ratio (SNR) and the area under the receiver operating characteristic curve (AUC) were obtained, yielding an overall discrimination performance metric. The performance of our new observer was evaluated for the particular binary classification task of differentiating between alternative plaque characterizations in carotid arteries. A clinically realistic model of signal variability was also included in our simulation of the discrimination tasks. The inclusion of signal variation is a key to applying the proposed observer method to spectral CT data. Hence, the task-based approaches based on the signal-known-exactly/background-known-exactly (SKE/BKE) framework and the clinical-relevant signal-known-statistically/background-known-exactly (SKS/BKE) framework were applied for analytical computation of figures of merit (FOM). Simulated data of a carotid-atherosclerosis patient were used to validate our methods. We used an extended cardiac-torso anthropomorphic digital phantom and three simulated plaque types (i.e., calcified plaque, fatty-mixed plaque, and iodine-mixed blood). The images were reconstructed using a standard filtered backprojection (FBP) algorithm for all the acquisition methods and were applied to perform two different discrimination tasks of: (1) calcified plaque versus fatty-mixed plaque and (2) calcified plaque versus iodine-mixed blood. MECT outperformed DECT and conventional CT systems for all cases of the SKE/BKE and SKS/BKE tasks (all p<0.01). On average of signal variability, MECT yielded the SNR improvements over other acquisition methods in the range of 46.8% to 65.3% (all p<0.01) for FBP-Ramp images and 53.2% to 67.7% (all p<0.01) for FBP-Hanning images for both identification tasks. This proposed numerical observer combined with our signal variability framework is promising for assessing material characterization obtained through the additional energy-dependent attenuation information of SCT. These methods can be further extended to other clinical tasks such as kidney or urinary stone identification applications. PMID:27429999

Accuracies of the synthesized monochromatic CT numbers and effective atomic numbers obtained with a rapid kVp switching dual energy CT scanner

DOE Office of Scientific and Technical Information (OSTI.GOV)

Goodsitt, Mitchell M.; Christodoulou, Emmanuel G.; Larson, Sandra C.

2011-04-15

Purpose: This study was performed to investigate the accuracies of the synthesized monochromatic images and effective atomic number maps obtained with the new GE Discovery CT750 HD CT scanner. Methods: A Gammex-RMI model 467 tissue characterization phantom and the CT number linearity section of a Phantom Laboratory Catphan 600 phantom were scanned using the dual energy (DE) feature on the GE CT750 HD scanner. Synthesized monochromatic images at various energies between 40 and 120 keV and effective atomic number (Z{sub eff}) maps were generated. Regions of interest were placed within these images/maps to measure the average monochromatic CT numbers andmore » average Z{sub eff} of the materials within these phantoms. The true Z{sub eff} values were either supplied by the phantom manufacturer or computed using Mayneord's equation. The linear attenuation coefficients for the true CT numbers were computed using the NIST XCOM program with the input of manufacturer supplied elemental compositions and densities. The effects of small variations in the assumed true densities of the materials were also investigated. Finally, the effect of body size on the accuracies of the synthesized monochromatic CT numbers was investigated using a custom lumbar section phantom with and without an external fat-mimicking ring. Results: Other than the Z{sub eff} of the simulated lung inserts in the tissue characterization phantom, which could not be measured by DECT, the Z{sub eff} values of all of the other materials in the tissue characterization and Catphan phantoms were accurate to 15%. The accuracies of the synthesized monochromatic CT numbers of the materials in both phantoms varied with energy and material. For the 40-120 keV range, RMS errors between the measured and true CT numbers in the Catphan are 8-25 HU when the true CT numbers were computed using the nominal plastic densities. These RMS errors improve to 3-12 HU for assumed true densities within the nominal density {+-}0.02 g/cc range. The RMS errors between the measured and true CT numbers of the tissue mimicking materials in the tissue characterization phantom over the 40-120 keV range varied from about 6 HU-248 HU and did not improve as dramatically with small changes in assumed true density. Conclusions: Initial tests indicate that the Z{sub eff} values computed with DECT on this scanner are reasonably accurate; however, the synthesized monochromatic CT numbers can be very inaccurate, especially for dense tissue mimicking materials at low energies. Furthermore, the synthesized monochromatic CT numbers of materials still depend on the amount of the surrounding tissues especially at low keV, demonstrating that the numbers are not truly monochromatic. Further research is needed to develop DE methods that produce more accurate synthesized monochromatic CT numbers.« less

Early life history and spatiotemporal changes in distribution of the rediscovered Suwannee moccasinshell Medionidus walkeri (Bivalvia: Unionidae)

USGS Publications Warehouse

Johnson, Nathan A.; Mcleod, John; Holcomb, Jordan; Rowe, Matthew T.; Williams, James D.

2016-01-01

Accurate distribution data are critical to the development of conservation and management strategies for imperiled species, particularly for narrow endemics with life history traits that make them vulnerable to extinction. Medionidus walkeri is a rare freshwater mussel endemic to the Suwannee River Basin in southeastern North America. This species was rediscovered in 2012 after a 16-year hiatus between collections and is currently proposed for listing under the Endangered Species Act. Our study fills knowledge gaps regarding changes in distribution and early life history requirements of M. walkeri. Spatiotemporal changes in M. walkeri distribution were displayed using a conservation status assessment map incorporating metadata from 98 historical (1916–1999) and 401 recent (2000–2015) site surveys from museums and field notes representing records for 312 specimens. Recent surveys detected M. walkeri only in the middle Suwannee subbasin (n = 86, 22 locations) and lower Santa Fe subbasin (n = 2, 2 locations), and it appears the species may be extirpated from 67% of historically occupied 10-digit HUCs. In our laboratory experiments, M. walkeri successfully metamorphosed on Percina nigrofasciata (56.2% ± 8.9) and Etheostoma edwini (16.1% ± 7.9) but not on Trinectes maculatus, Lepomis marginatus, Notropis texanus, Noturus leptacanthus, Etheostoma fusiforme, or Gambusia holbrooki. We characterize M. walkeri as a lure-displaying host fish specialist and a long-term brooder (bradytictic), gravid from fall to early summer of the following year. The early life history and distribution data presented here provide the baseline framework for listing decisions and future efforts to conserve and recover the species.

Relationship of weed shiner and young-of-year bluegill and largemouth bass abundance to submersed aquatic vegetation in Navigation Pools 4, 8, and 13 of the Upper Mississippi River, 1998-2012

USGS Publications Warehouse

DeLain, Steven A.; Popp, Walter A.

2014-01-01

Aquatic vegetation provides food resources and shelter for many species of fish. This study found a significant relationship between increases in submersed aquatic vegetation (SAV) in four study reaches of the Upper Mississippi River (UMR) and increases in catch-per-unit-effort (CPUE) of weed shiners (Notropis texanus) and age-0 bluegills (Lepomis macrochirus) and largemouth bass (Micropterus salmoides) when all of the study reaches were treated collectively using Long Term Resource Monitoring Program (LTRMP) vegetation and fish data for 1998–2012. The selected fishes were more abundant in study reaches with higher SAV frequencies (Pool 8 and Lower Pool 4) and less abundant in reaches with lower SAV frequencies (Pool 13 and Upper Pool 4). When each study reach was examined independently, the relationship between SAV frequency and CPUE of the three species was not significant in most cases, the primary exception being weed shiners in Lower Pool 4. Results of this study indicate that the prevalence of SAV does affect relative abundance of these vegetation-associated fish species. However, the poor annual relationship between SAV frequency and age-0 relative abundance in individual study reaches indicates that several other factors also govern age-0 abundance. The data indicate that there may be a SAV frequency threshold in backwaters above which there is not a strong relationship with abundance of these fish species. This is indicated by the high annual CPUE variability of the three selected fishes in backwaters of Pool 8 and Lower Pool 4 when SAV exceeded certain frequencies.

Selenium concentrations in the Colorado pikeminnow (Ptychocheilus lucius): Relationship with flows in the upper Colorado River

USGS Publications Warehouse

Osmundson, B.C.; May, T.W.; Osmundson, D.B.

2000-01-01

A Department of the Interior (DOI) irrigation drainwater study of the Uncompahgre Project area and the Grand Valley in western Colorado revealed high selenium concentrations in water, sediment, and biota samples. The lower Gunnison River and the Colorado River in the study area are designated critical habitat for the endangered Colorado pikeminnow (Ptychocheilus lucius) and razorback sucker (Xyrauchen texanus). Because of the endangered status of these fish, sacrificing individuals for tissue residue analysis has been avoided; consequently, little information existed regarding selenium tissue residues. In 1994, muscle plugs were collected from a total of 39 Colorado pikeminnow captured at various Colorado River sites in the Grand Valley for selenium residue analysis. The muscle plugs collected from 16 Colorado pikeminnow captured at Walter Walker State Wildlife Area (WWSWA) contained a mean selenium concentration of 17 ??g/g dry weight, which was over twice the recommended toxic threshold guideline concentration of 8 ??g/g dry weight in muscle tissue for freshwater fish. Because of elevated selenium concentrations in muscle plugs in 1994, a total of 52 muscle plugs were taken during 1995 from Colorado pikeminnow staging at WWSWA. Eleven of these plugs were from fish previously sampled in 1994. Selenium concentrations in 9 of the 11 recaptured fish were significantly lower in 1995 than in 1994. Reduced selenium in fish may in part be attributed to higher instream flows in 1995 and lower water selenium concentrations in the Colorado River in the Grand Valley. In 1996, muscle plugs were taken from 35 Colorado squawfish captured at WWSWA, and no difference in mean selenium concentrations were detected from those sampled in 1995. Colorado River flows during 1996 were intermediate to those measured in 1994 and 1995.

Identifying preservation and restoration priority areas for desert fishes in an increasingly invaded world.

PubMed

Pool, Thomas K; Strecker, Angela L; Olden, Julian D

2013-03-01

A commonly overlooked aspect of conservation planning assessments is that wildlife managers are increasingly focused on habitats that contain non-native species. We examine this management challenge in the Gila River basin (150,730 km(2)), and present a new planning strategy for fish conservation. By applying a hierarchical prioritization algorithm to >850,000 fish records in 27,181 sub-watersheds we first identified high priority areas (PAs) termed "preservation PAs" with high native fish richness and low non-native richness; these represent traditional conservation targets. Second, we identified "restoration PAs" with high native fish richness that also contained high numbers of non-native species; these represent less traditional conservation targets. The top 10 % of preservation and restoration PAs contained common native species (e.g., Catostomus clarkii, desert sucker; Catostomus insignis, Sonora sucker) in addition to native species with limited distributions (i.e., Xyrauchen texanus, razorback sucker; Oncorhynchus gilae apache, Apache trout). The top preservation and restoration PAs overlapped by 42 %, indicating areas with high native fish richness range from minimally to highly invaded. Areas exclusively identified as restoration PAs also encompassed a greater percentage of native species ranges than would be expected by the random addition of an equivalent basin area. Restoration PAs identified an additional 19.0 and 26.6 % of the total ranges of two federally endangered species-Meda fulgida (spikedace) and Gila intermedia (Gila chub), respectively, compared to top preservation PAs alone-despite adding only 5.8 % of basin area. We contend that in addition to preservation PAs, restoration PAs are well suited for complementary management activities benefiting native fishes.

Selenium impacts on razorback sucker, Colorado River, Colorado: I. Adults

USGS Publications Warehouse

Hamilton, S.J.; Holley, K.M.; Buhl, K.J.; Bullard, F.A.; Weston, L.K.; McDonald, S.F.

2005-01-01

Adult razorback sucker (Xyrauchen texanus) were exposed to various selenium concentrations in ponds and isolated river channels of the Colorado River near Grand Junction, CO, to determine effects on their growth and residue accumulation over an 11-month period. Adults at Horsethief ponds were fed a commercial diet, whereas fish at Adobe Creek channel and North Pond foraged on natural food items. Selenium concentrations at Horsethief were 2.2 μg/L in water, 0.1–1.4 μg/g in sediment, and 2.3–3.1 μg/g in food organisms (1.1 μg/g in commercial fish food), at Adobe Creek were 3.8 μg/L in water, 0.5–2.1 μg/g in sediment, and 4–56 μg/g in food organisms, and at North Pond were 9.5 μg/L in water, 7–55 μg/g in sediment, and 20–81 μg/g in food organisms. The selenium concentrations in muscle plugs from adults at Adobe Creek (11.7 μg/g, SD=0.4, n=6) and North Pond (16.6 μg/g, SD=1.0, n=6) were greater than at Horsethief (4.5 μg/g, SD=0.2, n=6). During a depuration period adults from Adobe Creek and North Pond lost 1–2% of their selenium burden in 32 days and 14–19% in 66 days. Selenium accumulated in razorback sucker above toxic thresholds reported in other studies, yet those residues were less than those reported in muscle plugs of 40% of wild razorback sucker caught in the Green River, Utah.

Selenium concentrations in the Colorado pikeminnow (Ptychocheilus lucius): relationship with flows in the upper Colorado River.

PubMed

Osmundson, B C; May, T W; Osmundson, D B

2000-05-01

A Department of the Interior (DOI) irrigation drainwater study of the Uncompahgre Project area and the Grand Valley in western Colorado revealed high selenium concentrations in water, sediment, and biota samples. The lower Gunnison River and the Colorado River in the study area are designated critical habitat for the endangered Colorado pikeminnow (Ptychocheilus lucius) and razorback sucker (Xyrauchen texanus). Because of the endangered status of these fish, sacrificing individuals for tissue residue analysis has been avoided; consequently, little information existed regarding selenium tissue residues. In 1994, muscle plugs were collected from a total of 39 Colorado pikeminnow captured at various Colorado River sites in the Grand Valley for selenium residue analysis. The muscle plugs collected from 16 Colorado pikeminnow captured at Walter Walker State Wildlife Area (WWSWA) contained a mean selenium concentration of 17 microg/g dry weight, which was over twice the recommended toxic threshold guideline concentration of 8 microg/g dry weight in muscle tissue for freshwater fish. Because of elevated selenium concentrations in muscle plugs in 1994, a total of 52 muscle plugs were taken during 1995 from Colorado pikeminnow staging at WWSWA. Eleven of these plugs were from fish previously sampled in 1994. Selenium concentrations in 9 of the 11 recaptured fish were significantly lower in 1995 than in 1994. Reduced selenium in fish may in part be attributed to higher instream flows in 1995 and lower water selenium concentrations in the Colorado River in the Grand Valley. In 1996, muscle plugs were taken from 35 Colorado squawfish captured at WWSWA, and no difference in mean selenium concentrations were detected from those sampled in 1995. Colorado River flows during 1996 were intermediate to those measured in 1994 and 1995.

Mating Success, Longevity, and Fertility of Diabrotica virgifera virgifera LeConte (Chrysomelidae: Coleoptera) in Relation to Body Size and Cry3Bb1-Resistant and Cry3Bb1-Susceptible Genotypes

PubMed Central

French, Bryan Wade; Hammack, Leslie; Tallamy, Douglas W.

2015-01-01

Insect resistance to population control methodologies is a widespread problem. The development of effective resistance management programs is often dependent on detailed knowledge regarding the biology of individual species and changes in that biology associated with resistance evolution. This study examined the reproductive behavior and biology of western corn rootworm beetles of known body size from lines resistant and susceptible to the Cry3Bb1 protein toxin expressed in transgenic Bacillus thuringiensis maize. In crosses between, and within, the resistant and susceptible genotypes, no differences occurred in mating frequency, copulation duration, courtship duration, or fertility; however, females mated with resistant males showed reduced longevity. Body size did not vary with genotype. Larger males and females were not more likely to mate than smaller males and females, but larger females laid more eggs. Moderately strong, positive correlation occurred between the body sizes of successfully mated males and females; however, weak correlation also existed for pairs that did not mate. Our study provided only limited evidence for fitness costs associated with the Cry3Bb1-resistant genotype that might reduce the persistence in populations of the resistant genotype but provided additional evidence for size-based, assortative mating, which could favor the persistence of resistant genotypes affecting body size. PMID:26569315

Physiological time model for predicting adult emergence of western corn rootworm (Coleoptera: Chrysomelidae) in the Texas High Plains.

PubMed

Stevenson, Douglass E; Michels, Gerald J; Bible, John B; Jackman, John A; Harris, Marvin K

2008-10-01

Field observations at three locations in the Texas High Plains were used to develop and validate a degree-day phenology model to predict the onset and proportional emergence of adult Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae) adults. Climatic data from the Texas High Plains Potential Evapotranspiration network were used with records of cumulative proportional adult emergence to determine the functional lower developmental temperature, optimum starting date, and the sum of degree-days for phenological events from onset to 99% adult emergence. The model base temperature, 10 degrees C (50 degrees F), corresponds closely to known physiological lower limits for development. The model uses a modified Gompertz equation, y = 96.5 x exp (-(exp(6.0 - 0.00404 x (x - 4.0), where x is cumulative heat (degree-days), to predict y, cumulative proportional emergence expressed as a percentage. The model starts degree-day accumulation on the date of corn, Zea mays L., emergence, and predictions correspond closely to corn phenological stages from tasseling to black layer development. Validation shows the model predicts cumulative proportional adult emergence within a satisfactory interval of 4.5 d. The model is flexible enough to accommodate early planting, late emergence, and the effects of drought and heat stress. The model provides corn producers ample lead time to anticipate and implement adult control practices.

Wing shape and size of the western corn rootworm (Coleoptera: Chrysomelidae) is related to sex and resistance to soybean-maize crop rotation.

PubMed

Mikac, K M; Douglas, J; Spencer, J L

2013-08-01

The western corn rootworm, Diabrotica virgifera virgifera LeConte, is a major pest of maize in the United States and more recently, Europe. Understanding the dispersal dynamics of this species will provide crucial information for its management. This study used geometric morphometric analysis of hind wing venation based on 13 landmarks in 223 specimens from nine locations in Illinois, Nebraska, Iowa, and Missouri, to assess whether wing shape and size differed between rotated and continuously grown maize where crop rotation-resistant and susceptible individuals are found, respectively. Before assessing differences between rotation-resistant and susceptible individuals, sexual dimorphism was investigated. No significant difference in wing (centroid) size was found between males and females; however, females had significantly different shaped (more elongated) wings compared with males. Wing shape and (centroid) size were significantly larger among individuals from rotated maize where crop-rotation resistance was reported; however, cross-validation of these results revealed that collection site resistance status was an only better than average predictor of shape in males and females. This study provides preliminary evidence of wing shape and size differences in D. v. virgifera from rotated versus continuous maize. Further study is needed to confirm whether wing shape and size can be used to track the movement of rotation-resistant individuals and populations as a means to better inform management strategies.

A novel method for estimating soybean herbivory in western corn rootworm (Coleoptera: Chrysomelidae).

PubMed

Seiter, Nicholas J; Richmond, Douglas S; Holland, Jeffrey D; Krupke, Christian H

2010-08-01

The western corn rootworm, Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae), is the key pest of corn, Zea mays L., in North America. The western corn rootworm variant is a strain found in some parts of the United States that oviposits in soybean, Glycine max (L.) Merr., thereby circumventing crop rotation. Soybean herbivory is closely associated with oviposition; therefore, evidence of herbivory could serve as a proxy for rotation resistance. A digital image analysis method based on the characteristic green abdominal coloration of rootworm adults with soybean foliage in their guts was developed to estimate soybean herbivory rates of adult females. Image analysis software was used to develop and apply threshold limits that allowed only colors within the range that is characteristic of soybean herbivory to be displayed. When this method was applied to adult females swept from soybean fields in an area with high levels of rotation resistance, 54.3 +/- 2.1% were estimated to have fed on soybean. This is similar to a previously reported estimate of 54.8%. Results when laboratory-generated negative controls were analyzed showed an acceptably low frequency of false positives. This method could be developed into a management tool if user-friendly software were developed for its implementation. In addition, researchers may find the method useful as a rapid, standardized screen for measuring frequencies of soybean herbivory.

Assessment of acute toxicity tests and rhizotron experiments to characterize lethal and sublethal control of soil-based pests.

PubMed

Agatz, Annika; Schumann, Mario M; French, Bryan W; Brown, Colin D; Vidal, Stefan

2018-03-24

Characterizing lethal and sublethal control of soil-based pests with plant protection products is particularly challenging due to the complex and dynamic interplay of the system components. Here, we present two types of studies: acute toxcity experiments (homogenous exposure of individuals in soil) and rhizotron experiments (heterogeneous exposure of individuals in soil) to investigate their ability to strengthen our understanding of mechanisms driving the effectivness of the plant protection product. Experiments were conducted using larvae of the western corn rootworm Diabrotica virgifera LeConte and three pesticide active ingredients: clothianidin (neonicotinoid), chlorpyrifos (organophosphate) and tefluthrin (pyrethroid). The order of compound concentrations needed to invoke a specific effect intensity (EC 50 values) within the acute toxicity tests was chlorpyrifos > tefluthrin > clothianidin. This order changed for the rhizotron experiments because application type, fate and transport of the compounds in the soil profile, and sublethal effects on larvae also influence their effectiveness in controlling larval feeding on corn roots. Beyond the pure measurement of efficacy through observing relative changes in plant injury to control plants, the tests generate mechanistic understanding for drivers of efficacy apart from acute toxicity. The experiments have the potential to enhance efficacy testing and product development, and might be useful tools for assessing resistance development in the future. © 2018 Society of Chemical Industry. © 2018 Society of Chemical Industry.

The utility of dual-energy CT for metal artifact reduction from intracranial clipping and coiling.

PubMed

Mera Fernández, D; Santos Armentia, E; Bustos Fiore, A; Villanueva Campos, A M; Utrera Pérez, E; Souto Bayarri, M

2018-04-23

To assess the ability of dual-energy CT (DECT) to reduce metal-related artifacts in patients with clips and coils in head CT angiography, and to analyze the differences in this reduction between both type of devices. Thirteen patients (6 clips, 7 coils) were selected and retrospectively analized. Virtual monoenergetic images (MEI) with photon energies from 40 to 150 keV were obtained. Noise was measured at the area of maximum artifact. Subjective evaluation of streak artifact was performed by two radiologists independently. Differences between noise values in all groups were tested by using the ANOVA test. Mann-Whitney U test was used to compare the differences between clips and coils. Coheńs κ statistic was used to determine interobserver agreement. The lowest noise value was observed at high energy levels (p<0,05). Noise was higher in the coil group than in the clip group (p<0.001). Interobserver agreement was good (κ=0.72). TCED with MEI helps to minimize the artifact from clips ands coils in patients who undergo head CT angiography. The reduction of the artifact is greater in patients with surgical clipping than in patients with endovascular coiling. Copyright © 2018 SERAM. Publicado por Elsevier España, S.L.U. All rights reserved.

Delayed enhancement cardiac computed tomography for the assessment of myocardial infarction: from bench to bedside

PubMed Central

2017-01-01

A large number of studies support the increasingly relevant prognostic value of the presence and extent of delayed enhancement (DE), a surrogate marker of fibrosis, in diverse etiologies. Gadolinium and iodinated based contrast agents share similar kinetics, thus leading to comparable myocardial characterization with cardiac magnetic resonance (CMR) and cardiac computed tomography (CT) at both first-pass perfusion and DE imaging. We review the available evidence of DE imaging for the assessment of myocardial infarction (MI) using cardiac CT (CTDE), from animal to clinical studies, and from 16-slice CT to dual-energy CT systems (DECT). Although both CMR and gadolinium agents have been originally deemed innocuous, a number of concerns (though inconclusive and very rare) have been recently issued regarding safety issues, including DNA double-strand breaks related to CMR, and gadolinium-associated nephrogenic systemic fibrosis and deposition in the skin and certain brain structures. These concerns have to be considered in the context of non-negligible rates of claustrophobia, increasing rates of patients with implantable cardiac devices, and a number of logistic drawbacks compared with CTDE, such as higher costs, longer scanning times, and difficulties to scan patients with impaired breath-holding capabilities. Overall, these issues might encourage the role of CTDE as an alternative for DE-CMR in selected populations. PMID:28540211

Optimization of dual-energy CT acquisitions for proton therapy using projection-based decomposition.

PubMed

Vilches-Freixas, Gloria; Létang, Jean Michel; Ducros, Nicolas; Rit, Simon

2017-09-01

Dual-energy computed tomography (DECT) has been presented as a valid alternative to single-energy CT to reduce the uncertainty of the conversion of patient CT numbers to proton stopping power ratio (SPR) of tissues relative to water. The aim of this work was to optimize DECT acquisition protocols from simulations of X-ray images for the treatment planning of proton therapy using a projection-based dual-energy decomposition algorithm. We have investigated the effect of various voltages and tin filtration combinations on the SPR map accuracy and precision, and the influence of the dose allocation between the low-energy (LE) and the high-energy (HE) acquisitions. For all spectra combinations, virtual CT projections of the Gammex phantom were simulated with a realistic energy-integrating detector response model. Two situations were simulated: an ideal case without noise (infinite dose) and a realistic situation with Poisson noise corresponding to a 20 mGy total central dose. To determine the optimal dose balance, the proportion of LE-dose with respect to the total dose was varied from 10% to 90% while keeping the central dose constant, for four dual-energy spectra. SPR images were derived using a two-step projection-based decomposition approach. The ranges of 70 MeV, 90 MeV, and 100 MeV proton beams onto the adult female (AF) reference computational phantom of the ICRP were analytically determined from the reconstructed SPR maps. The energy separation between the incident spectra had a strong impact on the SPR precision. Maximizing the incident energy gap reduced image noise. However, the energy gap was not a good metric to evaluate the accuracy of the SPR. In terms of SPR accuracy, a large variability of the optimal spectra was observed when studying each phantom material separately. The SPR accuracy was almost flat in the 30-70% LE-dose range, while the precision showed a minimum slightly shifted in favor of lower LE-dose. Photon noise in the SPR images (20 mGy dose) had lower impact on the proton range accuracy as comparable results were obtained for the noiseless situation (infinite dose). Root-mean-square range errors averaged over all irradiation angles associated to dual-energy imaging were comprised between 0.50 mm and 0.72 mm for the noiseless situation and between 0.51 mm and 0.77 mm for the realistic scenario. The impact of the dual-energy spectra and the dose allocation between energy levels on the SPR accuracy and precision determined through a projection-based dual-energy algorithm were evaluated to guide the choice of spectra for dual-energy CT for proton therapy. The dose balance between energy levels was not found to be sensitive for the SPR estimation. The optimal pair of dual-energy spectra was material dependent but on a heterogeneous anthropomorphic phantom, there was no significant difference in range accuracy and the choice of spectra could be driven by the precision, i.e., the energy gap. © 2017 American Association of Physicists in Medicine.

Dual energy CT: How well can pseudo-monochromatic imaging reduce metal artifacts?

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kuchenbecker, Stefan, E-mail: stefan.kuchenbecker@dkfz.de; Faby, Sebastian; Sawall, Stefan

2015-02-15

Purpose: Dual Energy CT (DECT) provides so-called monoenergetic images based on a linear combination of the original polychromatic images. At certain patient-specific energy levels, corresponding to certain patient- and slice-dependent linear combination weights, e.g., E = 160 keV corresponds to α = 1.57, a significant reduction of metal artifacts may be observed. The authors aimed at analyzing the method for its artifact reduction capabilities to identify its limitations. The results are compared with raw data-based processing. Methods: Clinical DECT uses a simplified version of monochromatic imaging by linearly combining the low and the high kV images and by assigning an energymore » to that linear combination. Those pseudo-monochromatic images can be used by radiologists to obtain images with reduced metal artifacts. The authors analyzed the underlying physics and carried out a series expansion of the polychromatic attenuation equations. The resulting nonlinear terms are responsible for the artifacts, but they are not linearly related between the low and the high kV scan: A linear combination of both images cannot eliminate the nonlinearities, it can only reduce their impact. Scattered radiation yields additional noncanceling nonlinearities. This method is compared to raw data-based artifact correction methods. To quantify the artifact reduction potential of pseudo-monochromatic images, they simulated the FORBILD abdomen phantom with metal implants, and they assessed patient data sets of a clinical dual source CT system (100, 140 kV Sn) containing artifacts induced by a highly concentrated contrast agent bolus and by metal. In each case, they manually selected an optimal α and compared it to a raw data-based material decomposition in case of simulation, to raw data-based material decomposition of inconsistent rays in case of the patient data set containing contrast agent, and to the frequency split normalized metal artifact reduction in case of the metal implant. For each case, the contrast-to-noise ratio (CNR) was assessed. Results: In the simulation, the pseudo-monochromatic images yielded acceptable artifact reduction results. However, the CNR in the artifact-reduced images was more than 60% lower than in the original polychromatic images. In contrast, the raw data-based material decomposition did not significantly reduce the CNR in the virtual monochromatic images. Regarding the patient data with beam hardening artifacts and with metal artifacts from small implants the pseudo-monochromatic method was able to reduce the artifacts, again with the downside of a significant CNR reduction. More intense metal artifacts, e.g., as those caused by an artificial hip joint, could not be suppressed. Conclusions: Pseudo-monochromatic imaging is able to reduce beam hardening, scatter, and metal artifacts in some cases but it cannot remove them. In all cases, the CNR is significantly reduced, thereby rendering the method questionable, unless special post processing algorithms are implemented to restore the high CNR from the original images (e.g., by using a frequency split technique). Raw data-based dual energy decomposition methods should be preferred, in particular, because the CNR penalty is almost negligible.« less

Further contributions to the Hydradephaga (Coleoptera, Haliplidae, Gyrinidae and Dytiscidae) fauna of Prince Edward Island, Canada: new records, distributions and faunal composition

PubMed Central

Alarie, Yves

2016-01-01

Abstract The Haliplidae, Gyrinidae and Dytiscidae (Coleoptera) of Prince Edward Island, Canada were surveyed during the years 2004–2005. A total of 2450 individuals from 79 species were collected from 98 different localities, among which 30 species are newly recorded from that region. Among these, Acilius sylvanus Hilsenhoff, Rhantus consimilis Motschulsky and Neoporus sulcipennis (Fall) stand out as representing the easternmost reports of these species in Canada. Once removed, Gyrinus aquiris LeConte (Gyrinidae) is reinstated in the faunal list of Prince Edward Island. According to this study and literature 84 species of Hydradephaga are currently known from Prince Edward Island. The Nearctic component of the fauna is made up of 68 species (80.9%) and the Holarctic component of 16 species (19.1%). Most species are characteristic of the Boreal and Atlantic Maritime Ecozones and have a transcontinental distribution. In an examination of the Hydradephaga of insular portions of Atlantic Canada, we found that despite significantly different land areas and different distances to the neighbouring continental mainland the island faunas of Prince Edward Island and insular Newfoundland are very similar in the number of species (84 and 94 species respectively) despite differences in composition. With a land area significantly larger than that of Prince Edward Island, however, the fauna of Cape Breton Island was 39% smaller consisting of 53 species. This difference could be due to the comparative lack of collecting efforts on Cape Breton Island. PMID:27408603

Assessment of Inheritance and Fitness Costs Associated with Field-Evolved Resistance to Cry3Bb1 Maize by Western Corn Rootworm.

PubMed

Paolino, Aubrey R; Gassmann, Aaron J

2017-05-11

The western corn rootworm, Diabrotica virgifera virgifera LeConte, is among the most serious insect pests of maize in North America. One strategy used to manage this pest is transgenic maize that produces one or more crystalline (Cry) toxins derived from the bacterium Bacillus thuringiensis (Bt). To delay Bt resistance by insect pests, refuges of non-Bt maize are grown in conjunction with Bt maize. Two factors influencing the success of the refuge strategy to delay resistance are the inheritance of resistance and fitness costs, with greater delays in resistance expected when inheritance of resistance is recessive and fitness costs are present. We measured inheritance and fitness costs of resistance for two strains of western corn rootworm with field-evolved resistance to Cry3Bb1 maize. Plant-based and diet-based bioassays revealed that the inheritance of resistance was non-recessive. In a greenhouse experiment, in which larvae were reared on whole maize plants in field soil, no fitness costs of resistance were detected. In a laboratory experiment, in which larvae experienced intraspecific and interspecific competition for food, a fitness cost of delayed larval development was identified, however, no other fitness costs were found. These findings of non-recessive inheritance of resistance and minimal fitness costs, highlight the potential for the rapid evolution of resistance to Cry3Bb1 maize by western corn rootworm, and may help to improve resistance management strategies for this pest.

Oil pipeline corridor through an intact forest alters ground beetle (Coleoptera: Carabidae) assemblages in southeastern Ohio.

PubMed

Silverman, Bareena; Horn, David J; Purrington, Foster F; Gandhi, Kamal J K

2008-06-01

Litter-dwelling ground beetle (Coleoptera: Carabidae) assemblages were monitored 1 yr after the construction of a corridor for installation of an oil pipeline along a xeric ridge-top forest in southeastern Ohio. After the creation of the corridor, three distinct habitats were evident in these sites: open corridor, ecotone areas around the corridor, and undisturbed forest interior. Carabidae were collected using directional pitfall traps that were placed parallel and perpendicular to the corridor in each of the three habitats. Results indicate that more carabids were present in the ecotone than in the other two habitats. Carabid diversity as estimated by rarefaction was highest in the corridor followed by ecotone and forest interior. Generalist and forest specialists such as Synuchus impunctatus (Say), Carabus goryi Dejean, and Pterostichus trinarius (Casey) were present in greater numbers in the forest interior and ecotone assemblages. In contrast, open-habitat specialists such as Harpalus pensylvanicus (DeGeer) and Selenophorus opalinus (LeConte) were present in greater numbers in the corridor assemblages. Carabid assemblages of the corridor were distinct from those of the ecotone and forest interior, whereas the latter two habitats had very similar assemblages. The successional pathway of the corridor carabid assemblage will therefore be likely different from that of the forest interior and ecotone. Overall, results indicate that construction of the oil pipeline corridor had significant short-term effects on the carabid numbers, diversity, and species composition because of ensuing habitat changes and fragmentation of the forest.

Effects of protective fencing on birds, lizards, and black-tailed hares in the Western Mojave Desert

USGS Publications Warehouse

Brooks, M.

1999-01-01

Effects of protective fencing on birds, lizards, black-tailed hares (Lepus californicus), perennial plant cover, and structural diversity of perennial plants were evaluated from spring 1994 through winter 1995 at the Desert Tortoise Research Natural Area (DTNA), in the Mojave Desert, California. Abundance and species richness of birds were higher inside than outside the DTNA, and effects were larger during breeding than wintering seasons and during a high than a low rainfall year. Ash-throated flycatchers (Myiarchus cinerascens), cactus wrens (Campylorhynchus brunneicapillus), LeConte's thrashers (Toxostoma lecontei), loggerhead shrikes (Lanius ludovicianus), sage sparrows (Amphispiza belli), and verdins (Auriparus flaviceps) were more abundant inside than outside the DTNA. Nesting activity was also more frequent inside. Total abundance and species richness of lizards and individual abundances of western whiptail lizards (Cnemidophorous tigris) and desert spiny lizards (Sceloporus magister) were higher inside than outside. In contrast, abundance of black-tailed hares was lower inside. Structural diversity of the perennial plant community did not differ due to protection, but cover was 50% higher in protected areas. Black-tailed hares generally prefer areas of low perennial plant cover, which may explain why they were more abundant outside than inside the DTNA. Habitat structure may not affect bird and lizard communities as much as availability of food at this desert site, and the greater abundance and species richness of vertebrates inside than outside the DTNA may correlate with abundances of seeds and invertebrate prey.

Invasive bark beetle-associated microbes degrade a host defensive monoterpene.

PubMed

Xu, Le-Tian; Lu, Min; Sun, Jiang-Hua

2016-04-01

Conifers respond to herbivore attack with defensive chemicals, which are toxic to both insects and their associated microorganisms. Microorganisms associated with insects have been widely reported to metabolize toxic chemicals, which may help both microorganisms and host insects overcome host conifer defense. Dendroctonus valens LeConte, an introduced exotic pest from North America to China, has killed millions of healthy pines. Alpha-pinene is the most abundant defensive monoterpene in Chinese Pinus tabuliformis. Although microorganisms associated with D. valens have already been investigated, little is known about their bioactivities when encountering host defensive monoterpenes. In this study, we evaluated the influences of different concentrations of α-pinene to D. valens and the three most frequently isolated yeasts and bacteria of D. valens, and further assayed microorganisms' capabilities to degrade α-pinene. Results showed that the gallery lengths and body weight changes of bark beetles were significantly affected by 6 mg/mL and 12 mg/mL of α-pinene applied in media compared to controls. The tolerance of experimental microorganisms to α-pinene varied depending on the microbial species. Two out of three yeast strains and all three bacterial strains degraded 20%-50% of α-pinene compared to controls in 24 h in vitro. The microorganisms capable of α-pinene degradation in vitro and their tolerance to high levels of α-pinene suggested that D. valens-associated microorganisms may help both microorganisms and the bark beetle overcome host α-pinene defense. © 2015 Institute of Zoology, Chinese Academy of Sciences.

Historic hybridization and persistence of a novel mito-nuclear combination in red-backed voles (genus Myodes)

PubMed Central

Runck, Amy M; Matocq, Marjorie D; Cook, Joseph A

2009-01-01

Background The role of hybridization in generating diversity in animals is an active area of discovery and debate. We assess hybridization across a contact zone of northern (Myodes rutilus) and southern (M. gapperi) red-backed voles using variation in skeletal features and both mitochondrial and nuclear loci. This transect extends approximately 550 km along the North Pacific Coast of North America and encompasses 26 populations (n = 485). We establish the history, geographic extent and directionality of hybridization, determine whether hybridization is ongoing, and assess the evolutionary stability of novel genomic combinations. Results Identification of M. rutilus and M. gapperi based on the degree of closure of the post-palatal bridge was concordant with the distribution of diagnostic nuclear MYH6 alleles; however, an 80 km zone of introgressed populations was identified. The introgressant form is characterized by having mitochondrial haplotypes closely related to the northern M. rutilus on a nuclear background and morphological characteristics of southern M. gapperi. Conclusion Introgression appears to have been historic as pure populations of M. rutilus are now isolated to the north from introgressants or pure M. gapperi by the LeConte Glacier. As we do not find pure M. rutilus or M. gapperi individuals throughout the distribution of the introgressant form, it appears that the introgressants are a self-sustaining entity not requiring continued hybridization between pure parental forms to generate this novel combination of characters. PMID:19460158

Monitoring presence and advance of the alien invasive western corn rootworm beetle in eastern Slovenia with highly sensitive Metcalf traps.

PubMed

Hummel, H E; Urek, G; Modic, S; Hein, D F

2005-01-01

The American Chrysomelid beetle Diabrotica virgifera virgifera LeConte (D.v.v.), also called the western corn rootworm, spread from the location of its original introduction into Europe, Belgrade airport (BACA 1993), in all directions. Within a decade it occupied almost all countries of South-eastern and Central Europe. However, it reached Slovenia as late as 2003: Only 19 specimen were found in maize fields of the eastern and also western provinces. Already in the summer of 2004, their number had risen to 386 which were mainly found in the eastern provinces near the borders to Croatia, Austria and Hungary. For their monitoring, a simple trap is being described which can be acquired in high numbers at a very low price and can guaranty a most sensitive detection of beetles. The Metcalf cup trap which in Slovenia so far has been unknown performed the task of monitoring quite well at five locations. It will also facilitate the future search for new and increasing infestations. Comparing 2004 with the year 2003, D.v.v. expanded its range in eastern Slovenia by about 15 km. These new infestations will include territories in which fields of the regionally Important oil seed pumpkin Cucurbita pepo are located. With important traffic connections between South-eastern and Central Europe, Slovenia will occupy a bridgehead function in the preventive protection of maize from D.v.v. spreading into more northerly European regions including western Austria and southern Germany.

Further contributions to the Hydradephaga (Coleoptera, Haliplidae, Gyrinidae and Dytiscidae) fauna of Prince Edward Island, Canada: new records, distributions and faunal composition.

PubMed

Alarie, Yves

2016-01-01

The Haliplidae, Gyrinidae and Dytiscidae (Coleoptera) of Prince Edward Island, Canada were surveyed during the years 2004-2005. A total of 2450 individuals from 79 species were collected from 98 different localities, among which 30 species are newly recorded from that region. Among these, Acilius sylvanus Hilsenhoff, Rhantus consimilis Motschulsky and Neoporus sulcipennis (Fall) stand out as representing the easternmost reports of these species in Canada. Once removed, Gyrinus aquiris LeConte (Gyrinidae) is reinstated in the faunal list of Prince Edward Island. According to this study and literature 84 species of Hydradephaga are currently known from Prince Edward Island. The Nearctic component of the fauna is made up of 68 species (80.9%) and the Holarctic component of 16 species (19.1%). Most species are characteristic of the Boreal and Atlantic Maritime Ecozones and have a transcontinental distribution. In an examination of the Hydradephaga of insular portions of Atlantic Canada, we found that despite significantly different land areas and different distances to the neighbouring continental mainland the island faunas of Prince Edward Island and insular Newfoundland are very similar in the number of species (84 and 94 species respectively) despite differences in composition. With a land area significantly larger than that of Prince Edward Island, however, the fauna of Cape Breton Island was 39% smaller consisting of 53 species. This difference could be due to the comparative lack of collecting efforts on Cape Breton Island.

Development of an RF-EMF Exposure Surrogate for Epidemiologic Research.

PubMed

Roser, Katharina; Schoeni, Anna; Bürgi, Alfred; Röösli, Martin

2015-05-22

Exposure assessment is a crucial part in studying potential effects of RF-EMF. Using data from the HERMES study on adolescents, we developed an integrative exposure surrogate combining near-field and far-field RF-EMF exposure in a single brain and whole-body exposure measure. Contributions from far-field sources were modelled by propagation modelling and multivariable regression modelling using personal measurements. Contributions from near-field sources were assessed from both, questionnaires and mobile phone operator records. Mean cumulative brain and whole-body doses were 1559.7 mJ/kg and 339.9 mJ/kg per day, respectively. 98.4% of the brain dose originated from near-field sources, mainly from GSM mobile phone calls (93.1%) and from DECT phone calls (4.8%). Main contributors to the whole-body dose were GSM mobile phone calls (69.0%), use of computer, laptop and tablet connected to WLAN (12.2%) and data traffic on the mobile phone via WLAN (6.5%). The exposure from mobile phone base stations contributed 1.8% to the whole-body dose, while uplink exposure from other people's mobile phones contributed 3.6%. In conclusion, the proposed approach is considered useful to combine near-field and far-field exposure to an integrative exposure surrogate for exposure assessment in epidemiologic studies. However, substantial uncertainties remain about exposure contributions from various near-field and far-field sources.

Development of an RF-EMF Exposure Surrogate for Epidemiologic Research

PubMed Central

Roser, Katharina; Schoeni, Anna; Bürgi, Alfred; Röösli, Martin

2015-01-01

Exposure assessment is a crucial part in studying potential effects of RF-EMF. Using data from the HERMES study on adolescents, we developed an integrative exposure surrogate combining near-field and far-field RF-EMF exposure in a single brain and whole-body exposure measure. Contributions from far-field sources were modelled by propagation modelling and multivariable regression modelling using personal measurements. Contributions from near-field sources were assessed from both, questionnaires and mobile phone operator records. Mean cumulative brain and whole-body doses were 1559.7 mJ/kg and 339.9 mJ/kg per day, respectively. 98.4% of the brain dose originated from near-field sources, mainly from GSM mobile phone calls (93.1%) and from DECT phone calls (4.8%). Main contributors to the whole-body dose were GSM mobile phone calls (69.0%), use of computer, laptop and tablet connected to WLAN (12.2%) and data traffic on the mobile phone via WLAN (6.5%). The exposure from mobile phone base stations contributed 1.8% to the whole-body dose, while uplink exposure from other people’s mobile phones contributed 3.6%. In conclusion, the proposed approach is considered useful to combine near-field and far-field exposure to an integrative exposure surrogate for exposure assessment in epidemiologic studies. However, substantial uncertainties remain about exposure contributions from various near-field and far-field sources. PMID:26006132

Spatial and temporal variability of personal environmental exposure to radio frequency electromagnetic fields in children in Europe.

PubMed

Birks, Laura Ellen; Struchen, Benjamin; Eeftens, Marloes; van Wel, Luuk; Huss, Anke; Gajšek, Peter; Kheifets, Leeka; Gallastegi, Mara; Dalmau-Bueno, Albert; Estarlich, Marisa; Fernandez, Mariana F; Meder, Inger Kristine; Ferrero, Amparo; Jiménez-Zabala, Ana; Torrent, Maties; Vrijkotte, Tanja G M; Cardis, Elisabeth; Olsen, Jørn; Valič, Blaž; Vermeulen, Roel; Vrijheid, Martine; Röösli, Martin; Guxens, Mònica

2018-08-01

Exposure to radiofrequency electromagnetic fields (RF-EMF) has rapidly increased and little is known about exposure levels in children. This study describes personal RF-EMF environmental exposure levels from handheld devices and fixed site transmitters in European children, the determinants of this, and the day-to-day and year-to-year repeatability of these exposure levels. Personal environmental RF-EMF exposure (μW/m 2 , power flux density) was measured in 529 children (ages 8-18 years) in Denmark, the Netherlands, Slovenia, Switzerland, and Spain using personal portable exposure meters for a period of up to three days between 2014 and 2016, and repeated in a subsample of 28 children one year later. The meters captured 16 frequency bands every 4 s and incorporated a GPS. Activity diaries and questionnaires were used to collect children's location, use of handheld devices, and presence of indoor RF-EMF sources. Six general frequency bands were defined: total, digital enhanced cordless telecommunications (DECT), television and radio antennas (broadcast), mobile phones (uplink), mobile phone base stations (downlink), and Wireless Fidelity (WiFi). We used adjusted mixed effects models with region random effects to estimate associations of handheld device use habits and indoor RF-EMF sources with personal RF-EMF exposure. Day-to-day and year-to-year repeatability of personal RF-EMF exposure were calculated through intraclass correlations (ICC). Median total personal RF-EMF exposure was 75.5 μW/m 2 . Downlink was the largest contributor to total exposure (median: 27.2 μW/m 2 ) followed by broadcast (9.9 μW/m 2 ). Exposure from uplink (4.7 μW/m 2 ) was lower. WiFi and DECT contributed very little to exposure levels. Exposure was higher during day (94.2 μW/m 2 ) than night (23.0 μW/m 2 ), and slightly higher during weekends than weekdays, although varying across regions. Median exposures were highest while children were outside (157.0 μW/m 2 ) or traveling (171.3 μW/m 2 ), and much lower at home (33.0 μW/m 2 ) or in school (35.1 μW/m 2 ). Children living in urban environments had higher exposure than children in rural environments. Older children and users of mobile phones had higher uplink exposure but not total exposure, compared to younger children and those that did not use mobile phones. Day-to-day repeatability was moderate to high for most of the general frequency bands (ICCs between 0.43 and 0.85), as well as for total, broadcast, and downlink for the year-to-year repeatability (ICCs between 0.49 and 0.80) in a small subsample. The largest contributors to total personal environmental RF-EMF exposure were downlink and broadcast, and these exposures showed high repeatability. Urbanicity was the most important determinant of total exposure and mobile phone use was the most important determinant of uplink exposure. It is important to continue evaluating RF-EMF exposure in children as device use habits, exposure levels, and main contributing sources may change. Copyright © 2018 Elsevier Ltd. All rights reserved.

Characterization of plasma vitellogenin and sex hormone concentrations during the annual reproductive cycle of the endangered razorback sucker

USGS Publications Warehouse

Hinck, Jo Ellen; Papoulias, Diana M.; Annis, Mandy L.; Tillitt, Donald E.; Marr, Carrie; Denslow, Nancy D.; Kroll, Kevin J.; Nachtmann, Jason

2011-01-01

Population declines of the endangered razorback sucker Xyrauchen texanus in the Colorado River basin have been attributed to predation by and competition with nonnative fishes, habitat alteration, and dam construction. The reproductive health and seasonal variation of the reproductive end points of razorback sucker populations are currently unknown. Using nonlethal methods, we characterized the plasma hormonal fluctuations of reproductively mature female and male razorback suckers over a 12-month period in a hatchery by measuring their vitellogenin (VTG) and three sex hormones: 17β-estradiol (E2), testosterone (T), and 11-ketotestosterone (KT). Fish were identified as reproductive or nonreproductive based on their body weight, VTG, and sex hormone profiles. In reproductive females, the E2 concentration increased in the fall and winter, and increases in T and VTG concentrations were generally associated with the spawning period. Mean T concentrations were consistently greater in reproductive females than in nonreproductive females, but this pattern was even more pronounced during the spawning period (spring). Consistently low T concentrations (<3 ng/mL) in adult females during the spawning period may indicate reproductive impairment. In reproductive males, spring increases in KT and T concentrations were associated with spawning; concentrations of E2 (<0.48 ng/mL) and VTG (<0.001 mg/mL) were low in males throughout the study. In addition, the E2 : KT ratio and T were the best metrics by which to distinguish female from male adult razorback suckers throughout the year. These metrics of reproductive health and condition may be particularly important to recovery efforts of razorback suckers given that the few remaining wild populations are located in a river where water quality and quantity issues are well documented. In addition to the size, age, and recruitment information currently considered in the recovery goals of this endangered species, reproductive end points could be included as recovery metrics with which to monitor seasonal trends and determine whether repatriated populations are cycling naturally.

Electrofishing and its harmful effects on fish

USGS Publications Warehouse

Snyder, Darrel E.

2003-01-01

Electrofishing, a valuable sampling technique in North America for over half a century, involves a very dynamic and complex mix of physics, physiology, and behavior that remains poorly understood. New hypotheses have been advanced regarding "power transfer" to fish and the epileptic nature of their responses to electric fields, but these too need to be more fully explored and validated. Fishery researchers and managers in the Colorado River Basin, and elsewhere, are particularly concerned about the harmful effects of electrofishing on fish, especially endangered species. Although often not externally obvious or fatal, spinal injuries and associated hemorrhages sometimes have been documented in over 50% of fish examined internally. Such injuries can occur anywhere in the electrofishing field at or above the intensity threshold for twitch. These injuries are believed to result from powerful convulsions of body musculature (possibly epileptic seizures) caused mostly by sudden changes in voltage as when electricity is pulsed or switched on or off. Significantly fewer spinal injuries are reported when direct current, low-frequency pulsed direct current (<30 Hz), or specially designed pulse trains are used. Salmoniae are especially susceptible. Endangered cyprinids of the Colorado River Basin are generally much less susceptible, enough so to allow cautious use of less harmful currents for most recovery monitoring and research. However, the endangered catostomid Xyrauchen texanus appears sufficiently susceptible to warrant a continued minimal-use policy. Other harmful effects, such as bleeding at gills or vent and excessive physiological stress, are also of concern. Mortality, usually by asphyxiation, is a common result of excessive exposure to tetanizing intensities near electrodes or poor handling of captured specimens. Reported effects on reproduction are contradictory, but electrofishing over spawning grounds can harm embryos. Electrofishing is often considered the most effective and benign technique for capturing moderate- to large-size fish, but when adverse effects are problematic and cannot be sufficiently reduced, its use should be severely restricted.

Toxicity of selenium and other elements in food organisms to razorback sucker larvae

USGS Publications Warehouse

Hamilton, Steven J.; Holley, Kathy M.; Buhl, Kevin J.; Bullard, Fern A.; Weston, L. Ken; McDonald, Susan F.

2002-01-01

Elevated selenium concentrations documented in water, sediment, and biota in irrigation drain water studies by U.S. Department of the Interior agencies and academia have raised concerns that selenium may be adversely affecting endangered fish in the upper Colorado River basin. The objective of the study was to determine the effects on endangered razorback sucker (Xyrauchen texanus) larvae from exposure to selenium and other trace elements in water and zooplankton collected from sites adjacent to the Colorado River near Grand Junction, CO. A 30-day study was initiated with 5-day-old larvae exposed in a 4×4 factor experiment with four food and four water treatments, and the biological endpoints measured were survival, growth, development, and whole-body residues of selenium. Mean selenium concentration in reference water (24-Road) was <0.7 μg/l, in reference food (brine shrimp) was 3.2 μg/g, at Horsethief was 1.6 μg/l in water and 6.0 μg/g in zooplankton, at Adobe Creek was 3.4 μg/l in water and 32 μg/g in zooplankton, and at Walter Walker was 13 μg/l in water and 52 μg/g in zooplankton. Although there were differences in concentrations of inorganic elements in water and biota among the three sites, selenium was apparently the only element elevated to concentrations of concern. Effects on survival were more prominent from dietary exposure compared to waterborne exposure. Selenium concentrations of ≥4.6 μg/g in food organisms adversely affected the survival of razorback sucker larvae. The onset of mortality in larvae exposed to food and water from Walter Walker seemed delayed compared to mortality in larvae exposed to food and water from Horsethief, which has been observed in two other studies. Elevated arsenic in one food source seemed to interact with selenium to reduce the toxic effects of selenium.

Assessing contaminant sensitivity of endangered and threatened aquatic species: Part III. Effluent toxicity tests

USGS Publications Warehouse

Dwyer, F.J.; Hardesty, D.K.; Henke, C.E.; Ingersoll, C.G.; Whites, D.W.; Augspurger, T.; Canfield, T.J.; Mount, D.R.; Mayer, F.L.

2005-01-01

Toxicity tests using standard effluent test procedures described by the U.S. Environmental Protection Agency were conducted with Ceriodaphnia dubia, fathead minnows (Pimephales promelas), and seven threatened and endangered (listed) fish species from four families: (1) Acipenseridae: shortnose sturgeon (Acipenser brevirostrum); (2) Catostomidae; razorback sucker (Xyrauchen texanus); (3) Cyprinidae: bonytail chub (Gila elegans), Cape Fear shiner (Notropis mekistocholas) Colorado pikeminnow (Ptychocheilus lucius), and spotfin chub (Cyprinella monacha); and (4) Poecillidae: Gila topminnow (Poeciliopsis occidentalis). We conducted 7-day survival and growth studies with embryo-larval fathead minnows and analogous exposures using the listed species. Survival and reproduction were also determined with C. dubia. Tests were conducted with carbaryl, ammonia-or a simulated effluent complex mixture of carbaryl, copper, 4-nonylphenol, pentachlorophenol and permethrin at equitoxic proportions. In addition, Cape Fear shiners and spotfin chub were tested using diazinon, copper, and chlorine. Toxicity tests were also conducted with field-collected effluents from domestic or industrial facilities. Bonytail chub and razorback suckers were tested with effluents collected in Arizona whereas effluent samples collected from North Carolina were tested with Cape Fear shiner, spotfin chub, and shortnose sturgeon. The fathead minnow 7-day effluent test was often a reliable estimator of toxic effects to the listed fishes. However, in 21 % of the tests, a listed species was more sensitive than fathead minnows. More sensitive species results varied by test so that usually no species was always more or less sensitive than fathead minnows. Only the Gila topminnow was consistently less sensitive than the fathead minnow. Listed fish species were protected 96% of the time when results for both fathead minnows and C. dubia were considered, thus reinforcing the value of standard whole-effluent toxicity tests using those two species. If the responses of specific listed species are important for management decisions, our study supports the value in developing culture and testing procedures for those species. ?? 2005 Springer Science+Business Media, Inc.

Toxicity of selenium and other elements in food organisms to razorback sucker larvae.

PubMed

Hamilton, Steven J; Holley, Kathy M; Buhl, Kevin J; Bullard, Fern A; Weston, L Ken; McDonald, Susan F

2002-09-24

Elevated selenium concentrations documented in water, sediment, and biota in irrigation drain water studies by U.S. Department of the Interior agencies and academia have raised concerns that selenium may be adversely affecting endangered fish in the upper Colorado River basin. The objective of the study was to determine the effects on endangered razorback sucker (Xyrauchen texanus) larvae from exposure to selenium and other trace elements in water and zooplankton collected from sites adjacent to the Colorado River near Grand Junction, CO. A 30-day study was initiated with 5-day-old larvae exposed in a 4 x 4 factor experiment with four food and four water treatments, and the biological endpoints measured were survival, growth, development, and whole-body residues of selenium. Mean selenium concentration in reference water (24-Road) was <0.7 microg/l, in reference food (brine shrimp) was 3.2 microg/g, at Horsethief was 1.6 microg/l in water and 6.0 microg/g in zooplankton, at Adobe Creek was 3.4 microg/l in water and 32 microg/g in zooplankton, and at Walter Walker was 13 microg/l in water and 52 microg/g in zooplankton. Although there were differences in concentrations of inorganic elements in water and biota among the three sites, selenium was apparently the only element elevated to concentrations of concern. Effects on survival were more prominent from dietary exposure compared to waterborne exposure. Selenium concentrations of >or=4.6 microg/g in food organisms adversely affected the survival of razorback sucker larvae. The onset of mortality in larvae exposed to food and water from Walter Walker seemed delayed compared to mortality in larvae exposed to food and water from Horsethief, which has been observed in two other studies. Elevated arsenic in one food source seemed to interact with selenium to reduce the toxic effects of selenium.

Impacts of silvicultural thinning treatments on beetle trap captures and tree attacks during low bark beetle populations in ponderosa pine forests of northern Arizona.

PubMed

Gaylord, M L; Hofstetter, R W; Wagner, M R

2010-10-01

Our research used a combination of passive traps, funnel traps with lures, baited trees, and surveys of long-term thinning plots to assess the impacts of different levels of stand basal area (BA) on bark beetle tree attack and on trap captures of Ips spp., Dendroctonus spp., and their predators. The study occurred at two sites in ponderosa pine, Pinus ponderosa Dougl. ex Laws., forests, from 2004 to 2007 during low bark beetle populations. Residual stand BA ranged from 9.0 to 37.0 m2/ha. More predators and bark beetles were collected in passive traps in stands of lower BA than in stands of higher BA; however, significance varied by species and site, and total number of beetles collected was low. Height of the clear panel passive traps affected trap catches for some species at some sites and years. When pheromone lures were used with funnel traps [Ips pini (Say) lure: lanierone, +03/-97 ipsdienol], we found no significant difference in trap catches among basal area treatments for bark beetles and their predators. Similarly, when trees were baited (Dendroctonus brevicomis LeConte lure: myrcene, exo-brevicomin and frontalin), we found no significant difference for days to first bark beetle attack. Surveys of long-term thinning treatments found evidence of bark beetle attacks only in unthinned plots (approximately 37 m2/ha basal area). We discuss our results in terms of management implications for bark beetle trapping and control.

Efficacy of verbenone for protecting ponderosa pine stands from western pine beetle (Coleoptera: Curculionidae: Scolytinae) attack in California.

PubMed

Fettig, Christopher J; McKelvey, Stephen R; Borys, Robert R; Dabney, Christopher P; Hamud, Shakeeb M; Nelson, Lori J; Seybold, Steven J

2009-10-01

The western pine beetle, Dendroctonus brevicomis LeConte (Coleoptera: Curculionidae: Scolytinae), is a major cause of ponderosa pine, Pinus ponderosa Dougl. ex Laws., mortality in much of western North America. Currently, techniques for managing D. brevicomis infestations are limited. Verbenone (4,6,6-trimethylbicyclo [3.1.1] hept-3-en-2-one) is an antiaggregation pheromone of several Dendroctonus spp., including D. brevicomis, and it has been registered as a biopesticide for control of mountain pine beetle, Dendroctonus ponderosae Hopkins, and southern pine beetle, Dendroctonus frontalis Zimmermann. We evaluated the efficacy of a 5-g verbenone pouch [82%-(-); 50 mg/d] applied at 125 Ulha for protecting P. ponderosa stands (2 ha) from D. brevicomis attack over a 3-yr period. No significant differences in levels of D. brevicomis-caused tree mortality or the percentage of unsuccessfully attacked trees were found between verbenone-treated and untreated plots during each year or cumulatively over the 3-yr period. Laboratory analyses of release rates and chemical composition of volatiles emanating from verbenone pouches after field exposure found no deterioration of the active ingredient or physical malfunction of the release device. The mean release rate of pouches from all locations and exposure periods was 44.5 mg/d. In a trapping bioassay, the range of inhibition of the 5-g verbenone pouch was determined to be statistically constant 2 m from the release device. We discuss the implications of these and other results to the development of verbenone as a semiochemical-based tool for management of D. brevicomis infestations in P. ponderosa stands.

Uncertainties in tidal theory: Implications for bloated hot Jupiters

NASA Astrophysics Data System (ADS)

Leconte, Jérémy; Chabrier, Gilles; Baraffe, Isabelle

2011-11-01

Thanks to the combination of transit photometry and radial velocity doppler measurements, we are now able to constrain theoretical models of the structure and evolution of objects in the whole mass range between icy giants and stars, including the giant planet/brown dwarf overlapping mass regime (Leconte et al. 2009). In the giant planet mass range, the significant fraction of planets showing a larger radius than predicted by the models suggests that a missing physical mechanism which is either injecting energy in the deep convective zone or reducing the net outward thermal flux is taking place in these objects. Several possibilities have been suggested for such a mechanism:•downward transport of kinetic energy originating from strong winds generated at the planet's surface (Showman & Guillot 2002),•enhanced opacity sources in hot-Jupiter atmospheres (Burrows et al. 2007),•ohmic dissipation in the ionized atmosphere (Batygin & Stevenson 2010),•(inefficient) layered or oscillatory convection in the planet's interior (Chabrier & Baraffe 2007),•Tidal heating due to circularization of the orbit, as originally suggested by Bodenheimer, Lin & Mardling (2001).Here we first review the differences between current models of tidal evolution and their uncertainties. We then revisit the viability of the tidal heating hypothesis using a tidal model which treats properly the highly eccentric and misaligned orbits commonly encountered in exoplanetary systems. We stress again that the low order expansions in eccentricity often used in constant phase lag tidal models (i.e. constant Q) necessarily yields incorrect results as soon as the (present or initial) eccentricity exceeds ~ 0.2, as can be rigorously demonstrated from Kepler's equations.

Examining Cuphea as a potential host for western corn rootworm (Coleoptera: Chrysomelidae): larval development.

PubMed

Behle, Robert W; Hibbard, Bruce E; Cermak, Steven C; Isbell, Terry A

2008-06-01

In previous crop rotation research, adult emergence traps placed in plots planted to Cuphea PSR-23 (a selected cross of Cuphea viscosissma Jacq. and Cuphea lanceolata Ait.) caught high numbers of adult western corn rootworms, Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae), suggesting that larvae may have completed development on this broadleaf plant. Because of this observation, a series of greenhouse and field experiments were conducted to test the hypothesis that Cuphea could serve as a host for larval development. Greenhouse-grown plants infested with neonates of a colonized nondiapausing strain of the beetle showed no survival of larvae on Cuphea, although larvae did survive on the positive control (corn, Zea mays L.) and negative control [sorghum, Sorghum bicolor (L.) Moench] plants. Soil samples collected 20 June, 7 July, and 29 July 2005 from field plots planted to Cuphea did not contain rootworm larvae compared with means of 1.28, 0.22, and 0.00 rootworms kg(-1) soil, respectively, for samples collected from plots planted to corn. Emergence traps captured a peak of eight beetles trap(-1) day(-1) from corn plots on 8 July compared with a peak of 0.5 beetle trap(-1) day(-1) on 4 August from Cuphea plots. Even though a few adult beetles were again captured in the emergence traps placed in the Cuphea plots, it is not thought to be the result of successful larval development on Cuphea roots. All the direct evidence reported here supports the conventional belief that rootworm larvae do not survive on broadleaf plants, including Cuphea.

Areas of potential suitability and survival of Dendroctonus valens in China under extreme climate warming scenario.

PubMed

He, S Y; Ge, X Z; Wang, T; Wen, J B; Zong, S X

2015-08-01

The areas in China with climates suitable for the potential distribution of the pest species red turpentine beetle (RTB) Dendroctonus valens LeConte (Coleoptera: Scolytidae) were predicted by CLIMEX based on historical climate data and future climate data with warming estimated. The model used a historical climate data set (1971-2000) and a simulated climate data set (2010-2039) provided by the Tyndall Centre for Climate Change (TYN SC 2.0). Based on the historical climate data, a wide area was available in China with a suitable climate for the beetle in which every province might contain suitable habitats for this pest, particularly all of the southern provinces. The northern limit of the distribution of the beetle was predicted to reach Yakeshi and Elunchun in Inner Mongolia, and the western boundary would reach to Keerkezi in Xinjiang Province. Based on a global-warming scenario, the area with a potential climate suited to RTB in the next 30 years (2010-2039) may extend further to the northeast. The northern limit of the distribution could reach most parts of south Heilongjiang Province, whereas the western limit would remain unchanged. Combined with the tendency for RTB to spread, the variation in suitable habitats within the scenario of extreme climate warming and the multiple geographical elements of China led us to assume that, within the next 30 years, RTB would spread towards the northeast, northwest, and central regions of China and could be a potentially serious problem for the forests of China.

[Seroprevalence of T. cruzi infection in Canis familiaris, state of Sucre, Venezuela].

PubMed

Berrizbeitia, Mariolga; Concepción, Juan Luis; Carzola, Valentina; Rodríguez, Jéssicca; Cáceres, Ana; Quiñones, Wilfredo

2013-01-01

Trypanosoma cruzi infection in humans has been extensively studied in Venezuela; however, in reservoirs it has been less investigated. The objective of this study was to determine the seroepidemiology of T. cruzi in the state of Sucre, Venezuela. A cross-sectional and prospective study conducted in 95 towns and 577 dwellings in the 15 municipalies of the state of Sucre, Venezuela, from August to November, 2008. The evaluation of serum samples was performed with the CruziELISA kit and the multiple antigens binding assays (MABA). Furthermore, epidemiological surveys were applied to evaluate the risk factors. A total of dogs (average age of 2, 6 + 2.2 years, 226 males and 137 females) was evaluated. The combination of the ELISA / MABA tests detected 78 positive sera, sixty-nine negative and 10 of inconclusive results. The seroprevalence of the T. cruzi infection in dogs in the state of Sucre, was 22.1% (CI 95%: 20.58-22.4%). No significant statistic association was found between the T. cruzi infection in dogs and the evaluated epidemiological variables: hunting dogs that slept oudoors roaming freely in the populated center, sex of the animal and eating habits. The T. cruzi infection was associated to the age of canines, being significantly higher in the group of 0 to 3 years, when compared with older dogs. The high T. cruzi seroprevalence dected in dogs shows that in this región of Venezuela there prevails an important risk factor of transmissibility of this parasite to human populations.

Effect of slice thickness on image noise and diagnostic content of single-source-dual energy computed tomography

NASA Astrophysics Data System (ADS)

Alshipli, Marwan; Kabir, Norlaili A.

2017-05-01

Computed tomography (CT) employs X-ray radiation to create cross-sectional images. Dual-energy CT acquisition includes the images acquired from an alternating voltage of X-ray tube: a low- and a high-peak kilovoltage. The main objective of this study is to determine the best slice thickness that reduces image noise with adequate diagnostic information using dual energy CT head protocol. The study used the ImageJ software and statistical analyses to aid the medical image analysis of dual-energy CT. In this study, ImageJ software and F-test were utilised as the combination methods to analyse DICOM CT images. They were used to investigate the effect of slice thickness on noise and visibility in dual-energy CT head protocol images. Catphan-600 phantom was scanned at different slice thickness values;.6, 1, 2, 3, 4, 5 and 6 mm, then quantitative analyses were carried out. The DECT operated in helical mode with another fixed scan parameter values. Based on F-test statistical analyses, image noise at 0.6, 1, and 2 mm were significantly different compared to the other images acquired at slice thickness of 3, 4, 5, and 6 mm. However, no significant differences of image noise were observed at 3, 4, 5, and 6 mm. As a result, better diagnostic image value, image visibility, and lower image noise in dual-energy CT head protocol was observed at a slice thickness of 3 mm.

Electromagnetic system for detection and localization of miners caught in mine accidents

NASA Astrophysics Data System (ADS)

Pronenko, Vira; Dudkin, Fedir

2016-12-01

The profession of a miner is one of the most dangerous in the world. Among the main causes of fatalities in underground coal mines are the delayed alert of the accident and the lack of information regarding the actual location of the miners after the accident. In an emergency situation (failure or destruction of underground infrastructure), personnel search behind and beneath blockage needs to be performed urgently. However, none of the standard technologies - radio-frequency identification (RFID), Digital Enhanced Cordless Telecommunications (DECT), Wi-Fi, emitting cables, which use the stationary technical devices in mines - provide information about the miners location with the necessary precision. The only technology that is able to provide guaranteed delivery of messages to mine personnel, regardless of their location and under any destruction in the mine, is low-frequency radio technology, which is able to operate through the thickness of rocks even if they are wet. The proposed new system for miner localization is based on solving the inverse problem of determining the magnetic field source coordinates using the data of magnetic field measurements. This approach is based on the measurement of the magnetic field radiated by the miner's responder beacon using two fixed and spaced three-component magnetic field receivers and the inverse problem solution. As a result, a working model of the system for miner's beacon search and localization (MILES - MIner's Location Emergency System) was developed and successfully tested. This paper presents the most important aspects of this development and the results of experimental tests.

Family-group names in Coleoptera (Insecta)

PubMed Central

Bouchard, Patrice; Bousquet, Yves; Davies, Anthony E.; Alonso-Zarazaga, Miguel A.; Lawrence, John F.; Lyal, Chris H. C.; Newton, Alfred F.; Reid, Chris A. M.; Schmitt, Michael; Ślipiński, S. Adam; Smith, Andrew B. T.

2011-01-01

Abstract We synthesize data on all known extant and fossil Coleoptera family-group names for the first time. A catalogue of 4887 family-group names (124 fossil, 4763 extant) based on 4707 distinct genera in Coleoptera is given. A total of 4492 names are available, 183 of which are permanently invalid because they are based on a preoccupied or a suppressed type genus. Names are listed in a classification framework. We recognize as valid 24 superfamilies, 211 families, 541 subfamilies, 1663 tribes and 740 subtribes. For each name, the original spelling, author, year of publication, page number, correct stem and type genus are included. The original spelling and availability of each name were checked from primary literature. A list of necessary changes due to Priority and Homonymy problems, and actions taken, is given. Current usage of names was conserved, whenever possible, to promote stability of the classification. New synonymies (family-group names followed by genus-group names): Agronomina Gistel, 1848 syn. nov. of Amarina Zimmermann, 1832 (Carabidae), Hylepnigalioini Gistel, 1856 syn. nov. of Melandryini Leach, 1815 (Melandryidae), Polycystophoridae Gistel, 1856 syn. nov. of Malachiinae Fleming, 1821 (Melyridae), Sclerasteinae Gistel, 1856 syn. nov. of Ptilininae Shuckard, 1839 (Ptinidae), Phloeonomini Ádám, 2001 syn. nov. of Omaliini MacLeay, 1825 (Staphylinidae), Sepedophilini Ádám, 2001 syn. nov. of Tachyporini MacLeay, 1825 (Staphylinidae), Phibalini Gistel, 1856 syn. nov. of Cteniopodini Solier, 1835 (Tenebrionidae); Agronoma Gistel 1848 (type species Carabus familiaris Duftschmid, 1812, designated herein) syn. nov. of Amara Bonelli, 1810 (Carabidae), Hylepnigalio Gistel, 1856 (type species Chrysomela caraboides Linnaeus, 1760, by monotypy) syn. nov. of Melandrya Fabricius, 1801 (Melandryidae), Polycystophorus Gistel, 1856 (type species Cantharis aeneus Linnaeus, 1758, designated herein) syn. nov. of Malachius Fabricius, 1775 (Melyridae), Sclerastes Gistel, 1856 (type species Ptilinus costatus Gyllenhal, 1827, designated herein) syn. nov. of Ptilinus Geoffroy, 1762 (Ptinidae), Paniscus Gistel, 1848 (type species Scarabaeus fasciatus Linnaeus, 1758, designated herein) syn. nov. of Trichius Fabricius, 1775 (Scarabaeidae), Phibalus Gistel, 1856 (type species Chrysomela pubescens Linnaeus, 1758, by monotypy) syn. nov. of Omophlus Dejean, 1834 (Tenebrionidae). The following new replacement name is proposed: Gompeliina Bouchard, 2011 nom. nov. for Olotelina Báguena Corella, 1948 (Aderidae). Reversal of Precedence (Article 23.9) is used to conserve usage of the following names (family-group names followed by genus-group names): Perigonini Horn, 1881 nom. protectum over Trechicini Bates, 1873 nom. oblitum (Carabidae), Anisodactylina Lacordaire, 1854 nom. protectum over Eurytrichina LeConte, 1848 nom. oblitum (Carabidae), Smicronychini Seidlitz, 1891 nom. protectum over Desmorini LeConte, 1876 nom. oblitum (Curculionidae), Bagoinae Thomson, 1859 nom. protectum over Lyprinae Gistel 1848 nom. oblitum (Curculionidae), Aterpina Lacordaire, 1863 nom. protectum over Heliomenina Gistel, 1848 nom. oblitum (Curculionidae), Naupactini Gistel, 1848 nom. protectum over Iphiini Schönherr, 1823 nom. oblitum (Curculionidae), Cleonini Schönherr, 1826 nom. protectum over Geomorini Schönherr, 1823 nom. oblitum (Curculionidae), Magdalidini Pascoe, 1870 nom. protectum over Scardamyctini Gistel, 1848 nom. oblitum (Curculionidae), Agrypninae/-ini Candèze, 1857 nom. protecta over Adelocerinae/-ini Gistel, 1848 nom. oblita and Pangaurinae/-ini Gistel, 1856 nom. oblita (Elateridae), Prosternini Gistel, 1856 nom. protectum over Diacanthini Gistel, 1848 nom. oblitum (Elateridae), Calopodinae Costa, 1852 nom. protectum over Sparedrinae Gistel, 1848 nom. oblitum (Oedemeridae), Adesmiini Lacordaire, 1859 nom. protectum over Macropodini Agassiz, 1846 nom. oblitum (Tenebrionidae), Bolitophagini Kirby, 1837 nom. protectum over Eledonini Billberg, 1820 nom. oblitum (Tenebrionidae), Throscidae Laporte, 1840 nom. protectum over Stereolidae Rafinesque, 1815 nom. oblitum (Throscidae) and Lophocaterini Crowson, 1964 over Lycoptini Casey, 1890 nom. oblitum (Trogossitidae); Monotoma Herbst, 1799 nom. protectum over Monotoma Panzer, 1792 nom. oblitum (Monotomidae); Pediacus Shuckard, 1839 nom. protectum over Biophloeus Dejean, 1835 nom. oblitum (Cucujidae), Pachypus Dejean, 1821 nom. protectum over Pachypus Billberg, 1820 nom. oblitum (Scarabaeidae), Sparrmannia Laporte, 1840 nom. protectum over Leocaeta Dejean, 1833 nom. oblitum and Cephalotrichia Hope, 1837 nom. oblitum (Scarabaeidae). PMID:21594053

Cross-resistance and synergism bioassays suggest multiple mechanisms of pyrethroid resistance in western corn rootworm populations

PubMed Central

Souza, Dariane; Zukoff, Sarah N.; Meinke, Lance J.; Siegfried, Blair D.

2017-01-01

Recently, resistance to the pyrethroid bifenthrin was detected and confirmed in field populations of western corn rootworm, Diabrotica virgifera virgifera LeConte from southwestern areas of Nebraska and Kansas. As a first step to understand potential mechanisms of resistance, the objectives of this study were i) to assess adult mortality at diagnostic concentration-LC99 to the pyrethroids bifenthrin and tefluthrin as well as DDT, ii) estimate adult and larval susceptibility to the same compounds as well as the organophosphate methyl-parathion, and iii) perform synergism experiments with piperonyl butoxide (PBO) (P450 inhibitor) and S,S,S-tributyl-phosphorotrithioate (DEF) (esterase inhibitor) in field populations. Most of the adult field populations exhibiting some level of bifenthrin resistance exhibited significantly lower mortality to both pyrethroids and DDT than susceptible control populations at the estimated LC99 of susceptible populations. Results of adult dose-mortality bioassays also revealed elevated LC50 values for bifenthrin resistant populations compared to the susceptible control population with resistance ratios ranging from 2.5 to 5.5-fold for bifenthrin, 28 to 54.8-fold for tefluthrin, and 16.3 to 33.0 for DDT. These bioassay results collectively suggest some level of cross-resistance between the pyrethroids and DDT. In addition, both PBO and DEF reduced the resistance ratios for resistant populations although there was a higher reduction in susceptibility of adults exposed to PBO versus DEF. Susceptibility in larvae varied among insecticides and did not correlate with adult susceptibility to tefluthrin and DDT, as most resistance ratios were < 5-fold when compared to the susceptible population. These results suggest that both detoxifying enzymes and target site insensitivity might be involved as resistance mechanisms. PMID:28628635

Efficacy of "Verbenone Plus" for protecting ponderosa pine trees and stands from Dendroctonus brevicomis (Coleoptera: Curculionidae) attack in British Columbia and California.

PubMed

Fettig, Christopher J; McKelvey, Stephen R; Dabney, Christopher P; Huber, Dezene P W; Lait, Cameron G; Fowler, Donald L; Borden, John H

2012-10-01

The western pine beetle, Dendroctonus brevicomis LeConte (Coleoptera: Curculionidae, Scolytinae), is a major cause of ponderosa pine, Pinus ponderosa Douglas ex Lawson, mortality in much of western North America. We review several years of research that led to the identification of Verbenone Plus, a novel four-component semiochemcial blend [acetophenone, (E)-2-hexen-1-ol + (Z)-2-hexen-1-ol, and (-)-verbenone] that inhibits the response of D. brevicomis to attractant-baited traps, and examine the efficacy of Verbenone Plus for protecting individual trees and forest stands from D. brevicomis infestations in British Columbia and California. In all experiments, semiochemicals were stapled around the bole of treated trees at approximately equal to 2 m in height. (-)-Verbenone alone had no effect on the density of total attacks and successful attacks by D. brevicomis on attractant-baited P. ponderosa, but significantly increased the percentage of pitchouts (unsuccessful D. brevicomis attacks). Verbenone Plus significantly reduced the density of D. brevicomis total attacks and D. brevicomis successful attacks on individual trees. A significantly higher percentage of pitchouts occurred on Verbenone Plus-treated trees. The application of Verbenone Plus to attractant-baited P. ponderosa significantly reduced levels of tree mortality. In stand protection studies, Verbenone Plus significantly reduced the percentage of trees mass attacked by D. brevicomis in one study, but in a second study no significant treatment effect was observed. Future research should concentrate on determining optimal release rates and spacings of release devices in stand protection studies, and expansion of Verbenone Plus into other systems where verbenone alone has not provided adequate levels of tree protection.

Antennal Transcriptome Analysis of Odorant Reception Genes in the Red Turpentine Beetle (RTB), Dendroctonus valens.

PubMed

Gu, Xiao-Cui; Zhang, Ya-Nan; Kang, Ke; Dong, Shuang-Lin; Zhang, Long-Wa

2015-01-01

The red turpentine beetle (RTB), Dendroctonus valens LeConte (Coleoptera: Curculionidae, Scolytinae), is a destructive invasive pest of conifers which has become the second most important forest pest nationwide in China. Dendroctonus valens is known to use host odors and aggregation pheromones, as well as non-host volatiles, in host location and mass-attack modulation, and thus antennal olfaction is of the utmost importance for the beetles' survival and fitness. However, information on the genes underlying olfaction has been lacking in D. valens. Here, we report the antennal transcriptome of D. valens from next-generation sequencing, with the goal of identifying the olfaction gene repertoire that is involved in D. valens odor-processing. We obtained 51 million reads that were assembled into 61,889 genes, including 39,831 contigs and 22,058 unigenes. In total, we identified 68 novel putative odorant reception genes, including 21 transcripts encoding for putative odorant binding proteins (OBP), six chemosensory proteins (CSP), four sensory neuron membrane proteins (SNMP), 22 odorant receptors (OR), four gustatory receptors (GR), three ionotropic receptors (IR), and eight ionotropic glutamate receptors. We also identified 155 odorant/xenobiotic degradation enzymes from the antennal transcriptome, putatively identified to be involved in olfaction processes including cytochrome P450s, glutathione-S-transferases, and aldehyde dehydrogenase. Predicted protein sequences were compared with counterparts in Tribolium castaneum, Megacyllene caryae, Ips typographus, Dendroctonus ponderosae, and Agrilus planipennis. The antennal transcriptome described here represents the first study of the repertoire of odor processing genes in D. valens. The genes reported here provide a significant addition to the pool of identified olfactory genes in Coleoptera, which might represent novel targets for insect management. The results from our study also will assist with evolutionary analyses of coleopteran olfaction.

Antennal Transcriptome Analysis of Odorant Reception Genes in the Red Turpentine Beetle (RTB), Dendroctonus valens

PubMed Central

Dong, Shuang-Lin; Zhang, Long-Wa

2015-01-01

Background The red turpentine beetle (RTB), Dendroctonus valens LeConte (Coleoptera: Curculionidae, Scolytinae), is a destructive invasive pest of conifers which has become the second most important forest pest nationwide in China. Dendroctonus valens is known to use host odors and aggregation pheromones, as well as non-host volatiles, in host location and mass-attack modulation, and thus antennal olfaction is of the utmost importance for the beetles’ survival and fitness. However, information on the genes underlying olfaction has been lacking in D. valens. Here, we report the antennal transcriptome of D. valens from next-generation sequencing, with the goal of identifying the olfaction gene repertoire that is involved in D. valens odor-processing. Results We obtained 51 million reads that were assembled into 61,889 genes, including 39,831 contigs and 22,058 unigenes. In total, we identified 68 novel putative odorant reception genes, including 21 transcripts encoding for putative odorant binding proteins (OBP), six chemosensory proteins (CSP), four sensory neuron membrane proteins (SNMP), 22 odorant receptors (OR), four gustatory receptors (GR), three ionotropic receptors (IR), and eight ionotropic glutamate receptors. We also identified 155 odorant/xenobiotic degradation enzymes from the antennal transcriptome, putatively identified to be involved in olfaction processes including cytochrome P450s, glutathione-S-transferases, and aldehyde dehydrogenase. Predicted protein sequences were compared with counterparts in Tribolium castaneum, Megacyllene caryae, Ips typographus, Dendroctonus ponderosae, and Agrilus planipennis. Conclusion The antennal transcriptome described here represents the first study of the repertoire of odor processing genes in D. valens. The genes reported here provide a significant addition to the pool of identified olfactory genes in Coleoptera, which might represent novel targets for insect management. The results from our study also will assist with evolutionary analyses of coleopteran olfaction. PMID:25938508

Changing Names with Changed Address: Integrated Taxonomy and Species Delimitation in the Holarctic Colymbetes paykulli Group (Coleoptera: Dytiscidae)

PubMed Central

Drotz, Marcus K.; Brodin, Tomas; Nilsson, Anders N.

2015-01-01

Species delimitation of geographically isolated forms is a long-standing problem in less studied insect groups. Often taxonomic decisions are based directly on morphologic variation, and lack a discussion regarding sample size and the efficiency of migration barriers or dispersal/migration capacity of the studied species. These problems are here exemplified in a water beetle complex from the Bering Sea region that separates North America from Eurasia. Only a few sampled specimens occur from this particular area and they are mostly found in museum and private collections. Here we utilize the theory of integrated taxonomy to discuss the speciation of the Holarctic Colymbetes paykulli water beetle complex, which historically has included up to five species of which today only two are recognized. Three delimitation methods are used; landmark based morphometry of body shape, variation in reticulation patterns of the pronotum exo-skeleton and sequence variation of the partial mitochondrial gene Cyt b. Our conclusion is that the Palearctic and Nearctic populations of C. paykulli are given the status of separate species, based on the fact that all methods showed significant separation between populations. As a consequence the name of the Palearctic species is C. paykulli Erichson and the Nearctic species should be known as C. longulus LeConte. There is no clear support for delineation between Palearctic and Nearctic populations of C. dahuricus based on mtDNA. However, significant difference in size and reticulation patterns from the two regions is shown. The combined conclusion is that the C. dahuricus complex needs a more thorough investigation to fully disentangle its taxonomic status. Therefore it is here still regarded as a Holarctic species. This study highlights the importance to study several diagnosable characters that has the potential to discriminate evolutionary lineage during speciation. PMID:26619278

Seasonal Phenology and Life-History of Dendroctonus simplex (Coleoptera: Curculionidae) in the Great Lakes Region of North America.

PubMed

McKee, Fraser R; Aukema, Brian H

2016-08-01

The eastern larch beetle, Dendroctonus simplex LeConte (Coleoptera: Curculionidae), is distributed throughout the North American boreal forest sympatric with its primary host, the eastern larch or tamarack, Larix laricina (Du Roi) K. Koch. Outbreaks of eastern larch beetles are typically small and associated with stressed tamaracks. Since 2000, however, an outbreak has killed >90,000 ha of tamarack in Minnesota and surrounding Great Lakes region. Identifying the causes of this epidemic is challenging due to knowledge gaps regarding the insect's biology. We present field data from 2011 to 2014 on degree days associated with spring emergence, dispersal, host colonization, and re-emergence from colonized hosts by mature adult beetles, as well as degree days associated with larval development, and prewinter emergence by adult progeny at study sites in northern Minnesota. After initial host colonization in early spring we found that a second brood was established in early summer by re-emerging parents. In 2012, a third brood was established. Across study years, first broods developed to adults by late summer, with many beetles relocating to the base of the host tree to overwinter. Second broods often reached adulthood and initiated prewinter emergence. The third brood of 2012 overwintered as adults, pupae, and late-instars, resuming development the following spring. Each spring, emergence of adult beetles from all broods established the previous year was highly synchronous. Knowledge of the biology of eastern larch beetles along the southern margin of their range aids in understanding how population dynamics may change with a changing climate. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Phenology, natural enemies, and efficacy of horticultural oil for control of Chionaspis heterophyllae (Homoptera: Diaspididae) on Christmas tree plantations.

PubMed

Fondren, Kirsten M; McCullough, Deborah G

2005-10-01

Pine needle scale, Chionaspis pinifoliae (Fitch), and Chionaspis heterophyllae Cooley are important pests of Scots pine, Pinus sylvestris L., and other conifers in much of North America. On Christmas tree plantations, these insects are typically controlled by spraying broad-spectrum insecticides when the vulnerable immature stages are present. However, effective control of bivoltine populations can be difficult to achieve due to asynchronous hatch and development of the second generation. Our objectives were to 1) determine the phenology of the second generation of C. heterophyllae in Michigan; 2) characterize the natural enemy complex; and 3) assess the effectiveness of horticultural oil for control of C. heterophyllae on P. sylvestris Christmas tree plantations. We monitored scale populations in three counties in lower Michigan for 3 yr. Scale phenology was consistently associated with cumulative degree-days base 10 degrees C (DD(10 degrees C)). Second-generation egg hatch began at approximately 1230-1300 DD(10 degrees C), and continued for approximately 3 wk. The peak of the second instar coincided with 1500-1600 DD(10 degrees C). Common predators included the coccinellids Chilocorus stigma (Say) and Microweisia misella (LeConte). On average, 70% of the C. heterophyllae population in unsprayed fields was killed by predators in 1999. Two endoparasitic wasps, Encarsia bella Gahan and Marietta mexicana Howard (Hymenoptera: Aphelinidae), also were recovered. In 2000 and 2001, we applied a highly refined horticultural spray oil with a backpack mist blower at 1500-1600 DD(10 degrees). Scale mortality on trees treated with oil ranged from 66 to 80% and was similar to control achieved using conventional insecticides in both years.

Italian Dermestidae: notes on some species and an updated checklist (Coleoptera)

PubMed Central

Nardi, Gianluca; Háva, Jiří

2013-01-01

Abstract An up-to-date checklist of the Italian Dermestidae is provided. The presence of 95 species in Italy is confirmed, while further 5 species (Dermestes (Dermestes) vorax Motschulsky, 1860, Thorictuspilosus Peyron, 1857, T. wasmanni Reitter, 1895, Attagenus (Attagenus) simonis Reitter, 1881 and Globicornis (G.) breviclavis (Reitter, 1878)) and 1 subspecies (A. (A.) tigrinus pulcher Faldermann, 1835) are excluded from the Italian fauna. Attagenus (Attagenus) calabricus Reitter, 1881 and A. (A.) lobatus Rosenhauer, 1856 are for the first time recorded from Abruzzi and Tuscany respectively; A. (A.) silvaticus Zhantiev, 1976 is recorded for the first time from mainland Italy (Apulia); Anthrenus (Anthrenus) angustefasciatus Ganglbauer, 1904 is new to northern Italy (Friuli-Venezia Giulia), central Italy (Tuscany), Apulia and Basilicata; A. (A.) munroi Hinton, 1943 is new to central Italy (Elba Island); A. (A.) delicatus Kiesenwetter, 1851 is for the first time recorded from Apulia; Globicornis (Globicornis) fasciata (Fairmaire & Brisout de Barneville, 1859) is new to southern Italy (Basilicata); G. (Hadrotoma) sulcata (C.N.F. Brisout de Barneville, 1866) is for the first time recorded from central Italy (Abruzzi), Campania and Sicily, whileTrogoderma inclusum LeConte, 1854 is new to Apulia. Seven species (Dermestes (Dermestes) peruvianus Laporte de Castelnau, 1840, D. (Dermestinus) carnivorus Fabricius, 1775, D. (Dermestinus) hankae Háva, 1999, D. (Dermestinus) intermedius intermedius Kalík, 1951, D. (Dermestinus) szekessyi Kalík, 1950, Anthrenus (Anthrenops) coloratus Reitter, 1881 and Trogodermaangustum (Solier, 1849)) recently recorded from Italy (without further details) are discussed. The lectotype and a paralectotype are designated forAttagenus (A.) calabricus Reitter, 1881 from Calabria. Attagenus pellio (Linnaeus, 1758) var. pilosissimus Roubal, 1932 is removed from synonymy with A. (A.) pellio and recognized as a valid species (stat. prom.); it is known from Lombardy, Apulia and Calabria. PMID:24363591

Quantitative Trait Loci Mapping of Western Corn Rootworm (Coleoptera: Chrysomelidae) Host Plant Resistance in Two Populations of Doubled Haploid Lines in Maize (Zea mays L.).

PubMed

Bohn, Martin O; Marroquin, Juan J; Flint-Garcia, Sherry; Dashiell, Kenton; Willmot, David B; Hibbard, Bruce E

2018-02-09

Over the last 70 yr, more than 12,000 maize accessions have been screened for their level of resistance to western corn rootworm, Diabrotica virgifera virgifera (LeConte; Coleoptera: Chrysomelidae), larval feeding. Less than 1% of this germplasm was selected for initiating recurrent selection or other breeding programs. Selected genotypes were mostly characterized by large root systems and superior root regrowth after root damage caused by western corn rootworm larvae. However, no hybrids claiming native (i.e., host plant) resistance to western corn rootworm larval feeding are currently commercially available. We investigated the genetic basis of western corn rootworm resistance in maize materials with improved levels of resistance using linkage disequilibrium mapping approaches. Two populations of topcrossed doubled haploid maize lines (DHLs) derived from crosses between resistant and susceptible maize lines were evaluated for their level of resistance in three to four different environments. For each DHL topcross an average root damage score was estimated and used for quantitative trait loci (QTL) analysis. We found genomic regions contributing to western corn rootworm resistance on all maize chromosomes, except for chromosome 4. Models fitting all QTL simultaneously explained about 30 to 50% of the genotypic variance for root damage scores in both mapping populations. Our findings confirm the complex genetic structure of host plant resistance against western corn rootworm larval feeding in maize. Interestingly, three of these QTL regions also carry genes involved in ascorbate biosynthesis, a key compound we hypothesize is involved in the expression of western corn rootworm resistance. © The Author(s) 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Applying Broadband Dielectric Spectroscopy (BDS) for the Biophysical Characterization of Mammalian Tissues under a Variety of Cellular Stresses

PubMed Central

Souli, Maria P.; Klonos, Panagiotis; Fragopoulou, Adamantia F.; Mavragani, Ifigeneia V.; Pateras, Ioannis S.; Kostomitsopoulos, Nikolaos; Margaritis, Lukas H.; Zoumpoulis, Pavlos; Kaklamanis, Loukas; Kletsas, Dimitris; Gorgoulis, Vassilis G.; Kyritsis, Apostolos; Pissis, Polycarpos; Georgakilas, Alexandros G.

2017-01-01

The dielectric properties of biological tissues can contribute non-invasively to a better characterization and understanding of the structural properties and physiology of living organisms. The question we asked, is whether these induced changes are effected by an endogenous or exogenous cellular stress, and can they be detected non-invasively in the form of a dielectric response, e.g., an AC conductivity switch in the broadband frequency spectrum. This study constitutes the first methodological approach for the detection of environmental stress-induced damage in mammalian tissues by the means of broadband dielectric spectroscopy (BDS) at the frequencies of 1–106 Hz. Firstly, we used non-ionizing (NIR) and ionizing radiation (IR) as a typical environmental stress. Specifically, rats were exposed to either digital enhanced cordless telecommunication (DECT) radio frequency electromagnetic radiation or to γ-radiation, respectively. The other type of stress, characterized usually by high genomic instability, was the pathophysiological state of human cancer (lung and prostate). Analyzing the results of isothermal dielectric measurements provided information on the tissues’ water fraction. In most cases, our methodology proved sufficient in detecting structural changes, especially in the case of IR and malignancy. Useful specific dielectric response patterns are detected and correlated with each type of stress. Our results point towards the development of a dielectric-based methodology for better understanding and, in a relatively invasive way, the biological and structural changes effected by radiation and developing lung or prostate cancer often associated with genomic instability. PMID:28420124

Patients with gastrointestinal complains due to enteric parasites, with reference to Entamoeba histolytica/dispar as dected by ELISA E. histolytica adhesion in stool.

PubMed

El-Kadi, Mohammad A; Dorrah, Ahmad O; Shoukry, Nahla M

2006-04-01

A total of 210 patients with gastrointestinal troubles, of both sex and a mean age of 32 +/- 6.1 years, selected from the outpatient's clinics of Al-Azhar University Hospitals. 115 (54.76%) had dysentery, 95 (45.23%) did not have dysentery, 15 (14%) suffered flatulence, 20 (9.52%) had epi-gastric pain, 19 (9.05%) had vague abdominal pain, 5 vomiting (5.2%) and 10 (4.9%) had fever. Two symptoms were in 29 (13.81%) patients and three symptoms in 12 (5.71%). Of the 210 patients, 20 (9.9%) had helminthes infection, 121 (57.6%) had intestinal protozoa and 69 (32.9%) had no parasitic infection. Of these parasite-free patients, 16 had Shigella sp. and nine had Campylobacter sp. Of the patients with intestinal protozoa, 34 (16.2%) had E. histolytica/dispar by stool examination of stained smears. By using ELISA for detection of E. histolytica adhesion in stool samples of 115 with diarrhea only 18 had true E. histolytica infection and of 3 without diarrhea only one had E. histolytica infection. Mean-while, ELISA did not cross-reacted E. coli, Giardia lamblia, Cryptosporidium parvum, Endolimax nana or Blastocystis hominis. So, ELISA for detection of E. histolytica adhesion in stool samples was more specific than microscopy and safe direction to the E. histolytica treatment. Apart from intestinal protozoan and bacteria, helminthes were seen in stool analysis. These were Schistosoma mansoni (0.95%), Capillaria sp. (0.95%), Enterobius vermicularis (1.90%) macroscopically, Hymenolepis nana (4.3%) and Ascaris lumbricoides (1.43%).

Assessment of RF exposures from emerging wireless communication technologies in different environments.

PubMed

Joseph, Wout; Verloock, Leen; Goeminne, Francis; Vermeeren, Gönter; Martens, Luc

2012-02-01

In situ electromagnetic (EM) radio frequency (RF) exposure to base stations of emerging wireless technologies is assessed at 311 locations, 68 indoor and 243 outdoor, spread over 35 areas in three European countries (Belgium, The Netherlands, and Sweden) by performing narrowband spectrum analyzer measurements. The locations are selected to characterize six different environmental categories (rural, residential, urban, suburban, office, and industrial). The maximal total field value was measured in a residential environment and equal to 3.9 V m(-1), mainly due to GSM900 signals. Exposure ratios for maximal electric field values, with respect to ICNIRP reference levels, range from 0.5% (WiMAX) to 9.3% (GSM900) for the 311 measurement locations. Exposure ratios for total field values vary from 3.1% for rural environments to 9.4% for residential environments. Exposures are lognormally distributed and are the lowest in rural environments and the highest in urban environments. Highest median exposures were obtained in urban environments (0.74 V m(-1)), followed by office (0.51 V m(-1)), industrial (0.49 V m(-1)), suburban (0.46 V m(-1)), residential (0.40 V m(-1)), and rural (0.09 V m(-1)) environments. The average contribution to the total electric field is more than 60% for GSM. Except for the rural environment, average contributions of UMTS-HSPA are more than 3%. Contributions of the emerging technologies LTE and WiMAX are on average less than 1%. The dominating outdoor source is GSM900 (95 percentile of 1.9 V m(-1)), indoor DECT dominates (95 percentile of 1.5 V m(-1)).

Phantom-less bone mineral density (BMD) measurement using dual energy computed tomography-based 3-material decomposition

NASA Astrophysics Data System (ADS)

Hofmann, Philipp; Sedlmair, Martin; Krauss, Bernhard; Wichmann, Julian L.; Bauer, Ralf W.; Flohr, Thomas G.; Mahnken, Andreas H.

2016-03-01

Osteoporosis is a degenerative bone disease usually diagnosed at the manifestation of fragility fractures, which severely endanger the health of especially the elderly. To ensure timely therapeutic countermeasures, noninvasive and widely applicable diagnostic methods are required. Currently the primary quantifiable indicator for bone stability, bone mineral density (BMD), is obtained either by DEXA (Dual-energy X-ray absorptiometry) or qCT (quantitative CT). Both have respective advantages and disadvantages, with DEXA being considered as gold standard. For timely diagnosis of osteoporosis, another CT-based method is presented. A Dual Energy CT reconstruction workflow is being developed to evaluate BMD by evaluating lumbar spine (L1-L4) DE-CT images. The workflow is ROI-based and automated for practical use. A dual energy 3-material decomposition algorithm is used to differentiate bone from soft tissue and fat attenuation. The algorithm uses material attenuation coefficients on different beam energy levels. The bone fraction of the three different tissues is used to calculate the amount of hydroxylapatite in the trabecular bone of the corpus vertebrae inside a predefined ROI. Calibrations have been performed to obtain volumetric bone mineral density (vBMD) without having to add a calibration phantom or to use special scan protocols or hardware. Accuracy and precision are dependent on image noise and comparable to qCT images. Clinical indications are in accordance with the DEXA gold standard. The decomposition-based workflow shows bone degradation effects normally not visible on standard CT images which would induce errors in normal qCT results.

Releasing captive-reared masked bobwhite for population recovery: A review

USGS Publications Warehouse

Gall, S.A.; Kuvlesky, W.P.; Gee, G.; Brennan, L.A.; Palmer, W.E.; Burger, L.W.; Pruden, T.L.

2000-01-01

Efforts to re-establish the endangered masked bobwhite (Colinus virginianus ridgwayi) to it's former southern Arizona range have been ongoing since establishment of the Buenos Aires National Wildlife Refuge in 1986. Pre-release conditioning techniques developed prior to Refuge establishment continued to be utilized in an effort to improve post-release survival of captive-reared masked bobwhite chicks. Foremost among these techniques was the use of wild Texas bobwhite (C. v. texanus) males as foster parents which were paired with all broods released on the Refuge. The efficacy of this technique was evaluated using radio telemetry in 1994, and the results indicated that the use of foster Texas males was not as effective as had been presumed because post-release chick survival was poor. Therefore, in 1995 pre-release conditioning protocol were modified in an effort to improve post-release survival. The primary intent of these modifications was to emphasize wild behavior among chicks prior to release. Modifications to established protocol included imprinting chicks to adult bobwhites immediately after eggs hatched and exposing 1-to-2 day old chicks to natural foods (insects and seeds) while they were in brooder units. Foster parents and their respective broods were then placed in flight pens that mimicked the natural conditions that would confront broods upon release. Family groups were held in flight pens for several weeks for acclimatization purposes and then transported to temporary enclosures erected at release sites where they were held for a week and then released. Finally all releases were conducted during fall after covey formation was apparent to ensure that foster parents and released chicks remained with a group of birds. Preliminary results indicated that post-release chick survival was higher than what was observed in 1994. Pre-conditioning research will continue in an effort to further quantify post-release survival of masked bobwhite chicks. Although the results of this research project are preliminary, it is possible that pre-release conditioning techniques developed for masked bobwhites will prove useful to quail reestablishment efforts throughout North America.

HEALTH SURVEY OF FREE-RANGING RACCOONS (PROCYON LOTOR) IN CENTRAL PARK, NEW YORK, NEW YORK, USA: IMPLICATIONS FOR HUMAN AND DOMESTIC ANIMAL HEALTH.

PubMed

Rainwater, Kimberly L; Marchese, Krysten; Slavinski, Sally; Humberg, Lee A; Dubovi, Edward J; Jarvis, Jodie A; McAloose, Denise; Calle, Paul P

2017-04-01

We conducted health assessments on 113 free-ranging raccoons ( Procyon lotor ) in Central Park, New York City, US, in February 2010, September 2010, and November 2011 in conjunction with a trap-vaccinate-release program to control a raccoon rabies epizootic. Five individuals were sampled at two time points for 118 raccoon examinations in total. We tested 13 of 13 and 8 of 13 euthanized raccoons for rabies and canine distemper virus (CDV), respectively, by antigen testing on brain tissue; all were negative for both viruses. Endoparasitism was the most common necropsy finding, with definitive identification of Baylisascaris procyonis in six of eight (75%) necropsied raccoons. Multiple intestinal parasites were detected in feces of living raccoons, including ascarid-type ova in 25 of 80 (31%) raccoons, with B. procyonis confirmed in one sample. Median blood lead level was 7.3 μg/dL (n=104). Rabies virus neutralizing antibody titer was ≥0.5 IU/mL in 9 of 88 (10%) raccoons naive to rabies vaccination and in 13 of 20 (65%) previously vaccinated raccoons. The majority of raccoons we tested were seropositive for canine parvovirus-2 (54/59, 92%) and Toxoplasma gondii (39/60, 65%). Fewer were seropositive for Rickettsia rickettsii (3/30, 10%). None were seropositive for CDV (n=108), canine adenovirus-1 (n=60), or Borrelia burgdorferi (n=30). Ectoparasites found during 16 of 118 (13.6%) physical examinations included Ixodes texanus ticks (15/118, 12.7%) and Trichodectes octomaculatus lice (1/118, 0.8%). We detected Campylobacter jejuni in 5 of 79 (6%) fecal samples. We detected 11 Salmonella enterica serotypes in 70 of 111 (63.1%) enteric cultures, the most common of which were Salmonella Newport (20/70, 29%) and Salmonella Oranienburg (20/70, 29%). These results indicate that raccoons in Central Park likely are involved in the environmental occurrence and potential disease transmission of a variety of infectious and noninfectious diseases of concern for human, wildlife, and domestic animal health.

Competing risks and the development of adaptive management plans for water resources: Field reconnaissance investigation of risks to fishes and other aquatic biota exposed to endocrine disrupting chemicals (edcs) in lake mead, Nevada USA

USGS Publications Warehouse

Linder, G.; Little, E.E.

2009-01-01

The analysis and characterization of competing risks for water resources rely on a wide spectrum of tools to evaluate hazards and risks associated with their management. For example, waters of the lower Colorado River stored in reservoirs such as Lake Mead present a wide range of competing risks related to water quantity and water quality. These risks are often interdependent and complicated by competing uses of source waters for sustaining biological resources and for supporting a range of agricultural, municipal, recreational, and industrial uses. USGS is currently conducting a series of interdisciplinary case-studies on water quality of Lake Mead and its source waters. In this case-study we examine selected constituents potentially entering the Lake Mead system, particularly endocrine disrupting chemicals (EDCs). Worldwide, a number of environmental EDCs have been identified that affect reproduction, development, and adaptive behaviors in a wide range of organisms. Many EDCs are minimally affected by current treatment technologies and occur in treated sewage effluents. Several EDCs have been detected in Lake Mead, and several substances have been identified that are of concern because of potential impacts to the aquatic biota, including the sport fishery of Lake Mead and endangered razorback suckers (Xyrauchen texanus) that occur in the Colorado River system. For example, altered biomarkers relevant to reproduction and thyroid function in fishes have been observed and may be predictive of impaired metabolism and development. Few studies, however, have addressed whether such EDC-induced responses observed in the field have an ecologically significant effect on the reproductive success of fishes. To identify potential linkages between EDCs and species of management concern, the risk analysis and characterization in this reconnaissance study focused on effects (and attendant uncertainties) that might be expressed by exposed populations. In addition, risk reduction measures that may be of interest to resource managers are considered relative to emerging contaminants in treated effluents, interdependencies among biological resources at risk, and uses of reservoir waters derived from multiple inflows of widely varying qualities. ??2009 ASCE.

Composition of Age-0 Fish Assemblages in the Apalachicola River, River Styx, and Battle Bend, Florida

USGS Publications Warehouse

Walsh, Stephen J.; Buttermore, Elissa N.; Burgess, O. Towns; Pine, William E.

2009-01-01

Light traps were used to sample the age-0 year class of fish communities in the Apalachicola River and associated floodplain water bodies of River Styx and Battle Bend, Florida, in 2006-2007. A total of 629 light traps were deployed during the spring and early summer months (341 between March 15 and June 6, 2006; 288 between March 9 and July 3, 2007). For combined years, 13.8 percent of traps were empty and a total of 20,813 age-0 fish were captured representing at least 40 taxa of 29 genera and 16 families. Trap catches were dominated by relatively few species, with the most abundant groups represented by cyprinids, centrarchids, percids, and catostomids. Six taxa accounted for about 80 percent of all fish collected: Micropterus spp. (28.9 percent), Notropis texanus (28.9 percent), Lepomis macrochirus (7.9 percent), Carpiodes cyprinus (6.2 percent), Cyprinidae sp. (4.6 percent), and Minytrema melanops (4.2 percent). Based on chronological appearance in light traps and catch-per-unit effort, including data from previous years of sampling, peak spawning periods for most species occurred between early March and mid-June. A complementary telemetry study of pre-reproductive adults of select target species (Micropterus spp., Lepomis spp., and M. melanops) revealed distinct patterns of habitat use, with some individual fish exclusively utilizing mainstem river habitat or floodplain habitat during spawning and post-spawning periods, and other individuals migrating between habitats. A comparison of light-trap catches between a pre-enhancement, high-water year (2003) and post-enhancement, low-water year (2007) for the oxbow at Battle Bend revealed some difference in community composition, with slightly greater values of diversity and evenness indices in 2007. Two dominant species, Lepomis macrochirus and Micropterus salmoides, were substantially greater in relative abundance among all age-0 fish collected in 2007 in comparison to 2003. Excavation of sediments at the mouth of Battle Bend improved river-floodplain connectivity during low flows such as occurred in 2007 and likely provided greater access and availability of fish spawning and nursery habitats.

Apoptotic cell death during Drosophila oogenesis is differentially increased by electromagnetic radiation depending on modulation, intensity and duration of exposure.

PubMed

Sagioglou, Niki E; Manta, Areti K; Giannarakis, Ioannis K; Skouroliakou, Aikaterini S; Margaritis, Lukas H

2016-01-01

Present generations are being repeatedly exposed to different types and doses of non-ionizing radiation (NIR) from wireless technologies (FM radio, TETRA and TV stations, GSM and UMTS phones/base stations, Wi-Fi networks, DECT phones). Although there is controversy on the published data regarding the non-thermal effects of NIR, studies have convincingly demonstrated bioeffects. Their results indicate that modulation, intensity, exposure duration and model system are important factors determining the biological response to irradiation. Attempting to address the dependence of NIR bioeffectiveness on these factors, apoptosis in the model biological system Drosophila melanogaster was studied under different exposure protocols. A signal generator was used operating alternatively under Continuous Wave (CW) or Frequency Modulation (FM) emission modes, at three power output values (10 dB, 0, -10 dB), under four carrier frequencies (100, 395, 682, 900 MHz). Newly emerged flies were exposed either acutely (6 min or 60 min on the 6th day), or repeatedly (6 min or 60 min daily for the first 6 days of their life). All exposure protocols resulted in an increase of apoptotic cell death (ACD) observed in egg chambers, even at very low electric field strengths. FM waves seem to have a stronger effect in ACD than continuous waves. Regarding intensity and temporal exposure pattern, EMF-biological tissue interaction is not linear in response. Intensity threshold for the induction of biological effects depends on frequency, modulation and temporal exposure pattern with unknown so far mechanisms. Given this complexity, translating such experimental data into possible human exposure guidelines is yet arbitrary.

Characterization of personal RF electromagnetic field exposure and actual absorption for the general public.

PubMed

Joseph, W; Vermeeren, G; Verloock, L; Heredia, Mauricio Masache; Martens, Luc

2008-09-01

In this paper, personal electromagnetic field exposure of the general public due to 12 different radiofrequency sources is characterized. Twenty-eight different realistic exposure scenarios based upon time, environment, activity, and location have been defined and a relevant number of measurements were performed with a personal exposure meter. Indoor exposure in office environments can be higher than outdoor exposure: 95th percentiles of field values due to WiFi ranged from 0.36 to 0.58 V m(-1), and for DECT values of 0.33 V m(-1) were measured. The downlink signals of GSM and DCS caused the highest outdoor exposures up to 0.52 V m(-1). The highest total field exposure occurred for mobile scenarios (inside a train or bus) from uplink signals of GSM and DCS (e.g., mobile phones) due to changing environmental conditions, handovers, and higher required transmitted signals from mobile phones due to penetration through windows while moving. A method to relate the exposure to the actual whole-body absorption in the human body is proposed. An application is shown where the actual absorption in a human body model due to a GSM downlink signal is determined. Fiftieth, 95th, and 99 th percentiles of the whole-body specific absorption rate (SAR) due to this GSM signal of 0.58 microW kg(-1), 2.08 microW kg(-1), and 5.01 microW kg(-1) are obtained for a 95th percentile of 0.26 V m(-1). A practical usable function is proposed for the relation between the whole-body SAR and the electric fields. The methodology of this paper enables epidemiological studies to make an analysis in combination with both electric field and actual whole-body SAR values and to compare exposure with basic restrictions.

Improved visualisation of early cerebral infarctions after endovascular stroke therapy using dual-energy computed tomography oedema maps.

PubMed

Grams, Astrid Ellen; Djurdjevic, Tanja; Rehwald, Rafael; Schiestl, Thomas; Dazinger, Florian; Steiger, Ruth; Knoflach, Michael; Gizewski, Elke Ruth; Glodny, Bernhard

2018-05-04

The aim was to investigate whether dual-energy computed tomography (DECT) reconstructions optimised for oedema visualisation (oedema map; EM) facilitate an improved detection of early infarctions after endovascular stroke therapy (EST). Forty-six patients (21 women; 25 men; mean age: 63 years; range 24-89 years) were included. The brain window (BW), virtual non-contrast (VNC) and modified VNC series based on a three-material decomposition technique optimised for oedema visualisation (EM) were evaluated. Follow-up imaging was used as the standard for comparison. Contralateral side to infarction differences in density (CIDs) were determined. Infarction detectability was assessed by two blinded readers, as well as image noise and contrast using Likert scales. ROC analyses were performed and the respective Youden indices calculated for cut-off analysis. The highest CIDs were found in the EM series (73.3 ± 49.3 HU), compared with the BW (-1.72 ± 13.29 HU) and the VNC (8.30 ± 4.74 HU) series. The EM was found to have the highest infarction detection rates (area under the curve: 0.97 vs. 0.54 and 0.90, p < 0.01) with a cut-off value of < 50.7 HU, despite slightly more pronounced image noise. The location of the infarction did not affect detectability (p > 0.05 each). The EM series allows higher contrast and better early infarction detection than the VNC or BW series after EST. • Dual-energy CT EM allows better early infarction detection than standard brain window. • Dual-energy CT EM series allow better early infarction detection than VNC series. • Dual-energy CT EM are modified VNC based on water content of tissue.

Study of potential health effects of electromagnetic fields of telephony and Wi-Fi, using chicken embryo development as animal model.

PubMed

Woelders, Henri; de Wit, Agnes; Lourens, Alexander; Stockhofe, Norbert; Engel, Bas; Hulsegge, Ina; Schokker, Dirkjan; van Heijningen, Paula; Vossen, Stefan; Bekers, Dave; Zwamborn, Peter

2017-04-01

The objective of this study is to investigate possible biological effects of radiofrequency electromagnetic fields (RF-EMF) as used in modern wireless telecommunication in a well-controlled experimental environment using chicken embryo development as animal model. Chicken eggs were incubated under continuous experimental exposure to GSM (1.8 GHz), DECT (1.88 GHz), UMTS (2.1 GHz), and WLAN (5.6 GHz) radiation, with the appropriate modulation protocol, using a homogeneous field distribution at a field strength of approximately 3 V/m, representing the maximum field level in a normal living environment. Radiation-shielded exposure units/egg incubators were operating in parallel for exposed and control eggs in a climatized homogeneous environment, using 450 eggs per treatment in three successive rounds per treatment. Dosimetry of the exposure (field characteristics and specific absorption rate) were studied. Biological parameters studied included embryo death during incubation, hatching percentage, and various morphological and histological parameters of embryos and chicks and their organs, and gene expression profiles of embryos on day 7 and day 18 of incubation by microarray and qPCR. No conclusive evidence was found for induced embryonic mortality or malformations by exposure to the used EMFs, or for effects on the other measured parameters. Estimated differences between treatment groups were always small and the effect of treatment was not significant. In a statistical model that ignored possible interaction between rounds and exposure units, some of the many pairwise comparisons of exposed versus control had P-values lower than 0.05, but were not significant after correction for multiple testing. Bioelectromagnetics. 38:186-203, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Interactions between a Sap Beetle, Sabal Palm, Scale Insect, Filamentous Fungi and Yeast, with Discovery of Potential Antifungal Compounds

PubMed Central

Cline, Andrew R.; Skelley, Paul E.; Kinnee, Scott A.; Rooney-Latham, Suzanne; Winterton, Shaun L.; Borkent, Christopher J.; Audisio, Paolo

2014-01-01

The multi-trophic relationship between insects, yeast, and filamentous fungi is reported on sabal palm (Sabal palmetto (Walter) Lodd. ex Schult. & Schult. f.). Gut content analyses and observations of adult and larval feeding of the sap beetle Brachypeplus glaber LeConte indicate that niche partitioning of fungal food substrata occurs between adults and larvae. This is the first report of specific mycophagous niche partitioning among beetle life stages based on gut content analyses. Fungi isolated from the beetle gut of adults, larvae, and pupae include species of Fusarium Link, Cladosporium Link, and Penicillium Link, which were differentially ingested by larvae and adults; Fusarium solani and Penicillium species in larvae, whereas F. oxysoproum, F. verticillioides, and Cladosporium in adults. These data indicate the first species-level host data for Brachypeplus Erichson species. Fusarium proliferatum (Matsush.) Nirenberg was the most commonly occurring fungal gut component, being isolated from the palm as well as gut of larvae, pupae, and adults; representing a commonly shared food resource. One species of yeast, Meyerozyma caribbica (Vaughan-Mart. et al.) Kurtzman & Suzuki (basionym = Pichia caribbica), was isolated from all life stages and is likely responsible for anti-fungal properties observed in the pupae and represents a promising source of antifungal compounds; rearing and diagnostic protocols are provided to aid biomedical researchers. Feeding and cleaning behaviors are documented using time-lapse video-micrography, and discussed in a behavioral and functional morphological context. Adults spent long periods feeding, often >1/3 of the two-hour observation period. A generic adult body posture was observed during feeding, and included substrate antennation before and after ingestion. Adult grooming behaviors were manifested in distinct antennal and tarsal cleaning mechanisms. Larval behaviors were different from adults, and larvae feeding on Fusarium fungi immediately ceased all subsequent feeding. This is the first ethogram for any adult or larval sap beetle. PMID:24586669

Distribution patterns of MCA-coated granules aerially applied to corn fields of Southern Hungary between 2000 and 2002.

PubMed

Wennemann, L; Hummel, H E

2003-01-01

Field studies in corn (Zea mays L.) were conducted to evaluate distribution patterns of 4-methoxy-cinnamaldehyde (MCA) coated corn grits after aerial application with a Dromader fixed wing aircraft. The kairomone mimic MCA is synthetically available and a quite specific and efficient adult attractant for the invasive alien maize pest western corn rootworm (WCR) Diabrotica virgifera virgifera LeConte. Orientation disruptive properties of MCA for WCR when applied at unphysiologically high concentrations are currently under investigation. For successful implementation of the MCA disruption technique, the distribution patterns of MCA coated corn granules ('grits') in the field are important. Grits are degrained corn cobs, shredded to different sizes, coated with MCA and used as a carrier material to disseminate MCA vapors into corn fields. Granules of 10-12 mesh size were aerially applied eight times at rates ranging from 12.4 to 25.0 kg/ha. The goal is to evaluate distribution patterns of corn grits treated with MCA in three fields located at Csanadpalota, Kardoskút and Mezöhegyes in Southern Hungary between 2000 and 2002. Increasing rates reflect our attempts in finding and optimising the most even distribution of granules in the field. Field experiments were evaluated by collecting grits in 30-cm plastic saucers and by counting grits accumulated on corn plant parts. Variation in grit number per unit area and frequency of corn granule number per plant showed some transient technical application problems. Analysis of grits collected in the saucers revealed some statistical difference between the different application dates as well as differences in rates applied. Altogether grits in saucers were more evenly distributed in comparison to the grits collected on plant parts. As the corn plants age, their leaves and whorls present a smaller and smaller surface area where granules can accumulate. Altogether, however, grit distribution patterns indicate that aerial application is a viable tool for disseminating MCA in corn fields.

Differential effects of RNAi treatments on field populations of the western corn rootworm.

PubMed

Chu, Chia-Ching; Sun, Weilin; Spencer, Joseph L; Pittendrigh, Barry R; Seufferheld, Manfredo J

2014-03-01

RNA interference (RNAi) mediated crop protection against insect pests is a technology that is greatly anticipated by the academic and industrial pest control communities. Prior to commercialization, factors influencing the potential for evolution of insect resistance to RNAi should be evaluated. While mutations in genes encoding the RNAi machinery or the sequences targeted for interference may serve as a prominent mechanism of resistance evolution, differential effects of RNAi on target pests may also facilitate such evolution. However, to date, little is known about how variation of field insect populations could influence the effectiveness of RNAi treatments. To approach this question, we evaluated the effects of RNAi treatments on adults of three western corn rootworm (WCR; Diabrotica virgifera virgifera LeConte) populations exhibiting different levels of gut cysteine protease activity, tolerance of soybean herbivory, and immune gene expression; two populations were collected from crop rotation-resistant (RR) problem areas and one from a location where RR was not observed (wild type; WT). Our results demonstrated that RNAi targeting DvRS5 (a highly expressed cysteine protease gene) reduced gut cysteine protease activity in all three WCR populations. However, the proportion of the cysteine protease activity that was inhibited varied across populations. When WCR adults were treated with double-stranded RNA of an immune gene att1, different changes in survival among WT and RR populations on soybean diets occurred. Notably, for both genes, the sequences targeted for RNAi were the same across all populations examined. These findings indicate that the effectiveness of RNAi treatments could vary among field populations depending on their physiological and genetic backgrounds and that the consistency of an RNAi trait's effectiveness on phenotypically different populations should be considered or tested prior to wide deployment. Also, genes that are potentially subjected to differential selection in the field should be avoided for RNAi-based pest control. Published by Elsevier Inc.

Visibility of bony structures around hip prostheses in dual-energy CT: With or without metal artefact reduction software.

PubMed

Jeong, Jewon; Kim, Hyun-Joo; Oh, Eunsun; Cha, Jang Gyu; Hwang, Jiyoung; Hong, Seong Sook; Chang, Yun Woo

2018-05-23

The development of dual-energy CT and metal artefact reduction software provides a further chance of reducing metal-related artefacts. However, there have been only a few studies regarding whether MARs practically affect visibility of structures around a metallic hip prosthesis on post-operative CT evaluation. Twenty-seven patients with 42 metallic hip prostheses underwent DECT. The datasets were reconstructed with 70, 90 and 110 keV with and without MARs. The areas were classified into 10 zones according to the reference zone. All the images were reviewed in terms of the severity of the beam-hardening artefacts, differentiation of the bony cortex and trabeculae and visualization of trabecular patterns with a three-point scale. The metallic screw diameter was measured in the acetabulum with 110 keV images. The scores were the worst on 70 keV images without MARs [mean scores:1.84-4.22 (p < 0.001-1.000)]. The structures in zone II were best visualized on 110 keV (p < 0.001-0.011, mean scores: 2.86-5.22). In other zones, there is general similarity in mean scores whether applying MARs or not (p < 0.001-0.920). The mean diameter of the screw was 5.85 mm without MARs and 3.44 mm with MARs (mean reference diameter: 6.48 mm). The 110 keV images without MARs are best for evaluating acetabular zone II. The visibility of the bony structures around the hip prosthesis is similar in the other zones with or without MARs regardless of keV. MARS may not be needed for the evaluation of the metallic hip prosthesis itself at sufficient high-energy levels; however, MARS still has a role in the evaluation of other soft tissues around the prosthesis. © 2018 The Royal Australian and New Zealand College of Radiologists.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Martin, R; Pan, T; Li, B

Purpose: Dual energy CT has a variety of uses in a small animal setting including quantification and enhanced visualization of contrast agent. This study aims to determine the best energy combinations for contrast enhanced DECT on the XRAD 225Cx (Precision x-ray), a small animal IGRT system with a nominal energy range of 20 – 225 kVp. Focus was placed on material density accuracy and low contrast detectability. Methods: Simulations of single energy scans of an object containing concentrations of iodine varying from 0.5 to 50 mg/ml were performed using the simulation package ImaSim. Energy spectra from 50 – 220 kVpmore » were calculated using the same software. For approximate Poisson noise modeling, mAs were chosen such that 30% of the total 10cGy dose was assigned to the low energy scan. A calibration involving projections of objects containing different thicknesses of iodine (0–0.5 mm) and water (0–50 mm) was performed for each energy and fit to a cubic equation as the calibration curve for each energy pair. Results: Contrast to noise ratios of the iodine material images and accuracies in iodine density measurements were measured. Gradual improvements in each metric were seen with increasing high energy. Larger improvements in CNR were observed for decreasing the low energy. Errors in iodine density were generally close to 5% for concentrations of iodine above 3 mg/ml but increased to around 15% for 50 kVp, likely due to its proximity to the discontinuity caused by the k-edge of iodine. Conclusion: Based on these simulations, the best energy combination for detecting low concentrations of iodine using a projection space calibration procedure is 50/200 kVp. However, if accuracy is most important 80/220 kVp is ideal, with 60/220 kVp being a good compromise to achieve both goals. Future work is necessary to verify these conclusions with physical data.« less

Sr-87/Sr-86 isotopic age determination of upper Cretaceous Santonian, Campanian and Maastrichtian chondrichthyan teeth of the Atlantic and Eastern Gulf Coastal Plains: Implications for sea level cyclicity and macrofossil time-averaging in depositional sequence lag deposits

NASA Astrophysics Data System (ADS)

Becker, Martin Andrew

1997-11-01

Unconformities and fossil rich layers are common elements in the stratigraphic architecture of upper Cretaceous sediments exposed on both the Atlantic and Eastern Gulf Coastal Plains. Contacts between the Eutaw Formation and Tombigbee Sands Member in Alabama, the Blufftown Formation and Cusseta Sands in Georgia and the Wenonah- Mt. Laurel and Navesink Formations in New Jersey are marked by erosional surfaces with overlying blankets and lenses of macrofossil residuum. These contacts correspond to bounding unconformities and transgressive lags separating Santonian-Campanian, lower Campanian-upper Campanian and Campanian-Maastrichtian depositional sequences. Regression and subsequent transgression of sea level at the top of these depositional sequences resulted in hydrodynamic sorting of sediments and fossils that had previously accumulated in shelf and lower shoreface paleoenvironments. Remobilization of sediments by shoreface retreat reworked fossil hard-parts which became concentrated above erosional surfaces as sea level rose. Because of the abundance of chondrichthyan, pelecypod and ammonite fossils, these lags have great biostratigraphic significance and provide a basis for examining time averaging in macrofossil zonation. Chondrichthyan teeth are composed of extremely durable and highly insoluble, biogenic apatite. This tooth apatite accurately records the Sr87/Sr86 isotopic signature of seawater, from which the numerical age of the teeth can be calculated using published age/concentration data. Teeth (e.g. Squalicorax kaupi, Scapanorhynchus texanus) from Santonian-Campanian lag deposits at the contact of the Eutaw Formation and Tombigbee Sands Member in Alabama yield approximate ages of 85-81 Ma. Teeth from lower-upper Campanian lag deposits at the contact of the Blufftown Formation and Cusseta Sands in Georgia yield approximate ages of 83-75 Ma. Teeth from Campanian-Maastrichtian lag deposits at the contact of the Wenonah-Mt. Laurel and Navesink Formations in New Jersey yield approximate ages of 80-76 Ma. Isotopic age determination from these chondrichthyan teeth indicate average hiatus of approximately 3-7 million years occur during the development of lag accumulations and transgressive unconformities. Santonian, Campanian and Maastrichtian macrofossils analyzed in this study are hydrodynamically stable components representing time-averaged fossil assemblages sorted together by physical processes and are not life cohorts. Abrupt appearance and disappearance of organisms found in upper Cretaceous lag deposits of the Atlantic and Eastern Gulf Coastal Plains are artifacts of a physical sorting processes associated with sea-level cyclicity.

Evaluation of Cuphea as a rotation crop for control of western corn rootworm (Coleoptera: Chrysomelidae).

PubMed

Behle, Robert W; Isbell, Terry A

2005-12-01

The ability to prevent significant root feeding damage to corn, Zea mays L., by the western corn rootworm, Diabrotica virgifera virgifera LeConte, by crop rotation with soybean, Glycine max (L.) Merr., has been lost in portions of the Corn Belt because this pest has adapted to laying eggs in soybean fields. Cuphea spp. has been proposed as a new broadleaf crop that may provide an undesirable habitat for rootworm adults because of its sticky surface and therefore may reduce or prevent oviposition in these fields. A 4-yr study (1 yr to establish seven rotation programs followed by 3 yr of evaluation) was conducted to determine whether crop rotation with Cuphea would provide cultural control of corn rootworm. In support of Cuphea as a rotation crop, fewer beetles were captured by sticky traps in plots of Cuphea over the 4 yr of this study compared with traps in corn and soybean, suggesting that fewer eggs may be laid in plots planted to Cuphea. Also, corn grown after Cuphea was significantly taller during vegetative growth, had significantly lower root damage ratings for 2 of 3 yr, and had significantly higher yields for 2 of 3 yr compared with continuous corn plots. In contrast to these benefits, growing Cuphea did not prevent economic damage to subsequent corn crops as indicated by root damage ratings > 3.0 recorded for corn plants in plots rotated from Cuphea, and sticky trap catches that exceeded the threshold of five beetles trap(-1) day(-1). Beetle emergence from corn plots rotated from Cuphea was significantly lower, not different and significantly higher compared with beetle emergence from continuous corn plots for 2002, 2003 and 2004 growing seasons, respectively. A high number of beetles were captured by emergence cages in plots planted to Cuphea, indicating that rootworm larvae may be capable of completing larval development by feeding on roots of Cuphea, although peak emergence lagged approximately 4 wk behind peak emergence from corn. Based on these data, it is unlikely that crop rotation with Cuphea will provide consistent, economical, cultural control of corn rootworm.

Influence of calcareous soil on Cry3Bb1 expression and efficacy in the field.

PubMed

Wangila, David S; Valencia J, Arnubio; Wang, Haichuan; Siegfried, Blair D; Meinke, Lance J

2017-06-01

Greater than expected injury by western corn rootworm (WCR) (Diabrotica virgifera virgifera LeConte) to Cry3Bb1 expressing maize hybrids (Zea mays L.) has been reported in southwestern Nebraska. Affected areas of some fields are often associated with high pH calcareous soils where maize growth is poor and iron chlorosis is common. As part of a comprehensive study to understand potential causes of unexpected injury, experiments were conducted during 2013 and 2014 to ascertain whether the calcareous soil conditions and associated poor maize growth negatively affect the expression of Cry3Bb1. Quantitative determination of Cry3Bb1 protein expression levels in root tissues was carried out on plants at V5-V6 growth stage using the enzyme-linked immunosorbent assay. Cry3Bb1 and non-Bt near isoline maize hybrids were artificially infested with Cry3Bb1-susceptible WCR eggs to measure survival and efficacy of Cry3Bb1 maize in calcareous and non-calcareous soils. Results showed that there was not a significant difference in expression of Cry3Bb1 protein between plants from calcareous and non-calcareous soils (18.9-21.2 µg/g fresh weight). Western corn rootworm survival was about sevenfold greater from the non-Bt isoline than Cry3Bb1 maize indicating that Cry3Bb1 performed as expected when infested with a Cry3Bb1 susceptible rootworm population. When survival from calcareous and non-calcareous soils was compared, no significant differences were observed in each soil. A significant positive correlation between soil pH and expression of Cry3Bb1 protein in roots was detected from samples collected in 2014 but not in 2013. No such correlation was found between soil pH and survival of WCR. Results suggest that Cry3Bb1 expression levels were sufficient to provide adequate root protection against WCR regardless of soil environment, indicating that lowered Cry3Bb1 expression is not a contributing factor to the greater than expected WCR injury observed in some southwestern Nebraska maize fields.

A systematic revision of Baconia Lewis (Coleoptera, Histeridae, Exosternini).

PubMed

Caterino, Michael S; Tishechkin, Alexey K

2013-01-01

Here we present a complete revision of the species of Baconia. Up until now there have been 27 species assigned to the genus (Mazur, 2011), in two subgenera (Binhister Cooman and Baconia s. str.), with species in the Neotropical, Nearctic, Palaearctic, and Oriental regions. We recognize all these species as valid and correctly assigned to the genus, and redescribe all of them. We synonymize Binhister, previously used for a polyphyletic assemblage of species with varied relationships in the genus. We move four species into Baconia from other genera, and describe 85 species as new, bringing the total for the genus to 116 species. We divide these into 12 informal species groups, leaving 13 species unplaced to group. We present keys and diagnoses for all species, as well as habitus photos and illustrations of male genitalia for nearly all. The genus now contains the following species and species groups: Baconia loricata group [Baconia loricata Lewis, 1885, B. patula Lewis, 1885, Baconia gounellei (Marseul, 1887a), Baconia jubaris (Lewis, 1901), Baconia festiva (Lewis, 1891), Baconia foliosoma sp. n., Baconia sapphirina sp. n., Baconia furtiva sp. n., Baconia pernix sp. n., Baconia applanatis sp. n., Baconia disciformis sp. n., Baconia nebulosa sp. n., Baconia brunnea sp. n.], Baconia godmani group [Baconia godmani (Lewis, 1888), Baconia venusta (J. E. LeConte, 1845), Baconia riehli (Marseul, 1862), comb. n., Baconia scintillans sp. n., Baconia isthmia sp. n., Baconia rossi sp. n., Baconia navarretei sp. n., Baconia maculata sp. n., Baconia deliberata sp. n., Baconia excelsa sp. n., Baconia violacea (Marseul, 1853), Baconia varicolor (Marseul, 1887b), Baconia dives (Marseul, 1862), Baconia eximia (Lewis, 1888), Baconia splendida sp. n., Baconia jacinta sp. n., Baconia prasina sp. n., Baconia opulenta sp. n., Baconia illustris (Lewis, 1900), Baconia choaspites (Lewis, 1901), Baconia lewisi Mazur, 1984], Baconia salobrus group [Baconia salobrus (Marseul, 1887b), Baconia turgifrons sp. n., Baconia crassa sp. n., Baconia anthracina sp. n., Baconia emarginata sp. n., Baconia obsoleta sp. n.], Baconia ruficauda group [Baconia ruficauda sp. n., Baconia repens sp. n.], Baconia angusta group [Baconia angusta Schmidt, 1893a, Baconia incognita sp. n., Baconia guartela sp. n., Baconia bullifrons sp. n., Baconia cavei sp. n., Baconia subtilis sp. n., Baconia dentipes sp. n., Baconia rubripennis sp. n., Baconia lunatifrons sp. n.], Baconia aeneomicans group [Baconia aeneomicans (Horn, 1873), Baconia pulchella sp. n., Baconia quercea sp. n., Baconia stephani sp. n., Baconia irinae sp. n., Baconia fornix sp. n., Baconia slipinskii Mazur, 1981, Baconia submetallica sp. n., Baconia diminua sp. n., Baconia rufescens sp. n., Baconia punctiventer sp. n., Baconia aulaea sp. n., Baconia mustax sp. n., Baconia plebeia sp. n., Baconia castanea sp. n., Baconia lescheni sp. n., Baconia oblonga sp. n., Baconia animata sp. n., Baconia teredina sp. n., Baconia chujoi (Cooman, 1941), Baconia barbarus (Cooman, 1934), Baconia reposita sp. n., Baconia kubani sp. n., Baconia wallacea sp. n., Baconia bigemina sp. n., Baconia adebratti sp. n., Baconia silvestris sp. n.], Baconia cylindrica group [Baconia cylindrica sp. n., Baconia chatzimanolisi sp. n.], Baconia gibbifer group [Baconia gibbifer sp. n., B. piluliformis sp. n., Baconia maquipucunae sp. n., Baconia tenuipes sp. n., Baconia tuberculifer sp. n., Baconia globosa sp. n.], Baconia insolita group [Baconia insolita (Schmidt, 1893a), comb. n., Baconia burmeisteri (Marseul, 1870), Baconia tricolor sp. n., Baconia pilicauda sp. n.], Baconia riouka group [Baconia riouka (Marseul, 1861), Baconia azuripennis sp. n.], Baconia famelica group [Baconia famelica sp. n., Baconia grossii sp. n., Baconia redemptor sp. n., Baconia fortis sp. n., Baconia longipes sp. n., Baconia katieae sp. n., Baconia cavifrons (Lewis, 1893), comb. n., Baconia haeterioides sp. n.], Baconia micans group [Baconia micans (Schmidt, 1889a), Baconia carinifrons sp. n., Baconia fulgida (Schmidt, 1889c)], Baconia incertae sedis [Baconia chilense (Redtenbacher, 1867), Baconia glauca (Marseul, 1884), Baconia coerulea (Bickhardt, 1917), Baconia angulifrons sp. n., Baconia sanguinea sp. n., Baconia viridimicans (Schmidt, 1893b), Baconia nayarita sp. n., Baconia viridis sp. n., Baconia purpurata sp. n., Baconia aenea sp. n., Baconia clemens sp. n., Baconia leivasi sp. n., Baconia atricolor sp. n.]. We designate lectotypes for the following species: Baconia loricata Lewis, 1885,Phelister gounellei Marseul, 1887, Baconia jubaris Lewis, 1901, Baconia festiva Lewis, 1891, Platysoma venustum J.E. LeConte, 1845, Phelister riehli Marseul, 1862, Phelister violaceus Marseul, 1853, Phelister varicolor Marseul, 1887b, Phelister illustris Lewis, 1900, Baconia choaspites Lewis, 1901, Epierus festivus Lewis, 1898, Phelister salobrus Marseul, 1887, Baconia angusta Schmidt, 1893a, Phelister insolitus Schmidt, 1893a, Pachycraerus burmeisteri Marseul, 1870, Phelister riouka Marseul, 1861, Homalopygus cavifrons Lewis, 1893, Phelister micans Schmidt, 1889a, Phelister coeruleus Bickhardt, 1917, and Phelister viridimicans Schmidt, 1893b. We designate neotypes for Baconia patula Lewis, 1885 and Hister aeneomicans Horn, 1873, whose type specimens are lost.

A systematic revision of Baconia Lewis (Coleoptera, Histeridae, Exosternini)

PubMed Central

Caterino, Michael S.; Tishechkin, Alexey K.

2013-01-01

Abstract Here we present a complete revision of the species of Baconia. Up until now there have been 27 species assigned to the genus (Mazur, 2011), in two subgenera (Binhister Cooman and Baconia s. str.), with species in the Neotropical, Nearctic, Palaearctic, and Oriental regions. We recognize all these species as valid and correctly assigned to the genus, and redescribe all of them. We synonymize Binhister, previously used for a polyphyletic assemblage of species with varied relationships in the genus. We move four species into Baconia from other genera, and describe 85 species as new, bringing the total for the genus to 116 species. We divide these into 12 informal species groups, leaving 13 species unplaced to group. We present keys and diagnoses for all species, as well as habitus photos and illustrations of male genitalia for nearly all. The genus now contains the following species and species groups: Baconia loricata group [Baconia loricata Lewis, 1885, B. patula Lewis, 1885, Baconia gounellei (Marseul, 1887a), Baconia jubaris (Lewis, 1901), Baconia festiva (Lewis, 1891), Baconia foliosoma sp. n., Baconia sapphirina sp. n., Baconia furtiva sp. n., Baconia pernix sp. n., Baconia applanatis sp. n., Baconia disciformis sp. n., Baconia nebulosa sp. n., Baconia brunnea sp. n.], Baconia godmani group [Baconia godmani (Lewis, 1888), Baconia venusta (J. E. LeConte, 1845), Baconia riehli (Marseul, 1862), comb. n., Baconia scintillans sp. n., Baconia isthmia sp. n., Baconia rossi sp. n., Baconia navarretei sp. n., Baconia maculata sp. n., Baconia deliberata sp. n., Baconia excelsa sp. n., Baconia violacea (Marseul, 1853), Baconia varicolor (Marseul, 1887b), Baconia dives (Marseul, 1862), Baconia eximia (Lewis, 1888), Baconia splendida sp. n., Baconia jacinta sp. n., Baconia prasina sp. n., Baconia opulenta sp. n., Baconia illustris (Lewis, 1900), Baconia choaspites (Lewis, 1901), Baconia lewisi Mazur, 1984], Baconia salobrus group [Baconia salobrus (Marseul, 1887b), Baconia turgifrons sp. n., Baconia crassa sp. n., Baconia anthracina sp. n., Baconia emarginata sp. n., Baconia obsoleta sp. n.], Baconia ruficauda group [Baconia ruficauda sp. n., Baconia repens sp. n.], Baconia angusta group [Baconia angusta Schmidt, 1893a, Baconia incognita sp. n., Baconia guartela sp. n., Baconia bullifrons sp. n., Baconia cavei sp. n., Baconia subtilis sp. n., Baconia dentipes sp. n., Baconia rubripennis sp. n., Baconia lunatifrons sp. n.], Baconia aeneomicans group [Baconia aeneomicans (Horn, 1873), Baconia pulchella sp. n., Baconia quercea sp. n., Baconia stephani sp. n., Baconia irinae sp. n., Baconia fornix sp. n., Baconia slipinskii Mazur, 1981, Baconia submetallica sp. n., Baconia diminua sp. n., Baconia rufescens sp. n., Baconia punctiventer sp. n., Baconia aulaea sp. n., Baconia mustax sp. n., Baconia plebeia sp. n., Baconia castanea sp. n., Baconia lescheni sp. n., Baconia oblonga sp. n., Baconia animata sp. n., Baconia teredina sp. n., Baconia chujoi (Cooman, 1941), Baconia barbarus (Cooman, 1934), Baconia reposita sp. n., Baconia kubani sp. n., Baconia wallacea sp. n., Baconia bigemina sp. n., Baconia adebratti sp. n., Baconia silvestris sp. n.], Baconia cylindrica group [Baconia cylindrica sp. n., Baconia chatzimanolisi sp. n.], Baconia gibbifer group [Baconia gibbifer sp. n., B. piluliformis sp. n., Baconia maquipucunae sp. n., Baconia tenuipes sp. n., Baconia tuberculifer sp. n., Baconia globosa sp. n.], Baconia insolita group [Baconia insolita (Schmidt, 1893a), comb. n., Baconia burmeisteri (Marseul, 1870), Baconia tricolor sp. n., Baconia pilicauda sp. n.], Baconia riouka group [Baconia riouka (Marseul, 1861), Baconia azuripennis sp. n.], Baconia famelica group [Baconia famelica sp. n., Baconia grossii sp. n., Baconia redemptor sp. n., Baconia fortis sp. n., Baconia longipes sp. n., Baconia katieae sp. n., Baconia cavifrons (Lewis, 1893), comb. n., Baconia haeterioides sp. n.], Baconia micans group [Baconia micans (Schmidt, 1889a), Baconia carinifrons sp. n., Baconia fulgida (Schmidt, 1889c)], Baconia incertae sedis [Baconia chilense (Redtenbacher, 1867), Baconia glauca (Marseul, 1884), Baconia coerulea (Bickhardt, 1917), Baconia angulifrons sp. n., Baconia sanguinea sp. n., Baconia viridimicans (Schmidt, 1893b), Baconia nayarita sp. n., Baconia viridis sp. n., Baconia purpurata sp. n., Baconia aenea sp. n., Baconia clemens sp. n., Baconia leivasi sp. n., Baconia atricolor sp. n.]. We designate lectotypes for the following species: Baconia loricata Lewis, 1885,Phelister gounellei Marseul, 1887, Baconia jubaris Lewis, 1901, Baconia festiva Lewis, 1891, Platysoma venustum J.E. LeConte, 1845, Phelister riehli Marseul, 1862, Phelister violaceus Marseul, 1853, Phelister varicolor Marseul, 1887b, Phelister illustris Lewis, 1900, Baconia choaspites Lewis, 1901, Epierus festivus Lewis, 1898, Phelister salobrus Marseul, 1887, Baconia angusta Schmidt, 1893a, Phelister insolitus Schmidt, 1893a, Pachycraerus burmeisteri Marseul, 1870, Phelister riouka Marseul, 1861, Homalopygus cavifrons Lewis, 1893, Phelister micans Schmidt, 1889a, Phelister coeruleus Bickhardt, 1917, and Phelister viridimicans Schmidt, 1893b. We designate neotypes for Baconia patula Lewis, 1885 and Hister aeneomicans Horn, 1873, whose type specimens are lost. PMID:24194656

TH-CD-202-03: Enhancing Soft-Tissue CT Contrast for Radiation Therapy Using Mono-Energetic Decompositions of Dual Energy CT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Noid, G; Tai, A; Liu, Y

Purpose: It is desirable to increase CT soft-tissue contrast to improve delineation of tumor target and/or surrounding organs at risk (OAR) in RT planning and delivery guidance. The purpose of this work is to investigate the use of monoenergetic decompositions obtained from dual energy (DE) CT to improve soft-tissue contrast. Methods: CT data were acquired for 5 prostate and 5 pancreas patients and a phantom with a CT Scanner (Definition AS Open, Siemens) using both sequential DE protocols and standard protocols. For the DE protocols, the scanner rapidly performs two acquisitions at 80 kVp and 140 kVp. The CT numbersmore » of soft tissue inserts in the phantom (CTED/Gammex) were measured across the spectrum of available monoenergetic decompositions (40 to 140 keV) and compared to the standard protocol (120 kVp, 0.6 pitch, 18 mGy CTDIvol). Contrast, defined as the difference in the average CT number between target and OAR, was measured for all subjects and compared between the DE and standard protocols. Results: Mono-energetic decompositions of the phantom demonstrate an enhancement of soft-tissue contrast as the energy is decreased. For instance, relative to the 120 kVp scans the Liver ED insert increased in CT number by 25 HU while the adipose ED insert decreased by 50 HU. The lowest energy decompositions featured the highest contrast between target and OAR. For every patient, the contrast increased by decomposing at 40 keV. The average increase in contrast relative to a 120 kVp scan for prostate patients at 40 keV was 25.05±17.28 HU while for pancreas patients it was 19.21±17.39 HU. Conclusion: Low energy monoenergetic decompositions from dual-energy CT substantially increase soft-tissue contrast. At the lowest achievable monoenergetic decompositions the maximum soft-tissue contrast is achieved and the delineation of target and OAR is improved. Thus it is beneficial to use DECT in radiation oncology. Supported by Siemens.« less

An assessment of the autonomic nervous system in the electrohypersensitive population: a heart rate variability and skin conductance study.

PubMed

Andrianome, Soafara; Gobert, Jonathan; Hugueville, Laurent; Stéphan-Blanchard, Erwan; Telliez, Frederic; Selmaoui, Brahim

2017-11-01

The aim of the study was twofold: first, to compare the activity of the autonomic nervous system (ANS) between the population self-declared as electrohypersensitive (EHS) and their matched control individuals without intended exposure to electromagnetic fields (EMF). The second objective was to determine whether acute exposure to different radiofrequency signals modifies ANS activity in EHS. For that purpose, two different experiments were undertaken, in which ANS activity was assessed through heart rate variability (HRV) and skin conductance (SC). In the first experiment, a comparison between the EHS group ( n = 30) and the control group ( n = 25) showed that the EHS has an increased number of responses to auditory stimuli as measured by skin conductance activity, and that none of the short-term heart rate variability parameters differ between the two matched study groups. The second experiment, performed in a shielded chamber, involved 10 EHS from the first experiment. The volunteers participated in two different sessions (sham and exposure). The participants were consecutively exposed to four EMF signals (GSM 900, GSM 1800, DECT, and Wi-Fi) at environmental level (1 V/m). The experiment was double blinded and counterbalanced. The HRV variables studied did not differ between the two sessions. Concerning electrodermal activity, the data issued from skin conductance and tonic activity did not differ between the sessions, but showed a time variability. In conclusion, the HRV and SC profiles did not significantly differ between the EHS and control populations under no exposure. Exposure did not have an effect on the ANS parameters we have explored. NEW & NOTEWORTHY This study provided analysis on the skin conductance parameters using a newly developed method (peak/min, extraction of skin conductance responses) that had not been performed previously. Additionally, the skin conductance signal was decomposed, considering tonic and phasic activities to be a distinct compound. Moreover, this is the first time a study has been designed into two steps to understand whether the autonomic nervous system is disturbed in the EHS population. Copyright © 2017 the American Physiological Society.

Nebria brevicollis (Fabricius, 1792) in North America, benign or malign? (Coleoptera, Carabidae, Nebriini).

PubMed

Labonte, James R

2011-01-01

Nebria brevicollis (Fabricius) is one of the most frequently encountered and widely distributed carabid beetles in Europe. Until recently, the only North American records were based on two single specimens, both from the 1930's in southeastern Canada. In 2008, this species was found at thirteen different sites in five counties in northwestern Oregon. As of the end of 2010, it has been found in thirty-four different sites in ten Oregon counties, with a north-south range of ~150 km and an east-west range of ~90 km. It was also detected in 2010 in southwestern Washington (Vancouver), just north of Portland and the Columbia River.The ecological amplitude of Nebria brevicollis in Oregon rivals that of the most eurytopic native carabid species, e.g., Pterostichus algidus LeConte and Scaphinotus marginatus (Fischer von Waldheim). It has been found in highly degraded heavy industrial sites, agricultural fields, city parks, gardens, second growth woodlands, mature conifer forests, montane rock gardens, and otherwise pristine stands of old growth noble fir, with elevations ranging from essentially sea level to 1,249 meters. Climates at these locales vary from that of the Mediterranean Willamette Valley floor, where snow rarely occurs and summers are hot and dry, to the summit of the Oregon Coast Range, where deep snow may be present from November through April and summers are cool. The carabid communities in which Nebria brevicollis has been found range from those predominantly of fellow exotic species, e.g., at heavily perturbed sites, to those where it is the only exotic species, such as at the Coast Range summit.Nebria brevicollis is clearly an invasive species in that it is not restricted to anthropogenic habitats, is rapidly expanding its North American range, and can be abundant in essentially pristine settings. What is not yet clear is whether it is or will become a damaging species. Although it is already the most abundant carabid species in some settings, based upon pitfall catches, it is unknown whether this represents competitive superiority, trap vulnerability, or utilization of previously untapped or non-limiting resources. Deleterious ecological effects could include not only competition with other predators (including other carabid species) in agricultural and natural settings but also predation upon non-adult stages of threatened and endangered species of butterflies.