3,788 research outputs found

    Mercury in tunas and blue marlin in the North Pacific Ocean

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    Models and data from the North Pacific Ocean indicate that mercury concentrations in water and biota are increasing in response to (global or hemispheric) anthropogenic mercury releases. In the present study, we provide an updated record of mercury in yellowfin tuna (Thunnus albacares) caught near Hawaii that confirms an earlier conclusion that mercury concentrations in these fish are increasing at a rate similar to that observed in waters shallower than 1000 m. We also compiled and reanalyzed data from bigeye tuna (Thunnus obesus) and blue marlin (Makaira nigricans) caught near Hawaii in the 1970s and 2000s. Increases in mercury concentrations in bigeye tuna are consistent with the trend found in yellowfin tuna, in both timing and magnitude. The data available for blue marlin do not allow for a fair comparison among years, because mercury concentrations differ between sexes for this species, and sex was identified (or reported) in only 3 of 7 studies. Also, mercury concentrations in blue marlin may be insensitive to modest changes in mercury exposure, because this species appears to have the ability to detoxify mercury. The North Pacific Ocean is a region of both relatively high rates of atmospheric mercury deposition and capture fisheries production. Other data sets that allow temporal comparisons in mercury concentrations, such as pacific cod (Gadus macrocephalus) in Alaskan waters and albacore tuna (Thunnus alalunga) off the US Pacific coast, should be explored further, to aid in understanding human health and ecological risks and to develop additional baseline knowledge for assessing changes in a region expected to respond strongly to reductions in anthropogenic mercury emissions. Environ Toxicol Chem 2017;36:1365–1374. © 2017 SETACPeer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/136698/1/etc3757_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/136698/2/etc3757.pd

    Lactate: brain fuel in human traumatic brain injury: a comparison with normal healthy control subjects.

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    We evaluated the hypothesis that lactate shuttling helps support the nutritive needs of injured brains. To that end, we utilized dual isotope tracer [6,6-(2)H2]glucose, that is, D2-glucose, and [3-(13)C]lactate techniques involving arm vein tracer infusion along with simultaneous cerebral (arterial [art] and jugular bulb [JB]) blood sampling. Traumatic brain injury (TBI) patients with nonpenetrating brain injuries (n=12) were entered into the study following consent of patients' legal representatives. Written and informed consent was obtained from control volunteers (n=6). Patients were studied 5.7±2.2 (mean±SD) days post-injury; during periods when arterial glucose concentration tended to be higher in TBI patients. As in previous investigations, the cerebral metabolic rate for glucose (CMRgluc, i.e., net glucose uptake) was significantly suppressed following TBI (p<0.001). However, lactate fractional extraction, an index of cerebral lactate uptake related to systemic lactate supply, approximated 11% in both healthy control subjects and TBI patients. Further, neither the CMR for lactate (CMRlac, i.e., net lactate release), nor the tracer-measured cerebral lactate uptake differed between healthy controls and TBI patients. The percentages of lactate tracer taken up and released as (13)CO2 into the JB accounted for 92% and 91% for control and TBI conditions, respectively, suggesting that most cerebral lactate uptake was oxidized following TBI. Comparisons of isotopic enrichments of lactate oxidation from infused [3-(13)C]lactate tracer and (13)C-glucose produced during hepatic and renal gluconeogenesis (GNG) showed that 75-80% of (13)CO2 released into the JB was from lactate and that the remainder was from the oxidation of glucose secondarily labeled from lactate. Hence, either directly as lactate uptake, or indirectly via GNG, peripheral lactate production accounted for ∼70% of carbohydrate (direct lactate uptake+uptake of glucose from lactate) consumed by the injured brain. Undiminished cerebral lactate fractional extraction and uptake suggest that arterial lactate supplementation may be used to compensate for decreased CMRgluc following TBI

    DESI Commissioning Instrument Metrology

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    The Dark Energy Spectroscopic Instrument (DESI) is under construction to measure the expansion history of the Universe using the Baryon Acoustic Oscillation technique. The spectra of 35 million galaxies and quasars over 14000 sq deg will be measured during the life of the experiment. A new prime focus corrector for the KPNO Mayall telescope will deliver light to 5000 fiber optic positioners. The fibers in turn feed ten broad-band spectrographs. We will describe the methods and results for the commissioning instrument metrology program. The primary goals of this program are to calculate the transformations and further develop the systems that will place fibers within 5um RMS of the target positions. We will use the commissioning instrument metrology program to measure the absolute three axis Cartesian coordinates of the five CCDs and 22 illuminated fiducials on the commissioning instrument

    Endogenous Nutritive Support after Traumatic Brain Injury: Peripheral Lactate Production for Glucose Supply via Gluconeogenesis.

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    We evaluated the hypothesis that nutritive needs of injured brains are supported by large and coordinated increases in lactate shuttling throughout the body. To that end, we used dual isotope tracer ([6,6-(2)H2]glucose, i.e., D2-glucose, and [3-(13)C]lactate) techniques involving central venous tracer infusion along with cerebral (arterial [art] and jugular bulb [JB]) blood sampling. Patients with traumatic brain injury (TBI) who had nonpenetrating head injuries (n=12, all male) were entered into the study after consent of patients' legal representatives. Written and informed consent was obtained from healthy controls (n=6, including one female). As in previous investigations, the cerebral metabolic rate (CMR) for glucose was suppressed after TBI. Near normal arterial glucose and lactate levels in patients studied 5.7±2.2 days (range of days 2-10) post-injury, however, belied a 71% increase in systemic lactate production, compared with control, that was largely cleared by greater (hepatic+renal) glucose production. After TBI, gluconeogenesis from lactate clearance accounted for 67.1% of glucose rate of appearance (Ra), which was compared with 15.2% in healthy controls. We conclude that elevations in blood glucose concentration after TBI result from a massive mobilization of lactate from corporeal glycogen reserves. This previously unrecognized mobilization of lactate subserves hepatic and renal gluconeogenesis. As such, a lactate shuttle mechanism indirectly makes substrate available for the body and its essential organs, including the brain, after trauma. In addition, when elevations in arterial lactate concentration occur after TBI, lactate shuttling may provide substrate directly to vital organs of the body, including the injured brain

    Undergraduate work placements: an analysis of the effects on career progression

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    Combining work experience with degree-level study is seen as a key differentiator for securing employment upon graduation in a competitive employment market. The positive benefits of sandwich courses, where up to twelve months is spent working in industry, are widely acknowledged in academic literature though data analysis tends to focus on cohorts in single subject areas with course-based factors possibly influencing outcomes. This paper explores the benefits of work placements on a cross-cohort basis with an institutional level study empirically analysing over three academic years the outcomes for placement students in comparison to non-placement students. The study found that completing a sandwich work placement is associated with improved academic performance in the final year of study. Placement students are also more likely to secure appropriate graduate-level work and higher starting salaries upon completion of their degree in comparison to non-placement students

    Adaptive windowing in contrast-enhanced intravascular ultrasound imaging

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    Intravascular ultrasound (IVUS) is one of the most commonly-used interventional imaging techniques and has seen recent innovations which attempt to characterize the risk posed by atherosclerotic plaques. One such development is the use of microbubble contrast agents to image vasa vasorum, fine vessels which supply oxygen and nutrients to the walls of coronary arteries and typically have diameters less than 200 µm. The degree of vasa vasorum neovascularization within plaques is positively correlated with plaque vulnerability. Having recently presented a prototype dual-frequency transducer for contrast agent-specific intravascular imaging, here we describe signal processing approaches based on minimum variance (MV) beamforming and the phase coherence factor (PCF) for improving the spatial resolution and contrast-to-tissue ratio (CTR) in IVUS imaging. These approaches are examined through simulations, phantom studies, ex vivo studies in porcine arteries, and in vivo studies in chicken embryos. In phantom studies, PCF processing improved CTR by a mean of 4.2 dB, while combined MV and PCF processing improved spatial resolution by 41.7%. Improvements of 2.2 dB in CTR and 37.2% in resolution were observed in vivo. Applying these processing strategies can enhance image quality in conventional B-mode IVUS or in contrast-enhanced IVUS, where signal-to-noise ratio is relatively low and resolution is at a premium

    The Effects of God Language on Perceived Attributes of God

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    Sixty-three participants listened to an audio· tape asking them to imagine themselves in God\u27s presence. Half the participants listened to a script in which God was presented as female and half listened to a script in which God was presented as male. Half of those in each group listened to a male narrator and the other half listened to a female narrator. Before and after listening to the script, participants rated the attributes of God on a forced-choice questionnaire. Those to whom God was presented as female were more likely to emphasize God\u27s mercy at posttest whereas those to whom God was presented as male were more likely to endorse God\u27s power. Those hearing a male voice describe a female God and those hearing a female voice describe a male God reported enjoying the experiment and the audiotape more than those hearing a narrator describing a God of the same gender. Implications are discussed

    The comorbidities of dysmenorrhea: a clinical survey comparing symptom profile in women with and without endometriosis

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    Purpose: Dysmenorrhea is a common disorder that substantially disrupts the lives of young women. The frequency of 14 associated symptoms both within and outside the pelvis was determined. Patients and methods: Symptom questionnaires were completed by 168 women with dysmenorrhea, allocated to three groups based on their diagnostic status for endometriosis confirmed (Endo+), endometriosis excluded (Endo−), or endometriosis diagnosis unknown (No Lap). Those with endometriosis confirmed were further divided into current users (Endo+ Hx+) and non-users of hormonal treatments (Endo+ Hx–). Users of hormonal treatments were further divided into users (Endo+ Hx+ LIUCD+) and non-users (Endo+ Hx+ LIUCD–) of a levonorgestrel-releasing intra-uterine contraceptive device (LIUCD). The frequency and number of symptoms within groups and the effect of previous distressing sexual events were sought. Results: Women with and without endometriosis lesions had similar symptom profiles, with a mean of 8.5 symptoms per woman. Only 0.6% of women reported dysmenorrhea alone. The presence of stabbing pelvic pains was associated with more severe dysmenorrhea (P=0.006), more days per month of dysmenorrhea (P=0.003), more days per month of pelvic pain (P=0.016), and a diagnosis of migraine (P=0.054). The symptom profiles of the Endo+ Hx+ and Endo+ Hx– groups were similar. A history of distressing sexual events was associated with an increased number of pain symptoms (P=0.003). Conclusion: Additional symptoms are common in women with dysmenorrhea, and do not correlate with the presence or absence of endometriosis lesions. Our study supports the role of central sensitization in the pain of dysmenorrhea. The presence of stabbing pelvic pains was associated with increased severity of dysmenorrhea, days per month of dysmenorrhea, days per month of pelvic pain, and a diagnosis of migraine headache. A past history of distressing sexual events is associated with an increased number of pain symptoms

    Molecular Acoustic Angiography: A New Technique for High-resolution Superharmonic Ultrasound Molecular Imaging

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    Ultrasound molecular imaging utilizes targeted microbubbles to bind to vascular targets such as integrins, selectins, and other extracellular binding domains. After binding, these microbubbles are typically imaged using low pressures and multi-pulse imaging sequences. In this article, we present an alternative approach for molecular imaging using ultrasound which relies on superharmonic signals produced by microbubble contrast agents. Bound bubbles were insonified near resonance using a low frequency (4 MHz) and superharmonic echoes were received at high frequencies (25–30 MHz). While this approach was observed to produce declining image intensity during repeated imaging in both in vitro and in vivo experiments due to bubble destruction, the feasibility of superharmonic molecular imaging was demonstrated for transmit pressures which are sufficiently high to induce shell disruption in bound microbubbles. This approach was validated using microbubbles targeted to the αvβ3 integrin in a rat fibrosarcoma model (n=5), and combined with superharmonic images of free microbubbles to produce high contrast, high resolution 3D volumes of both microvascular anatomy and molecular targeting. Image intensity over repeated scans and the effect of microbubble diameter were also assessed in vivo, indicating that larger microbubbles yield increased persistence in image intensity. Using ultrasound-based acoustic angiography images rather than conventional B-mode ultrasound to provide the underlying anatomical information facilitates anatomical localization of molecular markers. Quantitative analysis of relationships between microvasculature and targeting information indicated that most targeting occurred within 50 µm of a resolvable vessel (>100 µm diameter). The combined information provided by these scans may present new opportunities for analyzing relationships between microvascular anatomy and vascular targets, subject only to limitations of the current mechanically-scanned system and microbubble persistence to repeated imaging at moderate mechanical indices
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