1,367 research outputs found
Observations of bubbles in natural seep flares at MC 118 and GC 600 using in situ quantitative imaging
Author Posting. © American Geophysical Union, 2016. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Oceans 121 (2016): 2203–2230, doi:10.1002/2015JC011452.This paper reports the results of quantitative imaging using a stereoscopic, high-speed camera system at two natural gas seep sites in the northern Gulf of Mexico during the Gulf Integrated Spill Research G07 cruise in July 2014. The cruise was conducted on the E/V Nautilus using the ROV Hercules for in situ observation of the seeps as surrogates for the behavior of hydrocarbon bubbles in subsea blowouts. The seeps originated between 890 and 1190 m depth in Mississippi Canyon block 118 and Green Canyon block 600. The imaging system provided qualitative assessment of bubble behavior (e.g., breakup and coalescence) and verified the formation of clathrate hydrate skins on all bubbles above 1.3 m altitude. Quantitative image analysis yielded the bubble size distributions, rise velocity, total gas flux, and void fraction, with most measurements conducted from the seafloor to an altitude of 200 m. Bubble size distributions fit well to lognormal distributions, with median bubble sizes between 3 and 4.5 mm. Measurements of rise velocity fluctuated between two ranges: fast-rising bubbles following helical-type trajectories and bubbles rising about 40% slower following a zig-zag pattern. Rise speed was uncorrelated with hydrate formation, and bubbles following both speeds were observed at both sites. Ship-mounted multibeam sonar provided the flare rise heights, which corresponded closely with the boundary of the hydrate stability zone for the measured gas compositions. The evolution of bubble size with height agreed well with mass transfer rates predicted by equations for dirty bubbles.Gulf of Mexico Research Initiativ
Affective Systems Induce Formal Thought Disorder in Early-Stage Psychosis
Although formal thought disorder (FTD) has been described since early conceptualizations of psychosis, its underlying mechanisms are unclear. Evidence suggests FTD may be influenced by affective and cognitive systems; however, few have examined these relationships—with none focusing on early-stage psychosis (EP). In this study, positive FTD and speech production were measured in sex- and race-matched EP (n = 19) and healthy control (n = 19) groups by assessing “reactivity”—a change in experimental compared with baseline conditions—across baseline, affective, and cognitive conditions. Relationships with functioning were also examined within each group. Three key findings emerged: (a) the EP group displayed large differences in positive FTD and speech production, (b) those with EP exhibited affective reactivity for positive FTD, and (c) positive FTD and affective reactivity were linked with poor real-world functioning in EP and these relationships did not considerably change when controlling for positive symptom (e.g., delusions, hallucinations) severity. Our findings provide preliminary evidence that affective, but not cognitive, systems play a critical role in positive FTD. Affective reactivity, in particular, may aid in predicting those with EP who go on to develop serious social impairments. Future work should focus on whether affective systems differentially influence those at separate points on the psychosis-spectrum in an effort to establish evidence-based treatments for FTD
Fukushima 137Cs at the base of planktonic food webs off Japan
© The Author(s), 2015. This is the author's version of the work and is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Deep Sea Research Part I: Oceanographic Research Papers 106 (2015): 9-16, doi:10.1016/j.dsr.2015.09.006.The potential bioaccumulation of 137Cs in marine food webs off Japan became a concern
following the release of radioactive contaminants from the damaged Fukushima nuclear power
plant into the coastal ocean. Previous studies suggest that 137Cs activities increase with trophic
level in pelagic food webs, however, the bioaccumulation of 137Cs from seawater to primary
producers, to zooplankton has not been evaluated in the field. Since phytoplankton are
frequently the largest component of SPM (suspended particulate matter) we used SPM
concentrations and particle-associated 137Cs to understand bioaccumulation of 137Cs in through
trophic pathways in the field. We determined particle-associated 137Cs for samples collected at
20 m depth from six stations off Japan three months after the initial release from the Fukushima
nuclear power plant. At 20 m SPM ranged from 0.65 to 1.60 mg L-1 and rapidly declined with
depth. The ratios of particulate organic carbon to chlorophyll a suggested that phytoplankton
comprised much of the SPM in these samples. 137Cs activities on particles accounted for on
average 0.04% of the total 137Cs in seawater samples, and measured concentration factors of
137Cs on small suspended particles were comparatively low (~102). However, when 137Cs in
crustacean zooplankton was derived based only on modeling dietary 137Cs uptake, we found
predicted and measured 137Cs concentrations in good agreement. We therefore postulate the
possibility that the dietary route of 137Cs bioaccumulation (i.e., phytoplankton ingestion) could
be largely responsible for the measured levels in the copepod-dominated (%) zooplankton
assemblages in Japanese coastal waters. Finally, our data did not support the notion that
zooplankton grazing on phytoplankton results in a biomagnification of 137Cs.This project was funded by the Gordon and Betty Moore Foundation through Grants GBMF3007
and GBMF 3423, and JSPS KAKENHI Grant-in-Aid for Scientific Research on Innovative
Areas Grant Number 24110005.2016-09-2
Microbial iron uptake as a mechanism for dispersing iron from deep-sea hydrothermal vents
Author Posting. © The Author(s), 2014. This is the author's version of the work. It is posted here by permission of Nature Publishing Group for personal use, not for redistribution. The definitive version was published in Nature Communications 5 (2014): 3192, doi:10.1038/ncomms4192.Deep-sea hydrothermal vents are a significant source of oceanic iron. Although
hydrothermal iron rapidly precipitates as inorganic minerals upon mixing with
seawater, it can be stabilized by organic matter and dispersed more widely than
previously recognized. The nature and source of this organic matter is unknown.
Here we show that microbial genes involved in cellular iron uptake are highly
expressed in the Guaymas Basin deep-sea hydrothermal plume. The nature of
these microbial iron transporters, taken together with the low concentration of
dissolved iron and abundance of particulate iron in the plume, indicates that
iron minerals are the target for this microbial scavenging and uptake. Our
findings indicate that cellular iron uptake is a major process in plume microbial
communities and suggest new mechanisms for generating Fe-C complexes. This
“microbial iron pump” could represent an important mode of converting
hydrothermal iron into bioavailable forms that can be dispersed through the
oceans.This project is funded by the Gordon and Betty Moore
Foundation through grant GBMF 2609 to GJD/JAB/BMT and by the National
Science Foundation through grants OCE 1029242 to GJD, and R2K grant
OCE1038055 to JAB/BMT. We thank the University of Michigan Rackham Graduate
School Faculty Research Fellowship Program for their support.2014-08-0
Accessing Healthfulness through Intrapersonal Communication: The Correlations between Health Locus of Control and Health Outcomes, Behaviors, and Perceptions
The problem that the current study addressed was the absence of an intrapersonal health communication guide that profiled the different types of locus of control and the health outcomes, behaviors and perceptions that are associated with each type for individuals diagnosed with MS. Individuals suffering from MS and their healthcare providers do not understand the correlation between health beliefs and physical and emotional health. The research questions were designed to examine the relationship between these variables. Recruiting was completed through a social media based methodology that included online MS communities, Craigslist, Facebook, and Twitter. In total, 164 participants were recruited for the study. Participants completed an online survey that consisted of the Multidimensional Health Locus of Control Scale, the 36-Item Short Form Health Survey, the CAM usage questionnaire, and the Health Care Climate Questionnaire. Correlational analysis was used to determine that internal health locus of control was associated with improved general health, less pain, better physical, emotional, and social functioning, and more energy. Increased self-rated health was found to be correlated with increased acupuncture and yoga use, and less usage of general practitioners, hospitals, over-the counter medications, and pharmaceutical medications. This study has implications for physicians who can utilize the health beliefs of patients in the clinical setting and for the design and implementation of participatory intervention programs to assist individuals diagnosed with MS in recognizing the potential power of their health beliefs
Locomotor hyperactivity in 14-3-3Zeta KO mice is associated with dopamine transporter dysfunction
Dopamine (DA) neurotransmission requires a complex series of enzymatic reactions that are tightly linked to catecholamine exocytosis and receptor interactions on pre- and postsynaptic neurons. Regulation of dopaminergic signalling is primarily achieved through reuptake of extracellular DA by the DA transporter (DAT) on presynaptic neurons. Aberrant regulation of DA signalling, and in particular hyperactivation, has been proposed as a key insult in the presentation of schizophrenia and related neuropsychiatric disorders. We recently identified 14-3-3ζ as an essential component of neurodevelopment and a central risk factor in the schizophrenia protein interaction network. Our analysis of 14-3-3ζ-deficient mice now shows that baseline hyperactivity of knockout (KO) mice is rescued by the antipsychotic drug clozapine. 14-3-3ζ KO mice displayed enhanced locomotor hyperactivity induced by the DA releaser amphetamine. Consistent with 14-3-3ζ having a role in DA signalling, we found increased levels of DA in the striatum of 14-3-3ζ KO mice. Although 14-3-3ζ is proposed to modulate activity of the rate-limiting DA biosynthesis enzyme, tyrosine hydroxylase (TH), we were unable to identify any differences in total TH levels, TH localization or TH activation in 14-3-3ζ KO mice. Rather, our analysis identified significantly reduced levels of DAT in the absence of notable differences in RNA or protein levels of DA receptors D1–D5. Providing insight into the mechanisms by which 14-3-3ζ controls DAT stability, we found a physical association between 14-3-3ζ and DAT by co-immunoprecipitation. Taken together, our results identify a novel role for 14-3-3ζ in DA neurotransmission and provide support to the hyperdopaminergic basis of pathologies associated with schizophrenia and related disorders.H Ramshaw, X Xu, EJ Jaehne, P McCarthy, Z Greenberg, E Saleh, B McClure, J Woodcock, S Kabbara, S Wiszniak, Ting-Yi Wang, C Parish, M van den Buuse, BT Baune, A Lopez and Q Schwar
Accessing Healthfulness Through Intrapersonal Communication: The Correlations Between Health Locus of Control and Health Outcomes Behaviors, and Perceptions
Accessing Healthfulness Through Intrapersonal Communication: The Correlations Between Health Locus of Control and Health Outcomes Behaviors, and Perceptions
The problem that the current study addressed was the absence of an intrapersonal health communication guide that profiled the different types of locus of control and the health outcomes, behaviors and perceptions that are associated with each type for individuals diagnosed with MS. Individuals suffering from MS and their healthcare providers do not understand the correlation between health beliefs and physical and emotional health. The research questions were designed to examine the relationship between these variables. Recruiting was completed through a social media based methodology that included online MS communities, Craigslist, Facebook, and Twitter. In total, 164 participants were recruited for the study. Participants completed an online survey that consisted of the Multidimensional Health Locus of Control Scale, the 36-Item Short Form Health Survey, the CAM usage questionnaire, and the Health Care Climate Questionnaire. Correlational analysis was used to determine that internal health locus of control was associated with improved general health, less pain, better physical, emotional, and social functioning, and more energy. Increased self-rated health was found to be correlated with increased acupuncture and yoga use, and less usage of general practitioners, hospitals, over-the counter medications, and pharmaceutical medications. This study has implications for physicians who can utilize the health beliefs of patients in the clinical setting and for the design and implementation of participatory intervention programs to assist individuals diagnosed with MS in recognizing the potential power of their health beliefs
Type I collagen limits VEGFR-2 signaling by a SHP2 protein-tyrosine phosphatase-dependent mechanism 1.
During angiogenesis, a combined action between newly secreted extracellular matrix proteins and the repertoire of integrins expressed by endothelial cells contributes in the regulation of their biological functions. Extracellular matrix-engaged integrins influence tyrosine kinase receptors, thus promoting a regulatory cross-talk between adhesive and soluble stimuli. For instance, vitronectin has been reported to positively regulate VEGFR-2. Here, we show that collagen I downregulates VEGF-A-mediated VEGFR-2 activation. This activity requires the tyrosine phosphatase SHP2, which is recruited to the activated VEGFR-2 when cells are plated on collagen I, but not on vitronectin. Constitutive expression of SHP2(C459S) mutant inhibits the negative role of collagen I on VEGFR-2 phosphorylation. VEGFR-2 undergoes internalisation, which is associated with dynamin II phosphorylation. Expression of SHP2(C459S) impairs receptor internalisation suggesting that SHP2-dependent dephosphorylation regulates this process. These findings demonstrate that collagen I in provisional extracellular matrix surrounding nascent capillaries triggers a signaling pathway that negatively regulates angiogenesis
Temporal lobe white matter asymmetry and language laterality in epilepsy patients.
Recent studies using diffusion tensor imaging (DTI) have advanced our knowledge of the organization of white matter subserving language function. It remains unclear, however, how DTI may be used to predict accurately a key feature of language organization: its asymmetric representation in one cerebral hemisphere. In this study of epilepsy patients with unambiguous lateralization on Wada testing (19 left and 4 right lateralized subjects; no bilateral subjects), the predictive value of DTI for classifying the dominant hemisphere for language was assessed relative to the existing standard-the intra-carotid Amytal (Wada) procedure. Our specific hypothesis is that language laterality in both unilateral left- and right-hemisphere language dominant subjects may be predicted by hemispheric asymmetry in the relative density of three white matter pathways terminating in the temporal lobe implicated in different aspects of language function: the arcuate (AF), uncinate (UF), and inferior longitudinal fasciculi (ILF). Laterality indices computed from asymmetry of high anisotropy AF pathways, but not the other pathways, classified the majority (19 of 23) of patients using the Wada results as the standard. A logistic regression model incorporating information from DTI of the AF, fMRI activity in Broca\u27s area, and handedness was able to classify 22 of 23 (95.6%) patients correctly according to their Wada score. We conclude that evaluation of highly anisotropic components of the AF alone has significant predictive power for determining language laterality, and that this markedly asymmetric distribution in the dominant hemisphere may reflect enhanced connectivity between frontal and temporal sites to support fluent language processes. Given the small sample reported in this preliminary study, future research should assess this method on a larger group of patients, including subjects with bi-hemispheric dominance
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