BDNF is essential to promote persistence of long-term memory storage

PubMed Central

Bekinschtein, Pedro; Cammarota, Martín; Katche, Cynthia; Slipczuk, Leandro; Rossato, Janine I.; Goldin, Andrea; Izquierdo, Ivan; Medina, Jorge H.

2008-01-01

Persistence is a characteristic attribute of long-term memories (LTMs). However, little is known about the molecular mechanisms that mediate this process. We recently showed that persistence of LTM requires a late protein synthesis- and BDNF-dependent phase in the hippocampus. Here, we show that intrahippocampal delivery of BDNF reverses the deficit in memory persistence caused by inhibition of hippocampal protein synthesis. Importantly, we demonstrate that BDNF induces memory persistence by itself, transforming a nonlasting LTM trace into a persistent one in an ERK-dependent manner. Thus, BDNF is not only necessary, but sufficient to induce a late postacquisition phase in the hippocampus essential for persistence of LTM storage. PMID:18263738

Interactions between prefrontal cortex and cerebellum revealed by trace eyelid conditioning.

PubMed

Kalmbach, Brian E; Ohyama, Tatsuya; Kreider, Joy C; Riusech, Frank; Mauk, Michael D

2009-01-01

Eyelid conditioning has proven useful for analysis of learning and computation in the cerebellum. Two variants, delay and trace conditioning, differ only by the relative timing of the training stimuli. Despite the subtlety of this difference, trace eyelid conditioning is prevented by lesions of the cerebellum, hippocampus, or medial prefrontal cortex (mPFC), whereas delay eyelid conditioning is prevented by cerebellar lesions and is largely unaffected by forebrain lesions. Here we test whether these lesion results can be explained by two assertions: (1) Cerebellar learning requires temporal overlap between the mossy fiber inputs activated by the tone conditioned stimulus (CS) and the climbing fiber inputs activated by the reinforcing unconditioned stimulus (US), and therefore (2) trace conditioning requires activity that outlasts the presentation of the CS in a subset of mossy fibers separate from those activated directly by the CS. By use of electrical stimulation of mossy fibers as a CS, we show that cerebellar learning during trace eyelid conditioning requires an input that persists during the stimulus-free trace interval. By use of reversible inactivation experiments, we provide evidence that this input arises from the mPFC and arrives at the cerebellum via a previously unidentified site in the pontine nuclei. In light of previous PFC recordings in various species, we suggest that trace eyelid conditioning involves an interaction between the persistent activity of delay cells in mPFC-a putative mechanism of working memory-and motor learning in the cerebellum.

Perirhinal and Postrhinal, but Not Lateral Entorhinal, Cortices Are Essential for Acquisition of Trace Eyeblink Conditioning

ERIC Educational Resources Information Center

Suter, Eugenie E.; Weiss, Craig; Disterhoft, John F.

2013-01-01

The acquisition of temporal associative tasks such as trace eyeblink conditioning is hippocampus-dependent, while consolidated performance is not. The parahippocampal region mediates much of the input and output of the hippocampus, and perirhinal (PER) and entorhinal (EC) cortices support persistent spiking, a possible mediator of temporal…

Direct demonstration of persistent Na+ channel activity in dendritic processes of mammalian cortical neurones

PubMed Central

Magistretti, Jacopo; Ragsdale, David S; Alonso, Angel

1999-01-01

Single Na+ channel activity was recorded in patch-clamp, cell-attached experiments performed on dendritic processes of acutely isolated principal neurones from rat entorhinal-cortex layer II. The distances of the recording sites from the soma ranged from ≈20 to ≈100 μm.Step depolarisations from holding potentials of −120 to −100 mV to test potentials of −60 to +10 mV elicited Na+ channel openings in all of the recorded patches (n= 16).In 10 patches, besides transient Na+ channel openings clustered within the first few milliseconds of the depolarising pulses, prolonged and/or late Na+ channel openings were also regularly observed. This ‘persistent’ Na+ channel activity produced net inward, persistent currents in ensemble-average traces, and remained stable over the entire duration of the experiments (≈9 to 30 min).Two of these patches contained <= 3 channels. In these cases, persistent Na+ channel openings could be attributed to the activity of one single channel.The voltage dependence of persistent-current amplitude in ensemble-average traces closely resembled that of whole-cell, persistent Na+ current expressed by the same neurones, and displayed the same characteristic low threshold of activation.Dendritic, persistent Na+ channel openings had relatively high single-channel conductance (≈20 pS), similar to what is observed for somatic, persistent Na+ channels.We conclude that a stable, persistent Na+ channel activity is expressed by proximal dendrites of entorhinal-cortex layer II principal neurones, and can contribute a significant low-threshold, persistent Na+ current to the dendritic processing of excitatory synaptic inputs. PMID:10601494

Dopaminergic Modulation of the Persistence of One-Trial Hippocampus-Dependent Memory

ERIC Educational Resources Information Center

O'Carroll, Colin M.; Martin, Stephen J.; Sandin, Johan; Frenguelli, Bruno; Morris, Richard G. M.

2006-01-01

The persistence of new memory traces in the hippocampus, encoded following appropriate activation of glutamatergic receptors and the induction of synaptic plasticity, can be influenced by heterosynaptic activation of neuromodulatory brain systems. We therefore investigated the effects of a hippocampus-specific blockade of dopamine D1/D5 receptors…

Changes in patterns of persistent halogenated compounds through a pelagic food web in the Baltic Sea.

PubMed

Stephansen, Diana A; Svendsen, Tore C; Vorkamp, Katrin; Frier, Jens-Ole

2012-02-01

The concentrations and patterns of persistent halogenated compounds (PHCs), including polychlorinated biphenyls (PCBs), DDT, hexachlorocyclohexanes (HCHs), hexachlorobenzene (HCB) and polybrominated diphenyl ethers (PBDEs) were examined in a pelagic food web from the southern Baltic Sea consisting of sediment, zooplankton, sprat, Atlantic salmon and anadromous brown trout. Lipid-normalized concentrations generally increased from low trophic levels to high trophic levels, with the exception of HCHs. Due to high concentrations of PBDEs in some zooplankton samples, biomagnification of BDE-47 was only observed for salmon/sprat and trout/sprat. Sprat collected individually and from salmon stomach had significantly different lipid-normalized concentrations and varied in their PHC pattern as well, possibly indicating a large natural variation within the Baltic Sea. The highest lipid-normalized concentrations were found in brown trout. Salmon and brown trout were similar in their PHC pattern suggesting similar food sources. Variation in PHC patterns among trophic levels was not smaller than that among geographically distinct locations, confirming the importance of comparable trophic levels for the assessment of PHC patterns, e.g. for tracing migratory fish. Copyright © 2011 Elsevier Ltd. All rights reserved.

Selected Organochlorines in Human Blood and Urine in the South of the Russian Far East.

PubMed

Tsygankov, Vasiliy Yu; Khristoforova, Nadezhda K; Lukyanova, Olga N; Boyarova, Margarita D; Kiku, Pavel F; Yarygina, Marina V

2017-10-01

The trace OCP concentrations, such as α-, β-, and γ-HCH, DDT and its metabolites (DDD and DDE) in blood and urine of residents from the south of the Russian Far East was revealed. A large range of OCPs was found in the urine: α- and γ-isomers of HCH, DDT and DDE. The only β-HCH was detected in the blood; this indicates its persistence and the difficulty of excretion this substance from the organism. The total trace OCP concentration, found in the biological fluids of residents of the south of the Russian Far East, providing further evidence that these organic contaminants persist in the environment.

Synaptic and nonsynaptic plasticity approximating probabilistic inference

PubMed Central

Tully, Philip J.; Hennig, Matthias H.; Lansner, Anders

2014-01-01

Learning and memory operations in neural circuits are believed to involve molecular cascades of synaptic and nonsynaptic changes that lead to a diverse repertoire of dynamical phenomena at higher levels of processing. Hebbian and homeostatic plasticity, neuromodulation, and intrinsic excitability all conspire to form and maintain memories. But it is still unclear how these seemingly redundant mechanisms could jointly orchestrate learning in a more unified system. To this end, a Hebbian learning rule for spiking neurons inspired by Bayesian statistics is proposed. In this model, synaptic weights and intrinsic currents are adapted on-line upon arrival of single spikes, which initiate a cascade of temporally interacting memory traces that locally estimate probabilities associated with relative neuronal activation levels. Trace dynamics enable synaptic learning to readily demonstrate a spike-timing dependence, stably return to a set-point over long time scales, and remain competitive despite this stability. Beyond unsupervised learning, linking the traces with an external plasticity-modulating signal enables spike-based reinforcement learning. At the postsynaptic neuron, the traces are represented by an activity-dependent ion channel that is shown to regulate the input received by a postsynaptic cell and generate intrinsic graded persistent firing levels. We show how spike-based Hebbian-Bayesian learning can be performed in a simulated inference task using integrate-and-fire (IAF) neurons that are Poisson-firing and background-driven, similar to the preferred regime of cortical neurons. Our results support the view that neurons can represent information in the form of probability distributions, and that probabilistic inference could be a functional by-product of coupled synaptic and nonsynaptic mechanisms operating over several timescales. The model provides a biophysical realization of Bayesian computation by reconciling several observed neural phenomena whose functional effects are only partially understood in concert. PMID:24782758

An inter-laboratory comparison study on transfer, persistence and recovery of DNA from cable ties.

PubMed

Steensma, Kristy; Ansell, Ricky; Clarisse, Lindy; Connolly, Edward; Kloosterman, Ate D; McKenna, Louise G; van Oorschot, Roland A H; Szkuta, Bianca; Kokshoorn, Bas

2017-11-01

To address questions on the activity that led to the deposition of biological traces in a particular case, general information on the probabilities of transfer, persistence and recovery of cellular material in relevant scenarios is necessary. These figures may be derived from experimental data described in forensic literature when conditions relevant to the case were included. The experimental methodology regarding sampling, DNA extraction, DNA typing and profile interpretation that were used to generate these published data may differ from those applied in the case and thus the applicability of the literature data may be questioned. To assess the level of variability that different laboratories obtain when similar exhibits are analysed, we performed an inter-laboratory study between four partner laboratories. Five sets of 20 cable ties bound by different volunteers were distributed to the participating laboratories and sampled and processed according to the in-house protocols. Differences were found for the amount of retrieved DNA, as well as for the reportability and composition of the DNA profiles. These differences also resulted in different probabilities of transfer, persistence and recovery for each laboratory. Nevertheless, when applied to a case example, these differences resulted in similar assignments of weight of evidence given activity-level propositions. Copyright © 2017 Elsevier B.V. All rights reserved.

Perchlorate as an emerging contaminant in soil, water and food.

PubMed

Kumarathilaka, Prasanna; Oze, Christopher; Indraratne, S P; Vithanage, Meththika

2016-05-01

Perchlorate ( [Formula: see text] ) is a strong oxidizer and has gained significant attention due to its reactivity, occurrence, and persistence in surface water, groundwater, soil and food. Stable isotope techniques (i.e., ((18)O/(16)O and (17)O/(16)O) and (37)Cl/(35)Cl) facilitate the differentiation of naturally occurring perchlorate from anthropogenic perchlorate. At high enough concentrations, perchlorate can inhibit proper function of the thyroid gland. Dietary reference dose (RfD) for perchlorate exposure from both food and water is set at 0.7 μg kg(-1) body weight/day which translates to a drinking water level of 24.5 μg L(-1). Chromatographic techniques (i.e., ion chromatography and liquid chromatography mass spectrometry) can be successfully used to detect trace level of perchlorate in environmental samples. Perchlorate can be effectively removed by wide variety of remediation techniques such as bio-reduction, chemical reduction, adsorption, membrane filtration, ion exchange and electro-reduction. Bio-reduction is appropriate for large scale treatment plants whereas ion exchange is suitable for removing trace level of perchlorate in aqueous medium. The environmental occurrence of perchlorate, toxicity, analytical techniques, removal technologies are presented. Copyright © 2016 Elsevier Ltd. All rights reserved.

Evidence Value of Textile Fiber - Transfer and Persistence of Fibers.

PubMed

Siegel, J A

1997-12-01

Fibers comprise probably the most common form of trace evidence in forensic science today. They occur in perhaps one-quarter of all cases that involve trace evidence and a large majority of crime laboratories routinely characterize textile fibers. Although a great deal of research has been done on how to best characterize and compare fibers, relatively little time has been spent on determining the significance of fiber evidence. This article presents a summary of the studies of fiber transfer and persistence and determination of the significance of fiber evidence. This accumulated research and analysis will enable fiber examiners to better interpret evidence in cases where foreign fibers have been transferred during contact between victims and perpetrators of crimes. Copyright © 1997 Central Police University.

Persistent activation of an innate immune axis translates respiratory viral infection into chronic lung disease

PubMed Central

Kim, Edy Y.; Battaile, John T.; Patel, Anand C.; You, Yingjian; Agapov, Eugene; Grayson, Mitchell H.; Benoit, Loralyn A.; Byers, Derek E.; Alevy, Yael; Tucker, Jennifer; Swanson, Suzanne; Tidwell, Rose; Tyner, Jeffrey W.; Morton, Jeffrey D.; Castro, Mario; Polineni, Deepika; Patterson, G. Alexander; Schwendener, Reto A.; Allard, John D.; Peltz, Gary; Holtzman, Michael J.

2008-01-01

To understand the pathogenesis of chronic inflammatory disease, we analyzed an experimental mouse model of a chronic lung disease that resembles asthma and chronic obstructive pulmonary disease (COPD) in humans. In this model, chronic lung disease develops after infection with a common type of respiratory virus is cleared to trace levels of noninfectious virus. Unexpectedly, the chronic inflammatory disease arises independently of an adaptive immune response and is driven by IL-13 produced by macrophages stimulated by CD1d-dependent TCR-invariant NKT cells. This innate immune axis is also activated in the lungs of humans with chronic airway disease due to asthma or COPD. These findings provide new insight into the pathogenesis of chronic inflammatory disease with the discovery that the transition from respiratory viral infection into chronic lung disease requires persistent activation of a novel NKT cell-macrophage innate immune axis. PMID:18488036

Persistent wind-induced enhancement of diffusive CO2 transport in a mountain forest snowpack

Treesearch

D. R. Bowling; W. J. Massman

2011-01-01

Diffusion dominates the transport of trace gases between soil and the atmosphere. Pressure gradients induced by atmospheric flow and wind interacting with topographical features cause a small but persistent bulk flow of air within soil or snow. This forcing, called pressure pumping or wind pumping, leads to a poorly quantified enhancement of gas transport beyond the...

Potential health and environmental effects of trace elements and radionuclides from increased coal utilization.

PubMed Central

Van Hook, R I

1979-01-01

This report addresses the effects of coal-derived trace and radioactive elements. A summary of our current understanding of health and environmental effects of trace and radioactive elements released during coal mining, cleaning, combustion, and ash disposal is presented. Physical and biological transport phenomena which are important in determining organism exposure are also discussed. Biological concentration and transformation as well as synergistic and antagonistic actions among trace contaminants are discussed in terms of their importance in mobility, persistence, availability, and ultimate toxicity. The consequences of implementing the President's National Energy Plan are considered in terms of the impact of the NEP in 1985 and 2000 on the potential effects of trace and radioactive elements from the coal fuel cycle. Areas of needed research are identified in specific recommendations. PMID:540619

Diel cycling of trace elements in streams draining mineralized areas: a review

USGS Publications Warehouse

Gammons, Christopher H.; Nimick, David A.; Parker, Stephen R.

2015-01-01

Many trace elements exhibit persistent diel, or 24-h, concentration cycles in streams draining mineralized areas. These cycles can be caused by various physical and biogeochemical mechanisms including streamflow variation, photosynthesis and respiration, as well as reactions involving photochemistry, adsorption and desorption, mineral precipitation and dissolution, and plant assimilation. Iron is the primary trace element that exhibits diel cycling in acidic streams. In contrast, many cationic and anionic trace elements exhibit diel cycling in near-neutral and alkaline streams. Maximum reported changes in concentration for these diel cycles have been as much as a factor of 10 (988% change in Zn concentration over a 24-h period). Thus, monitoring and scientific studies must account for diel trace-element cycling to ensure that water-quality data collected in streams appropriately represent the conditions intended to be studied.

Assessment of trace metals using lichen transplant from automobile mechanic workshop in Ile-Ife metropolis, Nigeria.

PubMed

Odiwe, Anthony I; Adesanwo, Adeyemi T J; Olowoyo, Joshua O; Raimi, Idris O

2014-04-01

The level of air pollution around the automobile mechanic workshops has been generally overlooked. This study, examined the level of trace metals in automobile mechanic workshops and the suitability of using transplanted lichen thalli of Lepraria incana for measuring air pollution in such areas. Samples of the lichen thalli were transplanted into seven different sites and were attached to the bark of trees at each site. The samples were harvested from the sites after 3-month exposure. Concentrations of Pb, Cu, Cd, Fe, Zn, and S content were determined using an atomic absorption spectrophotometer. Results showed that there was a significant difference in the trace metals concentrations across the sites (p < 0.05). The analyzed lichen samples showed a range of 91.26-119.35 ppm for Fe, 30.23-61.32 ppm for Zn, 1.25-2.45 ppm for Cu, 0.017-0.043 ppm for Cd, 0.018-0.051 ppm, and 0.37-0.42 ppm for S. From the study, sites 6 and 7 presented higher concentrations of Cd, Pb, and Zn than other sites. The enrichment factor calculated showed that Zn, Cd, and Pb were greatly enriched from the workshops. The trend in the concentration of these heavy metals suggests that activities in these workshops might become a major source of certain heavy metals in the environment and if the pollution activities persist, it might become worrisome over time.

Specialised emission pattern of leaf trace in a late Permian (253 million-years old) conifer

PubMed Central

Wei, Hai-Bo; Feng, Zhuo; Yang, Ji-Yuan; Chen, Yu-Xuan; Shen, Jia-Jia; He, Xiao-Yuan

2015-01-01

Leaf traces are important structures in higher plants that connect leaves and the stem vascular system. The anatomy and emission pattern of leaf traces are well studied in extant vascular plants, but remain poorly understood in fossil lineages. We quantitatively analysed the leaf traces in the late Permian conifer Ningxiaites specialis from Northwest China based on serial sections through pith, primary and secondary xylems. A complete leaf traces emission pattern of a conifer is presented for the first time from the late Palaeozoic. Three to five monarch leaf traces are grouped in clusters, arranged in a helical phyllotaxis. The leaf traces in each cluster can be divided into upper, middle and lower portions, and initiate at the pith periphery and cross the wood horizontally. The upper leaf trace increases its diameter during the first growth increment and then diminishes completely, which indicates leaf abscission at the end of the first year. The middle trace immediately bifurcates once or twice to form two or three vascular bundles. The lower trace persists as a single bundle during its entire length. The intricate leaf trace dynamics indicates this fossil plant had a novel evolutionary habit by promoting photosynthetic capability for the matured plant. PMID:26198410

Hierarchical Traces for Reduced NSM Memory Requirements

NASA Astrophysics Data System (ADS)

Dahl, Torbjørn S.

This paper presents work on using hierarchical long term memory to reduce the memory requirements of nearest sequence memory (NSM) learning, a previously published, instance-based reinforcement learning algorithm. A hierarchical memory representation reduces the memory requirements by allowing traces to share common sub-sequences. We present moderated mechanisms for estimating discounted future rewards and for dealing with hidden state using hierarchical memory. We also present an experimental analysis of how the sub-sequence length affects the memory compression achieved and show that the reduced memory requirements do not effect the speed of learning. Finally, we analyse and discuss the persistence of the sub-sequences independent of specific trace instances.

Dietary exposure to short-chain chlorinated paraffins has increased in Beijing, China.

PubMed

Harada, Kouji H; Takasuga, Takumi; Hitomi, Toshiaki; Wang, Peiyu; Matsukami, Hidenori; Koizumi, Akio

2011-08-15

Short-chain chlorinated paraffins (SCCPs) persist in the environment and bioaccumulate in biota and are under review by the Stockholm Convention on persistent organic pollutants. SCCP levels were measured semiquantitatively in pooled 24 h food composite samples from Chinese (n = 10), Korean (n = 10), and Japanese (n = 40) adults in the 1990 s and 2007-2009. In Japan, SCCPs were detected in 14 of 20 pooled samples in the 1990 s and 13 of 20 pooled samples in 2009. Between these two time points, the geometric mean (GM) of the dietary intake of total SCCPs per body weight was comparable in Japan (54 ng kg-bw(-1) day(-1) in the 1990 s and 54 ng kg-bw(-1) day(-1) in the 2000s). In Beijing, SCCP levels were elevated by 2 orders of magnitude from 1993 to 2009 (GM: 620 ng kg-bw(-1) day(-1) in 2009). The 95th percentile estimate of the dietary intake was 1200 ng kg-bw(-1) day(-1) (>1% of tolerable daily intake). In Seoul, no samples in 1994 contained detectable SCCP levels and only one sample in 2007 showed trace levels of SCCPs. Preliminary evidence on the significant increase in SCCP exposure in Beijing in 2009 warrants urgent investigations to refine dietary intake estimates by targeting food types and source identification.

Does the Concept of “Sensitization” Provide a Plausible Mechanism for the Putative Link Between the Environment and Schizophrenia?

PubMed Central

Collip, Dina; Myin-Germeys, Inez; Van Os, Jim

2008-01-01

Previous evidence reviewed in Schizophrenia Bulletin suggests the importance of a range of different environmental factors in the development of psychotic illness. It is unlikely, however, that the diversity of environmental influences associated with schizophrenia can be linked to as many different underlying mechanisms. There is evidence that environmental exposures may induce, in interaction with (epi)genetic factors, psychological or physiological alterations that can be traced to a final common pathway of cognitive biases and/or altered dopamine neurotransmission, broadly referred to as “sensitization,” facilitating the onset and persistence of psychotic symptoms. At the population level, the behavioral phenotype for sensitization may be examined by quantifying, in populations exposed to environmental risk factors associated with stress or dopamine-agonist drugs, (1) the increased rate of persistence (indicating lasting sensitization) of normally transient developmental expressions of subclinical psychotic experiences and (2) the subsequent increased rate of transition to clinical psychotic disorder. PMID:18203757

Evaluation of Trace Elements in Potatoes (Solanum tuberosum) from a Suburban Area of Naples, Italy: The "Triangle of Death".

PubMed

Roma, Antonella De; Abete, Maria Cesarina; Brizio, Paola; Picazio, Giuseppe; Caiazzo, Marcello; D'auria, Jacopo Luigi; Esposito, Mauro

2017-07-01

Human exposure to contaminated food is a general health concern worldwide; it is necessary to evaluate food safety with respect to contaminants present in the edible parts of major food crops. This study evaluated the concentrations of 17 trace elements (As, Be, Cd, Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb, Sb, Se, Sn, Tl, V, and Zn) from 51 potato plantations in the Campania region, inside the area known as the "Triangle of Death," with inductively coupled plasma mass spectrometry analysis. Results confirm that the potatoes collected from the suburban area of Naples contained concentrations of trace elements below the safe limits prescribed by the Food and Agriculture Organization of the United Nations and the World Health Organization. The concentrations of elements were similar to those reported for potatoes grown in other countries. Monitoring the content of toxic and potentially toxic elements is one of the most important aspects of food quality assurance. The environmental persistence of metals may result in the accumulation of significant levels of these contaminants in plants. They are absorbed to different extents, depending on their source, soil and climatic factors, plant genotype, and agrotechnical conditions, thereby entering the food chain and representing a risk to human health.

Therapeutic Antiviral Effect of the Nucleic Acid Polymer REP 2055 against Persistent Duck Hepatitis B Virus Infection

PubMed Central

Noordeen, Faseeha; Scougall, Catherine A.; Grosse, Arend; Qiao, Qiao; Ajilian, Behzad B.; Reaiche-Miller, Georget; Finnie, John; Werner, Melanie; Broering, Ruth; Schlaak, Joerg F.; Vaillant, Andrew; Jilbert, Allison R.

2015-01-01

Previous studies have demonstrated that nucleic acid polymers (NAPs) have both entry and post-entry inhibitory activity against duck hepatitis B virus (DHBV) infection. The inhibitory activity exhibited by NAPs prevented DHBV infection of primary duck hepatocytes in vitro and protected ducks from DHBV infection in vivo and did not result from direct activation of the immune response. In the current study treatment of primary human hepatocytes with NAP REP 2055 did not induce expression of the TNF, IL6, IL10, IFNA4 or IFNB1 genes, confirming the lack of direct immunostimulation by REP 2055. Ducks with persistent DHBV infection were treated with NAP 2055 to determine if the post-entry inhibitory activity exhibited by NAPs could provide a therapeutic effect against established DHBV infection in vivo. In all REP 2055-treated ducks, 28 days of treatment lead to initial rapid reductions in serum DHBsAg and DHBV DNA and increases in anti-DHBs antibodies. After treatment, 6/11 ducks experienced a sustained virologic response: DHBsAg and DHBV DNA remained at low or undetectable levels in the serum and no DHBsAg or DHBV core antigen positive hepatocytes and only trace amounts of DHBV total and covalently closed circular DNA (cccDNA) were detected in the liver at 9 or 16 weeks of follow-up. In the remaining 5/11 REP 2055-treated ducks, all markers of DHBV infection rapidly rebounded after treatment withdrawal: At 9 and 16 weeks of follow-up, levels of DHBsAg and DHBcAg and DHBV total and cccDNA in the liver had rebounded and matched levels observed in the control ducks treated with normal saline which remained persistently infected with DHBV. These data demonstrate that treatment with the NAP REP 2055 can lead to sustained control of persistent DHBV infection. These effects may be related to the unique ability of REP 2055 to block release of DHBsAg from infected hepatocytes. PMID:26560490

Tracing Technological Development Trajectories: A Genetic Knowledge Persistence-Based Main Path Approach.

PubMed

Park, Hyunseok; Magee, Christopher L

2017-01-01

The aim of this paper is to propose a new method to identify main paths in a technological domain using patent citations. Previous approaches for using main path analysis have greatly improved our understanding of actual technological trajectories but nonetheless have some limitations. They have high potential to miss some dominant patents from the identified main paths; nonetheless, the high network complexity of their main paths makes qualitative tracing of trajectories problematic. The proposed method searches backward and forward paths from the high-persistence patents which are identified based on a standard genetic knowledge persistence algorithm. We tested the new method by applying it to the desalination and the solar photovoltaic domains and compared the results to output from the same domains using a prior method. The empirical results show that the proposed method can dramatically reduce network complexity without missing any dominantly important patents. The main paths identified by our approach for two test cases are almost 10x less complex than the main paths identified by the existing approach. The proposed approach identifies all dominantly important patents on the main paths, but the main paths identified by the existing approach miss about 20% of dominantly important patents.

Tracing Technological Development Trajectories: A Genetic Knowledge Persistence-Based Main Path Approach

PubMed Central

2017-01-01

The aim of this paper is to propose a new method to identify main paths in a technological domain using patent citations. Previous approaches for using main path analysis have greatly improved our understanding of actual technological trajectories but nonetheless have some limitations. They have high potential to miss some dominant patents from the identified main paths; nonetheless, the high network complexity of their main paths makes qualitative tracing of trajectories problematic. The proposed method searches backward and forward paths from the high-persistence patents which are identified based on a standard genetic knowledge persistence algorithm. We tested the new method by applying it to the desalination and the solar photovoltaic domains and compared the results to output from the same domains using a prior method. The empirical results show that the proposed method can dramatically reduce network complexity without missing any dominantly important patents. The main paths identified by our approach for two test cases are almost 10x less complex than the main paths identified by the existing approach. The proposed approach identifies all dominantly important patents on the main paths, but the main paths identified by the existing approach miss about 20% of dominantly important patents. PMID:28135304

Natural Attenuation of Persistent Chemical Warfare Agent VX ...

EPA Pesticide Factsheets

Report Natural attenuation of persistent CWAs such as VX was investigated and occurs, given sufficient time (days to weeks). Natural attenuation was found to be faster at warmer temperatures (i.e., 35 °C and 25 °C) than cooler temperatures (i.e., 10 °C). Attenuation of VX was material dependent with a general trend of faster to slower attenuation in the order ceramic tile - galvanized metal - silanized glass - painted drywall. Trace amounts of VX may still be present weeks to months after a contamination event.

A survey of recent results in passive sampling of water and air by semipermeable membrane devices

USGS Publications Warehouse

Prest, Harry F.; Huckins, James N.; Petty, Jimmie D.; Herve, Sirpa; Paasivirta, Jaakko; Heinonen, Pertti

1995-01-01

A survey is presented of some recent results for passive sampling of water and air for trace organic contaminants using lipid-filled semipermeable membrane devices (SPMDs). Results of water sampling for trace organochlorine compounds using simultaneously exposed SPMDs and the most universally applied biomonitor (bivalves) are discussed. In general, the total amounts of accumulated analytes available for analysis in bivalves and SPMDs were comparable. However, SPMD controls typically had negligible levels of contamination, which was not always the case for transplanted bivalves, even after prolonged depuration prior to exposure. In surveys of the spatial trends of organochlorines at a series of sites, data from bivalves and SPMDs provided the same picture of contaminant distribution and severity. An exception was ionizable contaminants such as the chlorinated phenolic compounds and their transformation products found in pulp mill effluents. In these cases the two monitoring approaches compliment each other, i.e. what is not found in bivalves appears in SPMDs and vice versa. SPMDs have also been applied in environments where biomonitoring is not feasible. SPMDs have shown their utility in studies of trace levels of polyaromatic hydrocarbons by locating and characterizing point sources. An example is given of their application to the calculation of contaminant half-lives from aqueous SPMD residues, a direct measurement of the persistence of contaminants in an environmental compartment. Similarly, results of air sampling with SPMDs in a relatively pristine coastal location are cited which reveal a tremendous enhancement in p,p′-DDE relative to open ocean values.

Behaviour and fate of nine recycled water trace organics during managed aquifer recharge in an aerobic aquifer

NASA Astrophysics Data System (ADS)

Patterson, B. M.; Shackleton, M.; Furness, A. J.; Bekele, E.; Pearce, J.; Linge, K. L.; Busetti, F.; Spadek, T.; Toze, S.

2011-03-01

The fate of nine trace organic compounds was evaluated during a 12 month large-scale laboratory column experiment. The columns were packed with aquifer sediment and evaluated under natural aerobic and artificial anaerobic geochemical conditions, to assess the potential for natural attenuation of these compounds during aquifer passage associated with managed aquifer recharge (MAR). The nine trace organic compounds were bisphenol A (BPA), 17β-estradiol (E2), 17α-ethynylestradiol (EE2), N-nitrosodimethylamine (NDMA), N-nitrosomorpholine (NMOR), carbamazepine, oxazepam, iohexol and iodipamide. In the low organic carbon content Spearwood sediment, all trace organics were non-retarded with retardation coefficients between 1.0 and 1.2, indicating that these compounds would travel at near groundwater velocities within the aquifer. The natural aerobic geochemical conditions provided a suitable environment for the rapid degradation for BPA, E2, iohexol (half life < 1 day). Lag-times for the start of degradation of these compounds ranged from < 15 to 30 days. While iodipamide was persistent under aerobic conditions, artificial reductive geochemical conditions promoted via the addition of ethanol, resulted in rapid degradation (half life < 1 days). Pharmaceuticals (carbamazepine and oxazepam) and disinfection by-products (NDMA and NMOR) did not degrade under either aerobic or anaerobic aquifer geochemical conditions (half life > 50 days). Field-based validation experiments with carbamazepine and oxazepam also showed no degradation. If persistent trace organics are present in recycled waters at concentrations in excess of their intended use, natural attenuation during aquifer passage alone may not result in extracted water meeting regulatory requirements. Additional pre treatment of the recycled water would therefore be required.

Persistent organic pollutants (POPs) in the atmosphere of coastal areas of the Ross Sea, Antarctica: Indications for long-term downward trends.

PubMed

Pozo, Karla; Martellini, Tania; Corsolini, Simonetta; Harner, Tom; Estellano, Victor; Kukučka, Petr; Mulder, Marie D; Lammel, Gerhard; Cincinelli, Alessandra

2017-07-01

Passive air samplers were used to evaluate long-term trends and spatial distribution of trace organic compounds in Antarctica. Duplicate PUF disk samplers were deployed at six automatic weather stations in the coastal area of the Ross sea (East Antarctica), between December 2010 and January 2011, during the XXVI Italian Scientific Research Expedition. Among the investigated persistent organic compounds, Hexachlorobenzene was the most abundant, with air concentrations ranging from 0.8 to 50 pg m -3 . In general, the following decreasing concentration order was found for the air samples analyzed: HCB > PeCB > PCBs > DDTs > HCHs. While HCB concentrations were in the same range as those reported in the atmosphere of other Antarctic sampling areas and did not show a decline, HCHs and DDTs levels were lower or similar to those determined one or two decades ago. In general, the very low concentrations reflected the pristine state of the East Antarctica air. Backward trajectories indicated the prevalence of air masses coming from the Antarctic continent. Local contamination and volatilization from ice were suggested as potential sources for the presence of persistent organic pollutants in the atmosphere. Copyright © 2017 Elsevier Ltd. All rights reserved.

Microphysical Characteristics of Clouds During the TRMM Field Campaign

NASA Technical Reports Server (NTRS)

Stith, Jeffrey L.

2003-01-01

Further analysis of the TRMM field campaign data was conducted to examine the growth of precipitation in updraft regions of the TRMM field campaign tropical clouds and to extend the earlier results to cover the whole TRMM data set collected by the University of North Dakota (UND). The results have been submitted for publication. In this paper, composite vertical profiles of liquid water, small particle concentration, and updraft/downdraft magnitudes were presented from each of the campaigns. They exhibited similar peak values for the two TRMM regions of LBA and Kwajalein. Updrafts were found to be favored locations for precipitation embryos in the form of liquid or frozen drizzle-sized droplets. Although liquid water concentrations decreased to undetectable levels between -5 and -18 C in most glaciating updrafts, occasional traces of liquid water were found in updrafts at colder temperatures, probably due to the persistence of liquid drizzle droplets. The updraft magnitudes where the traces of liquid water were observed at cold temperatures do not appear to be stronger than updrafts without liquid water at similar temperatures, however.

Impact of Elevated CO2 on Trace Element Release from Aquifer Sediments of the San Joaquin Valley, CA

NASA Astrophysics Data System (ADS)

Fox, P. M.; Nico, P. S.; Davis, J. A.; Spycher, N.

2014-12-01

Carbon capture and storage (CCS) is a promising technique for mitigating climate change by storing large volumes of carbon dioxide in deep saline aquifers. In California, the thick marine sediments of the Central and Salinas Valleys have been identified as prime targets for future CO2 storage. However, the potential impacts on water quality of overlying drinking-water aquifers must be studied before CCS can be implemented. In this study, we compare trace element release from San Joaquin Valley aquifer sediments with a wide range of textural and redox properties. Kinetic batch experiments were performed with artificial groundwater continuously equilibrated under CO2-saturated (at 1 atm) and background CO2 (0.002-0.006 atm) conditions, resulting in a shift of nearly 3 pH units. In addition, the reversibility of trace element release was studied by sequentially lowering the CO2 from 1.0 atm to 0.5 atm to background concentrations (0.002-0.006 atm) for CO2-saturated systems in order to mimic the dissipation of a CO2 plume in the aquifer. During exposure to high CO2, a number of elements displayed enhanced release compared to background CO2 experiments (Ca, Mg, Li, Si, B, As, Sr, Ni, Fe, Mn, V, Ti, and Co) with concentrations of As, Fe, and Mn exceeding EPA maximum contaminant levels in some cases. On the other hand, Mo and U showed suppressed release. Most intriguing, many of the elements showing enhanced release displayed at least some degree of irreversibility when CO2 concentrations were decreased to background levels. In fact, in some cases (i.e., for V), an element showed further release when CO2 concentrations were decreased. These results suggest that there may be longer-term effects on groundwater quality that persist even after the CO2 plume has dissipated. Several different mechanisms of trace element release including ion exchange, desorption, and carbonate mineral dissolution are explored. Preliminary modeling results suggest that carbonate mineral dissolution can play a key role in driving trace element release even in sediments where carbonates are in low abundance.

Student Engagement through Digital Data

ERIC Educational Resources Information Center

Gross, Liz; Meriwether, Jason L.

2016-01-01

This chapter suggests strategies and tools for student affairs professionals to leverage digital data to measure student engagement and learning outcomes, and refine programs that enhance institutional reputation and improve student persistence. The construct of student engagement is traced from its theoretical origins to recent research…

Effects of lead, molybdenum, rubidium, arsenic and organochlorines on spermatogenesis in fish: monitoring at Mekong Delta area and in vitro experiment.

PubMed

Yamaguchi, Sonoko; Miura, Chiemi; Ito, Aki; Agusa, Tetsuro; Iwata, Hisato; Tanabe, Shinsuke; Tuyen, Bui Cach; Miura, Takeshi

2007-06-05

To estimate the influence of water contaminants on fish reproduction in the Mekong Delta area, we sampled cultivated male catfish (Pangasianodon hypophthalmus), investigated testicular development, and measured persistent organic pollutants (POPs) and trace element levels in muscle and liver, respectively. Various testes sizes were observed although sampling took place during a short period. Histological analysis revealed that all developmental stages of germ cells were observed in catfish with large testis, whereas only necrotic spermatogonia but no other germ cells were observed in catfish with small testis. In small testis, furthermore, vacuolization and hypertrophy of Sertoli cells were observed. Measurement of POPs in muscle and trace elements in liver demonstrated that there were negative correlations between GSI and the concentrations of Pb, Mo, Rb and As. To clarify possible direct effects of Pb, Mo, Rb and As on spermatogenesis in fish, we investigated the effects of these trace elements on spermatogenesis using in vitro testicular organ culture of Japanese eel (Anguilla japonica). Treatment with each of the trace elements alone did not affect spermatogenesis. However, treatment with 10(-7)M of Pb, 10(-5) and 10(-4)M of Mo, 10(-5)-10(-3)M of Rb or 10(-5)M of As inhibited the spermatogenesis induced by 11-ketotestosterone (11KT). Furthermore, treatment with 10(-4)M of As in combination with 11KT caused necrosis of testicular fragments. Taken together, these results are consistent with the hypothesis that Pb, Mo, Rb and As can exert inhibitory effects on spermatogenesis in catfish inhabiting the Mekong Delta area.

Parsing apart the persisters: Etiological mechanisms and criminal offense patterns of moderate- and high-level persistent offenders.

PubMed

Amemiya, Jamie; Vanderhei, Susan; Monahan, Kathryn C

2017-08-01

Longitudinal investigations that have applied Moffitt's dual taxonomic framework to criminal offending have provided support for the existence of adolescent-limited and life-course persistent antisocial individuals, but have also identified additional trajectories. For instance, rather than a single persistent trajectory, studies have found both high-level and moderate-level persistent offenders. To inform theory and progress our understanding of chronic antisocial behavior, the present study used a sample of serious adolescent offenders (N =1,088) followed from middle adolescence to early adulthood (14-25 years), and examined how moderate-level persistent offenders differed from low-rate, desisting, and high-level persistent offenders. Results indicated that moderate-level persisters' etiology and criminal offense patterns were most similar to high-level persisters, but there were notable differences. Specifically, increasing levels of contextual adversity characterized both moderate-level and high-level persisting trajectories, but moderate-level persisters reported consistently lower levels of environmental risk. While both high- and moderate-level persisters committed more drug-related offenses in early adulthood compared to adolescence, moderate-level persisters engaged in lower levels of antisocial behavior across all types of criminal offenses. Taken cumulatively, the findings of this study suggest that sociocontextual interventions may be powerful in reducing both moderate- and high-level persistence in crime.

Effect of supplementary implantation of a sulcus-fixated intraocular lens in patients with negative dysphotopsia.

PubMed

Makhotkina, Natalia Y; Dugrain, Vincent; Purchase, Daniel; Berendschot, Tos T J M; Nuijts, Rudy M M A

2018-02-01

To evaluate whether the outcome of negative dysphotopsia treatment by implantation of a Sulcoflex intraocular lens (IOL) can be understood using individual biometry and optical modeling data. University Eye Clinic, Maastricht University Medical Centre, Maastricht, the Netherlands. Retrospective case series. Patients with negative dysphotopsia were treated with supplementary implantation of a sulcus-fixated IOL. Preoperative and postoperative ray-tracing optical models of eyes with negative dysphotopsia were constructed in the Zemax Optic Studio program using individual biometric data. The relationship between biometric parameters, ray-tracing data, and the course of negative dysphotopsia was evaluated. The study comprised 8 patients (10 eyes). After surgery, negative dysphotopsia resolved completely in 6 eyes, partially in 2 eyes, and persisted in 2 eyes. There was no relationship between the course of negative dysphotopsia and age, IOL power, or individual biometry results other than a larger angle κ that was observed in 2 patients with persistent negative dysphotopsia after surgery. Preoperative ray-tracing models showed a decrease in light irradiance at the periphery relative to the center of visual field. After sulcus-fixated IOL implantation, this decrease partially resolved, in particular, for a small pupil aperture (P < .05), and it was more prominent in patients in whom negative dysphotopsia resolved completely than in those with partial or persistent negative dysphotopsia (P = .065 at 1.5 mm aperture). Of all individual biometry results, only angle κ showed a relationship with the course of negative dysphotopsia. In patient-specific optical modeling of sulcus-fixated IOL implantation, the increase in simulated light irradiance at the periphery was related to the course of negative dysphotopsia. Copyright © 2018 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

Persistence of the dominant soil phylum Acidobacteria by trace gas scavenging

PubMed Central

Greening, Chris; Carere, Carlo R.; Rushton-Green, Rowena; Harold, Liam K.; Hards, Kiel; Taylor, Matthew C.; Morales, Sergio E.; Stott, Matthew B.; Cook, Gregory M.

2015-01-01

The majority of microbial cells in global soils exist in a spectrum of dormant states. However, the metabolic processes that enable them to survive environmental challenges, such as nutrient-limitation, remain to be elucidated. In this work, we demonstrate that energy-starved cultures of Pyrinomonas methylaliphatogenes, an aerobic heterotrophic acidobacterium isolated from New Zealand volcanic soils, persist by scavenging the picomolar concentrations of H2 distributed throughout the atmosphere. Following the transition from exponential to stationary phase due to glucose limitation, the bacterium up-regulates by fourfold the expression of an eight-gene operon encoding an actinobacteria-type H2-uptake [NiFe]-hydrogenase. Whole-cells of the organism consume atmospheric H2 in a first-order kinetic process. Hydrogen oxidation occurred most rapidly under oxic conditions and was weakly associated with the cell membrane. We propose that atmospheric H2 scavenging serves as a mechanism to sustain the respiratory chain of P. methylaliphatogenes when organic electron donors are scarce. As the first observation of H2 oxidation to our knowledge in the Acidobacteria, the second most dominant soil phylum, this work identifies new sinks in the biogeochemical H2 cycle and suggests that trace gas oxidation may be a general mechanism for microbial persistence. PMID:26240343

Dye tracing techniques used to determine ground-water flow in a carbonate aquifer system near Elizabethtown, Kentucky

USGS Publications Warehouse

Mull, D.S.; Smoot, J.L.; Liebermann, T.D.

1988-01-01

Because of the vulnerability of karst aquifers to contamination and the need for water managers to know recharge areas and groundwater flow characteristics for springs and wells used for public water supply, qualitative and quantitative dye tracing techniques were used during a groundwater investigation in the Elizabethtown area, Hardin County, in north-central Kentucky. The principal aquifer in the Elizabethtown area is thick, nearly horizontal beds of limestone, and thin beds of shale of Mississippi age. As much as 65% of all water pumped for the city water supply is obtained from two springs and two wells that obtain water from these rocks. Sinkholes were classified according to their ability to funnel runoff directly into the groundwater flow system, based primarily on the nature of the swallet draining the sinkhole. The presence of bedrock in the sinkhole nearly always ensured a well defined swallet leading to the subsurface. Qualitative and quantitative dye tracing techniques and equipment are discussed in detail. Qualitative dye tracing with fluorescein dye and passive dye detectors, consisting of activated coconut charcoal identified point to point connection between representative sinkholes, sinking streams, and karst windows and the city springs and wells. Qualitative tracing confirmed the presence of infiltrated surface water from a perennial stream, Valley Creek, in water from city wells and generally confirmed the direction of groundwater flow as shown by a water level contour map. Quantitative dye tracing with rhodamin WT, automatic samplers, discharge measurements, and fluorometric analyses were used to determine flow characteristics such as traveltime for arrival of the leading edge, peak concentration, trailing edge, and persistence of the dye cloud at the spring resurgence. Analyses of the dye recovery curves for quantitative dye traces completed between the same sinkholes and a city spring, and during different flow conditions showed that the arrival time of the leading edge of the dye cloud ranged from 5 to 24 hours and that the traveltime of the centroid of the dye cloud ranged from 6 to 31 hours when discharge was 4.6 and 0.53 cu ft/second, respectively. (Lantz-PTT)

Trace metal concentrations in Posidonia oceanica of North Corsica (northwestern Mediterranean Sea): use as a biological monitor?

PubMed Central

Gosselin, Marc; Bouquegneau, Jean-Marie; Lefèbvre, Frédéric; Lepoint, Gilles; Pergent, Gerard; Pergent-Martini, Christine; Gobert, Sylvie

2006-01-01

Background Within semi-closed areas like the Mediterranean Sea, anthropic wastes tend to concentrate in the environment. Metals, in particular, are known to persist in the environment and can affect human health due to accumulation in the food chain. The seagrass Posidonia oceanica, widely found in Mediterranean coastal waters, has been chosen as a "sentinel" to quantify the distribution of such pollutants within the marine environment. Using a technique similar to dendrochronology in trees, it can act as an indicator of pollutant levels over a timeframe of several months to years. In the present study, we measured and compared the levels of eight trace metals (Cr, Ni, Cu, Zn, As, Se, Cd, and Pb) in sheaths dated by lepidochronology and in leaves of shoots sampled from P. oceanica meadows collected from six offshore sites in northern Corsica between 1988 and 2004; in the aim to determine 1) the spatial and 2) temporal variations of these metals in these areas and 3) to compared these two types of tissues. Results We found low trace metal concentrations with no increase over the last decade, confirming the potential use of Corsican seagrass beds as reference sites for the Mediterranean Sea. Temporal trends of trace metal concentrations in sheaths were not significant for Cr, Ni, Cu, As or Se, but Zn, Cd, and Pb levels decreased, probably due to the reduced anthropic use of these metals. Similar temporal trends between Cu levels in leaves (living tissue) and in sheaths (dead tissue) demonstrated that lepidochronology linked with Cu monitoring is effective for surveying the temporal variability of this metal. Conclusion Leaves of P. oceanica can give an indication of the metal concentration in the environment over a short time period (months) with good accuracy. On the contrary, sheaths, which gave an indication of changes over long time periods (decades), seem to be less sensitive to variations in the metal concentration in the environment. Changes in human consumption of metals (e.g., the reduction of Pb in fuel) are clearly reflected in both organs. These results confirm that P. oceanica is a good bioindicator of metals and a good biomonitor species for assessing Cu in the environment. PMID:16965615

Rhombohedral Multilayer Graphene: A Magneto-Raman Scattering Study.

PubMed

Henni, Younes; Ojeda Collado, Hector Pablo; Nogajewski, Karol; Molas, Maciej R; Usaj, Gonzalo; Balseiro, Carlos A; Orlita, Milan; Potemski, Marek; Faugeras, Clement

2016-06-08

Graphene layers are known to stack in two stable configurations, namely, ABA or ABC stacking, with drastically distinct electronic properties. Unlike the ABA stacking, little has been done to experimentally investigate the electronic properties of ABC graphene multilayers. Here, we report on the first magneto optical study of a large ABC domain in a graphene multilayer flake, with ABC sequences exceeding 17 graphene sheets. ABC-stacked multilayers can be fingerprinted with a characteristic electronic Raman scattering response, which persists even at room temperatures. Tracing the magnetic field evolution of the inter Landau level excitations from this domain gives strong evidence for the existence of a dispersionless electronic band near the Fermi level, characteristic of such stacking. Our findings present a simple yet powerful approach to probe ABC stacking in graphene multilayer flakes, where this highly degenerated band appears as an appealing candidate to host strongly correlated states.

Uplift and subsidence reveal a nonpersistent megathrust rupture boundary (Sitkinak Island, Alaska)

USGS Publications Warehouse

Briggs, Richard W.; Engelhart, Simon E.; Nelson, Alan R.; Dura, Tina; Kemp, Andrew C.; Haeussler, Peter J.; Corbett, D. Reide; Angster, Stephen J.; Bradley, Lee-Ann

2014-01-01

We report stratigraphic evidence of land-level change and tsunami inundation along the Alaska-Aleutian megathrust during prehistoric and historical earthquakes west of Kodiak Island. On Sitkinak Island, cores and tidal outcrops fringing a lagoon reveal five sharp lithologic contacts that record coseismic land-level change. Radiocarbon dates, 137Cs profiles, CT scans, and microfossil assemblages are consistent with rapid uplift ca. 290-0, 520-300, and 1050-790 cal yr BP, and subsidence in AD 1964 and ca. 640-510 cal yr BP. Radiocarbon, 137Cs, and 210Pb ages bracketing a sand bed traced 1.5 km inland and evidence for sudden uplift are consistent with Russian accounts of an earthquake and tsunami in AD 1788. The mixed uplift and subsidence record suggests that Sitkinak Island sits above a non-persistent boundary near the southwestern limit of the AD 1964 Mw 9.2 megathrust rupture.

A wind tunnel study of air flow near model swine confinement buildings

USDA-ARS?s Scientific Manuscript database

One of the most significant and persistent environmental concerns regarding swine production is the transport of odor constituents, trace gases, and particulates from animal production and manure storage facilities. The objectives of this study were to determine how swine housing unit orientation af...

Romantic Relationship Patterns in Young Adulthood and Their Developmental Antecedents

ERIC Educational Resources Information Center

Rauer, Amy J.; Pettit, Gregory S.; Lansford, Jennifer E.; Bates, John E.; Dodge, Kenneth A.

2013-01-01

The delayed entry into marriage that characterizes modern society raises questions about young adults' romantic relationship trajectories and whether patterns found to characterize adolescent romantic relationships persist into young adulthood. The current study traced developmental transitions into and out of romantic relationships from age…

Near-infrared light excited upconverting persistent nanophosphors in vivo for imaging-guided cell therapy.

PubMed

Zheng, Bin; Bai, Yang; Chen, Hongbin; Pan, Huizhuo; Ji, Wanying; Gong, Xiaoqun; Wu, Xiaoli; Wang, Hanjie; Chang, Jin

2018-05-14

Optical imaging for biological applications is in need of more sensitive tool. Persistent luminescent nanophosphors enable highly sensitive in vivo optical detection and almost completely avoids tissue autofluorescence. Nevertheless, the actual persistent luminescent nanophosphors necessitates ex vivo activation before systemic operation, which severely restricted the use of long-term imaging in vivo. Hence, we introduced a novel generation of optical nanophosphors, based on (Zn2SiO4: Mn): Y3+, Yb3+, Tm3+ upconverting persistent luminescent nanophosphors, these nanophosphors can be excited in vivo through living tissues by highly penetrating near-infrared light. We can trace labeled tumor therapeutic macrophages in vivo after endocytosing these nanophosphors in vitro and follow macrophages biodistribution by a simple whole animal optical detection. These nanophosphors will open novel potentials for cell therapy research and for a variety of diagnosis applications in vivo.

Prediction of transition from common adolescent bipolar experiences to bipolar disorder: 10-year study.

PubMed

Tijssen, Marijn J A; van Os, Jim; Wittchen, Hans-Ulrich; Lieb, Roselind; Beesdo, Katja; Mengelers, Ron; Wichers, Marieke

2010-02-01

Although (hypo)manic symptoms are common in adolescence, transition to adult bipolar disorder is infrequent. To examine whether the risk of transition to bipolar disorder is conditional on the extent of persistence of subthreshold affective phenotypes. In a 10-year prospective community cohort study of 3021 adolescents and young adults, the association between persistence of affective symptoms over 3 years and the 10-year clinical outcomes of incident DSM-IV (hypo)manic episodes and incident use of mental healthcare was assessed. Transition to clinical outcome was associated with persistence of symptoms in a dose-dependent manner. Around 30-40% of clinical outcomes could be traced to prior persistence of affective symptoms. In a substantial proportion of individuals, onset of clinical bipolar disorder may be seen as the poor outcome of a developmentally common and usually transitory non-clinical bipolar phenotype.

Federal funding for syringe exchange in the US: Explaining a long-term policy failure.

PubMed

Showalter, David

2018-05-01

The United States prohibited federal funding for syringe exchange programs for people who inject drugs nearly continuously from 1988 to 2015, despite growing scientific evidence, diminishing AIDS-related controversy, and tens of thousands of deaths from injection-related AIDS. This study investigates the political and institutional bases of this long-term failure to support lifesaving public policy. This study draws on national, regional, and local media coverage, archival sources, and semi-structured, in-depth interviews with 6 long-time syringe exchange researchers and activists from California. I use case-oriented process tracing methods to explain the persistence and reform of the federal funding ban. Though previous studies focus on the symbolic clash between conservative morality and empirical science, I find that changing demographic and regional inequalities in the effects of the AIDS epidemic and dynamics produced by the federal structure of US government were more important factors in the creation and persistence of the funding ban. The persistence and eventual repeal of the ban on federal funding for syringe exchange was a product of the changing demographic, geographic, and political effects of the AIDS epidemic within the federal structure of US government, rather than a consequence of intractable morality politics. These contextual dynamics continue to shape AIDS and public health policy at all levels of government. Copyright © 2018. Published by Elsevier B.V.

Ground zero: not asthma at all.

PubMed

de Benedictis, Fernando Maria; de Benedictis, Diletta; Mirabile, Lorenzo; Pozzi, Marco; Guerrieri, Arcangela; Di Pillo, Sabrina

2015-09-01

Upper airway obstruction is commonly misdiagnosed as asthma. We report on four children with recurrent respiratory symptoms who had been erroneously diagnosed as having asthma and who received anti-asthma medication for several years. The evaluation of spirometry tracing was neglected in all cases. Subglottic stenosis, tracheomalacia secondary to tracheo-esophageal fistula, double aortic arch, and vocal cord dysfunction were suspected by direct inspection of the flow-volume curves and eventually diagnosed. The value of clinical history and careful evaluation of spirometry tracing in children with persistent respiratory symptoms is critically discussed. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Dinosaur Discourses: Taking Stock of Gendered Learning Myths

ERIC Educational Resources Information Center

Paule, Michele

2015-01-01

The persistence of gendered learning myths in educational contexts and the wider imaginary continues to trouble feminist educational researchers and practitioners. The tracing of such myths and the categories they create through authoritative and elite discourses of the past suggests how they have functioned across different fields to preserve a…

Judd's Debt to Wundt

ERIC Educational Resources Information Center

Dunkel, Harold B.

1977-01-01

Charles Judd identified closely with Wilhelm Wundt's philosophy and general psychological position. This article traces Judd's views on the American educational system in the early part of this century, some of the persistent themes that were part of Judd's thought, and Wundt's influence on Judd's thinking. Also discusses Judd's efforts to collect…

The relation between amyotrophic lateral sclerosis and inorganic selenium in drinking water: a population-based case-control study

PubMed Central

2010-01-01

Background A community in northern Italy was previously reported to have an excess incidence of amyotrophic lateral sclerosis among residents exposed to high levels of inorganic selenium in their drinking water. Methods To assess the extent to which such association persisted in the decade following its initial observation, we conducted a population-based case-control study encompassing forty-one newly-diagnosed cases of amyotrophic lateral sclerosis and eighty-two age- and sex-matched controls. We measured long-term intake of inorganic selenium along with other potentially neurotoxic trace elements. Results We found that consumption of drinking water containing ≥ 1 μg/l of inorganic selenium was associated with a relative risk for amyotrophic lateral sclerosis of 5.4 (95% confidence interval 1.1-26) after adjustment for confounding factors. Greater amounts of cumulative inorganic selenium intake were associated with progressively increasing effects, with a relative risk of 2.1 (95% confidence interval 0.5-9.1) for intermediate levels of cumulative intake and 6.4 (95% confidence interval 1.3-31) for high intake. Conclusion Based on these results, coupled with other epidemiologic data and with findings from animal studies that show specific toxicity of the trace element on motor neurons, we hypothesize that dietary intake of inorganic selenium through drinking water increases the risk for amyotrophic lateral sclerosis. PMID:21134276

Subarachnoidal-pleural fistula (SAPF) as an unusual cause of persistent pleural effusion. Beta-trace protein as a marker for SAPF. Case report and review of the literature.

PubMed

Deseyne, S; Vanhouteghem, K; Hallaert, G; Delanghe, J; Malfait, T

2015-02-01

We describe a case of a 56-year-old woman who developed a recurrent pleural effusion after a thoracoscopic resection of an anterior bulging thoracic disc hernia (level D9-D10). Despite several evacuating pleural punctions, dyspnea reoccurred due to recurrent pleural effusion, the same side as the disc resection. Because of increasing headache after each punction, a subarachnoidal pleural fistula (SAPF) was suspected. Although magnetic resonance imaging (MRI) showed features suggestive of SAPF, there was not enough evidence to justify a new thorascopy. Cerebrospinal fluid (CSF) leakage into the thoracic and abdominal cavity has been described as a result of trauma or surgery. Detection of beta-trace protein (BTP, a brain-specific protein) has been described to detect CSF fistulae causing rhino- and otoliquorrhea. Similarly, BTP determination could be used to identify the presence of CSF at other anatomical sites such as the thoracic cavity. Therefore, we decided to determine the concentration of BTP in the pleural effusion of this patient. BTP was assayed using immunonephelometry. The patient's BTP pleural fluid concentration was 14·0 mg/l, which was a 25-fold increase compared with the BTP serum concentration. After insertion of a subarachnoidal lumbal catheter, a video-assisted thorascopy was performed. Leakage of liquor through the parietal pleura into the thoracic cavity was observed. The SAPF was closed using a durasis patch and DuraSeal®. Postoperatively, there was no reoccurrence of pleural fluid. SAPF has to be included to the differential diagnosis of patients with persistent pleural effusion after spinal surgery. This case illustrates the importance of BTP in diagnosing SAPF, especially in cases where major therapeutic consequences may need to be drawn.

Trace Elements and Carbon and Nitrogen Stable Isotopes in Organisms from a Tropical Coastal Lagoon

PubMed Central

van Hattum, B.; de Boer, J.; van Bodegom, P. M.; Rezende, C. E.; Salomons, W.

2010-01-01

Trace elements (Fe, Mn, Al, Zn, Cr, Cu, Ni, Pb, Cd, Hg, and As) and stable isotope ratios (δ13C and δ15N) were analyzed in sediments, invertebrates, and fishes from a tropical coastal lagoon influenced by iron ore mining and processing activities to assess the differences in trace element accumulation patterns among species and to investigate relations with trophic levels of the organisms involved. Overall significant negative relations between trophic level (given by 15N) and trace element concentrations in gastropods and crustaceans showed differences in internal controls of trace element accumulation among the species of different trophic positions, leading to trace element dilution. Generally, no significant relation between δ15N and trace element concentrations was observed among fish species, probably due to omnivory in a number of species as well as fast growth. Trace element accumulation was observed in the fish tissues, with higher levels of most trace elements found in liver compared with muscle and gill. Levels of Fe, Mn, Al, and Hg in invertebrates, and Fe and Cu in fish livers, were comparable with levels in organisms and tissues from other contaminated areas. Trace element levels in fish muscle were below the international safety baseline standards for human consumption. PMID:20217062

Trace elements and carbon and nitrogen stable isotopes in organisms from a tropical coastal lagoon.

PubMed

Pereira, A A; van Hattum, B; de Boer, J; van Bodegom, P M; Rezende, C E; Salomons, W

2010-10-01

Trace elements (Fe, Mn, Al, Zn, Cr, Cu, Ni, Pb, Cd, Hg, and As) and stable isotope ratios (delta(13)C and delta(15)N) were analyzed in sediments, invertebrates, and fishes from a tropical coastal lagoon influenced by iron ore mining and processing activities to assess the differences in trace element accumulation patterns among species and to investigate relations with trophic levels of the organisms involved. Overall significant negative relations between trophic level (given by (15)N) and trace element concentrations in gastropods and crustaceans showed differences in internal controls of trace element accumulation among the species of different trophic positions, leading to trace element dilution. Generally, no significant relation between delta(15)N and trace element concentrations was observed among fish species, probably due to omnivory in a number of species as well as fast growth. Trace element accumulation was observed in the fish tissues, with higher levels of most trace elements found in liver compared with muscle and gill. Levels of Fe, Mn, Al, and Hg in invertebrates, and Fe and Cu in fish livers, were comparable with levels in organisms and tissues from other contaminated areas. Trace element levels in fish muscle were below the international safety baseline standards for human consumption.

Current status of persistent organic pesticides residues in air, water, and soil, and their possible effect on neighboring countries: a comprehensive review of India.

PubMed

Yadav, Ishwar Chandra; Devi, Ningombam Linthoingambi; Syed, Jabir Hussain; Cheng, Zhineng; Li, Jun; Zhang, Gan; Jones, Kevin C

2015-04-01

Though the use of pesticides has offered significant economic benefits by enhancing the production and yield of food and fibers and the prevention of vector-borne diseases, evidence suggests that their use has adversely affected the health of human populations and the environment. Pesticides have been widely distributed and their traces can be detected in all areas of the environment (air, water and soil). Despite the ban of DDT and HCH in India, they are still in use, both in domestic and agricultural settings. In this comprehensive review, we discuss the production and consumption of persistent organic pesticides, their maximum residual limit (MRL) and the presence of persistent organic pesticides in multicomponent environmental samples (air, water and soil) from India. In order to highlight the global distribution of persistent organic pesticides and their impact on neighboring countries and regions, the role of persistent organic pesticides in Indian region is reviewed. Based on a review of research papers and modeling simulations, it can be concluded that India is one of the major contributors of global persistent organic pesticide distribution. This review also considers the health impacts of persistent organic pesticides, the regulatory measures for persistent organic pesticides, and the status of India's commitment towards the elimination of persistent organic pesticides. Copyright © 2014 Elsevier B.V. All rights reserved.

Medial prefrontal cortex dopamine controls the persistent storage of aversive memories

PubMed Central

Gonzalez, María C.; Kramar, Cecilia P.; Tomaiuolo, Micol; Katche, Cynthia; Weisstaub, Noelia; Cammarota, Martín; Medina, Jorge H.

2014-01-01

Medial prefrontal cortex (mPFC) is essential for initial memory processing and expression but its involvement in persistent memory storage has seldom been studied. Using the hippocampus dependent inhibitory avoidance learning task and the hippocampus-independent conditioned taste aversion paradigm together with specific dopamine receptor agonists and antagonists we found that persistence but not formation of long-term aversive memories requires dopamine D1/D5 receptors activation in mPFC immediately after training and, depending on the task, between 6 and 12 h later. Our results indicate that besides its well-known participation in retrieval and early consolidation, mPFC also modulates the endurance of long-lasting aversive memories regardless of whether formation of the aversive mnemonic trace requires the participation of the hippocampus. PMID:25506318

Persistent Organic Pollutant Determination in Killer Whale Scat Samples: Optimization of a Gas Chromatography/Mass Spectrometry Method and Application to Field Samples.

PubMed

Lundin, Jessica I; Dills, Russell L; Ylitalo, Gina M; Hanson, M Bradley; Emmons, Candice K; Schorr, Gregory S; Ahmad, Jacqui; Hempelmann, Jennifer A; Parsons, Kim M; Wasser, Samuel K

2016-01-01

Biologic sample collection in wild cetacean populations is challenging. Most information on toxicant levels is obtained from blubber biopsy samples; however, sample collection is invasive and strictly regulated under permit, thus limiting sample numbers. Methods are needed to monitor toxicant levels that increase temporal and repeat sampling of individuals for population health and recovery models. The objective of this study was to optimize measuring trace levels (parts per billion) of persistent organic pollutants (POPs), namely polychlorinated-biphenyls (PCBs), polybrominated-diphenyl-ethers (PBDEs), dichlorodiphenyltrichloroethanes (DDTs), and hexachlorocyclobenzene, in killer whale scat (fecal) samples. Archival scat samples, initially collected, lyophilized, and extracted with 70 % ethanol for hormone analyses, were used to analyze POP concentrations. The residual pellet was extracted and analyzed using gas chromatography coupled with mass spectrometry. Method detection limits ranged from 11 to 125 ng/g dry weight. The described method is suitable for p,p'-DDE, PCBs-138, 153, 180, and 187, and PBDEs-47 and 100; other POPs were below the limit of detection. We applied this method to 126 scat samples collected from Southern Resident killer whales. Scat samples from 22 adult whales also had known POP concentrations in blubber and demonstrated significant correlations (p < 0.01) between matrices across target analytes. Overall, the scat toxicant measures matched previously reported patterns from blubber samples of decreased levels in reproductive-age females and a decreased p,p'-DDE/∑PCB ratio in J-pod. Measuring toxicants in scat samples provides an unprecedented opportunity to noninvasively evaluate contaminant levels in wild cetacean populations; these data have the prospect to provide meaningful information for vital management decisions.

The Sociotechnical Boundaries of Hardware and Software: A Humpty Dumpty History

ERIC Educational Resources Information Center

Jesiek, Brent K.

2006-01-01

This article traces the historical development of the boundaries around computer software and hardware. On one hand, the author documents ongoing discussions about the technical equivalence of hardware and software. On the other hand, he accounts for the stubborn persistence of these terms as markers for two distinct spheres of technology,…

TCDD-MEDIATED OXIDATIVE STRESS IN MALE RAT PUPS FOLLOWING PERINATAL EXPOSURE

EPA Science Inventory

TCDD is a highly persistent trace environmental contaminant and is one of the most potent toxicants known to man. Our laboratory has previously reported an increase in the production of reactive oxygen species (ROS) in the brain of female B6C3F1 mice following subchronic exposur...

Re-Mediating Literacy: Culture, Difference, and Learning for Students from Nondominant Communities

ERIC Educational Resources Information Center

Gutierrez, Kris D.; Morales, P. Zitlali; Martinez, Danny C.

2009-01-01

Deficit notions about the cognitive potential of individuals from nondominant communities have persisted in social science inquiry, particularly where literacy is concerned. The intellectual trails of current conflicting ideas about literacy can be traced in part to theories about the role of literacy in society. For example, the great divide…

Trace elements in fish from Taihu Lake, China: levels, associated risks, and trophic transfer.

PubMed

Hao, Ying; Chen, Liang; Zhang, Xiaolan; Zhang, Dongping; Zhang, Xinyu; Yu, Yingxin; Fu, Jiamo

2013-04-01

Concentrations of eight trace elements [iron (Fe), manganese (Mn), zinc (Zn), chromium (Cr), mercury (Hg), cadmium (Cd), lead (Pb), and arsenic (As)] were measured in a total of 198 samples covering 24 fish species collected from Taihu Lake, China, in September 2009. The trace elements were detected in all samples, and the total mean concentrations ranged from 18.2 to 215.8 μg/g dw (dry weight). The concentrations of the trace elements followed the sequence of Zn>Fe>Mn>Cr>As>Hg>Pb>Cd. The measured trace element concentrations in fish from Taihu Lake were similar to or lower than the reported values in fish around the world. The metal pollution index was used to compare the total trace element accumulation levels among various species. Toxabramis swinhonis (1.606) accumulated the highest level of the total trace elements, and Saurogobio dabryi (0.315) contained the lowest. The concentrations of human non-essential trace elements (Hg, Cd, Pb, and As) were lower than the allowable maximum levels in fish in China and the European Union. The relationships between the trace element concentrations and the δ(15)N values of fish species were used to investigate the trophic transfer potential of the trace elements. Of the trace elements, Hg might be biomagnified through the food chain in Taihu Lake if the significant level of p-value was set at 0.1. No biomagnification and biodilution were observed for other trace elements. Copyright © 2012 Elsevier Inc. All rights reserved.

Trace metals in fugitive dust from unsurfaced roads in the Viburnum Trend resource mining District of Missouri--implementation of a direct-suspension sampling methodology.

PubMed

Witt, Emitt C; Wronkiewicz, David J; Pavlowsky, Robert T; Shi, Honglan

2013-09-01

Fugitive dust from 18 unsurfaced roadways in Missouri were sampled using a novel cyclonic fugitive dust collector that was designed to obtain suspended bulk samples for analysis. The samples were analyzed for trace metals, Fe and Al, particle sizes, and mineralogy to characterize the similarities and differences between roadways. Thirteen roads were located in the Viburnum Trend (VT) mining district, where there has been a history of contaminant metal loading of local soils; while the remaining five roads were located southwest of the VT district in a similar rural setting, but without any mining or industrial process that might contribute to trace metal enrichment. Comparison of these two groups shows that trace metal concentration is higher for dusts collected in the VT district. Lead is the dominant trace metal found in VT district dusts representing on average 79% of the total trace metal concentration, and was found moderately to strongly enriched relative to unsurfaced roads in the non-VT area. Fugitive road dust concentrations calculated for the VT area substantially exceed the 2008 Federal ambient air standard of 0.15μgm(-3) for Pb. The pattern of trace metal contamination in fugitive dust from VT district roads is similar to trace metal concentrations patterns observed for soils measured more than 40years ago indicating that Pb contamination in the region is persistent as a long-term soil contaminant. Published by Elsevier Ltd.

Genome-wide-analyses of Listeria monocytogenes from food-processing plants reveal clonal diversity and date the emergence of persisting sequence types.

PubMed

Knudsen, Gitte M; Nielsen, Jesper Boye; Marvig, Rasmus L; Ng, Yin; Worning, Peder; Westh, Henrik; Gram, Lone

2017-08-01

Whole genome sequencing is increasing used in epidemiology, e.g. for tracing outbreaks of food-borne diseases. This requires in-depth understanding of pathogen emergence, persistence and genomic diversity along the food production chain including in food processing plants. We sequenced the genomes of 80 isolates of Listeria monocytogenes sampled from Danish food processing plants over a time-period of 20 years, and analysed the sequences together with 10 public available reference genomes to advance our understanding of interplant and intraplant genomic diversity of L. monocytogenes. Except for three persisting sequence types (ST) based on Multi Locus Sequence Typing being ST7, ST8 and ST121, long-term persistence of clonal groups was limited, and new clones were introduced continuously, potentially from raw materials. No particular gene could be linked to the persistence phenotype. Using time-based phylogenetic analyses of the persistent STs, we estimate the L. monocytogenes evolutionary rate to be 0.18-0.35 single nucleotide polymorphisms/year, suggesting that the persistent STs emerged approximately 100 years ago, which correlates with the onset of industrialization and globalization of the food market. © 2017 Society for Applied Microbiology and John Wiley & Sons Ltd.

Primary studies of trace quantities of green vegetation in Mono Lake area using 1990 AVIRIS data

NASA Technical Reports Server (NTRS)

Chen, Zhi-Kang; Elvidge, Chris D.; Groeneveld, David P.

1992-01-01

Our primary results in Jasper Ridge Biological Preserve indicate that high spectral resolution Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) data may provide a substantial advantage in vegetation, based on the chlorophyll red edge feature from 700-780 nm. The chlorophyll red edge was detected for green vegetation cover as low as 4.8 percent. The objective of our studies in Mono Lake area is to continue the experiments performed in Jasper Ridge and to examine the persistence of red edge feature of trace quantities of green vegetation for different plant communities with non-uniform soil backgrounds.

Groundwater dating with the helium-tritium method to assess the long-term persistence of pharmaceuticals and their residues in groundwater

NASA Astrophysics Data System (ADS)

Massmann, G.; Burke, V.; Hass, U.; Dünnbier, U.

2012-04-01

The helium-tritium dating method is based on the analysis of tritium combined with its decay product, the lighter and rare 3He isotope. It was first suggested by Tolstikhin and Kamenskiy (1969) and has since been used in many groundwater studies. We applied the method to date groundwater recharged by bank filtration and former sewage irrigation onto sewage farms in Berlin, Germany, in order to assess the long-term persistence of several organic trace pollutants. In recent years, the occurrence of organic trace pollutants, such as pharmaceuticals and personal care products (PPCPs) as well as their metabolites, in the aquatic environment has been of increasing public and scientific interest (e.g. Schwarzenbach et al., 2006). In (urban) partly closed water cycles like Berlin, poorly biodegradable polar compounds may travel along the water path from wastewater via surface water to the raw water used for drinking water production (Reemtsma et al., 2006). In addition, raw or treated sewage irrigation onto sewage farms and/or agricultural land was common practice in Berlin until the 80s. Combined age dating and trace compound analysis revealed that several phenazone-type compounds (AMDOPH, AMPH, FAA and AAA) as well as a number of psychoactive compounds (meprobamate, pyrithyldione, primidone, and its metabolites phenobarbital and phenylethylmalonamide) are present in three decade old groundwater down gradient of a decommissioned sewage farm in Berlin, while a number of phenazone-type compounds (phenazone, propyphenazone, AMDOPH, AMPH) were present in decade-old bank filtrate. The results prove the long-term-persistence of the respective compounds under anoxic redox conditions, which are prevalent at the investigated sites. At the bank filtration sites, some of the compounds may regionally even be used as time markers for a certain infiltration period and reflect the surface water quality changes of the past few decades.

Serratia marcescens in a neonatal intensive care unit: two long-term multiclone outbreaks in a 10-year observational study.

PubMed

Casolari, Chiara; Pecorari, Monica; Della Casa, Elisa; Cattani, Silvia; Venturelli, Claudia; Fabio, Giuliana; Tagliazucchi, Sara; Serpini, Giulia Fregni; Migaldi, Mario; Marchegiano, Patrizia; Rumpianesi, Fabio; Ferrari, Fabrizio

2013-10-01

We investigated two consecutive Serratia marcescens (S. marcescens) outbreaks which occurred in a neonatal intensive care unit (NICU) of a tertiary level hospital in North Italy in a period of 10 years (January 2003-December 2012). Risk factors associated with S. marcescens acquisition were evaluated by a retrospective case-control study. A total of 21,011 clinical samples was examined: S. marcescens occurred in 127 neonates: 43 developed infection and 3 died. Seven clusters were recorded due to 12 unrelated clones which persisted for years in the ward, although no environmental source was found. The main epidemic clone A sustaining the first cluster in 2003 reappeared in 2010 as an extended spectrum ?-lactamase (ESBL)-producing strain and supporting the second epidemic. Birth weight, gestational age, use of invasive devices and length of stay in the ward were significantly related to S. marcescens acquisition. The opening of a new ward for non-intensive care-requiring neonates, strict adherence to alcoholic hand disinfection, the timely identification and isolation of infected and colonized neonates assisted in containing the epidemics. Genotyping was effective in tracing the evolution and dynamics of the clones demonstrating their long-term persistence in the ward.

Corticosterone levels in relation to trace element contamination along an urbanization gradient in the common blackbird (Turdus merula).

PubMed

Meillère, Alizée; Brischoux, François; Bustamante, Paco; Michaud, Bruno; Parenteau, Charline; Marciau, Coline; Angelier, Frédéric

2016-10-01

In a rapidly urbanizing world, trace element pollution may represent a threat to human health and wildlife, and it is therefore crucial to assess both exposition levels and associated effects of trace element contamination on urban vertebrates. In this study, we investigated the impact of urbanization on trace element contamination and stress physiology in a wild bird species, the common blackbird (Turdus merula), along an urbanization gradient (from rural to moderately urbanized areas). Specifically, we described the contamination levels of blackbirds by 4 non-essential (Ag, Cd, Hg, Pb) and 9 essential trace elements (As, Co, Cr, Cu, Fe, Mn, Ni, Se, Zn), and explored the putative disrupting effects of the non-essential element contamination on corticosterone levels (a hormonal proxy for environmental challenges). We found that non-essential trace element burden (Cd and Pb specifically) increased with increasing urbanization, indicating a significant trace element contamination even in medium sized cities and suburban areas. Interestingly, the increased feather non-essential trace element concentrations were also associated with elevated feather corticosterone levels, suggesting that urbanization probably constrains birds and that this effect may be mediated by trace element contamination. Future experimental studies are now required to disentangle the influence of multiple urban-related constraints on corticosterone levels and to specifically test the influence of each of these trace elements on corticosterone secretion. Copyright © 2016 Elsevier B.V. All rights reserved.

Partitioning behavior of heavy metals and persistent organic pollutants among feto-maternal bloods and tissues.

PubMed

Kim, Jun-Tae; Son, Min-Hui; Lee, Duk-Hee; Seong, Won Joon; Han, Seunghee; Chang, Yoon-Seok

2015-06-16

Heavy metals and persistent organic pollutants (POPs), including Pb, Cd, T-Hg, MeHg, PCDD/Fs, PCBs, PBDEs, PCNs, and PBDD/Fs, were analyzed in 20 paired samples of cord blood, maternal blood, maternal urine, and placenta. The samples were collected from pregnant mothers and neonates from South Korea in 2010. The distribution of heavy metals among the samples varied with their physicochemical characteristics. The concentrations of Pb and Hg in the maternal and the cord blood samples were significantly correlated each other, implying efficient transplacental transport (TPT). Cd and Hg were accumulated in the placenta, forming protein conjugates, and T-Hg was higher in the cord blood samples than the maternal blood samples due to the binding affinity of Hg with fetal proteins. POPs generally showed the highest concentrations in the maternal serum samples, and the POPs levels in the cord serum and the placenta samples were dependent on the degree of halogenation. The TPT of POPs was seemingly related to lipoprotein transportation. Some PBDE congeners, however, showed their highest concentrations in the cord serum samples, suggesting an additional TPT mechanism. This is the first study to detect PCNs and PBDD/Fs in the cord serum samples, showing that the PCN levels were comparable to other POPs. According to the principal component analysis (PCA) results of the contaminant levels, POPs and heavy metals showed significantly different characteristics, whereas PBDEs had an intermediate attribute. Despite the limited number of participants, the comprehensive analysis of trace contaminants in the paired sample sets enabled us to infer the distribution and TPT mechanism of various contaminants.

Contextual Distinctiveness Produces Long-Lasting Priming of Pop-Out

ERIC Educational Resources Information Center

Thomson, David R.; Milliken, Bruce

2013-01-01

Maljkovic and Nakayama have demonstrated memory influences in singleton search from one trial to the next, an effect they termed "priming of pop-out" (PoP). This effect was described as resulting from the persistence of an implicit memory trace, the influence of which could be observed for around 5-8 subsequent trials. Thomson and…

Making Whites from the Dark Side: Teaching Whiteness Studies at San Francisco State University

ERIC Educational Resources Information Center

Sueyoshi, Amy

2013-01-01

While whiteness studies at most institutions aims to expose the persistence of white supremacy to a disbelieving audience, whiteness studies within the College of Ethnic Studies (COES) at San Francisco State University (SFSU) begins with the assumption that racism still exists. The course then traces how whiteness is constructed and fortified to…

Gender Implications in Curriculum and Entrance Exam Grouping: Institutional Factors and Their Effects

ERIC Educational Resources Information Center

Hsaieh, Hsiao-Chin; Yang, Chia-Ling

2014-01-01

While access to higher education has reached gender parity in Taiwan, the phenomenon of gender segregation and stratification by fields of study and by division of labor persist. In this article, we trace the historical evolution of Taiwan's education system and data using large-scale educational databases to analyze the association of…

Low zinc status and absorption exist in infants with jejunostomies or ileostomies which persists after intestinal repair

USDA-ARS?s Scientific Manuscript database

There is very little data regarding trace mineral nutrition in infants with small intestinal ostomies. Here we evaluated 14 infants with jejunal or ileal ostomies to measure their zinc absorption and retention and biochemical zinc and copper status. Zinc absorption was measured using a dual-tracer s...

Hurst exponent used as a tool to differentiate between magmatic and fluid-induced processes as reflected in crystal geochemistry

NASA Astrophysics Data System (ADS)

Domonik, A.; Słaby, E.; Śmigielski, M.

2012-04-01

A self-similarity parameter, the Hurst exponent (H) (called also roughness exponent) has been used to show the long-range dependence of element behaviour during the processes. The H value ranges between 0 and 1; a value of 0.5 indicates a random distribution indistinguishable from noise. For values greater or less than 0.5, the system shows non-linear dynamics. H < 0.5 represents anti-persistent (more chaotic) behaviour, whereas H > 0.5 corresponds to increasing persistence (less chaotic). Such persistence is characterized as an effect of a long-term memory, and thus by a large degree of positive correlation. In theory, the preceding data constantly affect the next in the whole temporal series. Applied to chaotic dynamics, the system shows a subtle sensitivity to initial conditions. The process can show some degree of chaos, due to local variations, but generally, the trend preserves its persistent character through time. If the exponent value is low, the process shows frequent and sudden reversals e.g. the trends of such a process show mutual negative correlation of the succeding values in the data series. Thus, the system can be described as having a high degree of deterministic chaos. Alkali feldspar megacrysts grown from mixed magmas and recrystallized due to interaction with fluids have been selected for the study (Słaby et al., 2011). Hurst exponent variability has been calculated within some primary-magmatic and secondary-recrystallized crystal domains for some elements redistributed by crystal fluid interaction. Based on the Hurst exponent value two different processes can easily be recognized. In the core of the megacrysts the element distribution can be ascribed to magmatic growth. By contrast, the marginal zones can relate to inferred late crystal-fluid interactions. Both processes are deterministic, not random. The spatial distribution of elements in the crystal margins is irregular, with high-H values identifying the process as persistent. The trace element distributions in feldspar cores are almost homogeneous and only relatively small and irregular variations in trace element contents makes their growth morphology slightly patchy. Despite homogenization the fractal statistics reveal that trace elements were incorporated chaotically into the growing crystal. The anti-persistent chaotic behaviour of elements during magmatic growth of the feldspars progressively changes into persistent behaviour within domains, where re-crystallization reaction took place. Elements demonstrate variable dynamics of this exchange corresponding to increasing persistency. This dynamics is different for individual elements compared to analogical, observed for crystallization process proceeding from mixed magmas. Consequently, it appears that fractal statistics clearly discriminate between two different processes, with contrasted element behaviour during these processes. One process is magma crystallization and it is recorded in the core of the megacrysts; the second is recorded in the crystal rims and along cleavages and cracks, such that it can be related to a post-crystallization process linked to fluid percolation. Słaby, E., Martin, H., Hamada, M., Śmigielski, M., Domonik, A., Götze, J., Hoefs, J., Hałas, S., Simon, K., Devidal, J-L., Moyen, J-F., Jayananda, M. (2011) Evidence in Archaean alkali-feldspar megacrysts for high-temperature interaction with mantle fluids. Journal of Petrology (on line). doi:10.1093/petrology/egr056

Environmental quality assessment of Grand Harbour (Valletta, Maltese Islands): a case study of a busy harbour in the Central Mediterranean Sea.

PubMed

Romeo, Teresa; D'Alessandro, Michela; Esposito, Valentina; Scotti, Gianfranco; Berto, Daniela; Formalewicz, Malgorzata; Noventa, Seta; Giuliani, Silvia; Macchia, Simona; Sartori, Davide; Mazzola, Angelo; Andaloro, Franco; Giacobbe, Salvatore; Deidun, Alan; Renzi, Monia

2015-12-01

Contamination levels by plastic debris, trace elements and persistent organic pollutants were assessed and related to macrobenthic diversity within soft bottoms of Grand Harbour (Malta, Central Mediterranean). Sediment toxicity was evaluated by ecotoxicological method, deploying Bacteria (Vibrio fischeri), Echinodermata (Paracentrotus lividus) and Crustacea (Corophium orientale). Univariate analysis (Pearson's test) was used to test relationships between biodiversity indices, pollutants and grain size. A multivariate approach (PERMANOVA) was applied to investigate for any significant differences among sampling stations concerning plastic abundances and to test the relationship between infaunal abundances and pollutant concentrations (the BIOENV test). Significant differences in the plastic abundances were found between sampling stations. The lowest value for Shannon-Wiener biodiversity index was associated to the highest sediment pollution level. Multivariate analyses suggest that MBT and TBT were factors that most influenced macrozoobenthic abundance and biodiversity. The bivalve Corbula gibba and the introduced polychaete Monticellina dorsobranchialis were the most abundant found species.

Development and decline of antiplasmodial indirect fluorescent antibodies in mice infected with Plasmodium berghei (NK65) and treated with drugs

PubMed Central

Waki, Seiji; Suzuki, Mamoru

1974-01-01

Malaria parasites in mice present a simplified rodent model for the immunological study of malaria. Experiments have been performed to determine the pattern and persistence of malaria antibody as detected by the indirect fluorescent antibody (IFA) test utilizing specific antimouse IgM and IgG conjugates. The antibody levels in mice inoculated with Plasmodium berghei and treated with antimalarial drugs were traced after complete elimination of the parasites from the host. Within 1-2 weeks after inoculation, both specific IgM and IgG reached peak levels, which thereafter declined rapidly. The results suggest that a high IFA titre may be taken as an indication of recent parasitaemia when the parasites are absent from the host. The protective role of the specific immunoglobulin was not found in the cured animals at the time when the animals showed a high IFA titer. It seems that the detected IFA may not reflect protective immunity against reinfection with malaria parasites. PMID:4617640

First simultaneous space measurements of atmospheric pollutants in the boundary layer from IASI: a case study in the North China Plain

NASA Astrophysics Data System (ADS)

Boynard, Anne; Clerbaux, Cathy; Clarisse, Lieven; Safieddine, Sarah; Pommier, Matthieu; Van Damme, Martin; Bauduin, Sophie; Oudot, Charlotte; Hadji-Lazaro, Juliette; Hurtmans, Daniel; Coheur, Pierre-François

2014-05-01

An extremely severe and persistent smog episode occurred in January 2013 over China. The levels of air pollution have been dangerously high, reaching 40 times recommended safety levels and have affected health of millions of people. China faced one of the worst periods of air quality in recent history and drew worldwide attention. This pollution episode was caused by the combination of anthropogenic emissions and stable meteorological conditions (absence of wind and temperature inversion) that trapped pollutants in the boundary layer. To characterize this episode, we used the IASI (Infrared Atmospheric Sounding Interferometer) instrument onboard the MetOp-A platform. IASI observations show high concentrations of key trace gases such as carbon monoxide (CO), sulfur dioxide (SO2) and ammonia (NH3) along with ammonium sulfate aerosol. We show that IASI is able to detect boundary layer pollution in case of large negative thermal contrast combined with high levels of pollution. Our findings demonstrate the ability of thermal infrared instrument such as IASI to monitor boundary layer pollutants, which can support air quality evaluation and management.

Passive degassing at Nyiragongo (D.R. Congo) and Etna (Italy) volcanoes: the chemical characterization of the emissions and assessment of their uptake of trace elements emissions on the local environment

NASA Astrophysics Data System (ADS)

Calabrese, Sergio; Scaglione, Sarah; Milazzo, Silvia; D'Alessandro, Walter; Bobrowski, Nicole; Giuffrida, Giovanni; Tedesco, Dario; Parello, Francesco

2014-05-01

Volcanoes are well known as an impressive large natural source of trace elements into the troposphere. Among others, Etna (Italy) and Nyiragongo (D.R. Congo), two noteworthy emitters on Earth, are two stratovolcanoes located in different geological settings, both characterized by persistent passive degassing from their summit craters. Here, we present some results on trace element composition in volcanic plume emissions, atmospheric bulk deposition (rainwater) and their uptake of the surrounding vegetation, with the aim to compare and identify differences and similarities between this these two volcanoes. Volcanic emissions were sampled by using active filter-pack for acid gases (sulfur and halogens) and specific teflon filters for particulates (major and trace elements). The impact of the volcanogenic deposition in the surrounding of the crater rims was investigated by using different sampling techniques: bulk rain collectors gauges were used to collect atmospheric bulk deposition, and biomonitoring technique was carried out to collect gases and particulates by using endemic plant species. Concentrations of major and trace elements of volcanic plume emissions (gases and particulates) were obtained by elution and microwave digestion of the collected filters: sulfur and halogens were determined by ion chromatography and ICP-MS, and untreated filters for particulate were acid digested and analysed by ICP-OES and ICP-MS. Rain water and plant samples were also analysed for major and trace elements by using ICP-OES and ICP-MS. In total 55 elements were determined. The estimates of the trace element fluxes confirm that Etna and Nyiragongo are large sources of metals to the atmosphere, especially considering their persistent state of passive degassing. In general, chemical composition of the volcanic aerosol particles of both volcanoes is characterized by two main components: one is related to the silicic component produced by magma bursting and fragmentation, enriching the plume in Si, Al, Fe, Ti, Mg, Ca, Na, K and other trace elements like Ni, Cr, Co, Th and U; another one components, is dominated by volatile trace elements (As, Bi, Cd, Cu, Hg, Se, Te, Tl) related to the gas volatile phase (H2O, CO2, SO2, HCl, HF) and transported to the atmosphere mainly as hydro-soluble salts and/or in gaseous form in some cases. The large amount of emitted trace elements have a strong impact on the close surrounding of both volcanoes. This is clearly reflected by in the chemical composition of rain water collected at the summit areas both for Etna and Nyiragongo. In fact, rain water samples have low pH values (<2) and high concentrations of dissolved toxic metals. Moreover, the biomonitoring results highlight that bioaccumulation of trace elements is extremely high in the proximity of the crater rim and decreases with the distance from the active craters. In particular, we found a good correlation between volatile elements (Tl, As, Bi, Cd, Se, Cu) concentrations in the leaves of Senecio species collected in on both volcanoes, showing a clear influence of volcanic deposition.

Differential Acetylcholine Release in the Prefrontal Cortex and Hippocampus During Pavlovian Trace and Delay Conditioning

PubMed Central

Flesher, M. Melissa; Butt, Allen E.; Kinney-Hurd, Brandee L.

2011-01-01

Pavlovian trace conditioning critically depends on the medial prefrontal cortex (mPFC) and hippocampus (HPC), whereas delay conditioning does not depend on these brain structures. Given that the cholinergic basal forebrain system modulates activity in both the mPFC and HPC, it was reasoned that the level of acetylcholine (ACh) release in these regions would show distinct profiles during testing in trace and delay conditioning paradigms. To test this assumption, microdialysis probes were implanted unilaterally into the mPFC and HPC of rats that were pre-trained in appetitive trace and delay conditioning paradigms using different conditional stimuli in the two tasks. On the day of microdialysis testing, dialysate samples were collected during a quiet baseline interval before trials were initiated, and again during performance in separate blocks of trace and delay conditioning trials in each animal. ACh levels were quantified using high performance liquid chromatography and electrochemical detection techniques. Consistent with our hypothesis, results showed that ACh release in the mPFC was greater during trace conditioning than during delay conditioning. The level of ACh released during trace conditioning in the HPC was also greater than the levels observed during delay conditioning. While ACh efflux in both the mPFC and HPC selectively increased during trace conditioning, ACh levels in the mPFC during trace conditioning testing showed the greatest increases observed. These results demonstrate a dissociation in cholinergic activation of the mPFC and HPC during performance in trace but not delay appetitive conditioning, where this cholinergic activity may contribute to attentional mechanisms, adaptive response timing, or memory consolidation necessary for successful trace conditioning. PMID:21514394

Mid-Infrared Spectroscopy of Persistent Leonid Trains

NASA Technical Reports Server (NTRS)

Russell, Ray W.; Rossano, George S.; Chatelain, Mark A.; Lynch, David K.; Tessensohn, Ted K.; Abendroth, Eric; Kim, Daryl; Jenniskens, Peter; DeVincenzi, Donald L. (Technical Monitor)

2000-01-01

The first infrared spectroscopy in the 3-13 micron region has been obtained of several persistent Leonid meteor trains with two different instrument types, one at a desert ground-based site and the other on-board a high-flying aircraft. The spectra exhibit common structures assigned to enhanced emissions of warm CH4, CO2, CO and H2O which may originate from heated trace air compounds or materials created in the wake of the meteor. This is the first time that any of these molecules has been observed in the spectra of persistent trains. Hence, the mid-IR observations offer a new perspective on the physical processes that occur in the path of the meteor at some time after the meteor itself has passed by. Continuum emission is observed also, but its origin has not yet been established. No 10 micron dust emission feature has been observed.

Fire danger rating in the United States of America: An evolution since 1916

Treesearch

Colin C. Hardy; Charles E. Hardy

2007-01-01

Fire scientists in the United States began exploring the relationships of fire-danger and hazard with weather, fuel moisture, and ignition probabilities as early as 1916. Many of the relationships identified then persist today in the form of our National Fire-Danger-Rating System. This paper traces the evolution of fire-danger rating in the United States, including...

The Construction, Negotiation, and Transformation of Racial Identity in American Football: A Study of Native and African Americans.

ERIC Educational Resources Information Center

Gems, Gerald R.

1998-01-01

Traces and compares the histories of Black and American-Indian participation in collegiate and professional football. Discusses athletic participation by minority groups as a challenge to segregation and notions of White superiority; as a challenge to the persistence of racist stereotypes in media coverage; and as a foundation for the…

IMPACTS OF LAND USE CHANGE AND FIRE ON NUTRIENT AND CARBON CYCLES AND TRACE GAS EXCHANGE IN SOILS OF THE CERRADO IN CENTRAL BRAZIL

EPA Science Inventory

The Brazilian cerrado is experiencing rapid land use changes that are often accompanied by fire. Here we report initial studies of the effects of fire and land use change on the composition and persistence of litter and soil organic carbon and nitrogen and related changes in the ...

INTERACTIONS OF NUTRIENT AND CARBON CYCLES AND TRACE GAS EXCHANGE WITH LAND USE CHANGE AND FIRE IN THE CERRADO OF CENTRAL BRAZIL

EPA Science Inventory

Land use changes accompanied by fire frequently occur in the Brazilian cerrado. Here we report measurements in the cerrado of the effects of fire and land use change on the composition and persistence of litter and soil organic carbon and nitrogen and related changes in the soil-...

Porewater dynamics of silver, lead and copper in coastal sediments and implications for benthic metal fluxes

USGS Publications Warehouse

Kalnejais, Linda H.; Martin, W. R.; Bothner, Michael H.

2015-01-01

To determine the conditions that lead to a diffusive release of dissolved metals from coastal sediments, porewater profiles of Ag, Cu, and Pb have been collected over seven years at two contrasting coastal sites in Massachusetts, USA. The Hingham Bay (HB) site is a contaminated location in Boston Harbor, while the Massachusetts Bay (MB) site is 11 km offshore and less impacted. At both sites, the biogeochemical cycles include scavenging by Fe-oxyhydroxides and release of dissolved metals when Fe-oxyhydroxides are reduced. Important differences in the metal cycles at the two sites, however, result from different redox conditions. Porewater sulfide and seasonal variation in redox zone depth is observed at HB, but not at MB. In summer, as the conditions become more reducing at HB, trace metals are precipitated as sulfides and are no longer associated with Fe-oxyhydroxides. Sulfide precipitation close to the sediment–water interface limits the trace metal flux in summer and autumn at HB, while in winter, oxidation of the sulfide phases drives high benthic fluxes of Cu and Ag, as oxic conditions return. The annual diffusive flux of Cu at HB is found to be significant and contributes to the higher than expected water column Cu concentrations observed in Boston Harbor. At MB, due to the lower sulfide concentrations, the association of trace metals with Fe-oxyhydroxides occurs throughout the year, leading to more stable fluxes. A surface enrichment of solid phase trace metals was found at MB and is attributed to the persistent scavenging by Fe-oxyhydroxides. This process is important, particularly at sites that are less reducing, because it maintains elevated metal concentrations at the surface despite the effects of bioturbation and sediment accumulation, and because it may increase the persistence of metal contamination in surface sediments.

Trace fossils revealed through x-radiography in facies analysis of Smackover Formation, southwest Alabama

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

Esposito, R.A.; King, D.T. Jr.

The use of x-radiography has been applied to slabbed cores of Jurassic Smackover limestones from southwestern Alabama to enhance the complete petrologic description of the rocks. Through x-radiography, trace fossils have been revealed in what would otherwise appear to be homogeneous rock. In these biogenic structures, organic material, partly fecal in origin, is concentrated as infill packing in actively filled burrows. A microreducing environment within the burrow results in the mineralization by finely disseminated FeS/sub 2/. The density difference between FeS/sub 2/, which has a high absorption coefficient, and the surrounding calcium carbonate highlights the burrows in the x-radiographs. Thismore » characteristic burrow mineralization is shown well in the Smackover where a Zoophycus-Thalassinoides trace-fossil assemblage has been identified. Zoophycus, a feeding structure, is characterized by concave-upward traces with whorled peaks, and is best seen in slabs cut perpendicular to bedding. Thalassinoides is a dwelling structure characterized by a boxwork burrow system and is best seen in cores cut parallel to bedding. This assemblage is restricted to facies that is laterally persistent throughout the Smackover in most of Escambia County, Alabama. This trace-fossil assemblage is found in an oolitic pelletal packstone. This unit is overlain by an oolitic grainstone and is stratigraphically above a sparsely fossiliferous, laminated wackestone and packstone. Trace fossils in this horizon are abundant, but the traces are not found in stratigraphically adjacent lithofacies. Detecting these otherwise unseen trace fossils by x-radiography assisted the paleoenvironmental interpretation of this depositional facies as a low-energy subwave-base carbonate-shelf deposit.« less

Herd size and bovine tuberculosis persistence in cattle farms in Great Britain.

PubMed

Brooks-Pollock, Ellen; Keeling, Matt

2009-12-01

Bovine tuberculosis (bTB) infection in cattle is one of the most complex and persistent problems faced by the cattle industry in Great Britain today. While a number of factors have been identified as increasing the risk of infection, there has been little analysis on the causes of persistent infection within farms. In this article, we use the Cattle Tracing System to examine changes in herd size and VetNet data to correlate herd size with clearance of bTB. We find that the number of active farms fell by 16.3% between 2002 and 2007. The average farm size increased by 17.9% between 2002 and 2005. Using a measure similar to the Critical Community Size, the VetNet data reveal that herd size is positively correlated with disease persistence. Since economic policy and subsidies have been shown to influence farm size, we used a simple financial model for ideal farm size which includes disease burden to conclude that increasing herd size for efficiency gains may contribute to increased disease incidence.

Effects-based spatial assessment of contaminated estuarine sediments from Bear Creek, Baltimore Harbor, MD, USA.

PubMed

Hartzell, Sharon E; Unger, Michael A; McGee, Beth L; Wilson, Sacoby M; Yonkos, Lance T

2017-10-01

Estuarine sediments in regions with prolonged histories of industrial activity are often laden to significant depths with complex contaminant mixtures, including trace metals and persistent organic pollutants. Given the complexity of assessing risks from multi-contaminant exposures, the direct measurement of impacts to biological receptors is central to characterizing contaminated sediment sites. Though biological consequences are less commonly assessed at depth, laboratory-based toxicity testing of subsurface sediments can be used to delineate the scope of contamination at impacted sites. The extent and depth of sediment toxicity in Bear Creek, near Baltimore, Maryland, USA, was delineated using 10-day acute toxicity tests with the estuarine amphipod Leptocheirus plumulosus, and chemical analysis of trace metals and persistent organic pollutants. A gradient of toxicity was demonstrated in surface sediments with 21 of 22 tested sites differing significantly from controls. Effects were most pronounced (100% lethality) at sites proximate to a historic industrial complex. Sediments from eight of nine core samples to depths of 80 cm were particularly impacted (i.e., caused significant lethality to L. plumulosus) even in locations overlain with relatively non-toxic surface sediments, supporting a conclusion that toxicity observed at the surface (top 2 cm) does not adequately predict toxicity at depth. In seven of nine sites, toxicity of surface sediments differed from toxicity at levels beneath by 28 to 69%, in five instances underestimating toxicity (28 to 69%), and in two instances overestimating toxicity (44 to 56%). Multiple contaminants exceeded sediment quality guidelines and correlated positively with toxic responses within surface sediments (e.g., chromium, nickel, polycyclic aromatic hydrocarbon (PAH), total petroleum hydrocarbon). Use of an antibody-based PAH biosensor revealed that porewater PAH concentrations also increased with depth at most sites. This study informs future management decisions concerning the extent of impact to Bear Creek sediments, and demonstrates the benefits of a spatial approach, relying primarily on toxicity testing to assess sediment quality in a system with complex contaminant mixtures.

Tracking in vivo migration and distribution of antigen-specific cytotoxic T lymphocytes by 5,6-carboxyfluorescein diacetate succinimidyl ester staining during cancer immunotherapy.

PubMed

Xu, Wei-li; Li, Suo-lin; Wen, Ming; Wen, Jun-ye; Han, Jie; Zhang, Hong-zhen; Gao, Fei; Cai, Jian-hui

2013-08-01

Killing of targeted tumors during adoptive cell transfer therapy is associated with cytotoxic T lymphocyte (CTL) numbers, immunophenotype, tumor-specificity, and in vivo residence time, migration, and distribution. Therefore, tracing in vivo persistence, migration, and distribution of CTLs is important for cancer immunotherapy. Optimal staining concentration for CTL proliferation was determined by cell counting kit-8 (CCK-8) assay and killing efficiencies of CTLs or carboxyfluorescein diacetate succinimidyl ester (CFSE)-labeled melanoma antigen-specific cytotoxic T lymphocytes (CFSE-CTLs) for malignant melanoma cells in vitro were compared. Additionally, CFSE-CTLs were intravenously transfused to mice receiving B16 melanoma, and their residence time, migration, and distribution in vivo were observed by measuring fluorescence intensities of CFSE-CTLs per gram of tissue (%FI/g) in various tissues and analyzing tumor/non-tumor (T/NT) values. Anti-tumor effects of transferred CTLs and correlation between %FI/g and D-value of tumor size were analyzed. Five-micromolar CFSE was optimal for labeling CTLs with minimal cytotoxicity. No significant difference occurred between CTLs and CFSE-CTLs for tumor cell killing (P = 0.849) or interleukin-2 (P = 0.318) and interferon-γ (P = 0.201) levels. Distribution of CTLs in vivo varied with time. A negative correlation between %FI/g in tumors and D-value of tumor sizes by Spearman correlation analysis was observed. CTLs were recruited to and killed tumors from 6 hours to 3 days after cell infusion. CTLs were observed up to three weeks later in the tumor, liver, kidneys, and spleen; this was related to the abundant blood supply or the nature of immune organs. CCK-8 assay is a novel method to select optimal CFSE staining concentrations. Fluorescence intensity of transferred CTLs reflects their killing efficiency of tumors. CFSE fluorescent markers can trace in vivo CTL persistence, migration, and distribution because of its stability, long half-life, and low toxicity.

Chemically assisted phytoextraction: a review of potential soil amendments for increasing plant uptake of heavy metals.

PubMed

Meers, E; Tack, F M G; Van Slycken, S; Ruttens, A; Du Laing, G; Vangronsveld, J; Verloo, M G

2008-01-01

The contamination of soils by trace metals has been an unfortunate sideeffect of industrialization. Some of these contaminants can interfere with vulnerable enduses of soil, such as agriculture or nature, already at relatively low levels of contamination. Reversely, conventional civil-technical soil-remediation techniques are too expensive to remediate extended areas of moderately contaminated soil. Phytoextraction has been proposed as a more economic complementary approach to deal with this specific niche of soil contamination. However, phytoextraction has been shown to be a slow-working process due to the low amounts of metals that can be annually removed from the soil under normal agronomic conditions. Therefore, extensive research has been conducted on process optimization by means of chemically improving plant availability and the uptake of heavy metals. A wide range of potential amendments has been proposed in the literature, with considerable attention being spent on aminopolycarboxylic acids such as ethylenediaminetetraacetic acid (EDTA). However, these compounds have received increasing criticism due to their environmental persistence and associated risks for leaching. This review presents an overview of potential soil amendments that can be employed for enhancing metal uptake by phytoextraction crops, with a distinct focus on more degradable alternatives to persistent compounds such as EDTA.

Sorption and degradation of wastewater-associated non-steroidal anti-inflammatory drugs and antibiotics in soils.

PubMed

Lin, Kunde; Gan, Jay

2011-04-01

Presence of pharmaceuticals at trace levels in recycled water is an emerging issue impacting the beneficial reuse of treated wastewater, including practices such as irrigation and groundwater recharge in arid and semi-arid regions. To assess the environmental risks of irrigation with recycled water containing such micropollutants, in this study we evaluated sorption and degradation of five pharmaceuticals that are antibiotic and anti-inflammatory drugs in two soils collected from arid regions. Naproxen and trimethoprim showed moderate to strong sorption, while the sorption of diclofenac, ibuprofen and sulfamethoxazole was negligible in both soils. Under aerobic conditions, the studied compounds were susceptible to microbial degradation with half-lives varying from 4.8 to 69.3d. Apart from sulfamethoxazole, the other compounds were relatively persistent under anaerobic conditions as indicated by a negligible loss over 84d of incubation or half-lives >50d. The degradation of the selected pharmaceuticals was influenced by microbial activities, oxygen status in the soil, soil type and compound characteristics. The poor sorption and relative persistence of diclofenac and ibuprofen under anaerobic conditions suggest that the two chemicals may pose a high leaching risk when using recycled for irrigation or groundwater replenishment. Copyright © 2010 Elsevier Ltd. All rights reserved.

Memory and consciousness: trace distinctiveness in memory retrievals.

PubMed

Brunel, Lionel; Oker, Ali; Riou, Benoit; Versace, Rémy

2010-12-01

The aim of this article was to provide experimental evidence that classical dissociation between levels of consciousness associated with memory retrieval (i.e., implicit or explicit) can be explained in terms of task dependency and distinctiveness of traces. In our study phase, we manipulated the level of isolation (partial vs. global) of the memory trace by means of an isolation paradigm (isolated words among non-isolated words). We then tested these two types of isolation in a series of tasks of increasing complexity: a lexical decision task, a recognition task, and a free recall task. The main result of this study was that distinctiveness effects were observed as a function of the type of isolation (level of isolation) and the nature of the task. We concluded that trace distinctiveness improves subsequent access to the trace, while the level of trace distinctiveness also appears to determine the possibility of conscious or explicit retrieval. Copyright © 2010 Elsevier Inc. All rights reserved.

PKMζ Inhibition Reverses Learning-Induced Increases in Hippocampal Synaptic Strength and Memory during Trace Eyeblink Conditioning

PubMed Central

Madroñal, Noelia; Gruart, Agnès; Sacktor, Todd C.; Delgado-García, José M.

2010-01-01

A leading candidate in the process of memory formation is hippocampal long-term potentiation (LTP), a persistent enhancement in synaptic strength evoked by the repetitive activation of excitatory synapses, either by experimental high-frequency stimulation (HFS) or, as recently shown, during actual learning. But are the molecular mechanisms for maintaining synaptic potentiation induced by HFS and by experience the same? Protein kinase Mzeta (PKMζ), an autonomously active atypical protein kinase C isoform, plays a key role in the maintenance of LTP induced by tetanic stimulation and the storage of long-term memory. To test whether the persistent action of PKMζ is necessary for the maintenance of synaptic potentiation induced after learning, the effects of ZIP (zeta inhibitory peptide), a PKMζ inhibitor, on eyeblink-conditioned mice were studied. PKMζ inhibition in the hippocampus disrupted both the correct retrieval of conditioned responses (CRs) and the experience-dependent persistent increase in synaptic strength observed at CA3-CA1 synapses. In addition, the effects of ZIP on the same associative test were examined when tetanic LTP was induced at the hippocampal CA3-CA1 synapse before conditioning. In this case, PKMζ inhibition both reversed tetanic LTP and prevented the expected LTP-mediated deleterious effects on eyeblink conditioning. Thus, PKMζ inhibition in the CA1 area is able to reverse both the expression of trace eyeblink conditioned memories and the underlying changes in CA3-CA1 synaptic strength, as well as the anterograde effects of LTP on associative learning. PMID:20454458

Recent advances and remaining challenges for the spectroscopic detection of explosive threats.

PubMed

Fountain, Augustus W; Christesen, Steven D; Moon, Raphael P; Guicheteau, Jason A; Emmons, Erik D

2014-01-01

In 2010, the U.S. Army initiated a program through the Edgewood Chemical Biological Center to identify viable spectroscopic signatures of explosives and initiate environmental persistence, fate, and transport studies for trace residues. These studies were ultimately designed to integrate these signatures into algorithms and experimentally evaluate sensor performance for explosives and precursor materials in existing chemical point and standoff detection systems. Accurate and validated optical cross sections and signatures are critical in benchmarking spectroscopic-based sensors. This program has provided important information for the scientists and engineers currently developing trace-detection solutions to the homemade explosive problem. With this information, the sensitivity of spectroscopic methods for explosives detection can now be quantitatively evaluated before the sensor is deployed and tested.

Infectious Agents As Markers of Human Migration toward the Amazon Region of Brazil

PubMed Central

Ishak, Ricardo; Machado, Luiz F. A.; Cayres-Vallinoto, Izaura; Guimarães Ishak, Marluísa de O.; Vallinoto, Antonio C. R.

2017-01-01

Infectious agents are common companions of humans and since ancient times they follow human migration on their search for a better place to live. The study of paleomicrobiology was significantly improved in its accuracy of measurement with the constant development of better methods to detect and analyze nucleic acids. Human tissues are constantly used to trace ancient infections and the association of anthropological evidences are important to confirm the microbiological information. Infectious agents which establish human persistent infections are particularly useful to trace human migrations. In the present article, the evidence of infection by viral agents such as human T-lymphotropic virus 1, human T-lymphotropic virus 2, human herpes virus-8, JC virus, and a bacterium, Chlamydia trachomatis, was described using different methodologies for their detection. Their presence was further used as biomarkers associated with anthropological and other relevant information to trace human migration into the Amazon region of Brazil. The approach also evidenced their microbiological origin, emergence, evolution, and spreading. The information obtained confirms much of the archeological information available tracing ancient and more recent human migration into this particular geographical region. In this article, the paleomicrobiological information on the subject was summarized and reviewed. PMID:28912770

The differential role of cortical protein synthesis in taste memory formation and persistence

NASA Astrophysics Data System (ADS)

Levitan, David; Gal-Ben-Ari, Shunit; Heise, Christopher; Rosenberg, Tali; Elkobi, Alina; Inberg, Sharon; Sala, Carlo; Rosenblum, Kobi

2016-05-01

The current dogma suggests that the formation of long-term memory (LTM) is dependent on protein synthesis but persistence of the memory trace is not. However, many of the studies examining the effect of protein synthesis inhibitors (PSIs) on LTM persistence were performed in the hippocampus, which is known to have a time-dependent role in memory storage, rather than the cortex, which is considered to be the main structure to store long-term memories. Here we studied the effect of PSIs on LTM formation and persistence in male Wistar Hola (n⩾5) rats by infusing the protein synthesis inhibitor, anisomycin (100 μg, 1 μl), into the gustatory cortex (GC) during LTM formation and persistence in conditioned taste aversion (CTA). We found that local anisomycin infusion to the GC before memory acquisition impaired LTM formation (P=8.9E-5), but had no effect on LTM persistence when infused 3 days post acquisition (P=0.94). However, when we extended the time interval between treatment with anisomycin and testing from 3 days to 14 days, LTM persistence was enhanced (P=0.01). The enhancement was on the background of stable and non-declining memory, and was not recapitulated by another amnesic agent, APV (10 μg, 1 μl), an N-methyl-D-aspartate receptor antagonist (P=0.54). In conclusion, CTA LTM remains sensitive to the action of PSIs in the GC even 3 days following memory acquisition. This sensitivity is differentially expressed between the formation and persistence of LTM, suggesting that increased cortical protein synthesis promotes LTM formation, whereas decreased protein synthesis promotes LTM persistence.

A characterization of persistence at short times in the WFC3/IR detector

NASA Astrophysics Data System (ADS)

Gennaro, M.; Bajaj, V.; Long, K.

2018-05-01

Persistence in the WFC3/IR detector appears to decay as a power law as a function of time elapsed since the end of a stimulus. In this report we study departures from the power law at times shorter than a few hundreds seconds after the stimulus. In order to have better short-time cadence, we use the Multiaccum (.ima) files, which trace the accumulated charge in the pixels as function of time, rather than the final pipeline products (.flt files), which instead report the electron rate estimated via a linear fit to the accumulated charge vs. time relation. We note that at short times after the stimulus, the absolute change in persistence is the strongest, thus a linear fit to the accumulated signal (the .flt values) can be a poor representation of the strongly varying persistence signal. The already observed power-law decay of the persistence signal, still holds at shorter times, with typical values of the power law index, gamma in [-0.8,-1] for stimuli that saturate the WFC3 pixels. To a good degree of approximation, a single power law is a good fit to the persistence signal decay from 100 to 5000 seconds. We also detect a tapering-off in the power-law decay at increasingly shorter times. This change in behavior is of the order of Delta Gamma 0.02 - 0.05 when comparing power-law fits performed to the persistence signal from 0 up to 250 seconds and from 0 up to 4000 seconds after the stimulus, indicating that persistence decays slightly more rapidly as time progresses. Our results may suggest that for even shorter times, not probed by our study, the WFC3 persistence signal might deviate from a single power-law model.

Trace element and stable isotope analysis of fourteen species of marine invertebrates from the Bay of Fundy, Canada.

PubMed

English, Matthew D; Robertson, Gregory J; Mallory, Mark L

2015-12-15

The Bay of Fundy, Canada, is a macrotidal bay with a highly productive intertidal zone, hosting a large abundance and diversity of marine invertebrates. We analysed trace element concentrations and stable isotopic values of δ(15)N and δ(13)C in 14 species of benthic marine invertebrates from the Bay of Fundy's intertidal zone to investigate bioaccumulation or biodilution of trace elements in the lower level of this marine food web. Barnacles (Balanus balanus) consistently had significantly greater concentrations of trace elements compared to the other species studied, but otherwise we found low concentrations of non-essential trace elements. In the range of trophic levels that we studied, we found limited evidence of bioaccumulation or biodilution of trace elements across species, likely due to the species examined occupying similar trophic levels in different food chains. Copyright © 2015 Elsevier Ltd. All rights reserved.

Oscillations in rational economies.

PubMed

Mishchenko, Yuriy

2014-01-01

Economic (business) cycles are some of the most noted features of market economies, also ranked among the most serious of economic problems. Despite long historical persistence, the nature and the origin of business cycles remain controversial. In this paper we investigate the problem of the nature of business cycles from the positions of the market systems viewed as complex systems of many interacting market agents. We show that the development of cyclic instabilities in these settings can be traced down to just two fundamental factors - the competition of market agents for market shares in the settings of an open market, and the depression of market caused by accumulation of durable overproduced commodities on the market. These findings present the problem of business cycles in a new light as a systemic property of efficient market systems emerging directly from the free market competition itself, and existing in market economies at a very fundamental level.

Tracking contaminants in seabirds of Arctic Canada: temporal and spatial insights.

PubMed

Mallory, Mark L; Braune, Birgit M

2012-07-01

Levels and trends of persistent organic pollutants and trace elements in seabirds breeding in the vast Canadian Arctic have been monitored since 1975. Data from this monitoring have indicated both spatial and temporal variation across the region, attributable in part to differences in species' diets, differences in regional deposition patterns, and unidirectional trends in contaminants reaching this area from emissions in temperate and tropical areas to the south. Seabird tissues have served as effective biomonitors to examine this variation, and national and international collaboration in this monitoring effort has promoted valuable synthetic assessments of spatial and temporal patterns in Arctic contaminants. Here we review the history of the monitoring program, the critical role played by Environment Canada's National Wildlife Specimen Bank, and we summarize important spatial and temporal trends in various contaminants in Canadian Arctic seabirds. Copyright © 2012 Elsevier Ltd. All rights reserved.

Oscillations in Rational Economies

PubMed Central

Mishchenko, Yuriy

2014-01-01

Economic (business) cycles are some of the most noted features of market economies, also ranked among the most serious of economic problems. Despite long historical persistence, the nature and the origin of business cycles remain controversial. In this paper we investigate the problem of the nature of business cycles from the positions of the market systems viewed as complex systems of many interacting market agents. We show that the development of cyclic instabilities in these settings can be traced down to just two fundamental factors – the competition of market agents for market shares in the settings of an open market, and the depression of market caused by accumulation of durable overproduced commodities on the market. These findings present the problem of business cycles in a new light as a systemic property of efficient market systems emerging directly from the free market competition itself, and existing in market economies at a very fundamental level. PMID:24505319

Forensic intelligence framework--Part I: Induction of a transversal model by comparing illicit drugs and false identity documents monitoring.

PubMed

Morelato, Marie; Baechler, Simon; Ribaux, Olivier; Beavis, Alison; Tahtouh, Mark; Kirkbride, Paul; Roux, Claude; Margot, Pierre

2014-03-01

Forensic intelligence is a distinct dimension of forensic science. Forensic intelligence processes have mostly been developed to address either a specific type of trace or a specific problem. Even though these empirical developments have led to successes, they are trace-specific in nature and contribute to the generation of silos which hamper the establishment of a more general and transversal model. Forensic intelligence has shown some important perspectives but more general developments are required to address persistent challenges. This will ensure the progress of the discipline as well as its widespread implementation in the future. This paper demonstrates that the description of forensic intelligence processes, their architectures, and the methods for building them can, at a certain level, be abstracted from the type of traces considered. A comparative analysis is made between two forensic intelligence approaches developed independently in Australia and in Europe regarding the monitoring of apparently very different kind of problems: illicit drugs and false identity documents. An inductive effort is pursued to identify similarities and to outline a general model. Besides breaking barriers between apparently separate fields of study in forensic science and intelligence, this transversal model would assist in defining forensic intelligence, its role and place in policing, and in identifying its contributions and limitations. The model will facilitate the paradigm shift from the current case-by-case reactive attitude towards a proactive approach by serving as a guideline for the use of forensic case data in an intelligence-led perspective. A follow-up article will specifically address issues related to comparison processes, decision points and organisational issues regarding forensic intelligence (part II). Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Dredging-related mobilisation of trace metals: a case study in The Netherlands.

PubMed

van den Berg, G A; Meijers, G G; van der Heijdt, L M; Zwolsman, J J

2001-06-01

Mobilisation of contaminants is an important issue in environmental risk assessment of dredging projects. This study has aimed at identifying the effects of dredging on mobilisation of trace metals (Zn, Cu, Cd and Pb). The intensities and time scales of trace metal mobilisation were investigated during an experimental dredging project conducted under field conditions. The loss of contaminated dredge spoil is mainly reflected by increasing levels of trace metals in the suspended matter, dissolved trace metal concentrations in the water column are not significantly influenced by the dredging activities. This indicates a strong binding mechanism of trace metals to the solid phase or a fast redistribution over sorptive phases in response to oxidation of e.g. trace metal sulphides. Given the differences in levels of reactive phases (Mn, Fe, sulphides and organic matter) between the riverine suspended matter and the sediments, changes in the levels of these parameters in the suspended matter upon dredging may give information on the processes influencing the behaviour of trace metals and on the potential loss of sediment during dredging operations. Therefore, we recommend to routinely measure these parameters in studies on contaminant behaviour related to dredging activities.

Organ donation as transition work: Policy discourse and clinical practice in The Netherlands.

PubMed

Paul, Katharina T; Avezaat, Cees J J; Ijzermans, Jan N; Friele, Roland D; Bal, Roland A

2014-07-01

An increasing number of patients become eligible for organ transplants. In the Netherlands, at the level of policy discourse, growing waiting lists are often referred to as a persistent "shortage" of organs, producing a "public health crisis." In this way, organ donation is presented as an ethical, social, and medical necessity. Likewise, policy discourse offers a range of seemingly unambiguous solutions: improving logistical infrastructure at the level of hospitals, developing organizational and legal protocols, as well as public information campaigns. Instead of taking these problem and solution definitions as given, we critically examine the relationship between policy discourse and clinical practice. Based on a historical review, first, we trace the key moments of transformation where organ donation became naturalized in Dutch policy discourse, particularly in its altruistic connotation. Second, based on in-depth interviews with medical professionals, we show how those involved in organ donation continue to struggle with the controversial nature of their clinical practice. More specifically, we highlight their use of different forms of knowledge that underlie clinicians' "transition work": from losing a patient to "gaining" a donor. © The Author(s) 2013.

Spatial distribution and biological effects of trace metals (Cu, Zn, Pb, Cd) and organic micropollutants (PCBs, PAHs) in mussels Mytilus galloprovincialis along the Algerian west coast.

PubMed

Benali, Imene; Boutiba, Zitouni; Grandjean, Dominique; de Alencastro, Luiz Felippe; Rouane-Hacene, Omar; Chèvre, Nathalie

2017-02-15

Native mussels Mytilus galloprovincialis are used as bioindicator organisms to assess the concentration levels and toxic effects of persistent chemicals, polychlorobiphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), and heavy metals using biomarker responses, such as catalase (CAT), glutathione s-transferase (GST), and condition indices, for the Algerian coast. The results show that mussels of Oran Harbour are extremely polluted by PCBs and PAHs, i.e., 97.6 and 2892.1μg/kg d.w., respectively. Other sites present low levels of pollution. Furthermore, high concentrations of zinc, lead and cadmium are found in mussels from fishing, agricultural and estuarine sites, respectively, while low concentrations of copper are found in all of the sites studied. CAT activity is negatively correlated with Cd and Cu, and Zn is positively correlated with GST and CAT. Site classification tools reveal the potential toxicity of coastal areas exposed to anthropogenic pressure and a gradient of toxicity along the Algerian west coast. Copyright © 2016 Elsevier Ltd. All rights reserved.

Distress tolerance: Associations with trauma and substance cue reactivity in low-income, inner-city adults with substance use disorders and posttraumatic stress.

PubMed

Vujanovic, Anka A; Wardle, Margaret C; Bakhshaie, Jafar; Smith, Lia J; Green, Charles E; Lane, Scott D; Schmitz, Joy M

2018-05-01

Cue reactivity has great potential to advance our understanding of posttraumatic stress disorder (PTSD), substance use disorder (SUD), and PTSD/SUD comorbidity. The present investigation examined distress tolerance (DT) with regard to trauma and substance cue reactivity. Participants included 58 low-income, inner-city adults (49.1% women; M age = 45.73, SD = 10.00) with substance dependence and at least 4 symptoms of PTSD. A script-driven cue reactivity paradigm was utilized. Four DT measures were administered, including the Distress Tolerance Scale (DTS), Mirror-Tracing Persistence Task (MTPT), Breath-Holding Task (BH), and Paced Auditory Serial Addition Task (PASAT). Lower DT, as indexed by MTPT duration, was significantly predictive of greater levels of self-reported substance cravings/urges in response to trauma cues, above and beyond covariates. Lower DTS scores predicted lower levels of self-reported control/safety ratings in response to substance cues. None of the DT indices was significantly predictive of heart rate variability. Clinical and research implications are discussed. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Twenty years after Erich Muhe: Persisting controversies with the gold standard of laparoscopic cholecystectomy.

PubMed

Jani, Kalpesh; Rajan, P S; Sendhilkumar, K; Palanivelu, C

2006-06-01

This review article is a tribute to the genius of Professor Erich Muhe, a man ahead of his times. We trace the development of laparoscopic cholecystectomy and detail the tribulations faced by Muhe. On the occasion of the twentieth anniversary of the first laparoscopic cholecystectomy, we take another look at some of the controversies surrounding this gold standard in the management of gallbladder disease.

Titanium Nanoparticle Size Influences Trace Concentration Levels in Skin Appendages.

PubMed

Tasat, Deborah R; Domingo, Mariela G; Bruno, Marcos E; Guglielmotti, María B; Olmedo, Daniel G

2017-07-01

As a result of biotribocorrosion, the surface of a titanium (Ti) biomedical device can be a potential source of systemic contamination with Ti nanoparticles (NPs). Although NPs can be chemically similar, differences in particle size may lead to different biological responses. The aim of this experimental study was to determine Ti trace levels in skin appendages and plasma and explore the influence of NP size on trace levels using a murine model. Results showed the presence of Ti traces in the nails, hair, and plasma. The concentration of the smallest NPs (5 Nm) was higher than that of 10 Nm NPs in all the studied samples. Irrespective of NP size, Ti levels were always lower in plasma than in skin appendages. Ti levels were higher in nails than in hair. Ti NPs size influenced trace concentration levels in hair/nails, suggesting that 5 Nm Ti particles are more easily eliminated through these skin appendages. Given that the nails showed the highest levels of Ti, and that these skin appendages are not exposed to agents that can leach out Ti, as occurs with hair, we propose the nails as the most suitable and reliable bioindicator for monitoring systemic contamination with Ti.

Serum trace metal levels in Alzheimer's disease and normal control groups.

PubMed

Park, Jun-Hyun; Lee, Dong-Woo; Park, Kyung Su; Joung, Hyojee

2014-02-01

To determine whether serum trace metals are related to abnormal cognition in Alzheimer's disease (AD). We studied serum lead (Pb), cadmium (Cd), mercury (Hg), and arsenic(As) in 89 patients with AD and in 118 cognitively normal individuals. We analyzed the results of the blood tests and the food intake. Serum Pb levels correlated with word list recall (P = .039) and word list recognition (P = .037). Without age adjustment, serum Cd levels (P = .044) were significantly higher in the AD group. After stratified age adjustment, the levels of selected trace metals did not differ significantly between AD and normal individuals. Food intakes regarding selected trace metals were not significantly different between the 2 groups. In this study, serum Pb, Cd, Hg, and As levels were not directly related to abnormal cognition in AD. Serum Pb levels were significantly negatively correlated with verbal memory scores.

Trace Elements in Marine Sediment and Organisms in the Gulf of Thailand

PubMed Central

Worakhunpiset, Suwalee

2018-01-01

This review summarizes the findings from studies of trace element levels in marine sediment and organisms in the Gulf of Thailand. Spatial and temporal variations in trace element concentrations were observed. Although trace element contamination levels were low, the increased urbanization and agricultural and industrial activities may adversely affect ecosystems and human health. The periodic monitoring of marine environments is recommended in order to minimize human health risks from the consumption of contaminated marine organisms. PMID:29677146

Assessment of serum trace elements and electrolytes in children with childhood and atypical autism.

PubMed

Skalny, Anatoly V; Simashkova, Natalia V; Klyushnik, Tatiana P; Grabeklis, Andrei R; Radysh, Ivan V; Skalnaya, Margarita G; Nikonorov, Alexandr A; Tinkov, Alexey A

2017-09-01

The existing data demonstrate a significant interrelation between ASD and essential and toxic trace elements status of the organism. However, data on trace element homeostasis in particular ASD forms are insufficient. Therefore, the objective of the present study was to assess the level of trace elements and electrolytes in serum of children with childhood and atypical autism. A total of 48 children with ASD (24 with childhood and 24 with atypical autism) and age- and sex-adjusted controls were examined. Serum trace elements and electrolytes were assessed using inductively-coupled plasma mass spectrometry. The obtained data demonstrate that children with ASD unspecified are characterized by significantly lower Ni, Cr, and Se levels as compared to the age- and sex-matched controls. At the same time, significantly decreased serum Ni and Se concentrations were detected in patients with childhood autism. In turn, children with atypical autism were characterized by more variable serum trace element spectrum. In particular, atypical autism is associated with lower serum Al, As, Ni, Cr, Mn, and Se levels in comparison to the control values. Moreover, Al and Mn concentration in this group was also lower than that in childhood autism patients. Generally, the obtained data demonstrate lower levels of both essential and toxic trace elements in atypical autism group, being indicative of profound alteration of trace elements metabolism. However, further detailed metabolic studies are required to reveal critical differences in metabolic pathways being responsible for difference in trace element status and clinical course of the disease. Copyright © 2016 Elsevier GmbH. All rights reserved.

Association between body levels of trace metals and glaucoma prevalence.

PubMed

Lin, Shuai-Chun; Singh, Kuldev; Lin, Shan C

2015-10-01

Abnormal body levels of essential elements and exposure to toxic trace metals have been postulated to contribute to the pathogenesis of diseases affecting many organ systems, including the eye. To investigate associations between body levels of trace metals and the prevalence of glaucoma in a cross-sectional population-based study. Blood or urine metallic element levels and information pertaining to ocular disease were available for 2680 individuals 19 years and older participating in the fourth Korea National Health and Nutrition Examination Survey between January 1, 2008, and December 31, 2009, the second and the third years of the survey (2007-2009). Glaucoma diagnosis was based on criteria established by the International Society of Geographic and Epidemiologic Ophthalmology. Demographic, comorbidity, and health-related behavior information was obtained via interview. Multivariable logistic regression analyses were performed to determine associations between blood and urine trace element levels and the odds of glaucoma diagnosis. All analyses were performed between September 2014 and December 2014. The presence or absence of glaucoma. After adjustment for potential confounders, blood manganese level was negatively associated with the odds of glaucoma diagnosis (odds ratio [OR], 0.44; 95% CI, 0.21-0.92). Blood mercury level was positively associated with glaucoma prevalence (OR, 1.01; 95% CI, 1.00-1.03). No definitive association was identified between blood cadmium or lead levels or urine arsenic level and a diagnosis of glaucoma. These findings in a cross-sectional study of the South Korean population suggest that a lower blood manganese level and a higher blood mercury level are associated with greater odds of glaucoma. For more confidence that trace metals may have a role in the pathogenesis of glaucoma, prospective studies would need to confirm that the presence of such trace metals increases the chance of developing glaucoma.

The synaptic plasticity and memory hypothesis: encoding, storage and persistence

PubMed Central

Takeuchi, Tomonori; Duszkiewicz, Adrian J.; Morris, Richard G. M.

2014-01-01

The synaptic plasticity and memory hypothesis asserts that activity-dependent synaptic plasticity is induced at appropriate synapses during memory formation and is both necessary and sufficient for the encoding and trace storage of the type of memory mediated by the brain area in which it is observed. Criteria for establishing the necessity and sufficiency of such plasticity in mediating trace storage have been identified and are here reviewed in relation to new work using some of the diverse techniques of contemporary neuroscience. Evidence derived using optical imaging, molecular-genetic and optogenetic techniques in conjunction with appropriate behavioural analyses continues to offer support for the idea that changing the strength of connections between neurons is one of the major mechanisms by which engrams are stored in the brain. PMID:24298167

Trace fossils and bioturbation in peritidal facies of the Potsdam-Theresa Formations (Cambrian-Ordovician), Northwest Adirondacks

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

Bjerstedt, T.W.; Erickson, J.M.

The Cambrian-Ordovician Potsdam Sandstone, Theresa Formation, and Canadian correlatives in the St. Lawrence Lowlands preserve tide-dominated facies during the basal Cambrian transgression. Low intertidal sand flats in the upper Potsdam contain a Skolithos Ichnofacies dominated by Diplocraterion parallelum in clean, herringbone cross-bedded sandstones indicative of high tidal current energy. Wind-wave-driven longshore and tidal currents along a macrotidal coastline were funneled northeast-southwest by Precambrian topographic relief of up to 65 m. This relief is now expressed as the Thousand Islands of New York and Canada. The conformably overlying Theresa Formation preserves a shoaling-upward sequence of mixed clastic-carbonate facies. Shallow subtidal andmore » peritidal facies contain a mixed Skolithos-Cruziana Ichnofacies in sharply alternating lithofacies consisting of gray, intensely bioturbated, poorly sorted calcareous sandstone, and meter-thick, white cross-bedded sandstone. The parallelism between ichnofacies and lithofacies indicates that environmental energy level and persistence rather than water depth controlled trace fossil distribution. Bioturbated sandstones contain a Cruziana ichnofacies of abundant deposit feeders including: Fustiglyphus , Gyrochorte , Neonereites uniserialis , Phycodes flabellum, Planolites beverlyensis, Rosselia socialis, and Teichichnus. Suspension feeders are represented by D. habichi, D. parallelum, Skolithos, Monocraterion, and possibly Palaeophycus tubularis. Scavenging or deposit-feeding arthropods are represented by rare Cruziana furrows. Cross-bedded sandstones contain a Skolithos Ichnofacies of shallow Skolithos and Monocraterion burrows, and an undescribed large epistratal eurypterid( ) trail.« less

A Persistence Model for African American Male Urban Community College Students.

ERIC Educational Resources Information Center

Mason, Harold P.

1998-01-01

Studies Kennedy-King College's low level of persistence among African-American "nontraditional" male students, and the resulting high rate of departure before completing specified goals. Proposes a model of persistence to develop modes of action, program enhancements, and activities within the college to increase persistence level. (24…

Predatory Bacteria as Natural Modulators of Vibrio parahaemolyticus and Vibrio vulnificus in Seawater and Oysters

PubMed Central

Fay, Johnna P.; Dickens, Keyana A.; Parent, Michelle A.; Soroka, Douglas S.; Boyd, E. Fidelma

2012-01-01

This study shows that naturally occurring Vibrio predatory bacteria (VPB) exert a major role in controlling pathogenic vibrios in seawater and shellfish. The growth and persistence of Vibrio parahaemolyticus and Vibrio vulnificus were assessed in natural seawater and in the Eastern oyster, Crassostrea virginica. The pathogens examined were V. vulnificus strain VV1003, V. parahaemolyticus O1:KUT (KUT stands for K untypeable), and V. parahaemolyticus O3:K6 and corresponding O3:K6 mutants deficient in the toxRS virulence regulatory gene or the rpoS alternative stress response sigma factor gene. Vibrios were selected for streptomycin resistance, which facilitated their enumeration. In natural seawater, oysters bioconcentrated each Vibrio strain for 24 h at 22°C; however, counts rapidly declined to near negligible levels by 72 h. In natural seawater with or without oysters, vibrios decreased more than 3 log units to near negligible levels within 72 h. Neither toxRS nor rpoS had a significant effect on Vibrio levels. In autoclaved seawater, V. parahaemolyticus O3:K6 counts increased 1,000-fold over 72 h. Failure of the vibrios to persist in natural seawater and oysters led to screening of the water samples for VPB on lawns of V. parahaemolyticus O3:K6 host cells. Many VPB, including Bdellovibrio and like organisms (BALOs; Bdellovibrio bacteriovorus and Bacteriovorax stolpii) and Micavibrio aeruginosavorus-like predators, were detected by plaque assay and electron microscopic analysis of plaque-purified isolates from Atlantic, Gulf Coast, and Hawaiian seawater. When V. parahaemolyticus O3:K6 was added to natural seawater containing trace amounts of VPB, Vibrio counts diminished 3 log units to nondetectable levels, while VPB increased 3 log units within 48 h. We propose a new paradigm that VPB are important modulators of pathogenic vibrios in seawater and oysters. PMID:22904049

Association between heavy metal and metalloid levels in topsoil and cancer mortality in Spain.

PubMed

Núñez, Olivier; Fernández-Navarro, Pablo; Martín-Méndez, Iván; Bel-Lan, Alejandro; Locutura Rupérez, Juan F; López-Abente, Gonzalo

2017-03-01

Spatio-temporal cancer mortality studies in Spain have revealed patterns for some tumours which display a distribution that is similar across the sexes and persists over time. Such characteristics would be common to tumours that shared risk factors, including the geochemical composition of the soil. The aim of this study was to assess the possible association between heavy metal and metalloid levels in topsoil (upper soil horizon) and cancer mortality in mainland Spain. Ecological cancer mortality study at a municipal level, covering 861,440 cancer deaths (27 different tumour locations) in 7917 Spanish mainland towns, from 1999 to 2008. The elements included in this analysis were Al, As, Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn. Topsoil levels (partial extraction) were determined by ICP-MS at 13,317 sampling points. For the analysis, the data on the topsoil composition have been transformed by the centred logratio (clr-transformation). Principal factor analysis was performed to obtain independent latent factors for the transformed variables. To estimate the effect of heavy metal levels in topsoil composition on mortality, we fitted Besag, York and Mollié models, which included each town's factor scores as the explanatory variable. Integrated Nested Laplace Approximation (INLA) was used as a tool for Bayesian inference. All results were adjusted for sociodemographic variables. The results showed an association between trace contents of heavy metals and metalloids in topsoil and mortality due to tumours of the digestive system in mainland Spain. This association was observed in both sexes, something that would support the hypothesis that the incorporation of heavy metals into the trophic chain might be playing a role in the aetiology of some types of cancer. Topsoil composition and the presence of potentially toxic elements in trace concentrations might be an additional component in the aetiology of some types of cancer, and go some way to determine the ensuing geographic differences in mortality in Spain. The results support the interest of inclusion of heavy metal levels in topsoil as a hypothesis in analytical epidemiological studies using biological markers of exposure to heavy metals and metalloids.

Persistent challenging behaviour in people with an intellectual disability.

PubMed

Totsika, Vasiliki; Hastings, Richard P

2009-09-01

The aim of the present review is to summarize recent research findings on the persistence of challenging behaviours in adults and children with an intellectual disability. Studies varied in their definition and measurement of persistence or change in challenging behaviours. Persistence levels tended to be high in adults and challenging behaviours were stable over time, especially in individuals with autism. Moderate to high stability levels were evident in children, although there was a tendency for decreases in mean scores for behaviour problems over time. A substantial proportion of people with an intellectual disability experience persistent and stable challenging behaviours across their lives. Our knowledge of the factors that drive these high levels of persistence remains limited.

Elemental economy: microbial strategies for optimizing growth in the face of nutrient limitation.

PubMed

Merchant, Sabeeha S; Helmann, John D

2012-01-01

Microorganisms play a dominant role in the biogeochemical cycling of nutrients. They are rightly praised for their facility for fixing both carbon and nitrogen into organic matter, and microbial driven processes have tangibly altered the chemical composition of the biosphere and its surrounding atmosphere. Despite their prodigious capacity for molecular transformations, microorganisms are powerless in the face of the immutability of the elements. Limitations for specific elements, either fleeting or persisting over eons, have left an indelible trace on microbial genomes, physiology, and their very atomic composition. We here review the impact of elemental limitation on microbes, with a focus on selected genetic model systems and representative microbes from the ocean ecosystem. Evolutionary adaptations that enhance growth in the face of persistent or recurrent elemental limitations are evident from genome and proteome analyses. These range from the extreme (such as dispensing with a requirement for a hard to obtain element) to the extremely subtle (changes in protein amino acid sequences that slightly, but significantly, reduce cellular carbon, nitrogen, or sulfur demand). One near-universal adaptation is the development of sophisticated acclimation programs by which cells adjust their chemical composition in response to a changing environment. When specific elements become limiting, acclimation typically begins with an increased commitment to acquisition and a concomitant mobilization of stored resources. If elemental limitation persists, the cell implements austerity measures including elemental sparing and elemental recycling. Insights into these fundamental cellular properties have emerged from studies at many different levels, including ecology, biological oceanography, biogeochemistry, molecular genetics, genomics, and microbial physiology. Here, we present a synthesis of these diverse studies and attempt to discern some overarching themes. Copyright © 2012 Elsevier Ltd. All rights reserved.

Elemental Economy: microbial strategies for optimizing growth in the face of nutrient limitation

PubMed Central

Merchant, Sabeeha S.; Helmann, John D.

2014-01-01

Microorganisms play a dominant role in the biogeochemical cycling of nutrients. They are rightly praised for their facility at fixing both carbon and nitrogen into organic matter, and microbial driven processes have tangibly altered the chemical composition of the biosphere and its surrounding atmosphere. Despite their prodigious capacity for molecular transformations, microorganisms are powerless in the face of the immutability of the elements. Limitations for specific elements, either fleeting or persisting over eons, have left an indelible trace on microbial genomes, physiology, and their very atomic composition. We here review the impact of elemental limitation on microbes, with a focus on selected genetic model systems and representative microbes from the ocean ecosystem. Evolutionary adaptations that enhance growth in the face of persistent or recurrent elemental limitations are evident from genome and proteome analyses. These range from the extreme (such as dispensing with a requirement for a hard to obtain element) to the extremely subtle (changes in protein amino acid sequences that slightly, but significantly, reduce cellular carbon, nitrogen, or sulfur demand). One near universal adaptation is the development of sophisticated acclimation programs by which cells adjust their chemical composition in response to a changing environment. When specific elements become limiting, acclimation typically begins with an increased commitment to acquisition and a concomitant mobilization of stored resources. If elemental limitation persists, the cell implements austerity measures including elemental-sparing and elemental-recycling. Insights into these fundamental cellular properties have emerged from studies at many different levels; including ecology, biological oceanography, biogeochemistry, molecular genetics, genomics, and microbial physiology. Here, we present a synthesis of these diverse studies and attempt to discern some overarching themes. PMID:22633059

Levels and Seasonal Variability of Persistent Organic Pollutants in Rural and Urban Atmosphere of Southern Ghana

NASA Astrophysics Data System (ADS)

Adu-Kumi, Sam; Klanova, Jana; Holoubek, Ivan

2010-05-01

Concentrations of persistent organic pollutants (POPs) in air are reported from the first full year of the RECETOX-Africa Air Monitoring (MONET_AFRICA) Project. Passive air samplers composed of polyurethane foam disks (PUF-disk samplers) were deployed for sampling background air concentrations from January-December 2008 at two urban sites in Ghana, namely, Ghana Atomic Energy Commission (Biotechnology and Nuclear Agricultural Research Institute, Kwabenya); and Ghana Meteorological Agency (East Legon). Another set of PUF-disk samplers were deployed at a rural/agricultural location (Lake Bosumtwi) from July-November 2008. For the purposes of this study, 28 days was the sampling period for polyaromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs); and 3 months for OCPs (Drins) and dioxins/furans (PCDD/Fs) respectively. MONET_AFRICA constituted part of the activities under the Global Monitoring Plan (GMP) for the effectiveness evaluation (Article 16) of the Stockholm Convention on POPs and the air sampling survey was conducted at 26 sites across the African continent with the aim to establish baseline information on contamination of ambient air with persistent organic pollutants (POPs) as a reference for future monitoring programmes in the region. For the pesticides, endosulfans constituted the highest contaminants measured followed by HCHs and DDTs in that order. The large temporal variability in the pesticide concentrations suggested seasonal application of endosulfans and γ-HCH. Levels of endosulfans were initially found to be below detection limit during the first sampling period (January - March 2008) but recorded the highest concentration than any other pesticide from all 16 sites in the African region during the second sampling period (April - June 2008). Concentrations of DDTs and HCHs were generally low throughout the sampling periods. p,p'-DDE/p,p'-DDT ratio in ambient air showed that the metabolite DDE was the most abundant and the concentrations of sums of DDTs were in tens of pg m-3. This suggests that the main source of DDTs was possibly due to past agricultural and public health usage. The soil concentrations of DDTs at the various sites were however negligible (approx. 1 ngg-1). The highest levels of HCHs were recorded in November and December 2008. HCB and PeCB concentrations in air were low and uniform and soil levels of HCB and PeCB were negligible. Only traces of aldrin, dieldrin, heptachlor and mirex were detected from both sites. PCBs were found at levels typical for the urban sites and the levels at the Kwabenya site were slightly lower than those measured at the East Legon site. Levels of PCBs at the rural/agricultural site (Lake Bosumtwi) were relatively lower than those measured at the urban sites. The levels of PAHs in ambient air were quite high at all sites with phenanthrene being the most abundant. Benzo(a)pyrene (a known carcinogen) levels in ambient air were however very low. The highest levels of PAHs were detected in January 2008, February 2008 and July/August 2008 at Kwabenya, East Legon, and Lake Bosumtwi, respectively. PCDD/F levels were also quite high, maximal I-TEQ was the third highest in the African region (after Egypt and Senegal). Keywords: Persistent Organic Pollutants; Background Concentrations; Ghana; PUF-disk sampler

Ebola virus disease contact tracing activities, lessons learned and best practices during the Duport Road outbreak in Monrovia, Liberia, November 2015.

PubMed

Wolfe, Caitlin M; Hamblion, Esther L; Schulte, Jacqueline; Williams, Parker; Koryon, Augustine; Enders, Jonathan; Sanor, Varlee; Wapoe, Yatta; Kwayon, Dash; Blackley, David J; Laney, Anthony S; Weston, Emily J; Dokubo, Emily K; Davies-Wayne, Gloria; Wendland, Annika; Daw, Valerie T S; Badini, Mehboob; Clement, Peter; Mahmoud, Nuha; Williams, Desmond; Gasasira, Alex; Nyenswah, Tolbert G; Fallah, Mosoka

2017-06-01

Contact tracing is one of the key response activities necessary for halting Ebola Virus Disease (EVD) transmission. Key elements of contact tracing include identification of persons who have been in contact with confirmed EVD cases and careful monitoring for EVD symptoms, but the details of implementation likely influence their effectiveness. In November 2015, several months after a major Ebola outbreak was controlled in Liberia, three members of a family were confirmed positive for EVD in the Duport Road area of Monrovia. The cluster provided an opportunity to implement and evaluate modified approaches to contact tracing. The approaches employed for improved contact tracing included classification and risk-based management of identified contacts (including facility based isolation of some high risk contacts, provision of support to persons being monitored, and school-based surveillance for some persons with potential exposure but not listed as contacts), use of phone records to help locate missing contacts, and modifications to data management tools. We recorded details about the implementation of these approaches, report the overall outcomes of the contact tracing efforts and the challenges encountered, and provide recommendations for management of future outbreaks. 165 contacts were identified (with over 150 identified within 48 hours of confirmation of the EVD cases) and all initially missing contacts were located. Contacts were closely monitored and promptly tested if symptomatic; no contacts developed disease. Encountered challenges related to knowledge gaps among contact tracing staff, data management, and coordination of contact tracing activities with efforts to offer Ebola vaccine. The Duport Road EVD cluster was promptly controlled. Missing contacts were effectively identified, and identified contacts were effectively monitored and rapidly tested. There is a persistent risk of EVD reemergence in Liberia; the experience controlling each cluster can help inform future Ebola control efforts in Liberia and elsewhere.

Ebola virus disease contact tracing activities, lessons learned and best practices during the Duport Road outbreak in Monrovia, Liberia, November 2015

PubMed Central

Schulte, Jacqueline; Williams, Parker; Koryon, Augustine; Enders, Jonathan; Sanor, Varlee; Wapoe, Yatta; Kwayon, Dash; Blackley, David J.; Laney, Anthony S.; Weston, Emily J.; Dokubo, Emily K.; Davies-Wayne, Gloria; Wendland, Annika; Daw, Valerie T. S.; Badini, Mehboob; Clement, Peter; Mahmoud, Nuha; Williams, Desmond; Gasasira, Alex; Nyenswah, Tolbert G.; Fallah, Mosoka

2017-01-01

Background Contact tracing is one of the key response activities necessary for halting Ebola Virus Disease (EVD) transmission. Key elements of contact tracing include identification of persons who have been in contact with confirmed EVD cases and careful monitoring for EVD symptoms, but the details of implementation likely influence their effectiveness. In November 2015, several months after a major Ebola outbreak was controlled in Liberia, three members of a family were confirmed positive for EVD in the Duport Road area of Monrovia. The cluster provided an opportunity to implement and evaluate modified approaches to contact tracing. Methods The approaches employed for improved contact tracing included classification and risk-based management of identified contacts (including facility based isolation of some high risk contacts, provision of support to persons being monitored, and school-based surveillance for some persons with potential exposure but not listed as contacts), use of phone records to help locate missing contacts, and modifications to data management tools. We recorded details about the implementation of these approaches, report the overall outcomes of the contact tracing efforts and the challenges encountered, and provide recommendations for management of future outbreaks. Results 165 contacts were identified (with over 150 identified within 48 hours of confirmation of the EVD cases) and all initially missing contacts were located. Contacts were closely monitored and promptly tested if symptomatic; no contacts developed disease. Encountered challenges related to knowledge gaps among contact tracing staff, data management, and coordination of contact tracing activities with efforts to offer Ebola vaccine. Conclusions The Duport Road EVD cluster was promptly controlled. Missing contacts were effectively identified, and identified contacts were effectively monitored and rapidly tested. There is a persistent risk of EVD reemergence in Liberia; the experience controlling each cluster can help inform future Ebola control efforts in Liberia and elsewhere. PMID:28575034

Salt stress-induced transcription of σB- and CtsR-regulated genes in persistent and non-persistent Listeria monocytogenes strains from food processing plants.

PubMed

Ringus, Daina L; Ivy, Reid A; Wiedmann, Martin; Boor, Kathryn J

2012-03-01

Listeria monocytogenes is a foodborne pathogen that can persist in food processing environments. Six persistent and six non-persistent strains from fish processing plants and one persistent strain from a meat plant were selected to determine if expression of genes in the regulons of two stress response regulators, σ(B) and CtsR, under salt stress conditions is associated with the ability of L. monocytogenes to persist in food processing environments. Subtype data were also used to categorize the strains into genetic lineages I or II. Quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR) was used to measure transcript levels for two σ(B)-regulated genes, inlA and gadD3, and two CtsR-regulated genes, lmo1138 and clpB, before and after (t=10 min) salt shock (i.e., exposure of exponential phase cells to BHI+6% NaCl for 10 min at 37°C). Exposure to salt stress induced higher transcript levels relative to levels under non-stress conditions for all four stress and virulence genes across all wildtype strains tested. Analysis of variance (ANOVA) of induction data revealed that transcript levels for one gene (clpB) were induced at significantly higher levels in non-persistent strains compared to persistent strains (p=0.020; two-way ANOVA). Significantly higher transcript levels of gadD3 (p=0.024; two-way ANOVA) and clpB (p=0.053; two-way ANOVA) were observed after salt shock in lineage I strains compared to lineage II strains. No clear association between stress gene transcript levels and persistence was detected. Our data are consistent with an emerging model that proposes that establishment of L. monocytogenes persistence in a specific environment occurs as a random, stochastic event, rather than as a consequence of specific bacterial strain characteristics.

A PKM Generated by Calpain Cleavage of a Classical PKC Is Required for Activity-Dependent Intermediate-Term Facilitation in the Presynaptic Sensory Neuron of "Aplysia"

ERIC Educational Resources Information Center

Farah, Carole A.; Hastings, Margaret H.; Dunn, Tyler W.; Gong, Katrina; Baker-Andresen, Danay; Sossin, Wayne S.

2017-01-01

Atypical PKM, a persistently active form of atypical PKC, is proposed to be a molecular memory trace, but there have been few examinations of the role of PKMs generated from other PKCs. We demonstrate that inhibitors used to inhibit PKMs generated from atypical PKCs are also effective inhibitors of other PKMs. In contrast, we demonstrate that…

Twenty years after Erich Muhe: Persisting controversies with the gold standard of laparoscopic cholecystectomy

PubMed Central

Jani, Kalpesh; Rajan, P S; Sendhilkumar, K; Palanivelu, C

2006-01-01

This review article is a tribute to the genius of Professor Erich Muhe, a man ahead of his times. We trace the development of laparoscopic cholecystectomy and detail the tribulations faced by Muhe. On the occasion of the twentieth anniversary of the first laparoscopic cholecystectomy, we take another look at some of the controversies surrounding this gold standard in the management of gallbladder disease PMID:21170235

Assessment of trace elements levels in patients with Type 2 diabetes using multivariate statistical analysis.

PubMed

Badran, M; Morsy, R; Soliman, H; Elnimr, T

2016-01-01

The trace elements metabolism has been reported to possess specific roles in the pathogenesis and progress of diabetes mellitus. Due to the continuous increase in the population of patients with Type 2 diabetes (T2D), this study aims to assess the levels and inter-relationships of fast blood glucose (FBG) and serum trace elements in Type 2 diabetic patients. This study was conducted on 40 Egyptian Type 2 diabetic patients and 36 healthy volunteers (Hospital of Tanta University, Tanta, Egypt). The blood serum was digested and then used to determine the levels of 24 trace elements using an inductive coupled plasma mass spectroscopy (ICP-MS). Multivariate statistical analysis depended on correlation coefficient, cluster analysis (CA) and principal component analysis (PCA), were used to analysis the data. The results exhibited significant changes in FBG and eight of trace elements, Zn, Cu, Se, Fe, Mn, Cr, Mg, and As, levels in the blood serum of Type 2 diabetic patients relative to those of healthy controls. The statistical analyses using multivariate statistical techniques were obvious in the reduction of the experimental variables, and grouping the trace elements in patients into three clusters. The application of PCA revealed a distinct difference in associations of trace elements and their clustering patterns in control and patients group in particular for Mg, Fe, Cu, and Zn that appeared to be the most crucial factors which related with Type 2 diabetes. Therefore, on the basis of this study, the contributors of trace elements content in Type 2 diabetic patients can be determine and specify with correlation relationship and multivariate statistical analysis, which confirm that the alteration of some essential trace metals may play a role in the development of diabetes mellitus. Copyright © 2015 Elsevier GmbH. All rights reserved.

Trace Elements Affect Methanogenic Activity and Diversity in Enrichments from Subsurface Coal Bed Produced Water

PubMed Central

Ünal, Burcu; Perry, Verlin Ryan; Sheth, Mili; Gomez-Alvarez, Vicente; Chin, Kuk-Jeong; Nüsslein, Klaus

2012-01-01

Microbial methane from coal beds accounts for a significant and growing percentage of natural gas worldwide. Our knowledge of physical and geochemical factors regulating methanogenesis is still in its infancy. We hypothesized that in these closed systems, trace elements (as micronutrients) are a limiting factor for methanogenic growth and activity. Trace elements are essential components of enzymes or cofactors of metabolic pathways associated with methanogenesis. This study examined the effects of eight trace elements (iron, nickel, cobalt, molybdenum, zinc, manganese, boron, and copper) on methane production, on mcrA transcript levels, and on methanogenic community structure in enrichment cultures obtained from coal bed methane (CBM) well produced water samples from the Powder River Basin, Wyoming. Methane production was shown to be limited both by a lack of additional trace elements as well as by the addition of an overly concentrated trace element mixture. Addition of trace elements at concentrations optimized for standard media enhanced methane production by 37%. After 7 days of incubation, the levels of mcrA transcripts in enrichment cultures with trace element amendment were much higher than in cultures without amendment. Transcript levels of mcrA correlated positively with elevated rates of methane production in supplemented enrichments (R2 = 0.95). Metabolically active methanogens, identified by clone sequences of mcrA mRNA retrieved from enrichment cultures, were closely related to Methanobacterium subterraneum and Methanobacterium formicicum. Enrichment cultures were dominated by M. subterraneum and had slightly higher predicted methanogenic richness, but less diversity than enrichment cultures without amendments. These results suggest that varying concentrations of trace elements in produced water from different subsurface coal wells may cause changing levels of CBM production and alter the composition of the active methanogenic community. PMID:22590465

The drinking water disparities framework: on the origins and persistence of inequities in exposure.

PubMed

Balazs, Carolina L; Ray, Isha

2014-04-01

With this article, we develop the Drinking Water Disparities Framework to explain environmental injustice in the context of drinking water in the United States. The framework builds on the social epidemiology and environmental justice literatures, and is populated with 5 years of field data (2005-2010) from California's San Joaquin Valley. We trace the mechanisms through which natural, built, and sociopolitical factors work through state, county, community, and household actors to constrain access to safe water and to financial resources for communities. These constraints and regulatory failures produce social disparities in exposure to drinking water contaminants. Water system and household coping capacities lead, at best, to partial protection against exposure. This composite burden explains the origins and persistence of social disparities in exposure to drinking water contaminants.

Patients with Long-Term Oral Carriage Harbor High-Persister Mutants of Candida albicans▿

PubMed Central

LaFleur, Michael D.; Qi, Qingguo; Lewis, Kim

2010-01-01

Fungal biofilms produce a small number of persister cells which can tolerate high concentrations of fungicidal agents. Persisters form upon attachment to a surface, an important step in the pathogenesis of Candida strains. The periodic application of antimicrobial agents may select for strains with increased levels of persister cells. In order to test this possibility, 150 isolates of Candida albicans and C. glabrata were obtained from cancer patients who were at high risk for the development of oral candidiasis and who had been treated with topical chlorhexidine once a day. Persister levels were measured by exposing biofilms growing in the wells of microtiter plates to high concentrations of amphotericin B and plating for survivors. The persister levels of the isolates varied from 0.2 to 9%, and strains isolated from patients with long-term carriage had high levels of persisters. High-persister strains were isolated from every patient with Candida carriage of more than 8 consecutive weeks but from no patients with transient carriage. All of the high-persister isolates had an amphotericin B MIC that was the same as that for the wild type, indicating that these strains were drug-tolerant rather than drug-resistant mutants. Biofilms of the majority of high-persister strains also showed an increased tolerance to chlorhexidine and had the same MIC for this antimicrobial as the wild type. This study suggests that persister cells are clinically relevant, and antimicrobial therapy selects for high-persister strains in vivo. The drug tolerance of persisters may be a critical but overlooked component responsible for antimicrobial drug failure and relapsing infections. PMID:19841146

Transport and fate of organic wastes in groundwater at the Stringfellow hazardous waste disposal site, southern California

USGS Publications Warehouse

Leenheer, J.A.; Hsu, J.; Barber, L.B.

2001-01-01

In January 1999, wastewater influent and effluent from the pretreatment plant at the Stringfellow hazardous waste disposal site were sampled along with groundwater at six locations along the groundwater contaminant plume. The objectives of this sampling and study were to identify at the compound class level the unidentified 40-60% of wastewater organic contaminants, and to determine what organic compound classes were being removed by the wastewater pretreatment plant, and what organic compound classes persisted during subsurface waste migration. The unidentified organic wastes are primarily chlorinated aromatic sulfonic acids derived from wastes from DDT manufacture. Trace amounts of EDTA and NTA organic complexing agents were discovered along with carboxylate metabolites of the common alkylphenolpolyethoxylate plasticizers and nonionic surfactants. The wastewater pretreatment plant removed most of the aromatic chlorinated sulfonic acids that have hydrophobic neutral properties, but the p-chlorobenzenesulfonic acid which is the primary waste constituent passed through the pretreatment plant and was discharged in the treated wastewaters transported to an industrial sewer. During migration in groundwater, p-chlorobenzenesulfonic acid is removed by natural remediation processes. Wastewater organic contaminants have decreased 3- to 45-fold in the groundwater from 1985 to 1999 as a result of site remediation and natural remediation processes. The chlorinated aromatic sulfonic acids with hydrophobic neutral properties persist and have migrated into groundwater that underlies the adjacent residential community. Copyright ?? 2001 .

Trace metal levels, sources, and ecological risk assessment in a densely agricultural area from Saudi Arabia.

PubMed

Al-Wabel, Mohammad I; Sallam, Abd El-Azeem S; Usman, Adel R A; Ahmad, Mahtab; El-Naggar, Ahmed Hamdy; El-Saeid, Mohammed Hamza; Al-Faraj, Abdulelah; El-Enazi, Khaled; Al-Romian, Fahad A

2017-06-01

The present study was conducted in one of the most densely cultivated area of Al-Qassim region in Kingdom of Saudi Arabia to (i) monitor trace metal (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) contents in surface and subsurface soils, (ii) assess the pollution and potential ecological risk levels of trace metals, and (iii) identify trace metal sources using enrichment factor (EF), correlation matrix, and principal component analysis (PCA). The pollution levels of the analyzed trace metals calculated by the geoaccumulation index (I geo ) and contamination factor (C f ) suggested that the soils were highly contaminated with Cd and moderately contaminated with Pb. Based on the average values of EF, soil samples were found to present extremely high enrichment for Cd, significant enrichment for Pb, moderate enrichment for Zn, and deficient to minimal enrichment for other trace metals. Among the analyzed trace metals, a very high ecological risk was observed only in the case of Cd at some sampling sites. Meanwhile, other investigated trace metals had a low ecological risk. The results of PCA combined with correlation matrix suggested that Fe, Mn, Zn, Cu, Cr Ni, Cu, and Co represent natural abundance in soil, but Cd, Pb, and Cu are of anthropogenic inputs, mainly due to agrochemical and fertilizer applications. It could be generally concluded that the obtained results can be useful for assessing and conducting a future program for trace metal monitoring in agricultural areas of Saudi Arabia.

A Global Overview of Exposure Levels and Biological Effects of Trace Elements in Penguins.

PubMed

Espejo, Winfred; Celis, José E; GonzÃlez-Acuña, Daniel; Banegas, Andiranel; Barra, Ricardo; Chiang, Gustavo

2018-01-01

Trace elements are chemical contaminants that can be present almost anywhere on the planet. The study of trace elements in biotic matrices is a topic of great relevance for the implications that it can have on wildlife and human health. Penguins are very useful, since they live exclusively in the Southern Hemisphere and represent about 90% of the biomass of birds of the Southern Ocean. The levels of trace elements (dry weight) in different biotic matrices of penguins were reviewed here. Maps of trace element records in penguins were included. Data on exposure and effects of trace elements in penguins were collected from the literature. The most reported trace elements in penguins are aluminum, arsenic, cadmium, lead, mercury, copper, zinc, and manganese. Trace elements have been measured in 11 of the 18 species of penguins. The most studied biotic matrices are feathers and excreta. Most of the studies have been performed in Antarctica and subantarctic Islands. Little is known about the interaction among metals, which could provide better knowledge about certain mechanisms of detoxification in penguins. Future studies of trace elements in penguins must incorporate other metals such as vanadium, cobalt, nickel, and chromium. Data of metals in the species such as Eudyptes pachyrhynchus, Eudyptes moseleyi, Eudyptes sclateri, Eudyptes robustus, Eudyptes schlegeli, Spheniscus demersus, Spheniscus mendiculus, and Megadyptes antipodes are urged. It is important to correlate levels of metals in different biotic matrices with the effects on different species and in different geographic locations.

Distribution and environmental assessment of trace elements contamination of water, sediments and flora from Douro River estuary, Portugal.

PubMed

Ribeiro, C; Couto, C; Ribeiro, A R; Maia, A S; Santos, M; Tiritan, M E; Pinto, E; Almeida, A A

2018-10-15

The present study evaluated the content and distribution of several trace elements (Li, Be, Al, V, Cr, Co, Ni, Cu, Zn, Se, Mo, Ag, Cd, Sb, Ba, Tl, Pb, and U) in the Douro River estuary. For that, three matrices were collected (water, sediments and native local flora) to assess the extent of contamination by these elements in this estuarine ecosystem. Results showed their occurrence in estuarine water and sediments, but significant differences were recorded on the concentration levels and pattern of distribution among both matrices and sampling points. Generally, the levels of trace elements were higher in the sediments than in the respective estuarine water. Nonetheless, no correlation among trace elements was determined between water and sediments, except for Cd. Al was the trace element found at highest concentration at both sediments and water followed by Zn. Pollution indices such as geo-accumulation (I geo ), enrichment factor (EF) and contamination factor (CF) were determined to understand the levels and sources of trace elements pollution. I geo showed strong contamination by anthropogenic activities for Li, Al, V, Cr, Ni, Cu, Zn, Ba and Pb at all sampling points while EF and CF demonstrated severe enrichment and contamination by Se, Sb and Pb. Levels of trace elements were compared to acceptable values for aquatic organisms and Sediment Quality Guidelines. The concentration of some trace elements, namely Al, Pb and Cu, were higher than those considered acceptable, with potential negative impact on local living organisms. Nevertheless, permissible values for all trace elements are still not available, demonstrating that further studies are needed in order to have a complete assessment of environmental risk. Furthermore, the occurrence and possible accumulation of trace elements by local plant species and macroalgae were investigated as well as their potential use as bioindicators of local pollution and for phytoremediation purposes. Copyright © 2018 Elsevier B.V. All rights reserved.

Survival of bactericidal antibiotic treatment by tolerant persister cells of Klebsiella pneumoniae.

PubMed

Li, Ying; Zhang, Luhua; Zhou, Yingshun; Zhang, Zhikun; Zhang, Xinzhuo

2018-03-01

Persister cells, a subpopulation of tolerant cells within the bacterial culture, are commonly thought to be responsible for antibiotic therapy failure and infection recurrence. Klebsiella pneumoniae is a notorious human pathogen for its increasing resistance to antibiotics and wide involvement in severe infections. In this study, we aimed to investigate the persister subpopulation of K. pneumoniae. The presence of persisters in K. pneumoniae was determined by treatment with high concentrations of antibiotics, used alone or in combination. The effect of low level of antibiotics on persister formation was investigated by pre-exposure of cells to antibiotics with low concentrations followed by higher doses. The dependence of persister levels on growth phase was determined by measuring the survival ability of cells along the growth stages upon exposure to a high concentration of antibiotic. Analysis on persister type was carried out by persister elimination assays.Results/Key findings. We show that K. pneumoniae produces high levels of tolerant persister cells to survive treatment by a variety of high concentrations of bactericidal antibiotics and persister formation is prevalent among K. pneumoniae clinical strains. Besides, we find that persister cells can be induced by low concentrations of antibiotics. Finally, we provide evidence that persister formation is growth phase-dependent and Type II persisters dominate the persister subpopulation during the entire exponential phase of K. pneumoniae. Our study describes the formation of tolerant persister cells that allow survival of treatment by high concentrations of antibiotics in K. pneumoniae.

Tracing groundwater with low-level detections of halogenated VOCs in a fractured carbonate-rock aquifer, Leetown Science Center, West Virginia, USA

USGS Publications Warehouse

Plummer, Niel; Sibrell, Philip L.; Casile, Gerolamo C.; Busenberg, Eurybiades; Hunt, Andrew G.; Schlosser, Peter

2013-01-01

Measurements of low-level concentrations of halogenated volatile organic compounds (VOCs) and estimates of groundwater age interpreted from 3H/3He and SF6 data have led to an improved understanding of groundwater flow, water sources, and transit times in a karstic, fractured, carbonate-rock aquifer at the Leetown Science Center (LSC), West Virginia. The sum of the concentrations of a set of 16 predominant halogenated VOCs (TDVOC) determined by gas chromatography with electron-capture detector (GC–ECD) exceeded that possible for air–water equilibrium in 34 of the 47 samples (median TDVOC of 24,800 pg kg−1), indicating that nearly all the water sampled in the vicinity of the LSC has been affected by addition of halogenated VOCs from non-atmospheric source(s). Leakage from a landfill that was closed and sealed nearly 20 a prior to sampling was recognized and traced to areas east of the LSC using low-level detection of tetrachloroethene (PCE), methyl chloride (MeCl), methyl chloroform (MC), dichlorodifluoromethane (CFC-12), and cis-1,2-dichloroethene (cis-1,2-DCE). Chloroform (CHLF) was the predominant VOC in water from domestic wells surrounding the LSC, and was elevated in groundwater in and near the Fish Health Laboratory at the LSC, where a leak of chlorinated water occurred prior to 2006. The low-level concentrations of halogenated VOCs did not exceed human or aquatic-life health criteria, and were useful in providing an awareness of the intrinsic susceptibility of the fractured karstic groundwater system at the LSC to non-atmospheric anthropogenic inputs. The 3H/3He groundwater ages of spring discharge from the carbonate rocks showed transient behavior, with ages averaging about 2 a in 2004 following a wet climatic period (2003–2004), and ages in the range of 4–7 a in periods of more average precipitation (2008–2009). The SF6 and CFC-12 data indicate older water (model ages of 10s of years or more) in the low-permeability shale of the Martinsburg Formation located to the west of the LSC. A two-a record of specific conductance, water temperature, and discharge recorded at 30-min intervals demonstrated an approximately 3-month lag in discharge at Gray Spring. The low groundwater ages of waters from the carbonate rocks support rapid advective transport of contaminants from the LSC vicinity, yet the nearly ubiquitous occurrence of low-level concentrations of halogenated VOCs at the LSC suggests the presence of long-term persistent sources, such as seepage from the closed and sealed landfill, infiltration of VOCs that may persist locally in the epikarst, exchange with low-permeability zones in fractured rock, and upward leakage of older water that may contain elevated concentrations of halogenated VOCs from earlier land use activities.

Transcriptome Analysis of Bombyx mori Larval Midgut during Persistent and Pathogenic Cytoplasmic Polyhedrosis Virus Infection

PubMed Central

Kolliopoulou, Anna; Van Nieuwerburgh, Filip; Stravopodis, Dimitrios J.; Deforce, Dieter; Swevers, Luc; Smagghe, Guy

2015-01-01

Many insects can be persistently infected with viruses but do not show any obvious adverse effects with respect to physiology, development or reproduction. Here, Bombyx mori strain Daizo, persistently infected with cytoplasmic polyhedrosis virus (BmCPV), was used to study the host’s transcriptional response after pathogenic infection with the same virus in midgut tissue of larvae persistently and pathogenically infected as 2nd and 4th instars. Next generation sequencing revealed that from 13,769 expressed genes, 167 were upregulated and 141 downregulated in both larval instars following pathogenic infection. Several genes that could possibly be involved in B. mori immune response against BmCPV or that may be induced by the virus in order to increase infectivity were identified, whereas classification of differentially expressed transcripts (confirmed by qRT-PCR) resulted in gene categories related to physical barriers, immune responses, proteolytic / metabolic enzymes, heat-shock proteins, hormonal signaling and uncharacterized proteins. Comparison of our data with the available literature (pathogenic infection of persistently vs. non-persistently infected larvae) unveiled various similarities of response in both cases, which suggests that pre-existing persistent infection does not affect in a major way the transcriptome response against pathogenic infection. To investigate the possible host’s RNAi response against BmCPV challenge, the differential expression of RNAi-related genes and the accumulation of viral small RNAs (vsRNAs) were studied. During pathogenic infection, siRNA-like traces like the 2-fold up-regulation of the core RNAi genes Ago-2 and Dcr-2 as well as a peak of 20 nt small RNAs were observed. Interestingly, vsRNAs of the same size were detected at lower rates in persistently infected larvae. Collectively, our data provide an initial assessment of the relative significance of persistent infection of silkworm larvae on the host response following pathogenic infection with CPV, while they also highlight the relative importance of RNAi as an antiviral mechanism. PMID:25816294

Rapid ultra-trace analysis of sucralose in multiple-origin aqueous samples by online solid-phase extraction coupled to high-resolution mass spectrometry.

PubMed

Batchu, Sudha Rani; Ramirez, Cesar E; Gardinali, Piero R

2015-05-01

Because of its widespread consumption and its persistence during wastewater treatment, the artificial sweetener sucralose has gained considerable interest as a proxy to detect wastewater intrusion into usable water resources. The molecular resilience of this compound dictates that coastal and oceanic waters are the final recipient of this compound with unknown effects on ecosystems. Furthermore, no suitable methodologies have been reported for routine, ultra-trace detection of sucralose in seawater as the sensitivity of traditional liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis is limited by a low yield of product ions upon collision-induced dissociation (CID). In this work, we report the development and field test of an alternative analysis tool for sucralose in environmental waters, with enough sensitivity for the proper quantitation and confirmation of this analyte in seawater. The methodology is based on automated online solid-phase extraction (SPE) and high-resolving-power orbitrap MS detection. Operating in full scan (no CID), detection of the unique isotopic pattern (100:96:31 for [M-H](-), [M-H+2](-), and [M-H+4](-), respectively) was used for ultra-trace quantitation and analyte identification. The method offers fast analysis (14 min per run) and low sample consumption (10 mL per sample) with method detection and confirmation limits (MDLs and MCLs) of 1.4 and 5.7 ng/L in seawater, respectively. The methodology involves low operating costs due to virtually no sample preparation steps or consumables. As an application example, samples were collected from 17 oceanic and estuarine sites in Broward County, FL, with varying salinity (6-40 PSU). Samples included the ocean outfall of the Southern Regional Wastewater Treatment Plant (WWTP) that serves Hollywood, FL. Sucralose was detected above MCL in 78% of the samples at concentrations ranging from 8 to 148 ng/L, with the exception of the WWTP ocean outfall (at pipe end, 28 m below the surface) where the measured concentration was 8418 ± 3813 ng/L. These results demonstrate the applicability of this monitoring tool for the trace-level detection of this wastewater marker in very dilute environmental waters.

Trace elements and oxidative stress levels in the blood of painters in Lagos, Nigeria: occupational survey and health concern.

PubMed

Awodele, Olufunsho; Akinyede, Akin; Babawale, Omotola Opeyemi; Coker, Herbert A Babatunde; Akintonwa, Alade

2013-06-01

Adverse effects attributed to exposure to paints are currently a concern because of the continued widespread use of paint containing trace elements. Thus, occupational survey amongst painters in Lagos and determination of trace elements and oxidative stress parameters were carried out. Descriptive cross-sectional survey was done using a standardized questionnaire to obtain job safety-related information. Forty-eight percent of the painters were aware of hazards associated with painting and 52 % of these workers were aware of the necessary precautionary measures during painting. There were no significant differences (p ≥ 0.05) between the levels of trace elements in the blood of painters and the control subjects. However, there was a significance increase (p ≤ 0.0001) in the level of malondialdehyde and a decrease (p ≤ 0.001) in the levels of reduced glutathione, superoxide dismutase, and catalase of the painters compared to the control. An increase in oxidative stress parameters may not only be due to trace element concentrations, but also the painters' exposure to some petrochemical solvents during mixing of paints.

Connecticut Music Trace Map for Grades 6 and 8. Revised.

ERIC Educational Resources Information Center

Connecticut State Board of Education, Hartford.

These Connecticut Curriculum Trace Maps for music are designed to help curriculum developers and teachers translate Connecticut's K-12 performance standards into objectives and classroom practices. Trace Maps provide specific descriptions of what students should know and be able to do at smaller grade level clusters. Elements in the Trace Maps are…

Measles virus induces persistent infection by autoregulation of viral replication.

PubMed

Doi, Tomomitsu; Kwon, Hyun-Jeong; Honda, Tomoyuki; Sato, Hiroki; Yoneda, Misako; Kai, Chieko

2016-11-24

Natural infection with measles virus (MV) establishes lifelong immunity. Persistent infection with MV is likely involved in this phenomenon, as non-replicating protein antigens never induce such long-term immunity. Although MV establishes stable persistent infection in vitro and possibly in vivo, the mechanism by which this occurs is largely unknown. Here, we demonstrate that MV changes the infection mode from lytic to non-lytic and evades the innate immune response to establish persistent infection without viral genome mutation. We found that, in the persistent phase, the viral RNA level declined with the termination of interferon production and cell death. Our analysis of viral protein dynamics shows that during the establishment of persistent infection, the nucleoprotein level was sustained while the phosphoprotein and large protein levels declined. The ectopic expression of nucleoprotein suppressed viral replication, indicating that viral replication is self-regulated by nucleoprotein accumulation during persistent infection. The persistently infected cells were able to produce interferon in response to poly I:C stimulation, suggesting that MV does not interfere with host interferon responses in persistent infection. Our results may provide mechanistic insight into the persistent infection of this cytopathic RNA virus that induces lifelong immunity.

Characterization of Listeria monocytogenes isolated from a fresh mixed sausage processing line in Pelotas-RS by PFGE

PubMed Central

von Laer, Ana Eucares; de Lima, Andréia Saldanha; Trindade, Paula dos Santos; Andriguetto, Cristiano; Destro, Maria Teresa; da Silva, Wladimir Padilha

2009-01-01

Listeria monocytogenes is a bacterium capable to adhere to the surfaces of equipment and utensils and subsequently form biofilms. It can to persist in the food processing environmental for extended periods of time being able to contaminate the final product. The aim of this study was to trace the contamination route of L. monocytogenes on a fresh mixed sausage processing line, from raw material to the final product. The isolates obtained were characterized by serotyping and molecular typing by pulsed-field gel electrophoresis (PFGE) using the restriction enzymes ApaI and AscI. L. monocytogenes was detected in 25% of the samples. The samples of raw material were not contaminated, however, the microorganism was detected in 21% of the environmental samples (food contact and non-food contact), 20.8% of the equipments, 20% of the food worker’s hands, 40% of the mass ready to packaging and in all the final products samples, demonstrating that the contamination of final product occurred during the processing and the importance of cross contamination. PFGE yielded 22 pulsotypes wich formed 7 clusters, and serotyping yielded 3 serotypes and 1 serogroup, however, the presence of serotypes 4b and 1/2b in the final product is of great concern for public health. The tracing of contamination showed that some strains are adapted and persisted in the processing environment in this industry. PMID:24031402

Nighttime Chemistry in the Polluted Boundary Layer (Invited)

NASA Astrophysics Data System (ADS)

Stutz, J.; Wong, K.; Tsai, C.; Pikelnaya, O.

2009-12-01

Chemistry in the urban nocturnal boundary layer (NBL) has received surprisingly little attention in the past. Surface observations often see low ozone and high NO levels, which lead to low nocturnal radical levels and consequently slow chemistry near the ground. Above the surface, however, ozone and radical levels, for example of NO3, are considerably higher, and more efficient chemical pathways for the removal of gaseous pollutants such as nitrogen oxides, ozone, and hydrocarbons, are active. The influence of nocturnal chemistry on aerosol composition is also largest aloft. These processes are poorly understood due to a lack of observations in the altitude range from 20 - 500m. The strong influence of vertical mixing and transport on the composition of the NBL poses an additional challenge, requiring the measurement of vertical concentration profiles and the use of chemical transport models for their interpretation. In addition, heterogeneous processes on the ground and on aerosol surfaces play an important role in the nocturnal atmosphere. In this presentation we will review our current understanding of nocturnal chemistry in the lowest 300m of the polluted atmosphere, with a focus on nitrogen compounds. A number of field experiments in recent years have given insight into the vertical distribution of some of the most important nocturnal trace gases in urban areas, such as ozone, NO2, NO3, N2O5, and HONO. In particular, two 6-week long experiments in Houston, TX, in 2006 and 2009, have shown the strong and persistent impact of vertical mixing on the distribution of all trace gases, as well as the chemistry in the lowest 300m of the atmosphere. These observations were accompanied by detailed meteorological observations and in-situ measurements of chemical species at 70m above the ground. The observations in Houston were interpreted with a 1D chemical transport model that allows quantification of chemistry and transport at night. Our results identify gaps in our understanding of the polluted nocturnal urban boundary layer will be discussed.

Serum concentrations of trace elements in patients with Crohn's disease receiving enteral nutrition.

PubMed

Johtatsu, Tomoko; Andoh, Akira; Kurihara, Mika; Iwakawa, Hiromi; Tsujikawa, Tomoyuki; Kashiwagi, Atsunori; Fujiyama, Yoshihide; Sasaki, Masaya

2007-11-01

We investigated the trace element status in Crohn's disease (CD) patients receiving enteral nutrition, and evaluated the effects of trace element-rich supplementation. Thirty-one patients with CD were enrolled in this study. All patients were placed on an enteral nutrition regimen with Elental(R) (Ajinomoto pharmaceutical. Ltd., Tokyo, Japan). Serum selenium, zinc and copper concentrations were determined by atomic absorption spectroscopy. Serum selenoprotein P levels were determined by an ELISA system. Average serum levels of albumin, selenium, zinc and copper were 4.1 +/- 0.4 g/dl, 11.2 +/- 2.8 microg/dl, 71.0 +/- 14.8 microg/dl, and 112.0 +/- 25.6 microg/dl, respectively. In 9 patients of 31 CD patients, serum albumin levels were lower than the lower limit of the normal range. Serum selenium, zinc and copper levels were lower than lower limits in 12 patients, 9 patients and 1 patient, respectively. Serum selenium levels significantly correlated with both serum selenoprotein P levels and glutathione peroxidase activity. Supplementation of selenium (100 microg/day) and zinc (10 mg/day) for 2 months significantly improved the trace element status in CD patients. In conclusion, serum selenium and zinc levels are lower in many CD patients on long-term enteral nutrition. In these patients, supplementation of selenium and zinc was effective in improving the trace element status.

Assessing Selenium, Manganese, and Iodine Status in Pediatric Patients Receiving Parenteral Nutrition.

PubMed

Johnsen, Jacob Clarke; Reese, Susan Anne; Mackay, Mark; Anderson, Collin R; Jackson, Daniel; Paul, Irasema Libertad

2017-08-01

Pediatric patients who are receiving parenteral nutrition (PN) unsupplemented with trace minerals can become deficient. Due to shortages in trace mineral products and the 2004 American Society for Parenteral and Enteral Nutrition report stating that individualized trace element supplementation may be warranted, a review was conducted concerning the trace minerals selenium (Se), manganese (Mn), and iodine (I). A retrospective review of pediatric patients receiving PN that contained Se and Mn was conducted to determine if a difference existed between them and patients receiving PN without Se and Mn. Statistical analysis was done to assess a difference between trace mineral levels and the time to deficiency between supplemented and unsupplemented patients. Unsupplemented I patients had urine I levels assessed to determine deficiencies in patients receiving PN. Plasma Se levels were measured at a mean of 20 days for supplemented patients (n = 131) and 19 days for nonsupplemented patients (n = 57) with no difference between groups ( P = .2973). Plasma Mn levels were measured at a mean of 28 days, showing no statistical difference ( P = .721). Of the 177 nonsupplemented I patients, 74% demonstrated I deficiencies without supplementation. Time to the development of a Se, Mn, or I deficiency is important to guide supplementation of exclusive PN in children when trace mineral products are short in supply. Our retrospective experience supports assessment of the trace minerals Se at 21 days and Mn at 30 days. It also suggests that some pediatric patients receiving PN are deficient in I.

Study to investigate the trace levels of contamination on surfaces when narcotic contraband is concealed in a vehicle

NASA Astrophysics Data System (ADS)

Wilson, Rod; Brittain, Alan H.

1997-01-01

When a vehicle is used to transport narcotic contraband material trace levels of that material can be found on surfaces of the vehicle, people associated with the vehicle and surface they contact. The detection of these trace levels can help to target vehicles associated with the smuggling of the contraband. A study to determine the typical levels of narcotic material that can be detected from these surfaces has been performed by personnel from Graseby, using a variety of drug materials. The size and packaging of the drug materials has been prepared to try to reflect that typically found in smuggling operations. These tests show that for all hard drugs easily detectable traces of drug material can be found on the vehicle, the proxy and secondary surfaces handled by the proxy. For detection of cannabis, the condition of the original material had a great bearing ont he reliability of detection.

Validation of a GC-MS/MS method for simultaneous determination of 86 persistent organic pollutants in marine sediments by pressurized liquid extraction followed by stir bar sorptive extraction.

PubMed

Camino-Sánchez, F J; Zafra-Gómez, Alberto; Pérez-Trujillo, J P; Conde-González, J E; Marques, J C; Vílchez, José Luis

2011-08-01

A multiresidue method for the analysis of 86 persistent pollutants in marine sediments at ultra-trace level has been developed and validated using pressurized liquid extraction (PLE) and stir-bar sorptive extraction (SBSE) coupled with thermal desorption and gas chromatography-triple quadrupole mass spectrometry (TD-GC-MS/MS QqQ). The compounds analyzed belong to various families such as polychlorinated biphenyls, polycyclic aromatic hydrocarbons, polybrominated diphenylethers, organophosphorus and organochlorine pesticides and other pesticides such as urons, and triazines. The analytes have very different polarities and log K(ow) values, which is an important parameter in the optimization of a SBSE method. Due to PLE high efficiency and throughput rates, along with the proven ability for multiresidue analysis and excellent sensitivity of SBSE, we present an efficient method. The limits of quantification obtained ranged from 0.014 to 1.0 ng g(-1), with detection limits below pg g(-1) levels. In order to validate the proposed methodology, quality parameters such as recovery, linearity and reproducibility were studied. Recoveries ranged from 63% to 119%, reproducibility (in terms of Relative Standard Deviation for ten determinations) was lower than 35% in all cases, and determination coefficients higher than 0.990 for all analytes. The main factors that affect PLE, SBSE and GC-MS/MS procedures were optimized. The method was applied to the analysis of nine marine sediments obtained from the nine main submarine wastewater discharge points (emissaries) presents along the coast of Tenerife Island (Canary Islands, Spain). Copyright © 2011 Elsevier Ltd. All rights reserved.

The transfer of diatoms from freshwater to footwear materials: An experimental study assessing transfer, persistence, and extraction methods for forensic reconstruction.

PubMed

Levin, E A; Morgan, R M; Scott, K R; Jones, V J

2017-09-01

In recent years there has been growing interest in environmental forms of trace evidence, and ecological trace evidence collected from footwear has proved valuable within casework. Simultaneously, there has been growing awareness of the need for empirical experimentation to underpin forensic inferences. Diatoms are unicellular algae, and each cell (or 'frustule') consists of two valves which are made of silica, a robust material that favours their preservation both in sediments and within forensic scenarios. A series of experiments were carried out to investigate the transfer and persistence of diatoms upon common footwear materials, a recipient surface that has historically been overlooked by studies of persistence. The effectiveness of two novel extraction techniques (jet rinsing, and heating and agitation with distilled water) was compared to the established extraction technique of hydrogen peroxide digestion, for a suite of five common footwear materials: canvas, leather, and 'suede' (representing upper materials), and rubber and polyurethane (representing sole materials). It was observed that the novel extraction technique of heating and agitation with distilled water did not extract fewer diatom valves, or cause increased fragmentation of valves, when compared to peroxide digestion, suggesting that the method may be viable where potentially hazardous chemical reactions may be encountered with the peroxide digestion method. Valves could be extracted from all five footwear materials after 3min of immersion, and more valves were extracted from the rougher, woven upper materials than the smoother sole materials. Canvas yielded the most valves (a mean of 2511/cm 2 ) and polyurethane the fewest (a mean of 15/cm 2 ). The persistence of diatoms on the three upper materials was addressed with a preliminary pilot investigation, with ten intervals sampled between 0 and 168h. Valves were seen to persist in detectable quantities after 168h on all three upper materials. However, some samples produced slides with no valves, and the earliest time after which no diatom valves were found was 4h after the transfer. Analysis of the particle size distributions over time, by image analysis, suggests that the retention of diatoms may be size-selective; after 168h, no particles larger than 200μm 2 could be found on the samples of canvas, and >95% of the particles on the samples of suede were less than or equal to 200μm 2 . A pilot investigation into the effects of immersion interval was carried out upon samples of canvas. Greater numbers of valves were extracted from the samples with longer immersion intervals, but even after 30s, >500 valves could be recovered per cm 2 , suggesting that footwear may be sampled for diatoms even if the contact with a water body may have been brief. These findings indicate that, if the variability within and between experimental runs can be addressed, there is significant potential for diatoms to be incorporated into the trace analysis of footwear and assist forensic reconstructions. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

Response of infaunal organisms represented by trace fossils to sea-level changes in the Ordovician Black River and Trenton Group limestones, upstate New York

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

Tegan, J.R.; Curran, H.A.

Small-scale fluctuations in sea level were revealed by detailed analysis of trace fossil assemblages formed by infaunal organisms within the Lowville (Black River Grp.), Napanee, and Kings Falls limestones (Trenton Grp.) at Ingham Mills. The paleodepositional environment of the Lowville Limestone (LL) is interpreted as peritidal, representing the high intertidal to shallow subtidal zones. The trace fossil assemblages define clearly several fluctuations within this environment. Large, well-formed specimens of the trace fossil Beaconites barretti occur within tidal channel and levee beds of the LL. In other regions this trace fossil has consistently been associated with channel and levee beds, mostmore » commonly in fluvial settings. The occurrence of Beaconites in the LL extends the age range of this ichnogenus to Ordovician time (oldest previous record is Silurian) and broadens its paleoenvironment range. The Napanee (Np) and lower Kings Falls (KF), limestones have most commonly been described as being deposited in a lagoonal setting. Both formations contain well-preserved trace fossils; the primary difference being that the Np exhibits much lower trace and body fossil diversities than the KF. The low diversity of trace fossils in the Np was most likely the result of limiting environmental conditions such as low oxygen and/or hypersalinity. The higher diversity of trace fossils in the KF indicates that the ancient lagoon became increasingly controlled by normal marine conditions, and, therefore, hospitable to a more diverse group of organisms. The trace fossil assemblages of the Black River and Trenton Group limestones indicate that the infaunal organisms of these Ordovician communities were highly sensitive to small-scale sea-level fluctuations.« less

Seasonal Dynamics of Trace Elements in Tidal Salt Marsh Soils as Affected by the Flow-Sediment Regulation Regime

PubMed Central

Bai, Junhong; Xiao, Rong; Zhao, Qingqing; Lu, Qiongqiong; Wang, Junjing; Reddy, K. Ramesh

2014-01-01

Soil profiles were collected in three salt marshes with different plant species (i.e. Phragmites australis, Tamarix chinensis and Suaeda salsa) in the Yellow River Delta (YRD) of China during three seasons (summer and fall of 2007 and the following spring of 2008) after the flow-sediment regulation regime. Total elemental contents of As, Cd, Cu, Pb and Zn were determined using inductively coupled plasma atomic absorption spectrometry to investigate temporal variations in trace elements in soil profiles of the three salt marshes, assess the enrichment levels and ecological risks of these trace elements in three sampling seasons and identify their influencing factors. Trace elements did not change significantly along soil profiles at each site in each sampling season. The highest value for each sampling site was observed in summer and the lowest one in fall. Soils in both P. australis and S. salsa wetlands tended to have higher trace element levels than those in T. chinensis wetland. Compared to other elements, both Cd and As had higher enrichment factors exceeding moderate enrichment levels. However, the toxic unit (TU) values of these trace elements did not exceed probable effect levels. Correlation analysis showed that these trace elements were closely linked to soil properties such as moisture, sulfur, salinity, soil organic matter, soil texture and pH values. Principal component analysis showed that the sampling season affected by the flow-sediment regulation regime was the dominant factor influencing the distribution patterns of these trace elements in soils, and plant community type was another important factor. The findings of this study could contribute to wetland conservation and management in coastal regions affected by the hydrological engineering. PMID:25216278

Thyroid functions and trace elements in pediatric patients with exogenous obesity.

PubMed

Cayir, Atilla; Doneray, Hakan; Kurt, Nezahat; Orbak, Zerrin; Kaya, Avni; Turan, Mehmet Ibrahim; Yildirim, Abdulkadir

2014-02-01

Obesity is a multifactorial disease developing following impairment of the energy balance. The endocrine system is known to be affected by the condition. Serum thyroid hormones and trace element levels have been shown to be affected in obese children. Changes in serum thyroid hormones may result from alterations occurring in serum trace element levels. The aim of this study was to evaluate whether or not changes in serum thyroid hormone levels in children with exogenous obesity are associated with changes in trace element levels. Eighty-five children diagnosed with exogenous obesity constituted the study group, and 24 age- and sex-matched healthy children made up the control group. Serum thyroid stimulating hormone (TSH), free thyroxine (fT4), free triiodothyronine (fT3), thyroglobulin (TG), selenium (Se), zinc (Zn), copper (Cu), and manganese (Mn) levels in the study group were measured before and at the third and sixth months of treatment, and once only in the control group. Pretreatment fT4 levels in the study group rose significantly by the sixth month (p = 0.006). Zn levels in the patient group were significantly low compared to the control group (p = 0.009). Mn and Se levels in the obese children before and at the third and sixth months of treatment were significantly higher than those of the control group (p = 0.001, p = 0.001). In conclusion, fT4, Zn, Cu, Mn, and Se levels are significantly affected in children diagnosed with exogenous obesity. The change in serum fT4 levels is not associated with changes in trace element concentrations.

Productive performance, eggshell quality, and eggshell ultrastructure of laying hens fed diets supplemented with organic trace minerals.

PubMed

Stefanello, C; Santos, T C; Murakami, A E; Martins, E N; Carneiro, T C

2014-01-01

This study was carried out with the purpose of evaluating the effect of supplementing hens' diets with trace minerals from inorganic or organic sources on the productive performance, eggshell quality, and eggshell ultrastructure of laying hens. Three hundred sixty Hy-Line W36 laying hens between 47 to 62 wk of age were used and distributed in a completely randomized experimental design with 9 treatments, 5 replicates, and 8 birds for each experimental unit. The treatments consisted of a control diet without supplementation of the trace minerals Mn, Zn, and Cu; 4 supplementation levels of these trace minerals from an inorganic source; and the same levels of supplementation from an organic source (proteinates). The supplementation levels in milligrams per kilogram for Mn, Zn, and Cu, were, respectively, 35-30-05, 65-60-10, 95-90-15, and 125-120-20. There was no effect of supplementation of trace minerals on the rate of posture, feed intake, feed conversion, specific weight, and Haugh unit of eggs. However, there was a quadratic effect (P < 0.05) of the levels of trace mineral supplementation on average egg weight and egg mass; the results did not differ regarding the source used. The increase in the levels of supplementation of Mn, Zn, and Cu provided a linear increase (P < 0.05) in the breaking strength and the percentage of eggshell. There was a linear decrease (P < 0.05) in the egg loss and the number of mammillary buttons in the shell. The best results were obtained using diets supplemented with trace minerals from an organic source because these diets provided lower egg loss, higher thickness, and increased strength of the shell. Structurally, organic Mn, Zn, and Cu provided higher thickness of the palisade layer and lower mammillary density. The trace mineral supplementation improved the structural characteristics and the quality of the eggshells.

Persistence of Undergraduate Women in STEM Fields

ERIC Educational Resources Information Center

Pedone, Maggie Helene

2016-01-01

The underrepresentation of women in science, technology, engineering, and mathematics (STEM) is a complex problem that continues to persist at the postsecondary level, particularly in computer science and engineering fields. This dissertation explored the pre-college and college level factors that influenced undergraduate women's persistence in…

The Drinking Water Disparities Framework: On the Origins and Persistence of Inequities in Exposure

PubMed Central

Balazs, Carolina L.; Ray, Isha

2014-01-01

With this article, we develop the Drinking Water Disparities Framework to explain environmental injustice in the context of drinking water in the United States. The framework builds on the social epidemiology and environmental justice literatures, and is populated with 5 years of field data (2005–2010) from California’s San Joaquin Valley. We trace the mechanisms through which natural, built, and sociopolitical factors work through state, county, community, and household actors to constrain access to safe water and to financial resources for communities. These constraints and regulatory failures produce social disparities in exposure to drinking water contaminants. Water system and household coping capacities lead, at best, to partial protection against exposure. This composite burden explains the origins and persistence of social disparities in exposure to drinking water contaminants. PMID:24524500

Einstein and Time in Physics and Philosophy

NASA Astrophysics Data System (ADS)

Canales, Jimena

Current debates about time have left ``a hole at the heart of physics'' (Scientific American, Sept 2002). The main problem with contemporary explanations is usually traced to Einstein's theory of relativity, to the notion of a ``block universe,'' and to his famous claim that ``the distinction between the past, present and future is only a stubbornly persistent illusion.'' While some scientist have tried to incorporate elements of our experience of time into our explanations of the universe, others continue to claim that our sense of time is simply illusory. Can these debates be solved by science alone or are they inescapably philosophical, historical and cultural? My talk will explore the origins of this persistent quandary by focusing on the relation of physics to philosophy, history and the humanities. Can we solve the problem of time without engaging in ``Science Wars''?

Evidence for decay in verbal short-term memory: a commentary on Berman, Jonides, and Lewis (2009).

PubMed

Campoy, Guillermo

2012-07-01

M. G. Berman, J. Jonides, and R. L. Lewis (2009) adapted the recent-probes task to investigate the causes of forgetting in short-term memory. In 7 experiments, they studied the persistence of memory traces by assessing the level of proactive interference generated by previous-trial items over a range of intertrial intervals. None of the experiments found a reduction in proactive interference over time, which they interpreted as evidence against time-based decay. However, it is possible that decay actually occurred over a shorter time period than was tested in this study, wherein the shortest decay interval was 3,300 ms. By reducing the time scale, the 2 experiments reported in the current commentary revealed a sharp decrease in proactive interference over time, with this reduction reaching a plateau in less than 3 s. This pattern suggests that decay operates in the early stages, whereas subsequent forgetting is likely to be due to interference. 2012 APA, all rights reserved

Tracing the trilobite tree from the root to the tips: a model marriage of fossils and phylogeny.

PubMed

Lieberman, Bruce S; Karim, Talia S

2010-01-01

Trilobites are a highly diverse group of extinct arthropods that persisted for nearly 300 million years. During that time, there was a profusion of morphological form, and they occupied a plethora of marine habitats. Their diversity, relative abundance, and complex morphology make them excellent candidates for phylogenetic analysis, and partly as a consequence they have been the subject of many cladistic studies. Although phylogenetic knowledge is certainly incomplete, our understanding of evolutionary patterns within the group has dramatically increased over the last 30 years. Moreover, trilobites have formed an important component of various studies of macroevolutionary processes. Here, we summarize the phylogenetic breadth of knowledge on the Trilobita, and present various hypotheses about phylogenetic patterns within the group, from the highest to the lowest taxonomic levels. Key topics we consider include the question of trilobite monophyly, the phylogenetic position of trilobites vis à vis extant arthropod groups, and inter- and intra-ordinal relationships. Copyright (c) 2009 Elsevier Ltd. All rights reserved.

Concentrations of Glyphosate, Its Degradation Product, Aminomethylphosphonic Acid, and Glufosinate in Ground- and Surface-Water, Rainfall, and Soil Samples Collected in the United States, 2001-06

USGS Publications Warehouse

Scribner, Elisabeth A.; Battaglin, William A.; Gilliom, Robert J.; Meyer, Michael T.

2007-01-01

The U.S. Geological Survey conducted a number of studies from 2001 through 2006 to investigate and document the occurrence, fate, and transport of glyphosate, its degradation product, aminomethylphosphonic acid (AMPA), and glufosinate in 2,135 ground- and surface-water samples, 14 rainfall samples, and 193 soil samples. Analytical methods were developed to detect and measure glyphosate, AMPA, and glufosinate in water, rainfall, and soil. Results show that AMPA was detected more frequently and occurred at similar or higher concentrations than the parent compound, glyphosate, whereas glufosinate was seldom found in the environment. Glyphosate and AMPA were detected more frequently in surface water than in ground water. Trace levels of glyphosate and AMPA may persist in the soil from year to year. The methods and data described in this report are useful to researchers and regulators interested in the occurrence, fate, and transport of glyphosate and AMPA in the environment.

Deposition patterns and transport mechanisms for the endocrine disruptor 4-nonylphenol across the Sierra Nevada Mountains, California.

PubMed

Lyons, Rebecca; Van de Bittner, Kyle; Morgan-Jones, Sean

2014-12-01

Dust and particulate distribution patterns are shifting as global climate change brings about longer drought periods. Particulates act as vehicles for long range transport of organic pollutants, depositing at locations far from their source. Nonylphenol, a biodegradation product of nonylphenol polyethoxylate, is a known endocrine disruptor. Nonylphenol polyethoxylate enters the environment as an inert ingredient in pesticide sprays, potentially traveling great distances from its application site. This is of concern when a highly agricultural region, California's Central Valley, lies adjacent to sensitive areas like the Eastern Sierra Nevada Mountains. The distribution and transport mechanisms for 4-nonylphenol were investigated in Eastern Sierra Nevada canyons. Regions close to canyon headwalls showed trace amounts of 4-nonylphenol in surface water, snow, and atmospheric deposition. Exposed areas had yearly average concentrations as high as 9 μg/L. Distribution patterns are consistent with particulate-bound transport. This suggests with increasing drought periods, higher levels of persistent organic pollutants are likely. Copyright © 2014 Elsevier Ltd. All rights reserved.

Potential diffusion of doramectin into a soil amended with female pig manure. A field experiment.

PubMed

Gil-Díaz, María Del Mar; Pérez-Sanz, Araceli; Martín, Margarita; Lobo, Maria Carmen

2011-10-12

Doramectin is a veterinary drug used as an antihelminthic and is excreted mainly in the feces as the nonmetabolized drug. This study investigated the time profile of doramectin excretion in pig feces and the potential transfer and persistence of doramectin in the soil when the pig manure is used as an organic amendment to the soil. The concentration of doramectin in feces peaked at 143.0 ng/g in the dry feces 4 days after treatment. On day 62, the drug was still detected in the pig feces. After the land application of pig manure, the maximum concentration of doramectin in soil (ppb level) was detected 6 days after treatment. Seven months after the manure application, traces of doramectin were detected in the soil from the surface to a depth of 90 cm. Successive applications of manure from pigs treated with doramectin in a specific area could produce an accumulation of this drug in the soil.

Zebrafish in the sea of mineral (iron, zinc, and copper) metabolism

PubMed Central

Zhao, Lu; Xia, Zhidan; Wang, Fudi

2014-01-01

Iron, copper, zinc, and eight other minerals are classified as essential trace elements because they present in minute in vivo quantities and are essential for life. Because either excess or insufficient levels of trace elements can be detrimental to life (causing human diseases such as iron-deficiency anemia, hemochromatosis, Menkes syndrome and Wilson's disease), the endogenous levels of trace minerals must be tightly regulated. Many studies have demonstrated the existence of systems that maintain trace element homeostasis, and these systems are highly conserved in multiple species ranging from yeast to mice. As a model for studying trace mineral metabolism, the zebrafish is indispensable to researchers. Several large-scale mutagenesis screens have been performed in zebrafish, and these screens led to the identification of a series of metal transporters and the generation of several mutagenesis lines, providing an in-depth functional analysis at the system level. Moreover, because of their developmental advantages, zebrafish have also been used in mineral metabolism-related chemical screens and toxicology studies. Here, we systematically review the major findings of trace element homeostasis studies using the zebrafish model, with a focus on iron, zinc, copper, selenium, manganese, and iodine. We also provide a homology analysis of trace mineral transporters in fish, mice and humans. Finally, we discuss the evidence that zebrafish is an ideal experimental tool for uncovering novel mechanisms of trace mineral metabolism and for improving approaches to treat mineral imbalance-related diseases. PMID:24639652

[Measurement of the status of trace elements in cattle using liver biopsy samples].

PubMed

Ouweltjes, W; de Zeeuw, A C; Moen, A; Counotte, G H M

2007-02-01

Serum, plasma, or urine samples are usually used for the measurement of the trace elements copper; zinc, iron, selenium, because these samples are easy to obtain; however; these samples are not always appropriate. For example, it is not possible to measure molybdenum, the major antagonist of copper; in blood or urine. Therefore measurement of trace elements in liver tissue is considered the gold standard. For the assessment of selenium the method of choice remains determination of glutathion peroxidase in erythrocytes and for the assessment of magnesium determination of magnesium in urine. We determined the accuracy and repeatability of measuring trace elements in liver biopsies and whole liver homogenates. The levels of trace elements measured were similar in both preparations (92% agreement). Liver biopsy in live animals is a relatively simple procedure but not common in The Netherlands. Reference levels of trace elements, classified as too low, low, adequate, high, and too high, were established on the basis of our research and information in the literature. In a second study we investigated the practical aspects of obtaining liver tissue samples and their use. Samples were collected from cattle on a commercial dairy farm. Liver biopsy provided additional information to that obtained from serum and urine samples. We prepared a biopsy protocol and a test package, which we tested on 14 farms where an imbalance of trace minerals was suspected. Biopsy samples taken from 4 to 6 animals revealed extreme levels of trace elements.

Responses of trace elements to aerobic maximal exercise in elite sportsmen.

PubMed

Otag, Aynur; Hazar, Muhsin; Otag, Ilhan; Gürkan, Alper Cenk; Okan, Ilyas

2014-02-21

Trace elements are chemical elements needed in minute quantities for the proper growth, development, and physiology of the organism. In biochemistry, a trace element is also referred to as a micronutrient. Trace elements, such as nickel, cadmium, aluminum, silver, chromium, molybdenum, germanium, tin, titanium, tungsten, scandium, are found naturally in the environment and human exposure derives from a variety of sources, including air, drinking water and food. The Purpose of this study was investigated the effect of aerobic maximal intensity endurance exercise on serum trace elements as well-trained individuals of 28 wrestlers (age (year) 19.64±1.13, weight (Kg) 70.07 ± 15.69, height (cm) 176.97 ± 6.69) during and after a 2000 meter Ergometer test protocol was used to perform aerobic (75 %) maximal endurance exercise. Trace element serum levels were analyzed from blood samples taken before, immediately after and one hour after the exercise. While an increase was detected in Chromium (Cr), Nickel (Ni), Molybdenum (Mo) and Titanium (Ti) serum levels immediately after the exercise, a decrease was detected in Aluminum (Al), Scandium (Sc) and Tungsten (W) serum levels. Except for aluminum, the trace elements we worked on showed statistically meaningful responses (P < 0.05 and P < 0.001). According to the responses of trace elements to the exercise showed us the selection and application of the convenient sport is important not only in terms of sportsman performance but also in terms of future healthy life plans and clinically.

Removal of bulk dissolved organic carbon (DOC) and trace organic compounds by bank filtration and artificial recharge.

PubMed

Grünheid, Steffen; Amy, Gary; Jekel, Martin

2005-09-01

Bank filtration and artificial recharge provide an important drinking water source to the city of Berlin. Due to the practice of water recycling through a semi-closed urban water cycle, the introduction of effluent organic matter (EfOM) and persistent trace organic pollutants in the drinking water is of potential concern. In the work reported herein, the research objectives are to study the removal of bulk and trace organics at bank filtration and artificial recharge sites and to assess important factors of influence for the Berlin area. The monthly analytical program is comprised of dissolved organic carbon (DOC), UV absorbance (UVA254), liquid chromatography with organic carbon detection (LC-OCD), differentiated adsorbable organic halogens (AOX) and single organic compound analysis of a few model compounds. More than 1 year of monitoring was conducted on observation wells located along the flowpaths of the infiltrating water at two field sites that have different characteristics regarding redox conditions, travel time, and travel distance. Two transects are highlighted: one associated with a bank filtration site dominated by anoxic/anaerobic conditions with a travel time of up to 4-5 months, and another with an artificial recharge site dominated by aerobic conditions with a travel time of up to 50 days. It was found that redox conditions and travel time significantly influence the DOC degradation kinetics and the efficiency of AOX and trace compound removal.

PhOTO Zebrafish: A Transgenic Resource for In Vivo Lineage Tracing during Development and Regeneration

PubMed Central

Dempsey, William P.; Fraser, Scott E.; Pantazis, Periklis

2012-01-01

Background Elucidating the complex cell dynamics (divisions, movement, morphological changes, etc.) underlying embryonic development and adult tissue regeneration requires an efficient means to track cells with high fidelity in space and time. To satisfy this criterion, we developed a transgenic zebrafish line, called PhOTO, that allows photoconvertible optical tracking of nuclear and membrane dynamics in vivo. Methodology PhOTO zebrafish ubiquitously express targeted blue fluorescent protein (FP) Cerulean and photoconvertible FP Dendra2 fusions, allowing for instantaneous, precise targeting and tracking of any number of cells using Dendra2 photoconversion while simultaneously monitoring global cell behavior and morphology. Expression persists through adulthood, making the PhOTO zebrafish an excellent tool for studying tissue regeneration: after tail fin amputation and photoconversion of a ∼100µm stripe along the cut area, marked differences seen in how cells contribute to the new tissue give detailed insight into the dynamic process of regeneration. Photoconverted cells that contributed to the regenerate were separated into three distinct populations corresponding to the extent of cell division 7 days after amputation, and a subset of cells that divided the least were organized into an evenly spaced, linear orientation along the length of the newly regenerating fin. Conclusions/Significance PhOTO zebrafish have wide applicability for lineage tracing at the systems-level in the early embryo as well as in the adult, making them ideal candidate tools for future research in development, traumatic injury and regeneration, cancer progression, and stem cell behavior. PMID:22431986

Persistence and performance of esfenvalerate residues on broccoli.

PubMed

Antonious, George F

2002-01-01

The efficacy of esfenvalerate (84 g litre-1 EC; Asana XL) at 7.0 g AI ha-1 on broccoli was tested against the flea beetle, Phyllotreta cruciferae Goeze (Chrysomelidae: Coleoptera) and the imported cabbage worm, Pieris rapae L (Pieridae: Lepidoptera) under field conditions. Insect populations were monitored before and after treatment. Periodic sweep-net collections and examination of the leaves in treated and untreated broccoli plots revealed mean reductions of P cruciferae levels of nearly 98% 1 week post-application compared with untreated plots. The residual toxicity of esfenvalerate was also effective for 2 weeks in reducing population density of P rapae by 69% on broccoli leaves. The impact of esfenvalerate on feeding damage to broccoli leaves was established by counting the number of feeding holes made by P cruciferae on spring broccoli and P rapae on fall broccoli. As the leaf area ingested increased, a linear relationship was seen between the number of holes and number of insects. Results indicated that forage destruction by the two pests was significantly reduced by esfenvalerate application. Esfenvalerate was extracted from broccoli at 1 h and 1, 3, 7, 10, and 14 days post-application for residue analysis. Residues on spring broccoli were 12.2, 5.2 and 2.9 micrograms cm-2 on the leaves and 0.13, 0.05 and 0.02 microgram g-1 on the heads at 1 h, 1 and 3 days, respectively. Only trace levels (0.001 microgram g-1) were detected in/on the heads 14 days after spraying. On the basis of half-life (T1/2) values, persistence of esfenvalerate on spring broccoli leaves (T1/2 = 1 day) was shorter than on fall broccoli (T1/2 = 1.6 days). T1/2 values were 2.1 and 3.6 days on spring and fall broccoli heads, respectively. The implications of these residue levels on re-entry times into treated fields are discussed.

Sensory profiling and consumer acceptability of new dark cocoa bars containing Tuscan autochthonous food products.

PubMed

Cantini, Claudio; Salusti, Patrizia; Romi, Marco; Francini, Alessandra; Sebastiani, Luca

2018-03-01

A new set of cocoa bars named Toscolata ® were developed containing top-quality extra virgin olive oil, dried apples cultivars, and chestnut flour. The present work has been conducted to define the sensory profile of these products through tasting by trained experts and consumers to study the acceptability, preference, and quality perception. The four sensorial profiles of the bars differed in the level of persistence, bitterness, aromaticity, acidity, astringency, and tastiness. In particular, the sour attribute could be traced to the presence of dried apple. Bars containing apple and chestnut flour obtained higher acceptance ratings, compared to those with extra virgin olive oil. The bar with chestnut flour was preferred by consumers who considered it to be sweeter due to the presence of natural sugars, which lowered the bitter sensation of cocoa. These results showed that the selection of the preferred bar by consumers was mainly based on the level of bitterness and, in particular, elderly consumers expressed a strong preference for the sweetest product. As far as we know, this is the first study comparing the results of a panel of expert tasters with that of consumers in the tasting of dark chocolate.

Cholinergic modulation of the CAN current may adjust neural dynamics for active memory maintenance, spatial navigation and time-compressed replay

PubMed Central

Yoshida, Motoharu; Knauer, Beate; Jochems, Arthur

2012-01-01

Suppression of cholinergic receptors and inactivation of the septum impair short-term memory, and disrupt place cell and grid cell activity in the medial temporal lobe (MTL). Location-dependent hippocampal place cell firing during active waking, when the acetylcholine level is high, switches to time-compressed replay activity during quiet waking and slow-wave-sleep (SWS), when the acetylcholine level is low. However, it remains largely unknown how acetylcholine supports short-term memory, spatial navigation, and the functional switch to replay mode in the MTL. In this paper, we focus on the role of the calcium-activated non-specific cationic (CAN) current which is activated by acetylcholine. The CAN current is known to underlie persistent firing, which could serve as a memory trace in many neurons in the MTL. Here, we review the CAN current and discuss possible roles of the CAN current in short-term memory and spatial navigation. We further propose a novel theoretical model where the CAN current switches the hippocampal place cell activity between real-time and time-compressed sequential activity during encoding and consolidation, respectively. PMID:22435051

Distribution and source apportionment studies of heavy metals in soil of cotton/wheat fields.

PubMed

Rafique, Nazia; Tariq, Saadia R

2016-05-01

Heavy metals enriched agricultural soils have been the subject of great concern because these metals have potential to be transferred to the soil solution and afterward accumulated in food chain. To study the trace metal persistence in crop soil, 90 representative soil samples were collected and analyzed for heavy metal (As, Cd, Cu, Fe, Mn, Ni, Pb, and Zn) and anions (chloride, nitrates, phosphates and sulfates). Cluster and factor analysis techniques were used for the source identification of these excessive heavy metal levels and ecological risk was determined with potential ecological risk assessment. The degree of enrichment of eight studied heavy metals in comparison with the corresponding background levels decreased in order: Cd > Pb > Fe > Ni > Mn > As > Cu ~ Zn. Arsenic and cadmium exhibited 1.30- and 1.64-fold exceeded levels than threshold limits set by National environment quality standards, respectively. Cd in cotton field's soil may lead to higher potential risk than other heavy metals. On overall basis, the cumulative mean potential ecological risk for the district (207.75) corresponded to moderate risk level with higher contributions from As and Pb especially from Cd. Cadmium formed strong positive correlation with phosphate content of soil at p < 0.01. Cluster analysis indicated that Cluster 1 (extremely polluted) probably originated from anthropogenic inputs of phosphate fertilizer and past usage of arsenical pesticides.

Virtual Ray Tracing as a Conceptual Tool for Image Formation in Mirrors and Lenses

ERIC Educational Resources Information Center

Heikkinen, Lasse; Savinainen, Antti; Saarelainen, Markku

2016-01-01

The ray tracing method is widely used in teaching geometrical optics at the upper secondary and university levels. However, using simple and straightforward examples may lead to a situation in which students use the model of ray tracing too narrowly. Previous studies show that students seem to use the ray tracing method too concretely instead of…

Influence of organic matter on trace metal flux in coastal sediments. [Sequim Bay

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

Schmidt, R.L.; Gibson, C.I.

1978-05-15

These studies indicate that organic matter in coastal sediment constitutes a primary sink for trace metals, both at natural and amended levels. Organic substances are also involved in controlling the mobility and flux of trace metals from sediments. Further, organically-bound trace metals in sediments appear to be an important source to deposit-feeding organisms.

A Method for Assessing the Retention of Trace Elements in Human Body Using Neural Network Technology

PubMed Central

Ragimov, Aligejdar; Faizullin, Rashat; Valiev, Vsevolod

2017-01-01

Models that describe the trace element status formation in the human organism are essential for a correction of micromineral (trace elements) deficiency. A direct trace element retention assessment in the body is difficult due to the many internal mechanisms. The trace element retention is determined by the amount and the ratio of incoming and excreted substance. So, the concentration of trace elements in drinking water characterizes the intake, whereas the element concentration in urine characterizes the excretion. This system can be interpreted as three interrelated elements that are in equilibrium. Since many relationships in the system are not known, the use of standard mathematical models is difficult. The artificial neural network use is suitable for constructing a model in the best way because it can take into account all dependencies in the system implicitly and process inaccurate and incomplete data. We created several neural network models to describe the retentions of trace elements in the human body. On the model basis, we can calculate the microelement levels in the body, knowing the trace element levels in drinking water and urine. These results can be used in health care to provide the population with safe drinking water. PMID:29065586

Space opportunities for tropospheric chemistry research

NASA Technical Reports Server (NTRS)

Levine, Joel S.; Hoell, James M.; Mcneal, Robert J.

1986-01-01

The use of the Space Shuttle to measure tropospheric trace species is examined. Factors which affect the measurement of tropospheric trace species are discussed. The Academy of Sciences 1985 report categorized the trace species into levels: first-level gases include water vapor, O3, CO, and CH4, and the second-level gases are N2O, NO2, NH3, SO2, chlorofluoromethanes, and HCl. The effects of first-level gases on the earth's climate, the photochemistry/chemistry of the troposphere, and the photochemical/chemical production and destruction of the hydroxyl radical are studied; the distribution and magnitude of the hydroxyl radical in the troposphere are analyzed in terms of water vapor, O3, CO, and CH4.

Bacterial persistence by RNA endonucleases

PubMed Central

Maisonneuve, Etienne; Shakespeare, Lana J.; Jørgensen, Mikkel Girke; Gerdes, Kenn

2011-01-01

Bacteria form persisters, individual cells that are highly tolerant to different types of antibiotics. Persister cells are genetically identical to nontolerant kin but have entered a dormant state in which they are recalcitrant to the killing activity of the antibiotics. The molecular mechanisms underlying bacterial persistence are unknown. Here, we show that the ubiquitous Lon (Long Form Filament) protease and mRNA endonucleases (mRNases) encoded by toxin-antitoxin (TA) loci are required for persistence in Escherichia coli. Successive deletion of the 10 mRNase-encoding TA loci of E. coli progressively reduced the level of persisters, showing that persistence is a phenotype common to TA loci. In all cases tested, the antitoxins, which control the activities of the mRNases, are Lon substrates. Consistently, cells lacking lon generated a highly reduced level of persisters. Moreover, Lon overproduction dramatically increased the levels of persisters in wild-type cells but not in cells lacking the 10 mRNases. These results support a simple model according to which mRNases encoded by TA loci are activated in a small fraction of growing cells by Lon-mediated degradation of the antitoxins. Activation of the mRNases, in turn, inhibits global cellular translation, and thereby induces dormancy and persistence. Many pathogenic bacteria known to enter dormant states have a plethora of TA genes. Therefore, in the future, the discoveries described here may lead to a mechanistic understanding of the persistence phenomenon in pathogenic bacteria. PMID:21788497

Function of child anger and sadness in response to a blocked goal.

PubMed

Tan, Lin; Smith, Cynthia L

2018-06-01

Drawing from the functional theory of emotion, anger is proposed to serve adaptive functions such as motivating children to persist in overcoming difficulties to achieve their goals, whereas sadness helps children to shift attention away from goals that they determine cannot be attained. Despite the theorized importance of anger to persistence, it does not always relate to persistence in expected ways empirically; the role that sadness might play in how anger relates to persistence is often not considered even though children often experience both anger and sadness when goals are blocked. We hypothesized that how anger relates to persistence would depend on the level of sadness that children felt and, thus, tested sadness as a moderator of the relation of anger to persistence. We expected that the relation of anger to persistence would be stronger when sadness is lower. Child anger, sadness, and persistence were observed in a locked-box frustration task when children were 4 or 5 years old (N = 116). Although higher levels of child anger were associated with more persistence, the association between anger and persistence was stronger when sadness was lower than when sadness was higher. The findings indicate that children's ability to use the motivational aspects of anger to promote persistence may depend on the levels of sadness felt. Copyright © 2018 Elsevier Inc. All rights reserved.

Four trace elements in pregnant women and their relationships with adverse pregnancy outcomes.

PubMed

Shen, P-J; Gong, B; Xu, F-Y; Luo, Y

2015-12-01

Lack of trace elements during pregnancy is detrimental to maternal and fetal health. Our aim is to study the changes in trace element levels in Chinese pregnant women and their association with adverse pregnancy outcomes. 1568 cases of Chinese pregnant women in remote areas were collected for a prospective cohort study. Serum copper, zinc, calcium and iron levels were measured at pre-pregnancy, 1st trimester (7w-12w), 2nd trimester (24w-28w) and 3rd trimester (35w-40w). (1) Serum copper levels was significantly higher after pregnancy than before, calcium and iron levels decreased, but zinc levels did not change significantly. (2) Copper and zinc deficiency in pregnant women was not a common finding, but lack of iron and calcium was frequently encountered; iron deficiency was especially common in the 3rd trimester (42.27%). (3) Serum zinc and iron levels in patients who either had a miscarriage or a preterm delivery were significantly lower than in the control group (p < 0.05). In patients with premature rupture of membranes, serum zinc levels were significantly lower (p < 0.05). In patients with intrauterine growth restriction (IUGR), serum copper, zinc, calcium and iron were significantly lower (p < 0.05). Trace elements is closely associated with fetal growth and development during pregnancy. Deficiency can lead to adverse pregnancy outcomes. Therefore, we should have a reasonable diet, replenish trace elements, therefore reducing the occurrence of adverse pregnancy outcomes.

Serum trace elements in obese women with or without diabetes

PubMed Central

Yerlikaya, F. Hümeyra; Toker, Aysun; Arıbaş, Alpay

2013-01-01

Background & objectives: Relationship of trace elements with obesity and diabetes is complex, alterations in their metabolism can be induced by the diseases and their complications. To study the role of the trace elements in diabetes and obesity, serum trace elements levels (Cr, Se, Fe, Zn, Cu and Mn) were measured in obese women with or without diabetes as well as healthy women. Further, correlation between serum trace elements levels and glucose, insulin, homeostasis model assessment (HOMA-IR), glycated haemoglobin (HbA1c), body mass index (BMI), waist circumferences, waist -to -hip ratio and high-sensitivity C-reactive protein(hsCRP) were also determined in these women. Methods: This study was performed with morbidly obese (BMI >40 kg/m2) women with diabetes (n=41), without diabetes (n=45) and 50 healthly non obese women. Anthropometric measurements were taken and levels of serum Zn, Cr, Fe Cu and Mn were determined. Biochemical parameters included serum glucose, insulin, lipids, haemoglobin, hsCRP and HbA1C. Results: The levels of Zn (P<0.001), Mn (P<0.05), Fe (P<0.05) were significantly lower and the level of Cu (P<0.001) and Cu / Zn ratio (P<0.05) were significantly higher in the diabetic obese women than those of the healthy women. Also, the levels of Zn and Fe were significantly lower and the levels of Cu were significantly higher in the non diabetic obese women than those of the healthy group. Serum Zn levels negatively and serum Cu levels positively correlated with anthropometric values in diabetic and non diabetic obese women. Further, serum Zn, Mn and Cr levels negatively correlated and serum Se levels positively correlated glycaemia control parameters in diabetic obese women. In addition, serum Zn levels negatively correlated with hsCRP in diabetic and nondiabetic obese females. Interpretation & conclusions: Our findings showed significant association between Zn and Fe deficiencies and obesity. Also, obese women with diabetes may be at a greater risk of developing imbalances and deficiencies of trace elements compared with obese women without diabetes. PMID:23563378

The Role of Trace Elements in Tinnitus.

PubMed

Yaşar, Mehmet; Şahin, Mehmet İlhan; Karakükçü, Çiğdem; Güneri, Erhan; Doğan, Murat; Sağıt, Mustafa

2017-03-01

In this study, we aimed to investigate the role of three trace elements, namely, zinc, copper, and lead, in tinnitus by analyzing the serum level of copper and lead and both the serum and tissue level of zinc. Eighty patients, who applied to outpatient otolaryngology clinic with the complaints of having tinnitus, and 28 healthy volunteers were included. High-frequency audiometry was performed, and participants who had hearing loss according to the pure tone average were excluded; tinnitus frequency and loudness were determined and tinnitus reaction questionnaire scores were obtained from the patients. Of all the participants, serum zinc, copper, and lead values were measured; moreover, zinc levels were examined in hair samples. The levels of trace elements were compared between tinnitus and control groups. The level of copper was found to be significantly lower in the tinnitus group (p = 0.02), but there was no significant difference between the groups in terms of the levels of zinc, neither in serum nor in hair, and lead in serum (p > 0.05). The lack of trace elements, especially that of "zinc," have been doubted for the etiopathogenesis of tinnitus in the literature; however, we only found copper levels to be low in patients having tinnitus.

Risk assessment of trace elements in cultured freshwater fishes from Jiangxi province, China.

PubMed

Zhang, Li; Zhang, Dawen; Wei, Yihua; Luo, Linguan; Dai, Tingcan

2014-04-01

The levels of trace elements (As, Cd, Cr, Cu, Fe, Ni, Pb, Se, and Zn) in eight species of cultured freshwater fishes from Jiangxi province were determined by inductively coupled plasma-mass spectroscopy. All the studied trace element levels in fish muscles from Jiangxi province did not exceed Chinese national standard and European Union standard, and they were often lower than previous studies. The calculated target hazard quotient values for all the studied trace elements in fish samples were much less than 1, suggesting that the studied trace elements in fish muscles from Jiangxi province had not pose obvious health hazards to consumers. As and Cd concentrations in northern snakehead were much higher than that in other fishes, demonstrating that this fish species could be valuable as a bioindicator of As and Cd in environmental surveys. In addition, the highest concentrations of Fe, Zn, and moderate contents of other essential trace elements in crucian carp indicated that crucian carp could be a good nutrient source of essential trace elements for human health.

Trace Element Levels and Cognitive Function in Rural Elderly Chinese

PubMed Central

Gao, Sujuan; Jin, Yinlong; Unverzagt, Frederick W.; Ma, Feng; Hall, Kathleen S.; Murrell, Jill R.; Cheng, Yibin; Shen, Jianzhao; Ying, Bo; Ji, Rongdi; Matesan, Janetta; Liang, Chaoke; Hendrie, Hugh C.

2009-01-01

Background Trace elements are involved in metabolic processes and oxidation-reduction reactions in the central nervous system and could have a possible effect on cognitive function. The relationship between trace elements measured in individual biological samples and cognitive function in an elderly population had not been investigated extensively. Methods The participant population is part of a large cohort study of 2000 rural elderly Chinese persons. Six cognitive assessment tests were used to evaluate cognitive function in this population, and a composite score was created to represent global cognitive function. Trace element levels of aluminum, calcium, cadmium, copper, iron, lead, and zinc were analyzed in plasma samples of 188 individuals who were randomly selected and consented to donating fasting blood. Analysis of covariance models were used to assess the association between each trace element and the composite cognitive score adjusting for demographics, medical history of chronic diseases, and the apolipoprotein E (APOE) genotype. Results Three trace elements—calcium, cadmium, and copper—were found to be significantly related to the composite cognitive score. Increasing plasma calcium level was associated with higher cognitive score (p < .0001). Increasing cadmium and copper, in contrast, were significantly associated with lower composite score (p = .0044 and p = .0121, respectively). Other trace elements did not show significant association with the composite cognitive score. Conclusions Our results suggest that calcium, cadmium, and copper may be associated with cognitive function in the elderly population. PMID:18559640

Trace element levels and cognitive function in rural elderly Chinese.

PubMed

Gao, Sujuan; Jin, Yinlong; Unverzagt, Frederick W; Ma, Feng; Hall, Kathleen S; Murrell, Jill R; Cheng, Yibin; Shen, Jianzhao; Ying, Bo; Ji, Rongdi; Matesan, Janetta; Liang, Chaoke; Hendrie, Hugh C

2008-06-01

Trace elements are involved in metabolic processes and oxidation-reduction reactions in the central nervous system and could have a possible effect on cognitive function. The relationship between trace elements measured in individual biological samples and cognitive function in an elderly population had not been investigated extensively. The participant population is part of a large cohort study of 2000 rural elderly Chinese persons. Six cognitive assessment tests were used to evaluate cognitive function in this population, and a composite score was created to represent global cognitive function. Trace element levels of aluminum, calcium, cadmium, copper, iron, lead, and zinc were analyzed in plasma samples of 188 individuals who were randomly selected and consented to donating fasting blood. Analysis of covariance models were used to assess the association between each trace element and the composite cognitive score adjusting for demographics, medical history of chronic diseases, and the apolipoprotein E (APOE) genotype. Three trace elements-calcium, cadmium, and copper-were found to be significantly related to the composite cognitive score. Increasing plasma calcium level was associated with higher cognitive score (p <.0001). Increasing cadmium and copper, in contrast, were significantly associated with lower composite score (p =.0044 and p =.0121, respectively). Other trace elements did not show significant association with the composite cognitive score. Our results suggest that calcium, cadmium, and copper may be associated with cognitive function in the elderly population.

Determination of trace metals in drinking water in Irbid City-Northern Jordan.

PubMed

Alomary, Ahmed

2013-02-01

Drinking water samples from Irbid, the second populated city in Jordan were analyzed for trace metals (As, Ba, Cd, Pb, Cr, Cu, Fe, Zn, Mn, Ni, and Se) content. The study was undertaken to determine if the metal concentrations were within the national and international guidelines. A total of 90 drinking water samples were collected from Al-Yarmouk University area. The samples were collected from three different water types: tap water (TW), home-purified water (HPW), and plant-purified water (PPW). All the samples were analyzed for trace metals using an inductively coupled plasma-optical emission spectrometry. All the samples analyzed were within the United States Environmental Protection Agency admissible pH limit (6.5-8.5). The results showed that concentrations of the trace metals vary significantly between the three drinking water types. The results showed that HPW samples have the lowest level of trace metals and the concentrations of some essential trace metals in these samples are less than the recommended amounts. Slight differences in the metal contents were found between HPW samples, little differences between PPW samples; however, significant differences were found between TW samples. Although some TW samples showed high levels of trace metals, however, the mean level of most elements determined in the samples were well within the Jordanian standards as well as the World Health Organization standards for drinking water.

New Stratospheric Dust Belt Due to the Chelyabinsk Bolide

NASA Technical Reports Server (NTRS)

Gorkavyi, Nick; Rault, D. F.; Newman, P. A.; da Silva, A. M.; Dudorov, A. E.

2013-01-01

The Ozone Mapping Profiler Suite (OMPS) Limb Profiler (LP) on the recently launched NASA/NOAA NPP/ Suomi satellite detected aerosol excess in the midstratosphere (25-45 km altitude) between 50degN and 70degN latitudes. OMPS/LP observations trace this aerosol plume to the meteor that struck near Chelyabinsk, Russia on 15 February 2013. This new dust layer, located above the Junge aerosol layer, has persisted over at least a 3 month period. Material collected on the ground following the bolide explosion showed that the meteor was mostly composed of olivine and pyroxenes. Simulations using Lagrangian and Eulerian atmospheric models trace the plume back to Chelyabinsk and confirm that the plume altitude was at altitudes between 25 and 45 km. The models also confirm the plume circumpolar longitudinal spreading observed by OMPS/LP, with propagation speeds up to 85 m/s.

Traffic-related trace elements in soils along six highway segments on the Tibetan Plateau: Influence factors and spatial variation.

PubMed

Wang, Guanxing; Zeng, Chen; Zhang, Fan; Zhang, Yili; Scott, Christopher A; Yan, Xuedong

2017-03-01

The accumulation of traffic-related trace elements in soil as the result of anthropogenic activities raises serious concerns about environmental pollution and public health. Traffic is the main source of trace elements in roadside soil on the Tibetan Plateau, an area otherwise devoid of industrial emissions. Indeed, the rapid development of tourism and transportation in this region means it is becoming increasingly important to identify the accumulation levels, influence distance, spatial distribution, and other relevant factors influencing trace elements. In this study, 229 soil samples along six segments of the major transportation routes on the Tibetan Plateau (highways G214, S308, and G109), were collected for analysis of eight trace elements (Cr, Co, Ni, As, Cu, Zn, Cd, and Pb). The results of statistical analyses showed that of the eight trace elements in soils, Cu, Zn, Cd, and Pb were primarily derived from traffic. The relationship between the trace element accumulation levels and the distance from the roadside followed an exponential decline, with the exception of Segment 3, the only unpaved gravel road studied. In addition, the distance of influence from the roadside varied by trace element and segment, ranging from 16m to 144m. Background values for each segment were different because of soil heterogeneity, while a number of other potential influencing factors (including traffic volume, road surface material, roadside distance, land cover, terrain, and altitude) all had significant effects on trace-element concentrations. Overall, however, concentrations along most of the road segments investigated were at, or below, levels defined as low on the Nemero Synthesis index. Copyright © 2017 Elsevier B.V. All rights reserved.

Chemical contaminants (trace metals, persistent organic pollutants) in albacore tuna from western Indian and south-eastern Atlantic Oceans: Trophic influence and potential as tracers of populations.

PubMed

Chouvelon, Tiphaine; Brach-Papa, Christophe; Auger, Dominique; Bodin, Nathalie; Bruzac, Sandrine; Crochet, Sylvette; Degroote, Maxime; Hollanda, Stephanie J; Hubert, Clarisse; Knoery, Joël; Munschy, Catherine; Puech, Alexis; Rozuel, Emmanuelle; Thomas, Bastien; West, Wendy; Bourjea, Jérôme; Nikolic, Natacha

2017-10-15

Albacore tuna (Thunnus alalunga) is a highly commercial fish species harvested in the world's Oceans. Identifying the potential links between populations is one of the key tools that can improve the current management across fisheries areas. In addition to characterising populations' contamination state, chemical compounds can help refine foraging areas, individual flows and populations' structure, especially when combined with other intrinsic biogeochemical (trophic) markers such as carbon and nitrogen stable isotopes. This study investigated the bioaccumulation of seven selected trace metals - chromium, nickel, copper (Cu), zinc (Zn), cadmium (Cd), mercury (Hg) and lead - in the muscle of 443 albacore tunas, collected over two seasons and/or years in the western Indian Ocean (WIO: Reunion Island and Seychelles) and in the south-eastern Atlantic Ocean (SEAO: South Africa). The main factor that explained metal concentration variability was the geographic origin of fish, rather than the size and the sex of individuals, or the season/year of sampling. The elements Cu, Zn, Cd and Hg indicated a segregation of the geographic groups most clearly. For similar sized-individuals, tunas from SEAO had significantly higher concentrations in Cu, Zn and Cd, but lower Hg concentrations than those from WIO. Information inferred from the analysis of trophic markers (δ 13 C, δ 15 N) and selected persistent organic pollutants, as well as information on stomach contents, corroborated the geographical differences obtained by trace metals. It also highlighted the influence of trophic ecology on metal bioaccumulation. Finally, this study evidenced the potential of metals and chemical contaminants in general as tracers, by segregating groups of individuals using different food webs or habitats, to better understand spatial connectivity at the population scale. Limited flows of individuals between the SEAO and the WIO are suggested. Albacore as predatory fish also provided some information on environmental and food web chemical contamination in the different study areas. Copyright © 2017 Elsevier B.V. All rights reserved.

Cumulative Inequality and Racial Disparities in Health: Private Insurance Coverage and Black/White Differences in Functional Limitations

PubMed Central

Taylor, Miles G.

2014-01-01

Objectives. To test different forms of private insurance coverage as mediators for racial disparities in onset, persistent level, and acceleration of functional limitations among Medicare age-eligible Americans. Method. Data come from 7 waves of the Health and Retirement Study (1996–2008). Onset and progression latent growth models were used to estimate racial differences in onset, level, and growth of functional limitations among a sample of 5,755 people aged 65 and older in 1996. Employer-provided insurance, spousal insurance, and market insurance were next added to the model to test how differences in private insurance mediated the racial gap in physical limitations. Results. In baseline models, African Americans had larger persistent level of limitations over time. Although employer-provided, spousal provided, and market insurances were directly associated with lower persistent levels of limitation, only differences in market insurance accounted for the racial disparities in persistent level of limitations. Discussion. Results suggest private insurance is important for reducing functional limitations, but market insurance is an important mediator of the persistently larger level of limitations observed among African Americans. PMID:24569001

Fate dynamics of environmentally exposed explosive traces.

PubMed

Kunz, Roderick R; Gregory, Kerin E; Aernecke, Matthew J; Clark, Michelle L; Ostrinskaya, Alla; Fountain, Augustus W

2012-04-12

The chemical and physical fates of trace amounts (<50 μg) of explosives containing 2,4,6-trinitrotoluene (TNT), hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), and pentaerythritol tetranitrate (PETN) were determined for the purpose of informing the capabilities of tactical trace explosive detection systems. From these measurements, it was found that the mass decreases and the chemical composition changes on a time scale of hours, with the loss mechanism due to a combination of sublimation and photodegradation. The rates for these processes were dependent on the explosive composition, as well as on both the ambient temperature and the size distribution of the explosive particulates. From these results, a persistence model was developed and applied to model the time dependence of both the mass and areal coverage of the fingerprints, resulting in a predictive capability for determining fingerprint fate. Chemical analysis confirmed that sublimation rates for TNT were depressed by UV (330-400 nm) exposure due to photochemically driven increases in the molecular weight, whereas the opposite was observed for RDX. No changes were observed for PETN upon exposure to UV radiation, and this was attributed to its low UV absorbance.

Effect of supplemental trace mineral level and form on peripubertal bulls

USDA-ARS?s Scientific Manuscript database

The objectives were to determine if different supplemental trace mineral levels and /or forms (sulfate and metal amino acid complexes) influence age at puberty, semen quality, endocrine status and scrotal circumference in peripubertal bulls. Fifty crossbred, peripubertal bulls were blocked by age (...

Effects of urbanization and long-term rainfall on the occurrence of organic compounds and trace elements in reservoir sediment cores, streambed sediment, and fish tissue from the Santa Ana River basin, California, 1998

USGS Publications Warehouse

Burton, Carmen A.

2002-01-01

Organcochlorine compounds, semivolatile-organic compounds (SVOC), and trace elements were analyzed in reservoir sediment cores, streambed sediment, and fish tissue in the Santa Ana River Basin as part of the U.S. Geological Survey's National Water-Quality Assessment Program. Three reservoirs were sampled in areas that have different degrees of urbanization. Streambed sediment and fish tissue collected at 12 sites were divided into two groups, urban and nonurban. More organochlorine compounds were detected in reservoir sediment cores, streambed sediment and fish tissue, and at higher concentrations at urban sites than at nonurban sites. At all sites, except West Street Basin, concentrations of organochlorine compounds were lower than the probable-effect concentration (PEC). At the highly urbanized West Street Basin, chlordane and p,p'-DDE exceeded the PEC throughout the historical record. The less stringent threshold-effect concentration (TEC) was exceeded for six compounds at eight sites. Most of the organochlorine compounds detected in streambed sediment and fish tissue were at urban sites on the Santa Ana River as opposed to its tributaries, suggesting accumulation and persistence in the river. More SVOCs were detected in reservoir sediment cores and streambed sediment, and at higher concentrations, at urban sites than at nonurban sites. At all the sites, except West Street Basin, concentrations of SVOCs were lower than the PEC. At West Street Basin, chrysene, pyrene, and total polycyclic-aromatic hydrocarbons exceeded the PEC throughout the historical record. The TEC was exceeded for 10 compounds at 3 sites. Most of the SVOCs were detected in streambed sediment at urban sites on tributaries to the Santa Ana River rather than the mainstem itself. The less frequent occurrence and lower concentrations in the Santa Ana River suggest that SVOCs are less persistent than organochlorine compounds, possibly as a result of volatization, gradation, or dilution. Most trace-element detections in reservoir sediment cores and streambed sediment were at urban sites, and the concentrations were generally higher than at nonurban sites. Lead and zinc exceeded their PECs at West Street Basin throughout the historical record; copper exceeded its PEC at Canyon Lake, an area of urban growth. The TEC was exceeded for 10 compounds at 11 sites. Frequency of detection and concentration did not differ between tributary and Santa Ana River sites, which may be attributed to the fact that trace elements occur naturally. Four trace elements (arsenic, copper, mercury, and selenium) had higher concentrations in fish tissue at nonurban sites than at urban sites. Concentrations decreased over time for organochlorine compounds at all three reservoirs, probably a result of the discontinued use of many of the compounds. Decreasing trends in SVOCs and trace elements were observed at West Street Basin, but increasing trends were observed at Canyon Lake. Concentrations of organochlorine compounds, SVOCs, and trace elements were higher during periods of above average rainfall at both West Street Basin and Canyon Lake.

Analysis of cellular autofluorescence in touch samples by flow cytometry: implications for front end separation of trace mixture evidence.

PubMed

Katherine Philpott, M; Stanciu, Cristina E; Kwon, Ye Jin; Bustamante, Eduardo E; Greenspoon, Susan A; Ehrhardt, Christopher J

2017-07-01

The goal of this study was to survey optical and biochemical variation in cell populations deposited onto a surface through touch or contact and identify specific features that may be used to distinguish and then sort cell populations from separate contributors in a trace biological mixture. Although we were not able to detect meaningful biochemical variation in touch samples deposited by different contributors through preliminary antibody surveys, we did observe distinct differences in red autofluorescence emissions (650-670 nm), with as much as a tenfold difference in mean fluorescence intensities observed between certain pairs of donors. Results indicate that the level of red autofluorescence in touch samples can be influenced by a donor's contact with specific material prior to handling the substrate from which cells were collected. In particular, we observed increased red autofluorescence in cells deposited subsequent to handling laboratory gloves, plant material, and certain types of marker ink, which could be easily visualized microscopically or using flow cytometry, and persisted after hand washing. To test whether these observed optical differences could potentially be used as the basis for a cell separation workflow, a controlled two-person touch mixture was separated into two fractions via fluorescence-activated cell sorting (FACS) using gating criteria based on intensity of 650-670 nm emissions and then subjected to DNA analysis. Genetic analysis of the sorted fractions provided partial DNA profiles that were consistent with separation of individual contributors from the mixture suggesting that variation in autofluorescence signatures, even if driven by extrinsic factors, may nonetheless be a useful means of isolating contributors to some touch mixtures. Graphical Abstract Conceptual workflow diagram. Trace biological mixtures containing cells from multiple individuals are analyzed by flow cytometry. Cells are then physically separated into two populations based on intensity of red autofluorescence using Fluorescence Activated Cell Sorting. Each isolated cell fraction is subjected to DNA analysis resulting in a DNA profile for each contributor.

Personality and Persistence in Education: A Longitudinal Study.

ERIC Educational Resources Information Center

Gottfredson, Denise C.

Persistence in educational pursuits is strongly related to the prestige level and income level of an occupation. Personality correlates of persistence in education were examined in the context of a causal model of attainment in an eight-year longitudinal study of a nationally representative sample of 2213 young men. Results imply that anxiety and…

An Updated Global Picture of Cigarette Smoking Persistence among Adults

PubMed Central

Troost, Jonathan P.; Barondess, David A.; Storr, Carla L.; Wells, J. Elisabeth; Al-Hamzawi, Ali Obaid; Andrade, Laura Helena; Bromet, Evelyn; Bruffaerts, Ronny; Florescu, Silvia; de Girolamo, Giovanni; de Graaf, Ron; Gureje, Oye; Haro, Josep Maria; Hu, Chiyi; Huang, Yueqin; Karam, Aimee N.; Kessler, Ronald C.; Lepine, Jean-Pierre; Matschinger, Herbert; Medina-Mora, Maria Elena; O'Neill, Siobhan; Posada-Villa, Jose; Sagar, Rajesh; Takeshima, Tadashi; Tomov, Toma; Williams, David R.; Anthony, James C.

2012-01-01

Background Cross-national variance in smoking prevalence is relatively well documented. The aim of this study is to estimate levels of smoking persistence across 21 countries with a hypothesized inverse relationship between country income level and smoking persistence. Methods Data from the World Health Organization World Mental Health Survey Initiative were used to estimate cross-national differences in smoking persistence–the proportion of adults who started to smoke and persisted in smoking by the date of the survey. Result There is large variation in smoking persistence from 25% (Nigeria) to 85% (China), with a random-effects meta-analytic summary estimate of 55% with considerable cross-national variation. (Cochran's heterogeneity Q statistic=6,845; p<0.001). Meta-regressions indicated observed differences are not attributable to differences in country income level, age distribution of smokers, or how recent the onset of smoking began within each country. Conclusion While smoking should remain an important public health issue in any country where smokers are present, this report identifies several countries with higher levels of smoking persistence (namely, China and India). PMID:23626929

Survey of findings in patients having persistent heartburn on proton pump inhibitor therapy.

PubMed

Mandaliya, R; DiMarino, A J; Cohen, S

2016-01-01

In patients with refractory heartburn while on proton pump inhibitor (PPI) therapy, changing drugs or increasing treatment to a twice a day (b.i.d.) dose has become a common practice. This study aims to study patients with persistent heartburn while on PPI therapy and to determine if persistent symptom indicates the need for more aggressive or different therapy. A retrospective review of impedance-pH tracings on PPI therapy (q.d. or b.i.d.) for patients with persistent heartburn was performed. DeMeester score, impedance, and symptom sensitive index (SSI) were used as indices. Statistical analyses were performed using chi-squared test with Yates correction and paired t-test. One hundred consecutive patients, (female 50%, male 50%, mean age 54 [range 16-83] years) were studied on q.d. (n = 45) or b.i.d. PPI (n = 55). Only 20% of the patients had abnormal DeMeester score; 41% had an abnormal impedance score and 56% had abnormal SSI; 29% had all indices normal. There was no difference between patients taking q.d. versus b.i.d. PPI for abnormal DeMeester score (22 vs. 18%), impedance (38 vs. 44%) and SSI (53 vs. 58%); P = 0.80, 0.69, and 0.77, respectively. In 56 patients with positive SSI, symptoms were due to acid reflux in 8 (14%) patients, nonacid reflux in 31 (55%) patients, and combined acid and nonacid reflux in 17 (30%) patients. Patients with persistent heartburn on PPI therapy show a variety of disorders: (i) acid reflux (20%); (ii) nonacid reflux (26%); (iii) positive SSI (56%); (iv) all normal indices (29%). These studies indicate that persistent heartburn on PPI therapy is a complex problem that may not respond to simply increasing acid inhibition. © 2014 International Society for Diseases of the Esophagus.

Electrochemical Sample Matrix Elimination for Trace Level Potentiometric Detection with Polymeric Membrane Ion-Selective Electrodes

PubMed Central

Chumbimuni-Torres, Karin Y.; Calvo-Marzal, Percy; Wang, Joseph; Bakker, Eric

2008-01-01

Potentiometric sensors are today sufficiently well understood and optimized to reach ultra-trace level (sub-nanomolar) detection limits for numerous ions. In many cases of practical relevance, however, a high electrolyte background hampers the attainable detection limits. A particularly difficult sample matrix for potentiometric detection is seawater, where the high saline concentration forms a major interfering background and reduces the activity of most trace metals by complexation. This paper describes for the first time a hyphenated system for the online electrochemically modulated preconcentration and matrix elimination (EMPM) of trace metals, combined with a downstream potentiometric detection with solid contact polymeric membrane ion-selective microelectrodes. Following the preconcentration at the bismuth coated electrodes, the deposited metals are oxidized and released to a medium favorable to potentiometric detection, in this case calcium nitrate. Matrix interferences arising from the saline sample medium are thus circumvented. This concept is successfully evaluated with cadmium as a model trace element and offers potentiometric detection down to low parts per billion levels in samples containing 0.5 M NaCl background electrolyte. PMID:18570385

Value-Based Requirements Traceability: Lessons Learned

NASA Astrophysics Data System (ADS)

Egyed, Alexander; Grünbacher, Paul; Heindl, Matthias; Biffl, Stefan

Traceability from requirements to code is mandated by numerous software development standards. These standards, however, are not explicit about the appropriate level of quality of trace links. From a technical perspective, trace quality should meet the needs of the intended trace utilizations. Unfortunately, long-term trace utilizations are typically unknown at the time of trace acquisition which represents a dilemma for many companies. This chapter suggests ways to balance the cost and benefits of requirements traceability. We present data from three case studies demonstrating that trace acquisition requires broad coverage but can tolerate imprecision. With this trade-off our lessons learned suggest a traceability strategy that (1) provides trace links more quickly, (2) refines trace links according to user-defined value considerations, and (3) supports the later refinement of trace links in case the initial value consideration has changed over time. The scope of our work considers the entire life cycle of traceability instead of just the creation of trace links.

THE CHALLENGE OF ACQUIRING ALPINE LARGE VOLUME LAKE WATER SAMPLES FOR ULTRA TRACE LEVEL ANALYSIS

EPA Science Inventory

The National Exposure Research Laboratory-Las Vegas, Nevada is interested in the emerging field technology of in-situ extraction of contaminants from surface water. A current research project involves ultra-trace level determination of agricultural pesticides from alpine lakes. T...

NATIONAL- AND STATE-LEVEL EMISSIONS ESTIMATES OF RADIATIVELY IMPORTANT TRACE GASES (RITGS) FROM ANTHROPOGENIC SOURCES

EPA Science Inventory

The report documents the development of national- and state- level emissions estimates of radiatively important trace gases (RlTGs). Emissions estimates are presented for the principal anthropogenic sources of carbon dioxide (CO2), methane (CH4), chlorofluorocarbons (CFCs), and o...

ANALYSIS OF TRACE-LEVEL ORGANIC COMBUSTION PROCESS EMISSIONS USING NOVEL MULTIDIMENSIONAL GAS CHROMATOGRAPHY-MASS SPECTROMETRY PROCEDURES

EPA Science Inventory

The paper discusses the analysis of trace-level organic combustion process emissions using novel multidimensional gas chromatography-mass spectrometry (MDGC-MS) procedures. It outlines the application of the technique through the analyses of various incinerator effluent and produ...

Cumulative Exposure Assessment for Trace-Level Polycyclic Aromatic Hydrocarbons (PAHs) using Human Blood and Plasma Analysis

EPA Science Inventory

Humans experience chronic cumulative trace-level exposure to mixtures of volatile, semi-volatile, and non-volatile polycyclic aromatic hydrocarbons (PAHs) present in the environment as by-products of combustion processes. Certain PAHs are known or suspected human carcinogens and ...

Assessing the risks of trace elements in environmental materials under selected greenhouse vegetable production systems of China.

PubMed

Chen, Yong; Huang, Biao; Hu, Wenyou; Weindorf, David C; Liu, Xiaoxiao; Niedermann, Silvana

2014-02-01

The risk assessment of trace elements of different environmental media in conventional and organic greenhouse vegetable production systems (CGVPS and OGVPS) can reveal the influence of different farming philosophy on the trace element accumulations and their effects on human health. These provide important basic data for the environmental protection and human health. This paper presents trace element accumulation characteristics of different land uses; reveals the difference of soil trace element accumulation both with and without consideration of background levels; compares the trace element uptake by main vegetables; and assesses the trace element risks of soils, vegetables, waters and agricultural inputs, using two selected greenhouse vegetable systems in Nanjing, China as examples. Results showed that greenhouse vegetable fields contained significant accumulations of Zn in CGVPS relative to rice-wheat rotation fields, open vegetable fields, and geochemical background levels, and this was the case for organic matter in OGVPS. The comparative analysis of the soil medium in two systems with consideration of geochemical background levels and evaluation of the geo-accumulation pollution index achieved a more reasonable comparison and accurate assessment relative to the direct comparison analysis and the evaluation of the Nemerow pollution index, respectively. According to the Chinese food safety standards and the value of the target hazard quotient or hazard index, trace element contents of vegetables were safe for local residents in both systems. However, the spatial distribution of the estimated hazard index for producers still presented certain specific hotspots which may cause potential risk for human health in CGVPS. The water was mainly influenced by nitrogen, especially for CGVPS, while the potential risk of Cd and Cu pollution came from sediments in OGVPS. The main inputs for trace elements were fertilizers which were relatively safe based on relevant standards; but excess application caused trace element accumulations in the environmental media. Copyright © 2013 Elsevier B.V. All rights reserved.

The Little Penguin (Eudyptula minor) as an indicator of coastal trace metal pollution.

PubMed

Finger, Annett; Lavers, Jennifer L; Dann, Peter; Nugegoda, Dayanthi; Orbell, John D; Robertson, Bruce; Scarpaci, Carol

2015-10-01

Monitoring trace metal and metalloid concentrations in marine animals is important for their conservation and could also reliably reflect pollution levels in their marine ecosystems. Concentrations vary across tissue types, with implications for reliable monitoring. We sampled blood and moulted feathers of the Little Penguin (Eudyptula minor) from three distinct colonies, which are subject to varying levels of anthropogenic impact. Non-essential trace metal and metalloid concentrations in Little Penguins were clearly linked to the level of industrialisation adjacent to the respective foraging zones. This trend was more distinct in blood than in moulted feathers, although we found a clear correlation between blood and feathers for mercury, lead and iron. This study represents the first reported examination of trace metals and metalloids in the blood of any penguin species and demonstrates that this high trophic feeder is an effective bioindicator of coastal pollution. Copyright © 2015 Elsevier Ltd. All rights reserved.

Trace elements are associated with urinary 8-hydroxy-2'-deoxyguanosine level: a case study of college students in Guangzhou, China.

PubMed

Lu, Shaoyou; Ren, Lu; Fang, Jianzhang; Ji, Jiajia; Liu, Guihua; Zhang, Jianqing; Zhang, Huimin; Luo, Ruorong; Lin, Kai; Fan, Ruifang

2016-05-01

Many trace heavy elements are carcinogenic and increase the incidence of cancer. However, a comprehensive study of the correlation between multiple trace elements and DNA oxidative damage is still lacking. The aim of this study is to investigate the relationships between the body burden of multiple trace elements and DNA oxidative stress in college students in Guangzhou, China. Seventeen trace elements in urine samples were determined by inductively coupled plasma-mass spectrometry (ICP-MS). Urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG), a biomarker of DNA oxidative stress, was also measured using liquid chromatography tandem mass spectrometer (LC-MS/MS). The concentrations of six essential elements including manganese (Mn), copper (Cu), nickel (Ni), selenium (Se), strontium (Sr), and molybdenum (Mo), and five non-essential elements including arsenic (As), cadmium (Cd), aluminum (Al), stibium (Sb), and thallium (Tl), were found to be significantly correlated with urinary 8-OHdG levels. Moreover, urinary levels of Ni, Se, Mo, As, Sr, and Tl were strongly significantly correlated with 8-OHdG (P < 0.01) concentration. Environmental exposure and dietary intake of these trace elements may play important roles in DNA oxidative damage in the population of Guangzhou, China.

Leveraging Semantic Labels for Multi-level Abstraction in Medical Process Mining and Trace Comparison.

PubMed

Leonardi, Giorgio; Striani, Manuel; Quaglini, Silvana; Cavallini, Anna; Montani, Stefania

2018-05-21

Many medical information systems record data about the executed process instances in the form of an event log. In this paper, we present a framework, able to convert actions in the event log into higher level concepts, at different levels of abstraction, on the basis of domain knowledge. Abstracted traces are then provided as an input to trace comparison and semantic process discovery. Our abstraction mechanism is able to manage non trivial situations, such as interleaved actions or delays between two actions that abstract to the same concept. Trace comparison resorts to a similarity metric able to take into account abstraction phase penalties, and to deal with quantitative and qualitative temporal constraints in abstracted traces. As for process discovery, we rely on classical algorithms embedded in the framework ProM, made semantic by the capability of abstracting the actions on the basis of their conceptual meaning. The approach has been tested in stroke care, where we adopted abstraction and trace comparison to cluster event logs of different stroke units, to highlight (in)correct behavior, abstracting from details. We also provide process discovery results, showing how the abstraction mechanism allows to obtain stroke process models more easily interpretable by neurologists. Copyright © 2018. Published by Elsevier Inc.

Essential trace elements and antioxidant status in relation to severity of HIV in Nigerian patients.

PubMed

Olaniyi, J A; Arinola, O G

2007-01-01

This study was designed to determine the plasma levels of some antioxidants and trace elements in three severity groups of HIV patients compared with non-HIV-infected controls. The plasma levels of antioxidants (total antioxidant, albumin, bilirubin and uric acid) and trace elements (Mg, Fe, Zn, Mn, Cu, Cr, Cd and Se) were estimated spectrophotometrically in controls and patients with CD4 counts of <200; 200-499 and > or =500 cells/microl. Uric acid and Zn were significantly higher, while vitamin E and all the trace elements (except Zn) were significantly lower in HIV-infected patients compared to healthy controls. The highest level of uric acid was observed in those with CD4 counts of <200 cells/microl. All the trace elements (except Zn) were higher in HIV subjects with a CD4 count of 200-499 cells/microl compared to >500 cells/microl. Only uric acid and Zn showed significant correlation with CD4 count. Based on the results of this study, we recommend routine assessment and appropriate supplementation of antioxidants/trace elements in HIV subjects. This supplementation is hoped to strengthen the immune system and reduce the adverse consequences of HIV- related oxidative stress. Copyright 2007 S. Karger AG, Basel.

Economic weights for genetic improvement of lactation persistency and milk yield.

PubMed

Togashi, K; Lin, C Y

2009-06-01

This study aimed to establish a criterion for measuring the relative weight of lactation persistency (the ratio of yield at 280 d in milk to peak yield) in restricted selection index for the improvement of net merit comprising 3-parity total yield and total lactation persistency. The restricted selection index was compared with selection based on first-lactation total milk yield (I(1)), the first-two-lactation total yield (I(2)), and first-three-lactation total yield (I(3)). Results show that genetic response in net merit due to selection on restricted selection index could be greater than, equal to, or less than that due to the unrestricted index depending upon the relative weight of lactation persistency and the restriction level imposed. When the relative weight of total lactation persistency is equal to the criterion, the restricted selection index is equal to the selection method compared (I(1), I(2), or I(3)). The restricted selection index yielded a greater response when the relative weight of total lactation persistency was above the criterion, but a lower response when it was below the criterion. The criterion varied depending upon the restriction level (c) imposed and the selection criteria compared. A curvilinear relationship (concave curve) exists between the criterion and the restricted level. The criterion increases as the restriction level deviates in either direction from 1.5. Without prior information of the economic weight of lactation persistency, the imposition of the restriction level of 1.5 on lactation persistency would maximize change in net merit. The procedure presented allows for simultaneous modification of multi-parity lactation curves.

Potential role of peroxisome proliferator activated receptor gamma activation on serum visfatin and trace elements in high fat diet induced type 2 diabetes mellitus.

PubMed

Tabassum, Arshia; Zaidi, Syeda Nuzhat Fatima; Yasmeen, Kausar; Mahboob, Tabassum

2018-07-15

Electrolytes and trace elements dysregulation play an important role in the progression of obesity and diabetes complications. The present study was designed to evaluate the insulin sensitizing effects of peroxisomes proliferators activated receptor gamma (PPAR-γ) agonist on trace elements in obesity induced type 2 diabetes mellitus and correlate with serum visfatin. Wistar rats were categorized into five groups. Group I served as control; Group II fed on high fat diet (HFD); Group III fed on HFD and treated with rosiglitazone (3 mg/kg) for 7 days; Group IV were T2DM rats induce by HFD and low dose of streptozotocin (i.p. 35 mg/kg); Group V was T2DM rats treated with rosiglitazone (3 mg/kg) for 7 days. Serum and tissues electrolytes levels and renal, hepatic and cardiac tissues trace elements were estimated by flame photometer and atomic absorption spectroscopy. Serum visfatin was estimated by ELISA. Pearson correlations were analyzed among fasting blood glucose (FBG), serum visfatin and tissues trace elements. Results of the current study showed hyponatremia, hyperkalemia, hypomagnesemia and hypercalcemia in HFD and T2DM groups. HFD and T2DM also showed elevated copper and iron levels; however, zinc and selenium levels were decreased. Rosiglitazone treatment increased the insulin sensitization and altered these changes. A Strong association was observed among FBG, serum visfatin and trace elements levels of HFD and T2DM. Obesity and diabetes mellitus disturbed visfatin, electrolytes and trace elements homeostasis. Rosiglitazone treatment restored these changes. The results of the study could serve as a basis for further studies for the prevention of diabetic complications. Copyright © 2018 Elsevier Inc. All rights reserved.

A Prospective Study of Serum Trace Elements in Healthy Korean Pregnant Women

PubMed Central

Choi, Rihwa; Sun, Jiyu; Yoo, Heejin; Kim, Seonwoo; Cho, Yoon Young; Kim, Hye Jeong; Kim, Sun Wook; Chung, Jae Hoon; Oh, Soo-young; Lee, Soo-Youn

2016-01-01

This prospective study sought to investigate serum levels of trace elements (cobalt, copper, zinc, and selenium) and to assess their effects on pregnancy and neonatal outcomes. Serum levels of trace elements in 245 Korean pregnant women (median gestational age at delivery was 39 + 4 weeks and interquartile range was 38 + 4–40 + 1 weeks) were compared with those of 527 general adults and those of previous studies in other ethnic groups. Pregnancy and neonatal outcomes including gestational diabetes, preeclampsia, neonatal birth weight, and congenital abnormalities were assessed. The median serum trace element concentrations of all pregnant women were: cobalt: 0.39 μg/L (interquartile range, IQR 0.29–0.53), copper: 165.0 μg/dL (IQR 144.0–187.0), zinc: 57.0 μg/dL (IQR 50.0–64.0), and selenium: 94.0 μg/L (IQR 87.0–101.0). Serum cobalt and copper concentrations were higher in pregnant women than in the general population, whereas zinc and selenium levels were lower (p < 0.01). Concentrations of all four trace elements varied significantly during the three trimesters (p < 0.05), and seasonal variation was found in copper, zinc, and selenium, but was not observed for cobalt. The prevalence of preeclampsia was significantly lower with high copper (p = 0.03). Trace element levels varied by pregnancy trimester and season, and alteration in copper status during pregnancy might influence pregnancy outcomes such as preeclampsia. PMID:27886083

A Prospective Study of Serum Trace Elements in Healthy Korean Pregnant Women.

PubMed

Choi, Rihwa; Sun, Jiyu; Yoo, Heejin; Kim, Seonwoo; Cho, Yoon Young; Kim, Hye Jeong; Kim, Sun Wook; Chung, Jae Hoon; Oh, Soo-Young; Lee, Soo-Youn

2016-11-23

This prospective study sought to investigate serum levels of trace elements (cobalt, copper, zinc, and selenium) and to assess their effects on pregnancy and neonatal outcomes. Serum levels of trace elements in 245 Korean pregnant women (median gestational age at delivery was 39 + 4 weeks and interquartile range was 38 + 4-40 + 1 weeks) were compared with those of 527 general adults and those of previous studies in other ethnic groups. Pregnancy and neonatal outcomes including gestational diabetes, preeclampsia, neonatal birth weight, and congenital abnormalities were assessed. The median serum trace element concentrations of all pregnant women were: cobalt: 0.39 μg/L (interquartile range, IQR 0.29-0.53), copper: 165.0 μg/dL (IQR 144.0-187.0), zinc: 57.0 μg/dL (IQR 50.0-64.0), and selenium: 94.0 μg/L (IQR 87.0-101.0). Serum cobalt and copper concentrations were higher in pregnant women than in the general population, whereas zinc and selenium levels were lower ( p < 0.01). Concentrations of all four trace elements varied significantly during the three trimesters ( p < 0.05), and seasonal variation was found in copper, zinc, and selenium, but was not observed for cobalt. The prevalence of preeclampsia was significantly lower with high copper ( p = 0.03). Trace element levels varied by pregnancy trimester and season, and alteration in copper status during pregnancy might influence pregnancy outcomes such as preeclampsia.

Intrinsic Chemiluminescence Generation during Advanced Oxidation of Persistent Halogenated Aromatic Carcinogens.

PubMed

Mao, Li; Liu, Yu-Xiang; Huang, Chun-Hua; Gao, Hui-Ying; Kalyanaraman, Balaraman; Zhu, Ben-Zhan

2015-07-07

The ubiquitous distribution coupled with their carcinogenicity has raised public concerns on the potential risks to both human health and the ecosystem posed by the halogenated aromatic compounds (XAr). Recently, advanced oxidation processes (AOPs) have been increasingly favored as an "environmentally-green" technology for the remediation of such recalcitrant and highly toxic XAr. Here, we show that AOPs-mediated degradation of the priority pollutant pentachlorophenol and all other XAr produces an intrinsic chemiluminescence that directly depends on the generation of the extremely reactive hydroxyl radicals. We propose that the hydroxyl radical-dependent formation of quinoid intermediates and electronically excited carbonyl species is responsible for this unusual chemiluminescence production. A rapid, sensitive, simple, and effective chemiluminescence method was developed to quantify trace amounts of XAr and monitor their real-time degradation kinetics. These findings may have broad biological and environmental implications for future research on this important class of halogenated persistent organic pollutants.

An analysis of fracture trace patterns in areas of flat-lying sedimentary rocks for the detection of buried geologic structure. [Kansas and Texas

NASA Technical Reports Server (NTRS)

Podwysocki, M. H.

1974-01-01

Two study areas in a cratonic platform underlain by flat-lying sedimentary rocks were analyzed to determine if a quantitative relationship exists between fracture trace patterns and their frequency distributions and subsurface structural closures which might contain petroleum. Fracture trace lengths and frequency (number of fracture traces per unit area) were analyzed by trend surface analysis and length frequency distributions also were compared to a standard Gaussian distribution. Composite rose diagrams of fracture traces were analyzed using a multivariate analysis method which grouped or clustered the rose diagrams and their respective areas on the basis of the behavior of the rays of the rose diagram. Analysis indicates that the lengths of fracture traces are log-normally distributed according to the mapping technique used. Fracture trace frequency appeared higher on the flanks of active structures and lower around passive reef structures. Fracture trace log-mean lengths were shorter over several types of structures, perhaps due to increased fracturing and subsequent erosion. Analysis of rose diagrams using a multivariate technique indicated lithology as the primary control for the lower grouping levels. Groupings at higher levels indicated that areas overlying active structures may be isolated from their neighbors by this technique while passive structures showed no differences which could be isolated.

Relations between Preschool Attention Span-Persistence and Age 25 Educational Outcomes

PubMed Central

McClelland, Megan M.; Acock, Alan C.; Piccinin, Andrea; Rhea, Sally Ann; Stallings, Michael C.

2012-01-01

This study examined relations between children’s attention span-persistence in preschool and later school achievement and college completion. Children were drawn from the Colorado Adoption Project using adopted and non-adopted children (N = 430). Results of structural equation modeling indicated that children’s age 4 attention span-persistence significantly predicted math and reading achievement at age 21 after controlling for achievement levels at age 7, adopted status, child vocabulary skills, gender, and maternal education level. Relations between attention span-persistence and later achievement were not fully mediated by age 7 achievement levels. Logistic regressions also revealed that age 4 attention span-persistence skills significantly predicted the odds of completing college by age 25. The majority of this relationship was direct and was not significantly mediated by math or reading skills at age 7 or age 21. Specifically, children who were rated one standard deviation higher on attention span-persistence at age 4 had 48.7% greater odds of completing college by age 25. Discussion focuses on the importance of children’s early attention span-persistence for later school achievement and educational attainment. PMID:23543916

Relations between Preschool Attention Span-Persistence and Age 25 Educational Outcomes.

PubMed

McClelland, Megan M; Acock, Alan C; Piccinin, Andrea; Rhea, Sally Ann; Stallings, Michael C

2013-04-01

This study examined relations between children's attention span-persistence in preschool and later school achievement and college completion. Children were drawn from the Colorado Adoption Project using adopted and non-adopted children ( N = 430). Results of structural equation modeling indicated that children's age 4 attention span-persistence significantly predicted math and reading achievement at age 21 after controlling for achievement levels at age 7, adopted status, child vocabulary skills, gender, and maternal education level. Relations between attention span-persistence and later achievement were not fully mediated by age 7 achievement levels. Logistic regressions also revealed that age 4 attention span-persistence skills significantly predicted the odds of completing college by age 25. The majority of this relationship was direct and was not significantly mediated by math or reading skills at age 7 or age 21. Specifically, children who were rated one standard deviation higher on attention span-persistence at age 4 had 48.7% greater odds of completing college by age 25. Discussion focuses on the importance of children's early attention span-persistence for later school achievement and educational attainment.

Saharan dust - A carrier of persistent organic pollutants, metals and microbes to the Caribbean?

USGS Publications Warehouse

Garrison, V.H.; Foreman, W.T.; Genualdi, S.; Griffin, Dale W.; Kellogg, C.A.; Majewski, M.S.; Mohammed, A.; Ramsubhag, A.; Shinn, E.A.; Simonich, S.L.; Smith, G.W.

2006-01-01

An international team of scientists from government agencies and universities in the United States, U.S. Virgin Islands (USVI), Trinidad & Tobago, the Republic of Cape Verde, and the Republic of Mali (West Africa) is working together to elucidate the role Saharan dust may play in the degradation of Caribbean ecosystems. The first step has been to identify and quantify the persistent organic pollutants (POPs), trace metals, and viable microorganisms in the atmosphere in dust source areas of West Africa, and in dust episodes at downwind sites in the eastern Atlantic (Cape Verde) and the Caribbean (USVI and Trinidad & Tobago). Preliminary findings show that air samples from Mali contain a greater number of pesticides, polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) and in higher concentrations than the Caribbean sites. Overall, POP concentrations were similar in USVI and Trinidad samples. Trace metal concentrations were found to be similar to crustal composition with slight enrichment of lead in Mali. To date, hundreds of cultureable micro-organisms have been identified from Mali, Cape Verde, USVI, and Trinidad air samples. The sea fan pathogen, Aspergillus sydowii, has been identified in soil from Mali and in air samples from dust events in the Caribbean. We have shown that air samples from a dust-source region contain orders of magnitude more cultureable micro-organisms per volume than air samples from dust events in the Caribbean, which in turn contain 3-to 4-fold more cultureable microbes than during non-dust conditions.

Expectancies as a Determinant of Interference Phenomena

ERIC Educational Resources Information Center

Hasher, Lynn; Greenberg, Michael

1977-01-01

One version, by Lockhart, Craik, and Jacoby, of a levels-of-processing model of memory asserts the importance of the role of expectancies about forthcoming information in determining the elaborateness of a memory trace. Confirmed expectancies result in less-elaborated memory traces; disconfirmed expectancies result in elaborate memory traces.…

Trace fossils and substrates of the terminal Proterozoic–Cambrian transition: Implications for the record of early bilaterians and sediment mixing

PubMed Central

Droser, Mary L.; Jensen, Sören; Gehling, James G.

2002-01-01

The trace fossil record is important in determining the timing of the appearance of bilaterian animals. A conservative estimate puts this time at ≈555 million years ago. The preservational potential of traces made close to the sediment–water interface is crucial to detecting early benthic activity. Our studies on earliest Cambrian sediments suggest that shallow tiers were preserved to a greater extent than typical for most of the Phanerozoic, which can be attributed both directly and indirectly to the low levels of sediment mixing. The low levels of sediment mixing meant that thin event beds were preserved. The shallow depth of sediment mixing also meant that muddy sediments were firm close to the sediment–water interface, increasing the likelihood of recording shallow-tier trace fossils in muddy sediments. Overall, trace fossils can provide a sound record of the onset of bilaterian benthic activity. PMID:12271130

An examination of body tracing among women with high body dissatisfaction.

PubMed

Williams, Gail A; Hudson, Danae L; Whisenhunt, Brooke L; Crowther, Janis H

2014-09-01

Within eating disorder treatment programs, a body tracing activity is often used to address body dissatisfaction and overestimation of body size; however, the effects of this activity have never been empirically evaluated. This research examined the effects of body tracing on body dissatisfaction and mood among 56 female participants assigned to either a body tracing or control group. Scores were collected on trait body dissatisfaction and a series of Visual Analogue Scales (VAS). Results showed that trait body dissatisfaction moderated the relationship between group and levels of state appearance dissatisfaction and anxiety. These results suggest that individuals experiencing higher levels of trait body dissatisfaction demonstrated greater state body dissatisfaction following participation in the body tracing activity. Individuals with lower trait body dissatisfaction experienced greater anxiety after drawing a human body. These findings have potential implications for the use of this strategy in the treatment of eating disorder patients. Copyright © 2014 Elsevier Ltd. All rights reserved.

The Laser Level as an Optics Laboratory Tool

ERIC Educational Resources Information Center

Kutzner, Mickey

2013-01-01

For decades now, the laser has been used as a handy device for performing ray traces in geometrical optics demonstrations and laboratories. For many ray- trace applications, I have found the laser level 3 to be even more visually compelling and easy for student use than the laser pointer.

Determination of Trace Level Triclosan in Water by Online Preconcentration and HPLC-UV Diode Array

EPA Science Inventory

An online high performance liquid chromatography (HPLC) method for the detection and quantification of trace levels of triclosan in water is discussed. Triclosan, an anti-bacterial agent, and related compounds have been shown to reach municipal waste waters through the disposal ...

Trace elements in dialysis.

PubMed

Filler, Guido; Felder, Sarah

2014-08-01

In end-stage chronic kidney disease (CKD), pediatric nephrologists must consider the homeostasis of the multiple water-soluble ions that are influenced by renal replacement therapy (RRT). While certain ions such as potassium and calcium are closely monitored, little is known about the handling of trace elements in pediatric dialysis. RRT may lead to accumulation of toxic trace elements, either due to insufficient elimination or due to contamination, or to excessive removal of essential trace elements. However, trace elements are not routinely monitored in dialysis patients and no mechanism for these deficits or toxicities has been established. This review summarizes the handling of trace elements, with particular attention to pediatric data. The best data describe lead and indicate that there is a higher prevalence of elevated lead (Pb, atomic number 82) levels in children on RRT when compared to adults. Lead is particularly toxic in neurodevelopment and lead levels should therefore be monitored. Monitoring of zinc (Zn, atomic number 30) and selenium (Se, atomic number 34) may be indicated in the monitoring of all pediatric dialysis patients to reduce morbidity from deficiency. Prospective studies evaluating the impact of abnormal trace elements and the possible therapeutic value of intervention are required.

Determination of trace elements and their concentrations in clay balls: problem of geophagia practice in Ghana.

PubMed

Arhin, Emmanuel; Zango, Musah S

2017-02-01

Ten samples of 100 g weight were subsampled from 1400 g of the clay balls from which the contained trace element levels were determined by X-ray fluorescence technique. The results of trace elements in the clay balls were calibrated using certified reference materials "MAJMON" and "BH-1." The results showed elevated concentrations but with different concentration levels in the regions, particularly with arsenic, chromium, cobalt, Cs, Zr and La. These trace elements contained in the clay balls are known to be hazardous to human health. Thence the relatively high concentrations of these listed trace elements in clay balls in the three regions, namely Ashanti, Upper East and Volta, which are widely sold in markets in Ghana, could present negative health impact on consumers if consumed at 70 g per day or more and on regular basis. On the basis of these, the study concludes an investigation to establish breakeven range for trace element concentrations in the clay balls as it has been able to demonstrate the uneven and elevated values in them. The standardized safe ranges of trace elements will make the practice safer for the people that ingest clay balls in Ghana.

Lead and trace element levels in milk and blood of buffaloes (Bubalus bubalis) from Hyderabad, India.

PubMed

Shailaja, M; Reddy, Yathapu Srinivasa; Kalakumar, B D P; Brinda, S A; Manohar, Gottimukkula; Kumar, B Dinesh

2014-06-01

The presence of lead (Pb) in milk and its interaction with trace elements is a serious health concern. Present study is aimed at determining Pb and trace element (Fe, Zn and Mg) levels in milk and blood/serum samples of lactating buffaloes (Bubalus bubalis) living in a market-area (Group-A) and a dairy-experimental station (Group-B), Hyderabad, India. In addition, kidney and liver function tests were assessed. Fodder, milk and blood Pb levels were significantly (p < 0.01) higher in Group-B. Elevated Pb levels correlated positively with reduced Fe and Zn levels in both serum and milk. A significant (p < 0.01) positive correlation between blood Pb and milk Pb levels was observed. Kidney and liver function markers were significantly higher in Group-B buffaloes. The results suggest that contaminated fodder might be one of the responsible factors for elevated Pb levels. In addition, lower levels of Fe and Zn might have led to bioaccumulation of Pb in blood and milk.

Combined visualization for noise mapping of industrial facilities based on ray-tracing and thin plate splines

NASA Astrophysics Data System (ADS)

Ovsiannikov, Mikhail; Ovsiannikov, Sergei

2017-01-01

The paper presents the combined approach to noise mapping and visualizing of industrial facilities sound pollution using forward ray tracing method and thin-plate spline interpolation. It is suggested to cauterize industrial area in separate zones with similar sound levels. Equivalent local source is defined for range computation of sanitary zones based on ray tracing algorithm. Computation of sound pressure levels within clustered zones are based on two-dimension spline interpolation of measured data on perimeter and inside the zone.

Environmental influence on trace element levels in human hair

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

Limic, N.; Valkovic, V.

1986-12-01

Trace element content of human hair depends on many factors. It has been shown by a large number of investigators that environmental factors play an important role. Elements from air particulates, water, shampoo or other media get incorporated into the hair structure. Here a model is proposed in which different contributions to trace element levels in human hair are factorized and the environmental contribution to the radial and longitudinal concentration profiles can be calculated. With the proper understanding of environmental contamination, hair analysis has better chances of being used as a diagnostic tool.

Pituitary gland levels of mercury, selenium, iron, and zinc in an Alzheimer`s disease study

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

Cornett, C.R.; Markesbery, W.R.; Wekstein, D.R.

1996-12-31

Mercury, iron, selenium, and zinc imbalances have been observed in comparisons between Alzheimer`s disease (AD) and control subject brains. Analyses of the pituitary gland have demonstrated that this organ retains relatively high concentrations of trace elements, including mercury, iron, and zinc. Our previous work has shown that the pituitary glands of AD and control subjects are typically higher in these trace elements than brain samples from the same subject. Instrumental neutron activation analysis (INAA) was used to compare the pituitary trace element levels of AD and control subjects. This study also describes the intrasubject relationships of brain trace element levelsmore » to those in the pituitary gland of AD and control subjects.« less

Risk assessment of trace metals in an extreme environment sediment: shallow, hypersaline, alkaline, and industrial Lake Acıgöl, Denizli, Turkey.

PubMed

Budakoglu, Murat; Karaman, Muhittin; Kumral, Mustafa; Zeytuncu, Bihter; Doner, Zeynep; Yildirim, Demet Kiran; Taşdelen, Suat; Bülbül, Ali; Gumus, Lokman

2018-02-23

The major and trace element component of 48 recent sediment samples in three distinct intervals (0-10, 10-20, and 20-30 cm) from Lake Acıgöl is described to present the current contamination levels and grift structure of detrital and evaporate mineral patterns of these sediments in this extreme saline environment. The spatial and vertical concentrations of major oxides were not uniform in the each subsurface interval. However, similar spatial distribution patterns were observed for some major element couples, due mainly to the detrital and evaporate origin of these elements. A sequential extraction procedure including five distinct steps was also performed to determine the different bonds of trace elements in the < 60-μ particulate size of recent sediments. Eleven trace elements (Ni, Fe, Cd, Pb, Cu, Zn, As, Co, Cr, Al and Mn) in nine surface and subsurface sediment samples were analyzed with chemical partitioning procedures to determine the trace element percentage loads in these different sequential extraction phases. The obtained accuracy values via comparison of the bulk trace metal loads with the total loads of five extraction steps were satisfying for the Ni, Fe, Cd, Zn, and Co. While, bulk analysis results of the Cu, Ni, and V elements have good correlation with total organic matter, organic fraction of sequential extraction characterized by Cu, As, Cd, and Pb. Shallow Lake Acıgöl sediment is characteristic with two different redox layer a) oxic upper level sediments, where trace metals are mobilized, b) reduced subsurface level, where the trace metals are precipitated.

Maternal educational level and the risk of persistent post-partum glucose metabolism disorders in women with gestational diabetes mellitus.

PubMed

Gante, Inês; Ferreira, Ana Carina; Pestana, Gonçalo; Pires, Daniela; Amaral, Njila; Dores, Jorge; do Céu Almeida, Maria; Sandoval, José Luis

2018-03-01

Gestational diabetes mellitus (GDM) occurs in 5-15% of pregnancies, and lower maternal educational attainment has been associated with higher risk of GDM. We aimed to determine if maternal education level is associated with persistent post-partum glucose metabolism disorders in women with GDM. Retrospective cohort study of women with GDM followed in 25 Portuguese health institutions between 2008 and 2012. Educational attainment was categorised into four levels. Prevalence of post-partum glucose metabolism disorders (type 2 diabetes mellitus, increased fasting plasma glucose or impaired glucose tolerance) was compared and adjusted odds ratios calculated controlling for confounders using logistic regression. We included 4490 women diagnosed with GDM. Educational level ranged as follows: 6.8% (n = 307) were at level 1 (≤ 6th grade), 34.6% (n = 1554) at level 2 (6-9th grade), 30.4% (n = 1364) at level 3 (10-12th grade) and 28.2% (n = 1265) at level 4 (≥ university degree). At 6 weeks post-partum re-evaluation, 10.9% (n = 491) had persistent glucose metabolism disorders. Educational levels 1 and 2 had a higher probability of persistent post-partum glucose metabolism disorders when compared to level 4 (OR = 2.37 [1.69;3.32], p < 0.001 and OR = 1.39 [1.09;1.76], p = 0.008, for level 1 and 2, respectively), an association that persisted in multivariable logistic regression adjusting for confounders (level 1 OR = 2.25 [1.53;3.33], p < 0.001; level 2 OR = 1.43 [1.09;1.89], p = 0.01). Persistent post-partum glucose metabolism disorders are frequent in women with GDM and associated with lower maternal educational level. Interventions aimed at this risk group may contribute towards a decrease in prevalence of post-partum glucose metabolism disorders.

Ichnology of fine-grained mixed carbonate-siliciclastic turbidites, Wood River Formation, Pennsylvanian-Permian south-central Idaho

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

Burton, B.R.; Link, P.K.

1991-06-01

In south-central Idaho, the Wood River Formation (Pennsylvanian-Permian) contains a stratigraphic megacycle over 2,000 m thick that is composed of fine-grained mixed carbonate-siliciclastic turbidites. Complete and partial (Bouma) turbidite structural sequences in these rocks are arranged in upward thinning cycles 15 to 30 m thick in which top-cut-out (Ta-c) turbidite facies in the lower part grade vertically into base-cut-out (Td-f) turbidites in the upper part. These cycles are interpreted to represent the autocyclic lateral migration of turbidite lobes. A mixed trace fossil assemblage of pascichnia and fordinichnia are present in these rocks and can be separated into pre-depositional and post-turbiditemore » ichnocoenoses. Quiet-water, pre-turbidite deposits are dark-colored, laminated, and carbonaceous, and represent anoxic to dysoxic inter-turbidite basinal conditions; they contain only Chondrites traces. Turbidity currents introduced oxygenated bottom water which fostered the temporary development of a post-turbidite ichnocoenose of pascichnia which is best developed in the medial portion of turbidite beds and lobes. Trace fossil tiering shows that a post-turbidite ichnocoenose of fodinichnia also developed, and persisted after the disappearance of pascichnia. Animals that produced the fodinichnial traces probably were part of an autochthonous benthic fauna rather than a short-lived allochthonous fauna. They may have migrated with the slowly avulsing turbidite lobes and exploited allochthonous oxygen and the carbonaceous food supply.« less

Trace elements in free-range hen eggs in the Campania region (Italy) analyzed by inductively coupled plasma mass spectrometry (ICP-MS).

PubMed

Esposito, Mauro; Cavallo, Stefania; Chiaravalle, Eugenio; Miedico, Oto; Pellicanò, Roberta; Rosato, Guido; Sarnelli, Paolo; Baldi, Loredana

2016-06-01

Eggs from hens raised on rural or domestic farms are a good indicator of environmental contamination, as the hens are in close contact with the ground and the air and can therefore accumulate heavy metals and other toxic contaminants from the environment as well as from the diet. In this paper, we report the results of the determination of 19 trace elements (As, Be, Cd, Co, Cr, Cu, Hg, Mo, Mn, Ni, Pb, Sb, Se, Sn, Sr, Tl, U, V, Zn) in 39 hen egg samples collected from domestic poultry farms in the territory dubbed the "Land of fires" in the Campania region (Italy). This area is characterized by environmental problems caused by the illegal dumping of industrial or domestic waste in fields or by roadsides. In some cases, these wastes have been burned, thereby spreading persistent contaminants into the atmosphere. The content of trace elements in whole egg samples was determined by mass spectrometer after a microwave-assisted digestion procedure. Because European legislation does not indicate maximum values of these elements in this foodstuff, the results were compared with the content of trace elements reported in literature for eggs, in particular home-produced eggs, in various countries. In some cases (Cd, Cu, Ni, Mn), the content determined in this study was in line with those reported elsewhere, in other cases (Pb, Cr), lower values were found.

Risk factors for persistent cervical intraepithelial neoplasia grades 1 and 2: managed by watchful waiting.

PubMed

Ho, Gloria Y F; Einstein, Mark H; Romney, Seymour L; Kadish, Anna S; Abadi, Maria; Mikhail, Magdy; Basu, Jayasri; Thysen, Benjamin; Reimers, Laura; Palan, Prabhudas R; Trim, Shelly; Soroudi, Nafisseh; Burk, Robert D

2011-10-01

: This study examines risk factors for persistent cervical intraepithelial neoplasia (CIN) and examines whether human papillomavirus (HPV) testing predicts persistent lesions. : Women with histologically diagnosed CIN 1 or CIN 2 (n = 206) were followed up every 3 months without treatment. Human papillomavirus genotyping, plasma levels of ascorbic acid, and red blood cell folate levels were obtained. Cervical biopsy at 12 months determined the presence of CIN. Relative risk (RR) was estimated by log-linked binomial regression models. : At 12 months, 70% of CIN 1 versus 54% of CIN 2 lesions spontaneously regressed (p < .001). Levels of folate or ascorbic acid were not associated with persistent CIN at 12 months. Compared with HPV-negative women, those with multiple HPV types (RRs ranged from 1.68 to 2.17 at each follow-up visit) or high-risk types (RRs range = 1.74-2.09) were at increased risk for persistent CIN; women with HPV-16/18 had the highest risk (RRs range = 1.91-2.21). Persistent infection with a high-risk type was also associated with persistent CIN (RRs range = 1.50-2.35). Typing for high-risk HPVs at 6 months only had a sensitivity of 46% in predicting persistence of any lesions at 12 months. : Spontaneous regression of CIN 1 and 2 occurs frequently within 12 months. Human papillomavirus infection is the major risk factor for persistent CIN. However, HPV testing cannot reliably predict persistence of any lesion.

Monitoring of trace metals and pharmaceuticals as anthropogenic and socio-economic indicators of urban and industrial impact on surface waters

NASA Astrophysics Data System (ADS)

Vystavna, Yuliya

2014-05-01

The research focuses on the monitoring of trace metals and pharmaceuticals as potential anthropogenic indicators of industrial and urban influences on surface water in poorly gauged transboundary Ukraine/Russia region. This study includes analysis of tracers use for the indication of water pollution events, including controlled and emerging discharges, and discussion of the detection method of these chemicals. The following criteria were proposed for the evaluation of indicators: specificity (physical chemical properties), variability (spatial and temporal) and practicality (capacity of the sampling and analytical techniques). The combination of grab and passive water sampling (i.e. DGT and POCIS) procedure was applied for the determination of dissolved and labile trace metals (Ag, Cd, Cr, Cu, Ni, Pb and Zn) and pharmaceuticals (carbamazepine, diazepam, paracetamol, caffeine, diclofenac and ketoprofen). Samples were analysed using ICP - MS (trace metals) and LC-MS/MS ESI +/- (pharmaceuticals). Our results demonstrate the distinctive spatial and temporal patterns of trace elements distribution along an urban watercourse. Accordingly, two general groups of trace metals have been discriminated: 'stable' (Cd and Cr) and 'time-varying' (Cu, Zn, Ni and Pb). The relationship Cd >> Cu > Ag > Cr ≥ Zn was proposed as an anthropogenic signature of the industrial and urban activities pressuring the environment from point sources (municipal wastewaters) and the group Pb - Ni was discussed as a relevant fingerprint of the economic activity (industry and transport) mainly from non-point sources (run-off, atmospheric depositions, etc.). Pharmaceuticals with contrasting hydro-chemical properties of molecules (water solubility, bioaccumulation, persistence during wastewater treatment processes) were discriminated on conservative, labile and with combined properties in order to provide information on wastewater treatment plant efficiency, punctual events (e.g. accidents on sewage works, run-off) and uncontrolled discharges. Applying mass balance modeling, medicaments were described as relevant socio-economic indicators, which can give a picture of main social aspects of the region.

Physical and environmental factors affecting the persistence of explosives particles (Conference Presentation)

NASA Astrophysics Data System (ADS)

Papantonakis, Michael R.; Nguyen, Viet K.; Furstenberg, Robert; White, Caitlyn; Shuey, Melissa; Kendziora, Christopher A.; McGill, R. Andrew

2017-05-01

Knowledge of the persistence of trace explosives materials is critical to aid the security community in designing detection methods and equipment. The physical and environmental factors affecting the lifetimes of particles include temperature, airflow, interparticle distance, adlayers, humidity, particle field size and vapor pressure. We are working towards a complete particle persistence model that captures the relative importance of these effects to allow the user, with known environmental conditions, to predict particle lifetimes for explosives or other chemicals. In this work, particles of explosives are sieved onto smooth glass substrates using particle sizes and loadings relevant to those deposited by fingerprint deposition. The coupon is introduced into a custom flow cell and monitored under controlled airflow, humidity and temperature. Photomicroscopy images of the sample taken at fixed time intervals are analyzed to monitor particle sublimation and characterized as a size-independent radial sublimation velocity for each particle in the ensemble. In this paper we build on previous work by comparing the relationship between sublimation of different materials and their vapor pressures. We also describe the influence of a sebum adlayer on particle sublimation, allowing us to better model `real world' samples.

Connecticut Music Trace Map for Grades 10 and 12. Revised.

ERIC Educational Resources Information Center

Connecticut State Board of Education, Hartford.

The Connecticut Curriculum Trace Maps for music are designed to help curriculum developers and teachers translate Connecticut's K-12 performance standards into objectives and classroom practice. The Trace Maps provide specific descriptions of what students should know and be able to do at smaller grade level clusters. The elements in the Trace…

Connecticut Music Trace Map for Grades 2 and 4. Revised.

ERIC Educational Resources Information Center

Connecticut State Board of Education, Hartford.

These Connecticut Curriculum Trace Maps for music are designed to help curriculum developers and teachers translate Connecticut's K-12 performance standards into objectives and classroom practice. The music Trace Maps provide specific descriptions of what students should know and be able to do at smaller grade level clusters. Connecticut's Trace…

Biogeochemical and hydrological controls on fate and distribution of trace metals in oiled Gulf salt marshes

NASA Astrophysics Data System (ADS)

Keevan, J.; Natter, M.; Lee, M.; Keimowitz, A.; Okeke, B.; Savrda, C.; Saunders, J.

2011-12-01

On April 20, 2010, the drilling rig Deepwater Horizon exploded in the Gulf of Mexico, resulting in the release of approximately 5 million barrels of crude oil into the environment. Oil and its associated trace metals have been demonstrated to have a detrimental effect on coastal wetland ecosystems. Wetlands are particularly susceptible to oil contamination because they are composed largely of fine-grained sediments, which have a high capacity to adsorb organic matter and metals. The biogeochemical cycling of trace metals can be strongly influenced by microbial activity, specifically those of sulfate- and iron-reducing bacteria. Microbial activity may be enhanced by an increase in amounts of organic matter such as oil. This research incorporates an assessment of levels of trace metals and associated biogeochemical changes from ten coastal marshes in Alabama, Mississippi, and Louisiana. These sampling sites range in their pollution levels from pristine to highly contaminated. A total digestion analysis of wetland sediments shows higher concentrations of certain trace metals (e.g., Ni, Cu, Pb, Zn, Sr, Co, V, Ba, Hg, As) in heavily-oiled areas compared to less-affected and pristine sites. Due to chemical complexation among organic compounds and metals, crude oils often contain elevated levels (up to hundreds of mg/kg) of trace metals At the heavily-oiled Louisiana sites (e.g., Bay Jimmy, Bayou Dulac, Bay Batiste), elevated levels of metals and total organic carbon have been found in sediments down to depths of 30 cm. Clearly the contamination is not limited to shallow sediments and oil, along with various associated metals, may be invading into deeper (pre-industrial) portions of the marsh sediments. Pore-waters extracted from contaminated sediments are characterized by very high levels of reduced sulfur (up to 80 mg/kg), in contrast to fairly low ferrous iron concentrations (<0.02 mg/kg). The influx of oil into the wetlands might provide the initial substrate and carbon source for stimulating sulfate-reducing bacteria. The high sulfur levels, coupled with the low levels of iron, indicate that iron-reducing bacteria are outcompeted by sulfate reducers in oiled salt marshes. Moreover, pore-water pH values show a general increasing trend (ranging from 6.6 to 8.0) with depth, possibly reflecting the combined effects of bacterial sulfate reduction and saltwater intrusion at depth. Despite high levels of trace metals in bulk sediments, concentrations of trace metals dissolved in pore-waters are generally low. It is very likely that high organic matter content and bacterially-mediated sulfate reduction promote metal retention through the formation of sulfide solids. Framboidal pyrites, as well as other sulfides, have been identified, and are currently undergoing XRD, SEM, and EDAX analyses. Continued research is needed to monitor possible re-mobilization of trace metals in changing redox and biogeochemical conditions.

Toxic Trace Elements in the Hair of Children with Autism

ERIC Educational Resources Information Center

Fido, Abdullahi; Al-Saad, Samira

2005-01-01

Excess or deficiency of natural trace elements has been implicated in the etiology of autism. This study explores whether concentration levels of toxic metals in the hair of children with autism significantly differ from those of age- and sex-matched healthy controls. In-hair concentration levels of antimony, uranium, arsenic, beryllium, mercury,…

PULSED SPLITLESS AND LARGE-VOLUME INJECTION IN CAPILLARY GAS CHROMATOGRAPHY MASS SPECTROMETRY FOR THE DETERMINATION OF ULTRA-TRACE LEVEL PESTICIDE RESIDUES

EPA Science Inventory

The possible presence of ultra-trace levels (sub- parts per trillion) of pesticides in pristine aquatic environments (e.g., alpine lakes) would raise questions regarding potential effects on biota. One hypothesis is that agricultural pesticides that are heavily applied in the San...

Contamination of soils by metals and organic micropollutants: case study of the Parisian conurbation.

PubMed

Gaspéri, Johnny; Ayrault, Sophie; Moreau-Guigon, Elodie; Alliot, Fabrice; Labadie, Pierre; Budzinski, Hélène; Blanchard, Martine; Muresan, Bogdan; Caupos, Emilie; Cladière, Mathieu; Gateuille, David; Tassin, Bruno; Bordier, Louise; Teil, Marie-Jeanne; Bourges, Catherine; Desportes, Annie; Chevreuil, Marc; Moilleron, Régis

2016-11-10

Soils are playing a central role in the transfer and accumulation of anthropogenic pollutants in urbanized regions. Hence, this study aimed at examining the contamination levels of selected soils collected within and around the Paris conurbation (France). This also evaluated factors controlling contamination. Twenty-three trace and major elements as well as 82 organic micropollutants including polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), phthalates (PAEs), polybrominated diphenyl ethers (PBDEs), alkylphenols (APs), and perfluoroalkylated substances (PFASs) were analyzed. Results reinforced the concern raised by the occurrence and levels of metals such as Zn, Pb, Cu, and Hg, identified as metallic markers of anthropogenic activities, but also pointed out the ubiquitous contamination of soils by organic micropollutants in the 0.2-55,000-μg/kg dw range. For well-documented compounds like PAHs, PCBs, and to a lesser extent PBDEs, contents were in the range of background levels worldwide. The pollutant stock in tested soil was compared to the annual atmospheric input. For PAHs; Pb; and to a lesser extent Zn, Cu, Cd, Hg, Sb, PAEs, and APs, a significant stock was observed, far more important than the recent annual atmospheric fluxes. This resulted from both (i) the persistence of a fraction of pollutants in surface soils and (ii) the cumulative atmospheric inputs over several decades. Regarding PBDEs and PFASs, stronger atmospheric input contributions were observed, thereby highlighting their recent dispersal into the environment.

Memory trace reactivation and behavioral response during retrieval are differentially modulated by amygdalar glutamate receptors activity: interaction between amygdala and insular cortex

PubMed Central

Osorio-Gómez, Daniel; Guzmán-Ramos, Kioko

2017-01-01

The insular cortex (IC) is required for conditioned taste aversion (CTA) retrieval. However, it remains unknown which cortical neurotransmitters levels are modified upon CTA retrieval. Using in vivo microdialysis, we observed that there were clear elevations in extracellular glutamate, norepinephrine, and dopamine in and around the center of the gustatory zone of the IC during CTA retrieval. Additionally, it has been reported that the amygdala–IC interaction is highly involved in CTA memory establishment. Therefore, we evaluated the effects of infusions of an AMPA receptor antagonist (CNQX) and a NMDA receptor antagonist (APV) into the amygdala on CTA retrieval and IC neurotransmitter levels. Infusion of APV into the amygdala impaired glutamate augmentation within the IC, whereas dopamine and norepinephrine levels augmentation persisted and a reliable CTA expression was observed. Conversely, CNQX infusion into the amygdala impaired the aversion response, as well as norepinephrine and dopamine augmentations in the IC. Interestingly, CNQX infusion did not affect glutamate elevation in the IC. To evaluate the functional meaning of neurotransmitters elevations within the IC on CTA response, we infused specific antagonists for the AMPA, NMDA, D1, and β-adrenergic receptor before retrieval. Results showed that activation of AMPA, D1, and β-adrenergic receptors is necessary for CTA expression, whereas NMDA receptors are not involved in the aversion response. PMID:27980072

Trace elements in patients on continuous renal replacement therapy.

PubMed

Broman, M; Bryland, A; Carlsson, O

2017-07-01

Intensive care patients with acute kidney injury (AKI), treated with continuous renal replacement therapy (CRRT) are at great risk for disturbances in plasma levels of trace elements due to the underlying illness, AKI, and dialysis. This study was performed to increase our knowledge regarding eight different trace elements during CRRT. Thirty one stable patients with AKI, treated with CRRT, were included in the study. Blood, plasma and effluent samples were taken at the start of the study and 36 ± 12 h later. A group of 48 healthy volunteers were included as controls and exposed to one fasting blood sample. Samples were analysed for trace elements (Cr, Cu, Mn, Co, Zn, Rb, Mo, Se) and standard blood chemistry. Blood and plasma levels of selenium and rubidium were significantly reduced while the levels of chromium, cobalt, and molybdenum were significantly increased in the study group vs. healthy volunteers. There was an uptake of chromium, manganese, and zinc. Molybdenum mass balance was around zero. For selenium, copper, and rubidium there were a marked loss. The low levels of selenium and rubidium in blood and plasma from CRRT patients, together with the loss via CRRT effluent, raises the possibility of the need for selenium supplementation in this group of patients, despite the unchanged levels during the short study period. Further investigations on the effect of additional administration of trace elements to CRRT patients would be of interest. © 2017 The Acta Anaesthesiologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

Solar Neutrino flare detection in Hyperkamiokande and SK

NASA Astrophysics Data System (ADS)

Fargion, Daniele

2016-07-01

The possible buid and near activity of a Megaton neutrino detection in HyperKamiokande and the older SK implementation by Gadolinium liqid might open to future detection of largest solar flare (pion trace at tens MeV) electron neutrino and antineutrino. The multiwave detection of X-gamma and neutrino event might offer a deep view of such solar acelleration and of neutrino flavor mix along its flight. The possoble near future discover of such events will open a third neutrino astronomy windows after rarest SN 1987A and persistent Solar nuclear signals.

Trace and major element levels in rats after oral administration of diesel and biodiesel derived from opium poppy (Papaver somniferum L.) seeds.

PubMed

Aksoy, Laçine; Sözbilir, Nalan Bayşu

2015-10-01

The study investigated the toxic effects of diesel and biodiesel derived from opium poppy (Papaver somniferum L.) oil seeds on the trace and major elements in kidney, lung, liver, and serum of rats. By the end of 21 days, trace and major element concentrations in kidney, lung, and liver tissues and the serum were measured using inductively coupled plasma-optical emission spectroscopy. We observed that trace and major element levels in kidney, lung, and liver tissues and the serum changed. Especially, important differences were detected in trace and major element concentrations in kidney and lung tissues. In kidney tissue, the concentration differences of calcium, sodium, and zinc (Zn) were found between diesel and biodiesel groups. In lung tissue, the concentration differences of cadmium, lithium, magnesium, manganese, and Zn were found between diesel and biodiesel groups. Among the significant findings, Zn concentration in serum and liver tissue of diesel and biodiesel were different from control (p < 0.05). However, the metal levels of biodiesel group were similar to control group. Due to lesser toxicity of biodiesel, it could be considered as an alternate fuel. © The Author(s) 2013.

Concentrations of trace elements and PCDD/Fs around a municipal solid waste incinerator in Girona (Catalonia, Spain). Human health risks for the population living in the neighborhood.

PubMed

Rovira, Joaquim; Nadal, Martí; Schuhmacher, Marta; Domingo, José L

2018-07-15

Previously to the modernization of the municipal solid waste incinerator (MSWI) of Campdorà (Girona, Catalonia, Spain) two sampling campaigns (2015 and 2016) were conducted. In each campaign, 8 soil and 4 air samples (PM 10 and total particle phase and gas phase) were collected. The levels of As, Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb, Sb, Sn, Tl and V, and PCDD/Fs were analysed at different distances and wind directions around the MSWI. Environmental levels of trace elements and PCDD/Fs were used to assess exposure and health risks (carcinogenic and non-carcinogenic) for the population living around the facility. In soils, no significant differences were observed for trace elements and PCDD/Fs between both campaigns. In air, significant higher levels of As, Cd, Co, Mn, Ni, Pb, Tl and V were detected in 2016. Regarding soil levels, only Cd (distances) and As, Cu, Mn, and Ni (wind directions) showed significant differences. No differences were noted in the concentrations of trace elements and PCDD/Fs in air levels with respect to distances and directions to the MSWI. No differences were registered in air levels (elements and PCDD/Fs) between points influenced by MSWI emissions and background point. However some differences in congener profile were noted regarding from where back-trajectories come from (HYSPLIT model results), pointing some influence of Barcelona metropolitan area. The concentrations of trace elements and PCDD/Fs were similar -or even lower- than those reported around other MSWIs in Catalonia and various countries. Non-carcinogenic risks were below the safety limit (HQ<1). In turn, carcinogenic risks due to exposure to trace elements and PCDD/Fs were in acceptable ranges, according to national and international standard regulations. Copyright © 2018 Elsevier B.V. All rights reserved.

Trace Element Levels in Congenital Hypogonadotrophic Hypogonadism.

PubMed

Aydogdu, A; Haymana, C; Soykut, B; Erdem, O; Basaran, Y; Baskoy, K; Dinc, M; Taslipinar, A; Sonmez, A; Bolu, E; Azal, O

2016-05-01

Cardiometabolic diseases are prevalent in hypogonadism. The pathophysiologic mechanism of increased cardiometabolic risk in hypogonadal patients is not clear. Recently, trace elements have been linked to the development of chronic disease especially cardiovascular disease. We investigated the trace element levels in an unconfounded population of congenital hypogonadotrophic hypogonadism (CHH) and also searched for the relationship with metabolic risk factors. A total of 89 patients with CHH (mean age 21.8 ± 2.0 years) and 80 healthy control subjects (mean age 21.3 ± 1.1 years) were enrolled. The demographic parameters, homeostatic model assessment of insulin resistance (HOMA-IR) levels and plasma zinc, copper, and selenium levels, were measured in patients and healthy controls. The patients had higher waist circumferences (p = 0.014), triglyceride (p = 0.04), insulin (p = 0.004), HOMA-IR levels (p = 0.001), and lower selenium (p = 0.049), zinc (p = 0.004), and copper (p = 0.012) levels when compared to the healthy controls. There was a significant relationship between zinc levels and HOMA-IR levels (p = 0.015). In the regression analysis, zinc levels were independently associated with the calculated HOMA-IR levels (p = 0.015). The results of the present study show that plasma selenium, zinc, and copper levels are decreased in patients with CHH. Also, plasma zinc levels are independently associated with insulin resistance in patients with hypogonadism. Long-term follow-up studies are warranted to investigate the effect of trace elements on the increased cardiometabolic risk in hypogonadism.

Hazardous metal pollution in a protected coastal area from Northern Patagonia (Argentina).

PubMed

Marinho, C H; Giarratano, E; Esteves, J L; Narvarte, M A; Gil, M N

2017-03-01

The San Antonio Bay is a protected natural coastal area of Argentina that has been exposed to mining wastes over the last three decades. Iron and trace metals of potential concern to biota and human health (Cd, Pb, Cu, and Zn) were investigated in the sediments from the bay and in the soils of the Pile (mining wastes). Concentrations of Cd (45 mg kg -1 ), Pb (42,853 mg kg -1 ), Cu (24,505 mg kg -1 ), and Zn (28,686 mg kg -1 ) in the soils Pile exceeded guidelines for agricultural, residential, and industrial land uses. Risk assessment due to exposure to contaminated soils (Pile) was performed. Hazard quotients were superior to non-risk (HQ >1) for all trace metals, while accumulative hazard quotient index indicated a high risk for children (HI = 93) and moderate for adults (HI = 9). In the bay, sediments closest to the Pile (mudflat and salt marsh) exceeded sediment quality guidelines for protection of biota. Results of different acid extraction methods suggest that most of the pseudototal content was potentially mobile. Principal component analysis indicated that the sites near the Pile (Encerrado channel) were more polluted than the distal ones. Tissues of Spartina spp. located within Encerrado channel showed the highest metal levels among all studied sites. These results show that the problem still persists and the mining wastes are the sources of the pollution. Furthermore, the Encerrado channel is a highly impacted area, as it is shown by their metal enriched sediments.

Distribution of persistent organic pollutants, polycyclic aromatic hydrocarbons and trace elements in soil and vegetation following a large scale landfill fire in northern Greece.

PubMed

Chrysikou, Loukia; Gemenetzis, Panagiotis; Kouras, Athanasios; Manoli, Evangelia; Terzi, Eleni; Samara, Constantini

2008-02-01

Polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), including hexaclorocyclohexanes (HCHs) and DDTs, as well as trace elements were determined in soil and vegetation samples collected from the surrounding area of the landfill "Tagarades", the biggest in northern Greece, following a large scale fire involving approximately 50,000 tons of municipal waste. High concentrations of total PAHs, PCBs and heavy metals were found inside the landfill (1475 microg kg(-1) dw, 399 microg kg(-1) dw and 29.8 mg kg(-1) dw, respectively), whereas concentrations in the surrounding soils were by far lower ranging between 11.2-28.1 microg kg(-1) dw for PAHs, 4.02-11.2 microg kg(-1) dw for PCBs and 575-1207 mg kg(-1) dw for heavy metals. The distribution of HCHs and DDTs were quite different since certain soils exhibited equal or higher concentrations than the landfill. In vegetation, the concentrations of PAHs, PCBs, HCHs and DDTs ranged from 14.1-34.7, 3.64-25.9, 1.41-32.1 and 0.61-4.03 microg kg(-1) dw, respectively, while those of heavy metals from 81 to 159 mg kg(-1) dw. The results of the study indicated soil and vegetation pollution levels in the surroundings of the landfill comparable to those reported for other Greek locations. The impact from the landfill fire was not evident partially due to the presence of recent and past inputs from other activities (agriculture, vehicular transport, earlier landfill fires).

Prevalence of human cell material: DNA and RNA profiling of public and private objects and after activity scenarios.

PubMed

van den Berge, M; Ozcanhan, G; Zijlstra, S; Lindenbergh, A; Sijen, T

2016-03-01

Especially when minute evidentiary traces are analysed, background cell material unrelated to the crime may contribute to detectable levels in the genetic analyses. To gain understanding on the composition of human cell material residing on surfaces contributing to background traces, we performed DNA and mRNA profiling on samplings of various items. Samples were selected by considering events contributing to cell material deposits in exemplary activities (e.g. dragging a person by the trouser ankles), and can be grouped as public objects, private samples, transfer-related samples and washing machine experiments. Results show that high DNA yields do not necessarily relate to an increased number of contributors or to the detection of other cell types than skin. Background cellular material may be found on any type of public or private item. When a major contributor can be deduced in DNA profiles from private items, this can be a different person than the owner of the item. Also when a specific activity is performed and the areas of physical contact are analysed, the "perpetrator" does not necessarily represent the major contributor in the STR profile. Washing machine experiments show that transfer and persistence during laundry is limited for DNA and cell type dependent for RNA. Skin conditions such as the presence of sebum or sweat can promote DNA transfer. Results of this study, which encompasses 549 samples, increase our understanding regarding the prevalence of human cell material in background and activity scenarios. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

The impact of lifestyle factors on age-related differences in hair trace element content in pregnant women in the third trimester.

PubMed

Skalny, Anatoly V; Tinkov, Alexey A; Voronina, Irina; Terekhina, Olga; Skalnaya, Margarita G; Bohan, Tatiana G; Agarkova, Lyubov A; Kovas, Yulia

2018-01-01

Trace elements play a significant role in the regulation of human reproduction, while advanced age may have a significant impact on trace element metabolism. The objective of the present study was to assess the impact of lifestyle factors on age-related differences in hair trace element content in pregnant women in the third trimester. A total of 124 pregnant women aged 20–29 (n = 72) and 30–39 (n = 52) were ex- amined. Scalp hair trace element content was assessed using inductively coupled plasma mass spectrometry at NexION 300D (Perkin Elmer, USA) after microwave digestion. The results showed that the elder pregnant women had 36% (p = 0.009), 14% (p = 0.045), and 45% (p = 0.044) lower hair Zn, V, and Cd content, and 16% (p = 0.044) higher hair B levels – in comparison to the respective younger group values. Multiple regression analysis demonstrated that the age of the women had a significant influence on hair V and Zn levels. B content was also significantly influenced by age at first intercourse, smoking status, and specific dietary habits. None of the lifestyle factors were associated with hair Cd content in pregnant women. Hair V levels were also affected by following a special diet. Interestingly, alcohol intake did not have a significant impact on hair trace element content. These data indicate that lifestyle factors have a significant influence on age-related changes in hair trace elements during pregnancy that may impact the outcome of pregnancy.

Trace fossils in diatomaceous strata of Miocene Monterey Formation: their character and implications

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

Savdra, C.E.; Bottjer, D.J.

Younger parts of the Miocene Monterey Formation are commonly characterized by relatively unaltered diatomaceous strata. A common characteristic of these deposits is the preservation of varvelike lamination, indicative of deposition under anoxic or nearly anoxic conditions. Although laminated rock types are volumetrically dominant, bioturbated intervals are by no means rare, but little attention has been paid to the trace fossils themselves. Our study of trace fossils in the Monterey Formation demonstrated the significance of these biogenic structures in paleoenvironmental and paleoecologic analyses. In particular, trace fossils provide a means for detailed reconstruction of paleo-oxygenation conditions during Monterey deposition. Trace fossilsmore » in several Monterey sections exposed in central and southern California were examined in detail. At all localities, three major ichnofossil assemblages or ichnofacies were recognized: (1) Chondrites, (2) Planolites, and (3) Thalassinoides. The size and diversity of the three major ichnofacies and their lithologic associations suggest that the distribution of these facies is controlled primarily by the level of paleo-bottom water oxygenation. The Chondrites ichnofacies represents very low paleo-oxygen levels just above the anoxic threshold. The Planolites ichnofacies, with greater variety of larger burrow types, is indicative of slightly higher levels of oxygenation. Moderately to well-oxygenated conditions are suggested by the Thalassinoides ichnofacies. More detailed information on paleoenvironmental conditions can be gleaned by applying a refined trace-fossil tiering model. When used in detailed (centimeter-scale) vertical sequence analyses, this tiering model permits the translation of data on the composition, size parameters, and cross-cutting relationships of trace-fossil assemblages into relative paleo-oxygenation curves.« less

Energy conversion modeling of the intrinsic persistent luminescence of solids via energy transfer paths between transition levels.

PubMed

Huang, Bolong; Sun, Mingzi

2017-04-05

An energy conversion model has been established for the intrinsic persistent luminescence in solids related to the native point defect levels, formations, and transitions. In this study, we showed how the recombination of charge carriers between different defect levels along the zero phonon line (ZPL) can lead to energy conversions supporting the intrinsic persistent phosphorescence in solids. This suggests that the key driving force for this optical phenomenon is the pair of electrons hopping between different charged defects with negative-U eff . Such a negative correlation energy will provide a sustainable energy source for electron-holes to further recombine in a new cycle with a specific quantum yield. This will help us to understand the intrinsic persistent luminescence with respect to native point defect levels as well as the correlations of electronics and energetics.

Predicting Undergraduates' Persistence in Science, Technology, Engineering, and Math Fields

NASA Astrophysics Data System (ADS)

Koch, Amanda Joy

A national shortage of workers in Science, Technology, Engineering, and Math (STEM) occupations has led to efforts to identify why people leave these fields. Lower persistence rates in STEM for females than for males have also led to examinations of features that cause females to leave STEM fields. The current study examines individual- and school-level features that influence undergraduate students' decisions to leave STEM majors, focusing on potential explanations for why females are more likely than males to leave. Persistence in STEM was examined in three samples: (a) persistence through the second year of college in a sample of high school seniors interested in STEM majors; (b) persistence through the fourth year of college in a sample of second year undergraduate STEM majors; and (c) persistence through the second, third, and fourth years of college in a sample of high school seniors interested in STEM majors. Differences between persistence in male-dominated and non-male-dominated STEM majors were also examined. In all samples, gender differences were found for most individual-level predictors, with males tending to score higher than females on measures such as SAT-Math, self-rated STEM ability, and high school extracurricular activities and awards in STEM. On the other hand, females earned better high school grades and had stronger relative non-STEM ability and achievement than males. Bivariate analyses indicated that those who persisted in STEM majors typically had higher scores than those who did not persist for SAT-Math, high school achievement, STEM course taking, undergraduate STEM grades, self-rated STEM ability, interest in STEM, extracurricular activities and awards in STEM, degree goals, and socioeconomic status. Multivariate analyses identified SAT-Math as one of the best predictors of persistence in high school samples, and undergraduate STEM GPA was one of the best predictors in the samples of second year undergraduates. In several samples, a significant cross-level interaction was found between gender and undergraduate females' college-level proportional representation in STEM; however, the effects were inconsistent across samples. Even when controlling for various individual- and school-level predictors, gender effects tended to remain significant, with females in most samples leaving STEM majors at higher rates than males.

Tracing past ambient air pollution and its consequences on human health

NASA Astrophysics Data System (ADS)

Pedersen, M. W.; Kjaer, K. H.; Dean, K.; Siggaard-Andersen, M. L.; Petersen, J.; Rasmussen, P.; Kjeldsen, K. K.; Ilsøe, P.; Rivers, A.; Andersen, T.; Schreiber, N.; Bjork, A. A.; Funder, S.; Larsen, N. K.; Ruter, A.; Schomacker, A.; Andresen, C. S.; Hamerlik, L.; Orlando, L.; Hansen, A.; Mollerup, S.; Murray, A. S.; Thomsen, K. J.; Jensen, N.; Bjorck, S.; Bønløkke, J.; Tringe, S. G.; Rubin, E.; Louchouarn, P.; Willerslev, E.

2017-12-01

The onset and magniture of the industrialization and its impact on human health remains debated. This is because information largely comes from historical written records that primarily contains socio-political descriptions and thus do not provide a comprehensive environmental history. Therefore, it is essential to have an independent means for reconstructing pollution and disease levels around the time of industrialization. Here, we demonstrate how heavy metals, black carbon (BC), polycyclic aromatic hydrocarbons (PAHs) and environmental DNA (eDNA) in lake sediments can be used to track pollution and disease levels over the last 360 years in one major European capital city, Copenhagen (Denmark). We find that increased air pollution commenced in 1760s but decrease by the end of the 1790s, however it is not until 1850s a persistent increase occurs supporting the minority view that industrialization in Copenhagen initiated at this time rather than 20 years later as commonly thought. Over the following 125 years the pollution levels increased thousand-fold reaching a maximum level during the 1950-70s. After this time, the clean-air political initiative reduced emissions for most pollutants, some of which almost returned to pre-industrial levels. The high PAH levels measured between 1900 and 1950 imply that IQ levels of Copenhagen citizens, were probably 2-6 points lower during that period than today based upon their known impact on children's cognitive abilities. Changes in eDNA composition reveals establishment and cultivation of Copenhagen's Botanical Garden in the 1870s as well as the onset of the 1853 cholera epidemic. That epidemic, fuelled by high population density, caused the death of 4,737 Copenhageners. Our study establishes lake sediments as novel archives for tracking pollution levels, environmental changes and epidemics during urban development and understanding the changes associated with urbanisation.

Determination of Trace Level Iodine in Biological and Botanical Reference Materials by Isotope Dilution Mass Spectrometry

PubMed Central

Gramlich, John W.; Murphy, Thomas J.

1989-01-01

A method has been developed for the determination of trace level iodine in biological and botanical materials. The method consists of spiking a sample with 129I, equilibration of the spike with the natural iodine, wet ashing under carefully controlled conditions, and separation of the iodine by co-precipitation with silver chloride. Measurement of the 129I/127I ratio is accomplished by negative thermal ionization mass spectrometry using LaB6 for ionization enhancement. The application of the method to the certification of trace iodine in two Standard Reference Materials is described. PMID:28053411

Method development for liquid chromatographic/triple quadrupole mass spectrometric analysis of trace level perfluorocarboxylic acids in articles of commerce

EPA Science Inventory

An analytical method to identify and quantify trace levels of C5 to C12 perfluorocarboxylic acids (PFCAs) in articles of commerce (AOC) is developed and rigorously validated. Solid samples were extracted in methanol, and liquid samples were diluted with a solvent consisting of 60...

Lead and wine. Eberhard Gockel and the colica Pictonum

PubMed Central

Eisinger, Josef

1982-01-01

The colica Pictonum or colic of Poitou, under these and many other names, was a frequent, widespread, and deadly disease from Roman times until the eighteenth century. Its unique pathognomonic, notably a severe colic succeeded by paralysis and other central nervous system dysfunction, makes it possible to identify the disease with certainty as chronic lead disease, usually caused by the ingestion of lead-adulterated wines. The custom of sweetening and preserving sour wines with lead-containing additives is traced to the Romans. They had made the empirical discovery that sapa, a syrup prepared by concentrating must in a lead vessel, kept wine from spoiling and that it had, moreover, an agreeable flavour. Reports of outbreaks of the colica Pictonum appear in the medical literature from Roman times, but the correct aetiology of the disease was not discovered until the seventeenth century following a series of outbreaks in Southern Germany which were related to unfavourable climatic and political conditions. The connexion between the disease and prevailing methods for “correcting” wines was drawn in 1696 by Eberhard Gockel, then the city physician of Ulm. This achievement can be traced to his familiarity with Samuel Stockhausen's work on plumbism among miners and potters, as well as to the favourable epidemiological situation presented by Gockel's monastic patients. From the literary evidence assembled here and from experimental determinations of the lead content of sapa and similar concentrates, it is possible to estimate the lead levels and toxicity of wines from various eras. The levels range up to 80 mg/l and make it apparent that many wines were sufficiently toxic to account for the incidence and severity of the colica Pictonum. Explanations for the disastrous persistence of the colic of Poitou are discussed, as are the similarities between Gockel's approach and the methods of modern environmental medicine. ImagesPlate 4.Plate 1.Plate 2.Plate 3. PMID:6750289

Cumulative inequality and racial disparities in health: private insurance coverage and black/white differences in functional limitations.

PubMed

Kail, Ben Lennox; Taylor, Miles G

2014-09-01

To test different forms of private insurance coverage as mediators for racial disparities in onset, persistent level, and acceleration of functional limitations among Medicare age-eligible Americans. Data come from 7 waves of the Health and Retirement Study (1996-2008). Onset and progression latent growth models were used to estimate racial differences in onset, level, and growth of functional limitations among a sample of 5,755 people aged 65 and older in 1996. Employer-provided insurance, spousal insurance, and market insurance were next added to the model to test how differences in private insurance mediated the racial gap in physical limitations. In baseline models, African Americans had larger persistent level of limitations over time. Although employer-provided, spousal provided, and market insurances were directly associated with lower persistent levels of limitation, only differences in market insurance accounted for the racial disparities in persistent level of limitations. Results suggest private insurance is important for reducing functional limitations, but market insurance is an important mediator of the persistently larger level of limitations observed among African Americans. © The Author 2014. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Culiseta subochrea as a Bioindicator of Metal Contamination in Shadegan International Wetland, Iran (Diptera: Culicidae)

PubMed Central

Nasirian, Hassan; Vazirianzadeh, Babak; Taghi Sadeghi, Sayyed Mohammad; Nazmara, Shahrokh

2014-01-01

Abstract The quantity of some trace metals of mosquito larvae in Shadegan International Wetland from Iran was evaluated. Water, waterbed sediment, and mosquito larvae samplings were carried out from an urban site in the east of the wetland, using standard methods in December 2011. The identified Culiseta subochrea (Edwards) and Aedes caspius s.l. (Pallas) larvae, water, and waterbed sediment samples were analyzed for As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Pb, and Zn trace metals using standard preparation and isolation procedure. Result showed that the waterbed sediment and Cu. subochrea larvae are polluted with all trace metals investigated except As and Hg. The trace metals bioaccumulated in the Cu. subochrea larvae range from 31.78 at the lowest level for Cr to 3822.7 at the highest level for Cd. In a conclusion, this is the first report confirmed that Cu. subochrea likely used as a bioindicator to trace metal pollution in marine ecosystems in the world, especially wetlands. PMID:25550357

Gull-derived trace elements trigger small-scale contamination in a remote Mediterranean nature reserve.

PubMed

Signa, Geraldina; Mazzola, Antonio; Tramati, Cecilia Doriana; Vizzini, Salvatrice

2013-09-15

The role of a yellow-legged gull (Larus michahellis) small colony in conveying trace elements (As, Cd, Cr, Cu, Ni, Pb, THg, V, Zn) was assessed in a Mediterranean nature reserve (Marinello ponds) at various spatial and temporal scales. Trace element concentrations in guano were high and seasonally variable. In contrast, contamination in the ponds was not influenced by season but showed strong spatial variability among ponds, according to the different guano input. Biogenic enrichment factor B confirmed the role of gulls in the release of trace elements through guano subsidies. In addition, comparing trace element pond concentrations to the US NOAA's SQGs, As, Cu and Ni showed contamination levels associated with possible negative biological effects. Thus, this study reflects the need to take seabirds into account as key factors influencing ecological processes and contamination levels even in remote areas, especially around the Mediterranean, where these birds are abundant but overlooked. Copyright © 2013 Elsevier Ltd. All rights reserved.

Overview of the International Space Station System Level Trace Contaminant Injection Test

NASA Technical Reports Server (NTRS)

Tatara, James D.; Perry, Jay L.; Franks, Gerald D.

1997-01-01

Trace contaminant control onboard the International Space Station will be accomplished not only by the Trace Contaminant Control Subassembly but also by other Environmental Control and Life Support System subassemblies. These additional removal routes include absorption by humidity condensate in the Temperature and Humidity Control Condensing Heat Exchanger and adsorption by the Carbon Dioxide Removal Assembly. The Trace Contaminant Injection Test, which was performed at NASA's Marshall Space Flight Center, investigated the system-level removal of trace contaminants by the International Space Station Atmosphere Revitalization, and Temperature/Humidity Control Subsystems, (November-December 1997). It is a follow-on to the Integrated Atmosphere Revitalization Test conducted in 1996. An estimate for the magnitude of the assisting role provided by the Carbon Dioxide Removal Assembly and the Temperature and Humidity Control unit was obtained. In addition, data on the purity of Carbon Dioxide Removal Assembly carbon dioxide product were obtained to support Environmental Control and Life Support System Air Revitalization Subsystem loop closure.

Use of sediment-trace element geochemical models for the identification of local fluvial baseline concentrations

USGS Publications Warehouse

Horowitz, A.J.; Elrick, K.A.; Demas, C.R.; Demcheck, D.K.

1991-01-01

Studies have demonstrated the utility of fluvial bed sediment chemical data in assesing local water-quality conditions. However, establishing local background trace element levels can be difficult. Reference to published average concentrations or the use of dated cores are often of little use in small areas of diverse local petrology, geology, land use, or hydrology. An alternative approach entails the construction of a series of sediment-trace element predictive models based on data from environmentally diverse but unaffected areas. Predicted values could provide a measure of local background concentrations and comparison with actual measured concentrations could identify elevated trace elements and affected sites. Such a model set was developed from surface bed sediments collected nationwide in the United States. Tests of the models in a small Louisiana basin indicated that they could be used to establish local trace element background levels, but required recalibration to account for local geochemical conditions outside the range of samples used to generate the nationwide models.

Assessment of trace metal pollution in sediments and intertidal fauna at the coast of Cameroon.

PubMed

Ngeve, Magdalene N; Leermakers, Martine; Elskens, Marc; Kochzius, Marc

2015-06-01

Coastal systems act as a boundary between land and sea. Therefore, assessing pollutant concentrations at the coast will provide information on the impact that land-based anthropogenic activities have on marine ecosystems. Sediment and fauna samples from 13 stations along the whole coast of Cameroon were analyzed to assess the level of trace metal pollution in sediments and intertidal fauna. Sediments showed enrichment of As, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, V, and Zn. However, pollution of greater concern was observed for Cd, Cr, Cu, Ni, and Zn at the northern stations. Some sites recorded trace metal levels higher than recommended in sediment quality guidelines. Species diversity was low, and high bioaccumulation of trace metals was observed in biological samples. Some edible gastropod species accumulated trace metals above the safety limits of the World Health Organization, European Medicine Agency, and the US Environment Protection Agency. Although industrial pollution is significant along Cameroon's coast, natural pollution from the volcano Mount Cameroon is also of concern.

Genome-Wide RNAi Ionomics Screen Reveals New Genes and Regulation of Human Trace Element Metabolism

PubMed Central

Malinouski, Mikalai; Hasan, Nesrin M.; Zhang, Yan; Seravalli, Javier; Lin, Jie; Avanesov, Andrei; Lutsenko, Svetlana; Gladyshev, Vadim N.

2017-01-01

Trace elements are essential for human metabolism and dysregulation of their homeostasis is associated with numerous disorders. Here we characterize mechanisms that regulate trace elements in human cells by designing and performing a genome-wide high-throughput siRNA/ionomics screen, and examining top hits in cellular and biochemical assays. The screen reveals high stability of the ionomes, especially the zinc ionome, and yields known regulators and novel candidates. We further uncover fundamental differences in the regulation of different trace elements. Specifically, selenium levels are controlled through the selenocysteine machinery and expression of abundant selenoproteins; copper balance is affected by lipid metabolism and requires machinery involved in protein trafficking and posttranslational modifications; and the iron levels are influenced by iron import and expression of the iron/heme-containing enzymes. Our approach can be applied to a variety of disease models and/or nutritional conditions, and the generated dataset opens new directions for studies of human trace element metabolism. PMID:24522796

Short-term acute hypercapnia affects cellular responses to trace metals in the hard clams Mercenaria mercenaria.

PubMed

Ivanina, Anna V; Beniash, Elia; Etzkorn, Markus; Meyers, Tiffany B; Ringwood, Amy H; Sokolova, Inna M

2013-09-15

Estuarine and coastal habitats experience large fluctuations of environmental factors such as temperature, salinity, partial pressure of CO2 ( [Formula: see text] ) and pH; they also serve as the natural sinks for trace metals. Benthic filter-feeding organisms such as bivalves are exposed to the elevated concentrations of metals in estuarine water and sediments that can strongly affect their physiology. The effects of metals on estuarine organisms may be exacerbated by other environmental factors. Thus, a decrease in pH caused by high [Formula: see text] (hypercapnia) can modulate the effects of trace metals by affecting metal bioavailability, accumulation or binding. To better understand the cellular mechanisms of interactions between [Formula: see text] and trace metals in marine bivalves, we exposed isolated mantle cells of the hard clams (Mercenaria mercenaria) to different levels of [Formula: see text] (0.05, 1.52 and 3.01 kPa) and two major trace metal pollutants - cadmium (Cd) and copper (Cu). Elevated [Formula: see text] resulted in a decrease in intracellular pH (pHi) of the isolated mantle cells from 7.8 to 7.4. Elevated [Formula: see text] significantly but differently affected the trace metal accumulation by the cells. Cd uptake was suppressed at elevated [Formula: see text] levels while Cu accumulation has greatly accelerated under hypercapnic conditions. Interestingly, at higher extracellular Cd levels, labile intracellular Cd(2+) concentration remained the same, while intracellular levels of free Zn(2+) increased suggesting that Cd(2+) substitutes bound Zn(2+) in these cells. In contrast, Cu exposure did not affect intracellular Zn(2+) but led to a profound increase in the intracellular levels of labile Cu(2+) and Fe(2+). An increase in the extracellular concentrations of Cd and Cu led to the elevated production of reactive oxygen species under the normocapnic conditions (0.05 kPa [Formula: see text] ); surprisingly, this effect was mitigated in hypercapnia (1.52 and 3.01 kPa). Overall, our data reveal complex and metal-specific interactions between the cellular effects of trace metals and [Formula: see text] in clams and indicate that variations in environmental [Formula: see text] may modulate the biological effects of trace metals in marine organisms. Copyright © 2013 Elsevier B.V. All rights reserved.

Dopamine cells respond to predicted events during classical conditioning: evidence for eligibility traces in the reward-learning network.

PubMed

Pan, Wei-Xing; Schmidt, Robert; Wickens, Jeffery R; Hyland, Brian I

2005-06-29

Behavioral conditioning of cue-reward pairing results in a shift of midbrain dopamine (DA) cell activity from responding to the reward to responding to the predictive cue. However, the precise time course and mechanism underlying this shift remain unclear. Here, we report a combined single-unit recording and temporal difference (TD) modeling approach to this question. The data from recordings in conscious rats showed that DA cells retain responses to predicted reward after responses to conditioned cues have developed, at least early in training. This contrasts with previous TD models that predict a gradual stepwise shift in latency with responses to rewards lost before responses develop to the conditioned cue. By exploring the TD parameter space, we demonstrate that the persistent reward responses of DA cells during conditioning are only accurately replicated by a TD model with long-lasting eligibility traces (nonzero values for the parameter lambda) and low learning rate (alpha). These physiological constraints for TD parameters suggest that eligibility traces and low per-trial rates of plastic modification may be essential features of neural circuits for reward learning in the brain. Such properties enable rapid but stable initiation of learning when the number of stimulus-reward pairings is limited, conferring significant adaptive advantages in real-world environments.

Evaluation of Trace Metal Levels in Tissues of Two Commercial Fish Species in Kapar and Mersing Coastal Waters, Peninsular Malaysia

PubMed Central

Bashir, Fathi Alhashmi; Shuhaimi-Othman, Mohammad; Mazlan, A. G.

2012-01-01

This study is focused on evaluating the trace metal levels in water and tissues of two commercial fish species Arius thalassinus and Pennahia anea that were collected from Kapar and Mersing coastal waters. The concentrations of Fe, Zn, Al, As, Cd and Pb in these coastal waters and muscle, liver and gills tissues of the fishes were quantified. The relationship among the metal concentrations and the height and weight of the two species were also examined. Generally, the iron has the highest concentrations in both water and the fish species. However, Cd in both coastal waters showed high levels exceeding the international standards. The metal level concentration in the sample fishes are in the descending order livers > gills > muscles. A positive association between the trace metal concentrations and weight and length of the sample fishes was investigated. Fortunately the level of these metal concentrations in fish has not exceeded the permitted level of Malaysian and international standards. PMID:22046193

Effect of censoring trace-level water-quality data on trend-detection capability

USGS Publications Warehouse

Gilliom, R.J.; Hirsch, R.M.; Gilroy, E.J.

1984-01-01

Monte Carlo experiments were used to evaluate whether trace-level water-quality data that are routinely censored (not reported) contain valuable information for trend detection. Measurements are commonly censored if they fall below a level associated with some minimum acceptable level of reliability (detection limit). Trace-level organic data were simulated with best- and worst-case estimates of measurement uncertainty, various concentrations and degrees of linear trend, and different censoring rules. The resulting classes of data were subjected to a nonparametric statistical test for trend. For all classes of data evaluated, trends were most effectively detected in uncensored data as compared to censored data even when the data censored were highly unreliable. Thus, censoring data at any concentration level may eliminate valuable information. Whether or not valuable information for trend analysis is, in fact, eliminated by censoring of actual rather than simulated data depends on whether the analytical process is in statistical control and bias is predictable for a particular type of chemical analyses.

Composition and leaching of construction and demolition waste: inorganic elements and organic compounds.

PubMed

Butera, Stefania; Christensen, Thomas H; Astrup, Thomas F

2014-07-15

Thirty-three samples of construction and demolition waste collected at 11 recycling facilities in Denmark were characterised in terms of total content and leaching of inorganic elements and presence of the persistent organic pollutants PCBs and PAHs. Samples included (i) "clean" (i.e. unmixed) concrete waste, (ii) mixed masonry and concrete, (iii) asphalt and (iv) freshly cast concrete cores; both old and newly generated construction and demolition waste was included. PCBs and PAHs were detected in all samples, generally in non-critical concentrations. Overall, PAHs were comparable to background levels in urban environments. "Old" and "new" concrete samples indicated different PCB congener profiles and the presence of PCB even in new concrete suggested that background levels in raw materials may be an issue. Significant variability in total content of trace elements, even more pronounced for leaching, was observed indicating that the number of analysed samples may be critical in relation to decisions regarding management and utilisation of the materials. Higher leaching of chromium, sulphate and chloride were observed for masonry-containing and partly carbonated samples, indicating that source segregation and management practices may be important. Generally, leaching was in compliance with available leaching limits, except for selenium, and in some cases chromium, sulphate and antimony. Copyright © 2014 Elsevier B.V. All rights reserved.

Retrospective biomonitoring of chemical contamination in the marine coastal environment of Terra Nova Bay (Ross Sea, Antarctica) by environmental specimen banking.

PubMed

Grotti, Marco; Pizzini, Sarah; Abelmoschi, Maria Luisa; Cozzi, Giulio; Piazza, Rossano; Soggia, Francesco

2016-12-01

Antarctica offers a good opportunity to investigate planetary-scale pollution and climate change, and provides baseline values for contaminants such as Trace Elements (TEs) and Persistent Organic Pollutants (POPs). Literature data on contaminant levels in the Antarctic environment indicate that long-range atmospheric transport is the primary pathway by which pollutants from surrounding continents are carried to this pristine environment. However, local contamination sources represented by the scientific stations are also not negligible. Climate change and global warming are altering the global budget of anthropogenic contaminants and their monitoring in Antarctica ecosystems is very important to protect the global environment. In this work, eighty specimens of Adamussium colbecki (Smith, 1902), a benthic Antarctic scallop, collected from 1996 to 2009 and stored in the Antarctic Environmental Specimen Bank, were analyzed to quantify TEs and POPs, including polychlorinated biphenyls (PCBs), polychlorinated naphthalenes (PCNs) and polycyclic aromatic hydrocarbons (PAHs). Metals concentrations were not affected by anthropogenic contributions, highlighting a natural accumulation with the age of the organism. Similarly, no temporal trend was found for PCNs, PCBs and PAHs. However, specimens collected during the summer 1997-98 showed enhanced concentration levels of PCBs and PAHs that could refer to a local anthropogenic source of contamination. Copyright © 2016 Elsevier Ltd. All rights reserved.

Contact-dependent growth inhibition induces high levels of antibiotic-tolerant persister cells in clonal bacterial populations.

PubMed

Ghosh, Anirban; Baltekin, Özden; Wäneskog, Marcus; Elkhalifa, Dina; Hammarlöf, Disa L; Elf, Johan; Koskiniemi, Sanna

2018-05-02

Bacterial populations can use bet-hedging strategies to cope with rapidly changing environments. One example is non-growing cells in clonal bacterial populations that are able to persist antibiotic treatment. Previous studies suggest that persisters arise in bacterial populations either stochastically through variation in levels of global signalling molecules between individual cells, or in response to various stresses. Here, we show that toxins used in contact-dependent growth inhibition (CDI) create persisters upon direct contact with cells lacking sufficient levels of CdiI immunity protein, which would otherwise bind to and neutralize toxin activity. CDI-mediated persisters form through a feedforward cycle where the toxic activity of the CdiA toxin increases cellular (p)ppGpp levels, which results in Lon-mediated degradation of the immunity protein and more free toxin. Thus, CDI systems mediate a population density-dependent bet-hedging strategy, where the fraction of non-growing cells is increased only when there are many cells of the same genotype. This may be one of the mechanisms of how CDI systems increase the fitness of their hosts. © 2018 The Authors.

Unscrambling Egg Allergy: The Diagnostic Value of Specific IgE Concentrations and Skin Prick Tests for Ovomucoid and Egg White in the Management of Children with Hen's Egg Allergy.

PubMed

Marriage, D E; Erlewyn-Lajeunesse, M; Unsworth, D J; Henderson, A J

2012-01-01

Resolution of egg allergy occurs in the majority of egg allergic children. Positive specific IgE antibodies to ovomucoid (OVM) have been suggested to be of greater predictive value for persistent egg allergy than specific IgE to egg white. The performance of OVM-specific IgE antibody levels in a cohort of children referred for a routine egg challenge was compared with egg white specific IgE levels in predicting a positive egg challenge. 24/47 subjects had persistent egg allergy. Receiver operating characteristic analysis showed that OVM-specific IgE testing was the most useful test for the diagnosis of persistent egg allergy. The optimal decision points for the prediction of persistent egg allergy were >0.35 kUA/L for specific IgE levels to both EW and OVM, and ≥3 mm for SPT. Children with specific IgE levels suggestive of persistent egg allergy need not be subject to an egg provocation challenge, reducing both costs and risks to the child.

Risk factors for persistent gestational trophoblastic neoplasia.

PubMed

Kuyumcuoglu, Umur; Guzel, Ali Irfan; Erdemoglu, Mahmut; Celik, Yusuf

2011-01-01

This retrospective study evaluated the risk factors for persistent gestational trophoblastic disease (GTN) and determined their odds ratios. This study included 100 cases with GTN admitted to our clinic. Possible risk factors recorded were age, gravidity, parity, size of the neoplasia, and beta-human chorionic gonadotropin levels (beta-hCG) before and after the procedure. Statistical analyses consisted of the independent sample t-test and logistic regression using the statistical package SPSS ver. 15.0 for Windows (SPSS, Chicago, IL, USA). Twenty of the cases had persistent GTN, and the differences between these and the others cases were evaluated. The size of the neoplasia and histopathological type of GTN had no statistical relationship with persistence, whereas age, gravidity, and beta-hCG levels were significant risk factors for persistent GTN (p < 0.05). The odds ratios (95% confidence interval (CI)) for age, gravidity, and pre- and post-evacuation beta-hCG levels determined using logistic regression were 4.678 (0.97-22.44), 7.315 (1.16-46.16), 2.637 (1.41-4.94), and 2.339 (1.52-3.60), respectively. Patient age, gravidity, and beta-hCG levels were risk factors for persistent GTN, whereas the size of the neoplasia and histopathological type of GTN were not significant risk factors.

Directional analysis of CO2 persistence at a rural site.

PubMed

Pérez, Isidro A; Sánchez, M Luisa; García, M Ángeles; Paredes, Vanessa

2011-09-01

Conditional probability was used to establish persistence of CO(2) concentrations at a rural site. Measurements extended over three years and were performed with a CO(2) continuous monitor and a sodar. Concentrations in the usual range at this site were proposed as the truncation level to calculate conditional probability, allowing us to determine the extent of CO(2) sequences. Extension of episodes may be inferred from these values. Persistence of wind directions revealed two groups of sectors, one with a persistence of about 16 h and another of about 9 h. Cumulative distribution of CO(2) was calculated in each wind sector and three groups, associated with different concentration origins, were established. One group was linked to transport and local sources, another to the rural environment, and a third to transport of clean air masses. Daily evolution of concentrations revealed major differences during the night and monthly analysis allowed us to associate group 1 with the vegetation cycle and group 3 with wind speed from December to April. Persistence of concentrations was obtained, and group 3 values were lower for concentrations above the truncation level, whereas persistence of groups 1 and 2 was similar. However, group 3 persistence was, in general, between group 1 and 2 persistence for concentrations below the truncation level. Copyright © 2011 Elsevier B.V. All rights reserved.

Trace Element Concentrations in Beef Cattle Related to the Breed Aptitude.

PubMed

Pereira, Victor; Carbajales, Paloma; López-Alonso, Marta; Miranda, Marta

2018-02-24

Animal feed has traditionally been supplemented with trace elements at dietary concentrations well above physiological needs. However, environmental concerns have led to calls for better adjustment of mineral supplementation to actual physiological needs and, in this context, consideration of breed-related differences in trace element requirements. The aim of this study was to analyze trace element concentrations in the main breeds used for intensive beef production in northern Spain (Holstein-Friesian [HF], Galician Blonde [GB], and GB × HF cross). Samples of blood, internal organs, and muscle were obtained at slaughter from 10 HF, GB, and GB × HF cross calves in the same feedlot. Overall, trace element concentrations in serum and internal organs were within adequate ranges and did not differ between those of breeds, suggesting that trace mineral supplementation was adequate in all groups. The only exception to this was copper, and hepatic copper concentrations were above adequate levels in all calves. This was particularly evident in the HF calves, and the maximum recommended level for human consumption was exceeded in 90% of these animals. Copper, iron, manganese, selenium, and zinc concentrations in muscle were significantly higher in the HF than those in the GB calves, with intermediate values for the crosses. These breed-related differences in trace element concentrations in the muscle may be related to lower muscle mass and/or higher hepatic activity in the HF (dairy) calves than in GB (beef) calves. As meat is an essential source of highly available trace elements in human diets, breed-related differences in trace element concentrations in meat deserve further investigation.

Determination of trace elements in Ethiopian, Vietnamese, and Japanese women using high-resolution IC-PMS.

PubMed

Tekeste, Zinaye; Amare, Bemnet; Asfaw, Fanaye; Fantahun, Bereket; van Nguyen, Nhien; Nishikawa, Takeshi; Yabutani, Tomoki; Okayasu, Takako; Ota, Fusao; Kassu, Afework

2015-10-01

Humans and other living organisms require small quantities of trace elements throughout life. Both insufficient and excessive intakes of trace elements can have negative consequences. However, there is little information on serum level of trace elements in different populations. This study examines serum levels of trace elements in Ethiopian, Japanese, and Vietnamese women. Random samples of healthy women who were referred for routine hospital laboratory examinations in the cities of Hanoi, Sapporo, and Gondar were invited to participate in the study. Serum levels of magnesium, zinc, copper, iron, selenium, and calcium were determined using an inductively coupled plasma mass spectrometer. Furthermore, body mass index of each study participant was determined. The mean ± SD serum concentrations of zinc (μg/dL), copper (μg/dL), iron (μg/dL), selenium (μg/dL) and calcium (mg/dL), respectively, were 76.51 ± 39.16, 152.20 ± 55.37, 385.68 ± 217.95, 9.15 ± 4.21, and 14.18 ± 3.91 in Ethiopian women; 111.49 ± 52.92, 105.86 ± 26.02, 155.09 ± 94.83, 14.11 ± 3.41, and 11.66 ± 2.51 in Vietnamese women; and 60.69 ± 9.76, 107 ± 156, 268 ± 128, 8.33 ± 3.65, and 11.18 ± 0.68 in Japanese participants. Ethiopian women had significantly higher level of serum calcium than Vietnamese and Japanese women (both P < 0.05). Although the mean calcium concentration in Vietnamese women was higher than in women from Japan, the difference was not statistically significant (P > 0.05). Furthermore, compared with Japanese women, Ethiopian women had significantly high iron and copper concentrations (P < 0.05). Serum selenium and zinc levels were higher in Vietnamese than Ethiopian women. The study revealed a remarkable difference in serum concentrations of trace elements in women from different countries, implying differences in trace elements in the food or soil. Copyright © 2015 Elsevier Inc. All rights reserved.

Medical Geology in the Middle East: Potential Health Risks from Mineralized Dust Exposure

NASA Astrophysics Data System (ADS)

Lyles, M. B.; Fredrickson, H. L.; Bednar, A. J.; Fannin, H. B.; Griffin, D. W.; Sobecki, T. M.

2012-04-01

In the Middle East, dust and sand storms are a persistent problem delivering significant amounts of mineralized particulates via inhalation into the mouth, nasal pharynx, and lungs. The health risks of this dust inhalation are presently being studied but accurate characterization as to the potential health effects is still lacking. Experiments were designed to study the chemical composition, mineral content, and microbial flora of Kuwaiti and Iraqi dust particles for the potential to cause adverse human health effects both acute and chronic. Multiple site samples were collected and chemical and physical characterization including particle size distribution and inorganic analysis was conducted, followed by analysis and identification of biologic flora to include bacteria, fungi and viruses. Additionally, PM10 exposure data was collected hourly over a 12 day period (>10,000 ug/m3). Data indicates that the mineralized dust is composed of calcium carbonate and magnesium sulfate coating over a precipitated matrix of metallic silicate nanocrystals of various forms containing a variety of trace and heavy metals constituting ~3 % of the particles by weight. This includes ~ 1% by weight bioaccessible aluminum and reactive iron with the remaining 1% a mixture of bioaccessible trace and heavy metals. Microbial analysis reveals a significant biodiversity of bacteria of which ~25 % are known pathogens. Of the microbes identified, several have hemolytic properties and most have significant antibiotic resistance. Viral analysis indicates a tremendous amount of virons with a large percent of RNA viruses. The level of total suspended particle mass at PM10 constitutes an excessive exposure micro-particulates including PM 2.5 (~1,0000 ug/m3). Reported data on cell culture and animal studies have indicated a high level of toxicity to these dust particles. Taken together, these data suggest that at the level of dust exposure commonly found in the Middle East (i.e., Iraq, Kuwait, and Afghanistan), in addition to the microbial and metal content, mineralized dust constitutes a significant health risk, both acute and chronic, to deployed troops and native inhabitants.

Fuzzy-trace theory: dual processes in memory, reasoning, and cognitive neuroscience.

PubMed

Brainerd, C J; Reyna, V F

2001-01-01

Fuzzy-trace theory has evolved in response to counterintuitive data on how memory development influences the development of reasoning. The two traditional perspectives on memory-reasoning relations--the necessity and constructivist hypotheses--stipulate that the accuracy of children's memory for problem information and the accuracy of their reasoning are closely intertwined, albeit for different reasons. However, contrary to necessity, correlational and experimental dissociations have been found between children's memory for problem information that is determinative in solving certain problems and their solutions of those problems. In these same tasks, age changes in memory for problem information appear to be dissociated from age changes in reasoning. Contrary to constructivism, correlational and experimental dissociations also have been found between children's performance on memory tests for actual experience and memory tests for the meaning of experience. As in memory-reasoning studies, age changes in one type of memory performance do not seem to be closely connected to age changes in the other type of performance. Subsequent experiments have led to dual-process accounts in both the memory and reasoning spheres. The account of memory development features four other principles: parallel verbatim-gist storage, dissociated verbatim-gist retrieval, memorial bases of conscious recollection, and identity/similarity processes. The account of the development of reasoning features three principles: gist extraction, fuzzy-to-verbatim continua, and fuzzy-processing preferences. The fuzzy-processing preference is a particularly important notion because it implies that gist-based intuitive reasoning often suffices to deliver "logical" solutions and that such reasoning confers multiple cognitive advantages that enhance accuracy. The explanation of memory-reasoning dissociations in cognitive development then falls out of fuzzy-trace theory's dual-process models of memory and reasoning. More explicitly, in childhood reasoning tasks, it is assumed that both verbatim and gist traces of problem information are stored. Responding accurately to memory tests for presented problem information depends primarily on verbatim memory abilities (preserving traces of that information and accessing them when the appropriate memory probes are administered). However, accurate solutions to reasoning problems depend primarily on gist-memory abilities (extracting the correct gist from problem information, focusing on that gist during reasoning, and accessing reasoning operations that process that gist). Because verbatim and gist memories exhibit considerable dissociation, both during storage and when they are subsequently accessed on memory tests, dissociations of verbatim-based memory performance from gist-based reasoning are predictable. Conversely, associations are predicted in situations in which memory and reasoning are based on the same verbatim traces (Brainerd & Reyna, 1988) and in situations in which memory and reasoning are based on the same gist traces (Reyna & Kiernan, 1994). Fuzzy-trace theory's memory and reasoning principles have been applied in other research domains. Four such domains are developmental cognitive neuroscience studies of false memory, studies of false memory in brain-damaged patients, studies of reasoning errors in judgment and decision making, and studies of retrieval mechanisms in recall. In the first domain, the principles of parallel verbatim-gist storage, dissociated verbatim-gist retrieval, and identity/similarity processes have been used to explain both spontaneous and implanted false reports in children and in the elderly. These explanations have produced some surprising predictions that have been verified: false reports do not merely decline with age during childhood but increase under theoretically specified conditions; reports of events that were not experienced can nevertheless be highly persistent over time; and false reports can be suppressed by retrieving verbatim traces of corresponding true events. In the second domain, the same principles have been invoked to explain why some forms of brain damage lead to elevated levels of false memory and other forms lead to reduced levels of false memory. In the third domain, the principles of gist extraction, fuzzy-to-verbatim continua, and fuzzy-processing preferences have been exploited to formulate a general theory of loci of processing failures in judgment and decision making, cluminating in a developmental account of degrees of rationality that distinguishes more and less advanced reasoning. This theory has in turn been used to formulate local models, such as the inclusion illusions model, that explain the characteristic reasoning errors that are observed on specific judgment and decision-making tasks. Finally, in the fourth domain, a dual-process conception of recall has been derived from the principles of parallel verbatim-gist storage and dissociated verbatim-gist retrieval. In this conception, which has been used to explain cognitive triage effects in recall and robust false recall, targets are recalled either by directly accessing their verbatim traces and reading the retrieved information out of consciousness or by reconstructively processing their gist traces.

Trace Elements in River Waters

NASA Astrophysics Data System (ADS)

Gaillardet, J.; Viers, J.; Dupré, B.

2003-12-01

Trace elements are characterized by concentrations lower than 1 mg L-1 in natural waters. This means that trace elements are not considered when "total dissolved solids" are calculated in rivers, lakes, or groundwaters, because their combined mass is not significant compared to the sum of Na+, K+, Ca2+, Mg2+, H4SiO4, HCO3-, CO32-, SO42-, Cl-, and NO3-. Therefore, most of the elements, except about ten of them, occur at trace levels in natural waters. Being trace elements in natural waters does not necessarily qualify them as trace elements in rocks. For example, aluminum, iron, and titanium are major elements in rocks, but they occur as trace elements in waters, due to their low mobility at the Earth's surface. Conversely, trace elements in rocks such as chlorine and carbon are major elements in waters.The geochemistry of trace elements in river waters, like that of groundwater and seawater, is receiving increasing attention. This growing interest is clearly triggered by the technical advances made in the determination of concentrations at lower levels in water. In particular, the development of inductively coupled plasma mass spectrometry (ICP-MS) has considerably improved our knowledge of trace-element levels in waters since the early 1990s. ICP-MS provides the capability of determining trace elements having isotopes of interest for geochemical dating or tracing, even where their dissolved concentrations are extremely low.The determination of trace elements in natural waters is motivated by a number of issues. Although rare, trace elements in natural systems can play a major role in hydrosystems. This is particularly evident for toxic elements such as aluminum, whose concentrations are related to the abundance of fish in rivers. Many trace elements have been exploited from natural accumulation sites and used over thousands of years by human activities. Trace elements are therefore highly sensitive indexes of human impact from local to global scale. Pollution impact studies require knowledge of the natural background concentrations and knowledge of pollutant behavior. For example, it is generally accepted that rare earth elements (REEs) in waters behave as good analogues for the actinides, whose natural levels are quite low and rarely measured. Water quality investigations have clearly been a stimulus for measurement of toxic heavy metals in order to understand their behavior in natural systems.From a more fundamental point of view, it is crucial to understand the behavior of trace elements in geological processes, in particular during chemical weathering and transport by waters. Trace elements are much more fractionated by weathering and transport processes than major elements, and these fractionations give clues for understanding the nature and intensity of the weathering+transport processes. This has not only applications for weathering studies or for the past mobilization and transport of elements to the ocean (potentially recorded in the sediments), but also for the possibility of better utilization of trace elements in the aqueous environment as an exploration tool.In this chapter, we have tried to review the recent literature on trace elements in rivers, in particular by incorporating the results derived from recent ICP-MS measurements. We have favored a "field approach" by focusing on studies of natural hydrosystems. The basic questions which we want to address are the following: What are the trace element levels in river waters? What controls their abundance in rivers and fractionation in the weathering+transport system? Are trace elements, like major elements in rivers, essentially controlled by source-rock abundances? What do we know about the chemical speciation of trace elements in water? To what extent do colloids and interaction with solids regulate processes of trace elements in river waters? Can we relate the geochemistry of trace elements in aquatic systems to the periodic table? And finally, are we able to satisfactorily model and predict the behavior of most of the trace elements in hydrosystems?An impressive literature has dealt with experimental works on aqueous complexation, uptake of trace elements by surface complexation (inorganic and organic), uptake by living organisms (bioaccumulation) that we have not reported here, except when the results of such studies directly explain natural data. As continental waters encompass a greater range of physical and chemical conditions, we focus on river waters and do not discuss trace elements in groundwaters, lakes, and the ocean. In lakes and in the ocean, the great importance of life processes in regulating trace elements is probably the major difference from rivers.Section 5.09.2 of this chapter reports data. We will review the present-day literature on trace elements in rivers to show that our knowledge is still poor. By comparing with the continental abundances, a global mobility index is calculated for each trace element. The spatial and temporal variability of trace-element concentrations in rivers will be shown to be important. In Section 5.09.3, sources of trace elements in river waters are indicated. We will point out the great diversity of sources and the importance of global anthropogenic contamination for a number of elements. The question of inorganic and organic speciation of trace elements in river water will then be addressed in Section 5.09.4, considering some general relationships between speciation and placement in the periodic table. In Section 5.09.5, we will show that studies on organic-rich rivers have led to an exploration of the "colloidal world" in rivers. Colloids are small particles, passing through the conventional filters used to separate dissolved and suspended loads in rivers. They appear as major carriers of trace elements in rivers and considerably complicate aqueous-speciation calculation. Finally, in Section 5.09.6, the significance of interactions between solutes and solid surfaces in river waters will be reviewed. Regulation by surfaces is of major importance for a great range of elements. Although for both colloids and surface interactions, some progress has been made, we are still far from a unified model that can accurately predict trace-element concentrations in natural water systems. This is mainly due to our poor physical description of natural colloids, surface site complexation, and their interaction with solutes.

On the use of colour reflectivity plots to monitor the structure of the troposphere and stratosphere

NASA Technical Reports Server (NTRS)

Rottger, J.; Fu, I. J.; Kuo, F. S.; Liu, C. H.; Chao, J. K.

1986-01-01

The radar reflectivity, defined as the range squared corrected power of VHF radar echoes, can be used to monitor and study the temporal development of inversion layer, frontal boundaries and convective turbulence. From typical featurs of upward or downward motion of reflectivity structures, the advection/convection of cold and warm air can be predicted. High resolution color plots appear to be useful to trace and to study the life history of these structures, particularly their persistency, descent and ascent. These displays allow an immediate determination of the tropopause height as well as the determination of the tropopause structure. The life history of warm fronts, cold fronts, and occlusions can be traced, and these reflectivity plots allow detection of even very weak events which cannot be seen in the traditional meteorological data sets. The life history of convective turbulence, particular evolving from the planetary boundary layer, can be tracked quite easily. Its development into strong convection reaching the middle troposphere can be followed and predicted.

Water quality of the Little Arkansas River and Equus Beds Aquifer before and concurrent with large-scale artificial recharge, south-central Kansas, 1995-2012

USGS Publications Warehouse

Tappa, Daniel J.; Lanning-Rush, Jennifer L.; Klager, Brian J.; Hansen, Cristi V.; Ziegler, Andrew C.

2015-01-01

Recharge activities at Phase I recharge wells have not resulted in substantial effects on groundwater quality in the area, likely because the total amount of water recharged is relatively small (1 billion gallons) compared to aquifer storage volume (greater than 990 billion gallons in winter 2012). The eastward movement of the Burrton chloride plume is likely being slowed by a line of recharge locations associated with Phase I; however, chloride concentrations in deep groundwater still advanced to less than one half mile from the central part of the study area. Water-quality constituents of concern (major ions, nutrients, trace elements, triazine herbicides, and fecal indicator bacteria) have not increased substantially and are likely more affected by climatological (natural recharge by precipitation) and natural (geochemical oxidation/reduction, metabolic and decay rates) processes than artificial recharge. Arsenic remains a water-quality constituent of concern because of natural and continued persistence of concentrations exceeding the Federal maximum contaminant level of 10 micrograms per liter, especially in the deeper parts of theEquus Beds aquifer.

Environmental cue saliency influences the vividness of a remote spatial memory in rats.

PubMed

Lopez, Joëlle; de Vasconcelos, Anne Pereira; Cassel, Jean-Christophe

2008-07-01

The Morris water maze is frequently used to evaluate the acquisition and retrieval of spatial memories. Few experiments, however, have investigated the effects of environmental cue saliency on the strength or persistence of such memories after a short vs. long post-acquisition interval. Using a Morris water maze, we therefore tested in rats the effect of the saliency of distal cues on the vividness of a recent (5 days) vs. remote (25 days) memory. Rats trained in a cue-enriched vs. a cue-impoverished context showed a better overall level of performance during acquisition. Furthermore, the probe trials revealed that the rats trained and tested in the cue-impoverished context (1) spent less time in the target quadrant at the 25-day delay, and (2) swam shorter distances in the target area, with fewer crossings at both 5- and 25-day delays, as compared to their counterparts trained and tested in the cue-enriched context. Thus, the memory trace formed in the cue-enriched context shows better resistance to time, suggesting an implication of cue saliency in the vividness of a spatial memory.

Brine Spills Associated with Unconventional Oil Development in North Dakota.

PubMed

Lauer, Nancy E; Harkness, Jennifer S; Vengosh, Avner

2016-05-17

The rapid rise of unconventional oil production during the past decade in the Bakken region of North Dakota raises concerns related to water contamination associated with the accidental release of oil and gas wastewater to the environment. Here, we characterize the major and trace element chemistry and isotopic ratios ((87)Sr/(86)Sr, δ(18)O, δ(2)H) of surface waters (n = 29) in areas impacted by oil and gas wastewater spills in the Bakken region of North Dakota. We establish geochemical and isotopic tracers that can identify Bakken brine spills in the environment. In addition to elevated concentrations of dissolved salts (Na, Cl, Br), spill waters also consisted of elevated concentrations of other contaminants (Se, V, Pb, NH4) compared to background waters, and soil and sediment in spill sites had elevated total radium activities ((228)Ra + (226)Ra) relative to background, indicating accumulation of Ra in impacted soil and sediment. We observed that inorganic contamination associated with brine spills in North Dakota is remarkably persistent, with elevated levels of contaminants observed in spills sites up to 4 years following the spill events.

The Phosphoria Formation at the Hot Springs Mine in Southeast Idaho; a source of selenium and other trace elements to surface water, ground water, vegetation, and biota

USGS Publications Warehouse

Piper, David Z.; Skorupa, J.P.; Presser, T.S.; Hardy, M.A.; Hamilton, S.J.; Huebner, M.; Gulbrandsen, R.A.

2000-01-01

Major-element oxides and trace elements in the Phosphoria Formation at the Hot Springs Mine, Idaho were determined by a series of techniques. In this report, we examine the distribution of trace elements between the different solid components aluminosilicates, apatite, organic matter, opal, calcite, and dolomite that largely make up the rocks. High concentrations of several trace elements throughout the deposit, for example, As, Cd, Se, Tl, and U, at this and previously examined sites have raised concern about their introduction into the environment via weathering and the degree to which mining and the disposal of mined waste rock from this deposit might be accelerating that process. The question addressed here is how might the partitioning of trace elements between these solid host components influence the introduction of trace elements into ground water, surface water, and eventually biota, via weathering? In the case of Se, it is partitioned into components that are quite labile under the oxidizing conditions of subaerial weathering. As a result, it is widely distributed throughout the environment. Its concentration exceeds the level of concern for protection of wildlife at virtually every trophic level.

Vaccines and companion diagnostic tests for foot-and-mouth disease virus. An overview of the experience in South America.

PubMed

Bergmann, I E; Malirat, V; Neitzert, E; Correa Melo, E

2003-01-01

Vaccination constitutes an important control policy for foot-and-mouth disease (FMD) in affected areas with advanced eradication programmes, as well as in free regions that decide to use immunization as a control measure after a recent introduction of the disease. However, considering that vaccinated animals exposed to FMD virus can establish sub-clinical infection and eventually remain persistently infected, availability of tools to identify sub-clinical infection and its silent transmission within and between herds, regardless of their vaccination state, is of utmost importance. In response to the need for new diagnostic tools to support the eradication campaigns implemented in 1988 in South America, during the past decade we have developed, validated and applied a highly sensitive and specific immuno-enzymatic system for recognition of persistence at a herd level. The system is based on the detection of antibodies against non-capsid proteins required for viral replication. These proteins, in principle, are removed from the viral suspensions destined for production of BEI inactivated vaccines. Within the validation steps, evaluation of potential induction of antibodies to non-capsid proteins caused by traces of these proteins eventually remaining in the vaccines was a major concern. This report presents a review on the experience gathered through the application of the system to various experimental and field immunization conditions. It was concluded that vaccination is not expected to induce antibody responses to non-capsid proteins that could lead to misinterpretation of serological investigations. Progress on the development of approaches towards vaccine certification to guarantee absence of interference will be discussed.

Treatment of 2,4-D, mecoprop, and dicamba using membrane bioreactor technology.

PubMed

Ghoshdastidar, Avik J; Tong, Anthony Z

2013-08-01

Phenoxyacetic and benzoic acid herbicides are widely used agricultural, commercial, and domestic pesticides. As a result of high water solubility, mobility, and persistence, 2,4-dichlorophenoxyacetic acid (2,4-D), methylchlorophenoxypropionic acid (mecoprop), and 3,6-dichloro-2-methoxybenzoic acid (dicamba) have been detected in surface and waste waters across Canada. As current municipal wastewater treatment plants do not specifically address chronic, trace levels of contaminants like pesticides, an urgent need exists for an efficient, environmentally friendly means of breaking down these toxic herbicides. A commercially available herbicide mix, WeedEx, containing 2,4-D, mecoprop, and dicamba, was subjected to treatment using membrane bioreactor (MBR) technology. The three herbicides, in simulated wastewater with a chemical oxygen demand of 745 mg/L, were introduced to the MBR at concentrations ranging from 300 μg/L to 3.5 mg/L. Herbicides and biodegradation products were extracted from MBR effluent using solid-phase extraction followed by detection using high-performance liquid chromatography coupled with mass spectrometry. 2,4-D was reduced by more than 99.0 % within 12 days. Mecoprop and dicamba were more persistent and reduced by 69.0 and 75.4 %, respectively, after 112 days of treatment. Half-lives of 2,4-D, mecoprop and dicamba during the treatment were determined to be 1.9, 10.5, and 28.3 days, respectively. Important water quality parameters of the effluent such as dissolved oxygen, pH, ammonia, chemical oxygen demand, etc. were measured daily. MBR was demonstrated to be an environmentally friendly, compact, and efficient method for the treatment of toxic phenoxyacetic and benzoic acid herbicides.

Massive Organic Matter Fall Processing and Organic Enrichment in Deep Sea Sediments: the Role of Fall Type

NASA Astrophysics Data System (ADS)

Hannides, A. K.; Smith, C. R.; Baco-Taylor, A. R.

2005-12-01

Resource-limited deep-sea sedimentary settings are occasionally punctuated with massive organic matter (MOM) falls, such as fish and marine mammal carcasses, macrophytes and wood. In the case of whale falls, previous studies have shown that sharp gradients in microbial activity exist within a few meters of these falls. These sites are characterized by intense sulfate reduction and sulfide generation, which are commonly attributed to sedimentary organic enrichment from MOM, and in part support extensive chemosynthetic communities that rely on endosymbiotic oxidation of this sulfide for energy. Enrichment is brought about by the fragmentation and dissemination activities of deep-sea megafauna: scavengers in the case of carcasses and macrophytes, and wood borers in the case of wood.Differences in MOM fall composition and structure and the subsequent megafaunal processing raise questions concerning the patterns of organic enrichment around these falls and how these patterns vary with fall type. We present an extensive data set of surface sediment organic carbon and nitrogen content at whale, kelp and wood falls of various ages in the California Borderland Basins region. Evidence for organic enrichment around whale falls is lacking, corroborating previous findings. However, distinctly low C:N ratios in surface sediments adjacent to whale falls suggest more complex processing of MOM in this zone. This pattern persists regardless of whale fall age. On the contrary, evidence for organic enrichment around kelp and wood falls abounds. Organic carbon and nitrogen content values adjacent to 3 month-old kelp falls are 25-50 % higher than those 1 m away from the falls and traces of this signal persist for at least 3 more months. In the case of wood falls, 6 month-old falls do not show any significant traces of enrichment, but 3 years after the fall event organic carbon content adjacent to the falls increases by 2-5 times that of background. C:N ratios concomitantly increase to startling levels of 80-100. Comparison of falls of different ages but similar masses reveals that kelp falls result in rapid (<3 months) enrichment peaks, while wood falls only generate significant signals on the order of years. Comparison of organic enrichment patterns with pore water sulfide distributions suggests a role of MOM type or quality in stimulating increases in sedimentary organic matter decomposition rates.

The geographic distribution of trace elements in the environment: the REGARDS study.

PubMed

Rembert, Nicole; He, Ka; Judd, Suzanne E; McClure, Leslie A

2017-02-01

Research on trace elements and the effects of their ingestion on human health is often seen in scientific literature. However, little research has been done on the distribution of trace elements in the environment and their impact on health. This paper examines what characteristics among participants in the Reasons for Geographic and Racial Differences in Stroke (REGARDS) study are associated with levels of environmental exposure to arsenic, magnesium, mercury, and selenium. Demographic information from REGARDS participants was combined with trace element concentration data from the US Geochemical Survey (USGS). Each trace element was characterized as either low (magnesium and selenium) or high (arsenic and mercury) exposure. Associations between demographic characteristics and trace element concentrations were analyzed with unadjusted and adjusted logistic regression models. Individuals who reside in the Stroke Belt have lower odds of high exposure (4th quartile) to arsenic (OR 0.33, CI 0.31, 0.35) and increased exposure to mercury (OR 0.65, CI 0.62, 0.70) than those living outside of these areas, while the odds of low exposure to trace element concentrations were increased for magnesium (OR 5.48, CI 5.05, 5.95) and selenium (OR 2.37, CI 2.22, 2.54). We found an association between levels of trace elements in the environment and geographic region of residence, among other factors. Future studies are needed to further examine this association and determine whether or not these differences may be related to geographic variation in disease.

Harm avoidance and persistence are associated with somatoform disorder psychopathology: A study in Taiwan.

PubMed

Huang, Wei-Lieh; Chen, Tzu-Ting; Chen, I-Ming; Chang, Li-Ren; Lin, Yu-Hsuan; Liao, Shih-Cheng; Gau, Susan Shur-Fen

2016-05-15

Whether personality features affect the development of somatoform disorders and their psychopathologies is an important issue. Aim of this study was to resolve this issue by comparing indicators of psychopathology and personality features in subjects with somatoform disorders and healthy controls. This study recruited 148 subjects with somatoform disorders and 146 healthy controls. The severity of psychopathology was measured with the Patient Health Questionnaire-15 (PHQ-15), Health Anxiety Questionnaire (HAQ), Beck Depression Inventory-II (BDI-II), and Beck Anxiety Inventory (BAI). The Tridimensional Personality Questionnaire (TPQ) was used to assess personality features. Demographic data, psychopathology indicators, and TPQ scores were compared between groups. Correlation and multivariate linear regression analysis were used to identify the personality dimensions or demographic variables associated with psychopathology. The somatoform group had lower novelty seeking (NS) and reward dependence (RD) and higher harm avoidance (HA) and severity of psychopathologies. Multiple regression analysis revealed that fatigability, persistence, gender, and education level were predictive of PHQ-15; HA, educational level, persistence, and dependence were predictive of HAQ; HA, persistence, education level, and NS were predictive of BDII-II; and fatigability, education level, persistence, and anticipatory worry were predictive of BAI. The development of somatoform disorders was associated with fatigability, age, residence location, education level, and attachment. The limitations include heterogeneity of the diagnosis, the high proportion of undifferentiated somatoform disorder, and the cross-sectional study design. HA/fatigability, persistence, and education level are associated with each type of psychopathology. Fatigability is a powerful predictor of somatoform disorder development. Copyright © 2016. Published by Elsevier B.V.

Trace elements and antioxidant enzymes in Behçet's disease.

PubMed

Saglam, K; Serce, A F; Yilmaz, M I; Bulucu, F; Aydin, A; Akay, C; Sayal, A

2002-07-01

Free oxygen radicals and insufficiency of antioxidant enzymes have been implicated in the pathogenesis of Behçet's disease (BD). Trace elements function as cofactors to antioxidant enzymes. The antioxidant system and trace elements were investigated in many different studies, including BD, but these subjects have not been investigated as a whole in these patients. The aim of the present study was to investigate the antioxidative system and trace elements in BD to contribute to the knowledge of pathogenesis and treatment of this disease. We examined glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) activities together with selenium (Se), copper (Cu), zinc (Zn), manganese (Mn), and iron (Fe) levels in plasma and erythrocytes of 50 patients with BD and 30 healthy controls. It was found that in patients with BD, erythrocyte GSH-Px and SOD activities and erythrocyte Se, plasma Fe, Mn, and Zn levels were significantly lower than those of controls and that plasma Cu, erythrocyte Zn, and Mn levels were significantly higher in patients with BD. Insufficient antioxidant enzyme activities were observed in patients with BD. The mechanism(s) of this phenomenon is not clear. Therefore, supplementation with trace elements involved in the antioxidative processes may increase scavenger enzyme activities, and consequently, an improvement in clinical symptoms may be expected.

Effects of preoperative oral carbohydrates and trace elements on perioperative nutritional status in elective surgery patients.

PubMed

Oyama, Yoshimasa; Iwasaka, Hideo; Shiihara, Keisuke; Hagiwara, Satoshi; Kubo, Nobuhiro; Fujitomi, Yutaka; Noguchi, Takayuki

2011-10-01

In order to enhance postoperative recovery, preoperative consumption of carbohydrate (CHO) drinks has been used to suppress metabolic fluctuations. Trace elements such as zinc and copper are known to play an important role in postoperative recovery. Here, we examined the effects of preoperatively consuming a CHO drink containing zinc and copper. Subjects were 122 elective surgery patients divided into two groups (overnight fasting and CHO groups); each group was further divided into morning or afternoon surgery groups. Subjects in the CHO group consumed 300 mL of a CHO drink the night before surgery, followed by 200 ml before morning surgery or 700 ml before afternoon surgery (> or =2 hours before anesthesia induction). Blood levels of glucose, nonesterified fatty acids (NEFA), retinol-binding protein, zinc, and copper were determined. One subject in the CHO group was excluded after refusing the drink. There were no adverse effects from the CHO drink. NEFA levels increased in the fasting groups. Although zinc levels increased in the CHO group immediately after anesthesia induction, no group differences were observed the day after surgery. Preoperative consumption of a CHO drink containing trace elements suppressed preoperative metabolic fluctuations without complications and prevented trace element deficiency. Further beneficial effects during the perioperative period can be expected by adding trace elements to CHO supplements.

Improved electron probe microanalysis of trace elements in quartz

USGS Publications Warehouse

Donovan, John J.; Lowers, Heather; Rusk, Brian G.

2011-01-01

Quartz occurs in a wide range of geologic environments throughout the Earth's crust. The concentration and distribution of trace elements in quartz provide information such as temperature and other physical conditions of formation. Trace element analyses with modern electron-probe microanalysis (EPMA) instruments can achieve 99% confidence detection of ~100 ppm with fairly minimal effort for many elements in samples of low to moderate average atomic number such as many common oxides and silicates. However, trace element measurements below 100 ppm in many materials are limited, not only by the precision of the background measurement, but also by the accuracy with which background levels are determined. A new "blank" correction algorithm has been developed and tested on both Cameca and JEOL instruments, which applies a quantitative correction to the emitted X-ray intensities during the iteration of the sample matrix correction based on a zero level (or known trace) abundance calibration standard. This iterated blank correction, when combined with improved background fit models, and an "aggregate" intensity calculation utilizing multiple spectrometer intensities in software for greater geometric efficiency, yields a detection limit of 2 to 3 ppm for Ti and 6 to 7 ppm for Al in quartz at 99% t-test confidence with similar levels for absolute accuracy.

Work factors as predictors of persistent fatigue: a prospective study of nurses' aides.

PubMed

Eriksen, W

2006-06-01

To identify work factors that predict persistent fatigue in nurses' aides. The sample comprised 5547 Norwegian nurses' aides, not on leave when they completed a mailed questionnaire in 1999. Of these, 4645 (83.7%) completed a second questionnaire 15 months later. The outcome measure was the occurrence of persistent fatigue, defined as having felt "usually fatigued" or "always fatigued" in daytime during the previous 14 days. In respondents without persistent fatigue at baseline, medium and high work demands, heavy smoking, being single, and having long term health problems were associated with increased risk of persistent fatigue at follow up. Medium and high rewards for well done work, medium levels of leadership fairness, and regular physical exercise were associated with reduced risk of persistent fatigue at follow up. In respondents with persistent fatigue at baseline, medium and high levels of positive challenges at work, high support from immediate superior, medium feedback about quality of one's work, and changes of work or work tasks that resulted in less heavy work or lower work pace were associated with increased odds of recovery (no persistent fatigue at follow up). Working in a nursing home and being intensely bothered by long term health problems were associated with reduced odds of recovery. High demands and lack of rewards at work may cause persistent fatigue in nurses' aides. Reduction of demands, adequate feedback, and mental stimulation in the form of support and positive challenges may facilitate recovery in those who have persistent fatigue. Leaders in the health services may be in a position to regulate factors that influence the level of fatigue in nurses' aides.

Delayed Noradrenergic Activation in the Dorsal Hippocampus Promotes the Long-Term Persistence of Extinguished Fear

PubMed Central

Chai, Ning; Liu, Jian-Feng; Xue, Yan-Xue; Yang, Chang; Yan, Wei; Wang, Hui-Min; Luo, Yi-Xiao; Shi, Hai-Shui; Wang, Ji-Shi; Bao, Yan-Ping; Meng, Shi-Qiu; Ding, Zeng-Bo; Wang, Xue-Yi; Lu, Lin

2014-01-01

Fear extinction has been extensively studied, but little is known about the molecular processes that underlie the persistence of extinction long-term memory (LTM). We found that microinfusion of norepinephrine (NE) into the CA1 area of the dorsal hippocampus during the early phase (0 h) after extinction enhanced extinction LTM at 2 and 14 days after extinction. Intra-CA1 infusion of NE during the late phase (12 h) after extinction selectively promoted extinction LTM at 14 days after extinction that was blocked by the β-receptor antagonist propranolol, protein kinase A (PKA) inhibitor Rp-cAMPS, and protein synthesis inhibitors anisomycin and emetine. The phosphorylation levels of PKA, cyclic adenosine monophosphate response element-binding protein (CREB), GluR1, and the membrane GluR1 level were increased by NE during the late phase after extinction that was also blocked by propranolol and Rp-cAMPS. These results suggest that the enhancement of extinction LTM persistence induced by NE requires the activation of the β-receptor/PKA/CREB signaling pathway and membrane GluR1 trafficking. Moreover, extinction increased the phosphorylation levels of Erk1/2, CREB, and GluR1, and the membrane GluR1 level during the late phase, and anisomycin/emetine alone disrupted the persistence of extinction LTM, indicating that the persistence of extinction LTM requires late-phase protein synthesis in the CA1. Propranolol and Rp-cAMPS did not completely disrupt the persistence of extinction LTM, suggesting that another β-receptor/PKA-independent mechanism underlies the persistence of extinction LTM. Altogether, our results showed that enhancing hippocampal noradrenergic activity during the late phase after extinction selectively promotes the persistence of extinction LTM. PMID:24553734

Formation of Particulate Matter during Wintertime Inversions in the Salt Lake Valley.

NASA Astrophysics Data System (ADS)

Hrdina, A. I. H.; Baasandorj, M.; Lin, J. C.; Murphy, J. G.; McKeen, S. A.

2017-12-01

In the wintertime, the air quality in Salt Lake City is frequently impacted by inversions that cause high levels of particulate matter. An inversion describes a highly stable air mass, where a cold air pool (CAP) is trapped by warmer air aloft. In the right conditions, these CAPs can persist for several days allowing the accumulation of various pollutants, such as NOx and NH3, leading to secondary particle formation. Concentrations of reactive trace gases (HCl, HNO3, HONO, NH3, SO2) and particle phase constituents (Cl-, NO2-, NO3-, SO42-, Na+, NH4+, K+, Mg2+, Ca2+) from particles less than 2.5 microns in diameter (PM2.5) were continuously measured using an online ambient ion monitor ion chromatograph (AIM-IC) within the Salt Lake Valley, Utah, from Jan 17 - Feb 21 2017, as part of the Utah Fine Particulate Study (UWFPS 2017). A consistent diurnal pattern of ammonia mixing ratios was observed, with mixing ratios ranging from 0.1 - 7 ppb. Two persistent cold air pool events occurred during the measurement period during which the suppression of vertical mixing led to the buildup of PM2.5 in the valley. The total PM2.5 level in the valley was as high as 60 μg m-3 and was dominated by ammonium nitrate. The air pollution transport within the valley during the entire campaign period was examined using Stochastic Time-Inverted Lagrangian Transport (STILT) model. Calculated flux footprints, based on back-trajectories with 15 minute time steps at a grid resolution of 0.1 degree, highlight the potential source regions for PM2.5 precursors during the observed PCAP events. Observations were also compared to output from the Weather Research and Forecasting model coupled with chemistry (WRF-Chem) simulations of the UWFPS campaign.

Identifying Metals as Marker for Waste Burning Aerosol Particles in New Delhi

NASA Astrophysics Data System (ADS)

Kumar, Sudhanshu

2012-07-01

{Identifying Metals as Marker for Waste Burning Aerosol Particles in New Delhi } Tracing of aerosol sources is an important task helpful for making control strategy, and for climate change study. However, it is a difficult job as aerosols have several sources, involve in complex atmospheric processing, degradation and removal processes. Several approaches have been used for this task, e.g., models, which are based on the input of chemical species; stable- and radio-isotope compositions of certain species; chemical markers in which trace metals are the better options because they persist in atmosphere until the life of a particle. For example, K and Hg are used for biomass and coal burning tracings, respectively. Open waste burning has recently been believed to be a considerable source of aerosols in several mega cities in India and China. To better understand this source contribution in New Delhi aerosols, we have conducted aerosol sampling at a landfill site (Okhla), and in proximity (within 1 km distance) of this site. Aerosol filter samples were acid digested in microwave digestion system and analyzed using inductively coupled plasma -- high resolution mass spectrometry (ICP-HRMS) for getting metal signatures in particles. The metals, e.g., Sn, Sb and As those are found almost negligible in remote aerosols, are maximized in these waste burning aerosols. Sample collected in other location of New Delhi also shows the considerable presence of these metals in particles. Preliminary studies of isotopic ratios of these metals suggested that these metals, especially Sn can be used as marker for tracing the open waste burning sources of aerosols in New Delhi.

Practical applications of trace minerals for dairy cattle.

PubMed

Overton, T R; Yasui, T

2014-02-01

Trace minerals have critical roles in the key interrelated systems of immune function, oxidative metabolism, and energy metabolism in ruminants. To date, the primary trace elements of interest in diets for dairy cattle have included Zn, Cu, Mn, and Se although data also support potentially important roles of Cr, Co, and Fe in diets. Trace minerals such as Zn, Cu, Mn, and Se are essential with classically defined roles as components of key antioxidant enzymes and proteins. Available evidence indicates that these trace minerals can modulate aspects of oxidative metabolism and immune function in dairy cattle, particularly during the transition period and early lactation. Chromium has been shown to influence both immune function and energy metabolism of cattle; dairy cows fed Cr during the transition period and early lactation have evidence of improved immune function, increased milk production, and decreased cytological endometritis. Factors that complicate trace mineral nutrition at the farm level include the existence of a large number of antagonisms affecting bioavailability of individual trace minerals and uncertainty in terms of requirements under all physiological and management conditions; therefore, determining the optimum level and source of trace minerals under each specific situation continues to be a challenge. Typical factorial approaches to determine requirements for dairy cattle do not account for nuances in biological function observed with supplementation with various forms and amounts of trace minerals. Trace mineral nutrition modulates production, health, and reproduction in cattle although both formal meta-analysis and informal survey of the literature reveal substantial heterogeneity of response in these outcome variables. The industry has largely moved away from oxide-based programs toward sulfate-based programs; however, some evidence favors shifting supplementation strategies further toward more bioavailable forms of inorganic and organic trace minerals. Furthermore, opportunities for specific modulation of aspects of health, milk production, and reproduction through supplementation strategies for diets of transition dairy cows are attractive because of the known dynamics of energy metabolism, immune function, and oxidative metabolism during this timeframe.

Enrichment and Bioavailability of Trace Elements in Soil in Vicinity of Railways in Japan.

PubMed

Wang, Zhen; Watanabe, Izumi; Ozaki, Hirozaku; Zhang, Jianqiang

2018-01-01

This study focuses on the concentrations, distribution, pollution levels, and bioavailability of 12 trace elements in soils along 6 different railways in Japan. Three diesel powered railways and three electricity powered railways were chosen as target. Surface soils (< 3 cm) were collected in vicinity of railways for analysis. Digestion and extraction were performed before concentration and bioavailability analysis. Enrichment factor was applied to investigate contamination levels of selected elements. The mean concentrations of Cr, Co, Ni, Cu, Zn, Sn, and Pb in soil samples were higher than soil background value in Japan. Concentrations of trace elements in soils along different railway had different characteristics. Horizontal distribution of Cu, Zn, Cd, Sn, and Pb in soil samples showed obviously downtrend with distance along railways with high frequency. Concentrations of V, Mn, Fe, and Co were higher in soils along railways which pass through city center. According to principal component analysis and cluster analysis, concentrations of Cu, Zn, Sn, and Pb could be considered as the indicators of soil contamination level along electricity powered trains, whereas indicators along diesel powered trains were not clear. Enrichment factor analysis proved that operation of freight trains had impact on pollution level of Cr, Ni, and Cd. Bioavailability of Mn, Co, Zn, and Cd in soil along electricity-powered railways were higher, and bioavailability of Pb in railways located in countryside was lower. Thus, enrichment and bioavailability of trace elements can be indicators of railway-originated trace elements pollution in soil.

CO 2 leakage impacts on shallow groundwater. Field-scale reactive-transport simulations informed by observations at a natural analog site

DOE PAGES

Keating, Elizabeth H.; Hakala, J. Alexandra; Viswanathan, Hari; ...

2013-03-01

It is challenging to predict the degree to which shallow groundwater might be affected by leaks from a CO 2 sequestration reservoir, particularly over long time scales and large spatial scales. In this study observations at a CO 2 enriched shallow aquifer natural analog were used to develop a predictive model which is then used to simulate leakage scenarios. This natural analog provides the opportunity to make direct field observations of groundwater chemistry in the presence of elevated CO 2, to collect aquifer samples and expose them to CO 2 under controlled conditions in the laboratory, and to test themore » ability of multiphase reactive transport models to reproduce measured geochemical trends at the field-scale. The field observations suggest that brackish water entrained with the upwelling CO 2 are a more significant source of trace metals than in situ mobilization of metals due to exposure to CO 2. The study focuses on a single trace metal of concern at this site: U. Experimental results indicate that cation exchange/adsorption and dissolution/precipitation of calcite containing trace amounts of U are important reactions controlling U in groundwater at this site, and that the amount of U associated with calcite is fairly well constrained. Simulations incorporating these results into a 3-D multi-phase reactive transport model are able to reproduce the measured ranges and trends between pH, pCO 2, Ca, total C, U and Cl -at the field site. Although the true fluxes at the natural analog site are unknown, the cumulative CO 2 flux inferred from these simulations are approximately equivalent to 37.8E-3 MT, approximately corresponding to a .001% leak rate for injection at a large (750 MW) power plant. The leakage scenario simulations suggest that if the leak only persists for a short time the volume of aquifer contaminated by CO 2-induced mobilization of U will be relatively small, yet persistent over 100 a.« less

Trace elements in Mediterranean seagrasses and macroalgae. A review.

PubMed

Bonanno, Giuseppe; Orlando-Bonaca, Martina

2018-03-15

This review investigates the current state of knowledge on the levels of the main essential and non-essential trace elements in Mediterranean vascular plants and macroalgae. The research focuses also on the so far known effects of high element concentrations on these marine organisms. The possible use of plants and algae as bioindicators of marine pollution is discussed as well. The presence of trace elements is overall well known in all five Mediterranean vascular plants, whereas current studies investigated element concentrations in only c. 5.0% of all native Mediterranean macroalgae. Although seagrasses and macroalgae can generally accumulate and tolerate high concentrations of trace elements, phytotoxic levels are still not clearly identified for both groups of organisms. Moreover, although the high accumulation of trace elements in seagrasses and macroalgae is considered as a significant risk for the associated food webs, the real magnitude of this risk has not been adequately investigated yet. The current research provides enough scientific evidence that seagrasses and macroalgae may act as effective bioindicators, especially the former for trace elements in sediments, and the latter in seawater. The combined use of seagrasses and macroalgae as bioindicators still lacks validated protocols, whose application should be strongly encouraged to biomonitor exhaustively the presence of trace elements in the abiotic and biotic components of coastal ecosystems. Copyright © 2017 Elsevier B.V. All rights reserved.

Determination of Pb in Biological Samples by Graphite Furnace Atomic Absorption Spectrophotometry: An Exercise in Common Interferences and Fundamental Practices in Trace Element Determination

ERIC Educational Resources Information Center

Spudich, Thomas M.; Herrmann, Jennifer K.; Fietkau, Ronald; Edwards, Grant A.

2004-01-01

An experiment is conducted to ascertain trace-level Pb in samples of bovine liver or muscle by applying graphite furnace atomic absorption spectrophotometry (GFAAS). The primary objective is to display the effects of physical and spectral intrusions in determining trace elements, and project the usual methods employed to minimize accuracy errors…

Effect of water level drawdown on decomposition in boreal peatlands

NASA Astrophysics Data System (ADS)

Straková, Petra; Penttilä, Timo; Laiho, Raija

2010-05-01

Plant litter production and decomposition are key processes in element cycling in most ecosystems. In peatlands, there has been a long-term imbalance between litter production and decay caused by high water levels (WL) and consequent anoxia. This has resulted in peatlands being a significant sink of carbon (C) from the atmosphere. However, peatlands are experiencing both "natural" (global climate change) and anthropogenic (ditching) changes that threaten their ability to retain this ecosystem identity and function. Many of these alterations can be traced back to WL drawdown, which can cause increased aeration, higher acidity, falling temperatures, and a greater probability of drought. Such changes are also associated with an increasing decomposition rate, and therefore a greater amount of C released back to the atmosphere. Yet studies about how the overall C balance of peatlands will be affected have come up with conflicting conclusions, demonstrating that the C store could increase, decrease, or remain static. A factor that has been largely overlooked is the change in litter type composition following persistent WL drawdown. It is the aim of our study, then, to help to resolve this issue. We studied the effects of short-term (ca. 4 years) and long-term (ca. 40 years) persistent WL drawdown on the decomposition of numerous types of above-ground and below-ground plant litters at three boreal peatland sites: bog, oligotrophic fen and mesotrophic fen. We thus believe that enough permutations have been created to obtain a good assessment of how each factor, site nutrient level, WL regime, and litter type composition, influences decomposition. We used the litter bag method to measure the decomposition rates: placed measured amounts of plant litter, or cellulose strips as a control, into closed mesh bags, and installed the bags in the natural environment for decomposition for each litter type for varying amounts of time. Following litter bag recovery, the litter was cleaned of excess debris and analyzed for changes in mass, enzyme activity, mesofauna presence, and microbial community composition, among other things. The experiment has a run-time of ten years, the results from the first two years are presented in the poster.

Analysis of trace metals in water by inductively coupled plasma emission spectrometry using sodium dibenzyldithiocarbamate for preconcentration

USGS Publications Warehouse

Smith, C.L.; Motooka, J.M.; Willson, W.R.

1984-01-01

Since concentrations of trace elements in most natural waters seldom exceed the ??g/L level, analysis of trace elements in natural waters by inductively coupled plasma emission spectrometry (ICP) requires a preconcentration procedure. The elements Ag, Bi, Cd, Co, Cu, Fe, Mo, Ni, Pb, Sn, V, W, and Zn were separated and concentrated from 500 mL of water by coprecipitating them with sodium dibenzyldithiocarbamate (NaDBDTC) using nickel or silver as a carrier. The precipitated trace elements were collected on a membrane filter, redissolved from the filter with hot nitric and hydrochloric acids, and analyzed using ICP. Recoveries for all the trace elements except tungsten exceeded 80%. Coprecipitation of trace elements with NaDBDTC eliminated the use of difficult-to-inject organic solvents, and NaDBDTC coprecipitated a wider array of trace elements than ammoniumpyrrolidinedithiocarbamate (APDC), another commonly used coprecipitate.

Definition and preoperative predictors of persistently elevated prostate-specific antigen after radical prostatectomy: results from the Shared Equal Access Regional Cancer Hospital (SEARCH) database.

PubMed

Moreira, Daniel M; Presti, Joseph C; Aronson, William J; Terris, Martha K; Kane, Christopher J; Amling, Christopher L; Freedland, Stephen J

2010-06-01

To define a level of persistently elevated prostate-specific antigen (PSA) after radical prostatectomy (RP) that equates with high-risk for disease progression, and to identify preoperative predictors of PSA persistence among men from the Shared Equal Access Regional Cancer Hospital (SEARCH) database. A total of 901 men treated with RP between 2001 and 2008 were separated into groups based upon PSA nadir within 6 months after RP. We explored the association between nadir groups and time to biochemical recurrence (BCR) using multivariate Cox proportional hazards and determined the preoperative predictors of PSA persistence using logistic regression. Relative to men with undetectable PSA levels, those with a PSA nadir of 0.03 (hazard ratio [HR] 3.88, P < 0.001), 0.04 (HR 4.87, P < 0.001), 0.05-0.09 (HR 12.69, P < 0.001), 0.1-0.19 (HR 13.17, P < 0.001), and 0.2 ng/mL (HR 13.23, P < 0.001) were at increased risk of BCR while men with a nadir of 0.01 (HR 1.36, P = 0.400) and 0.02 (HR 1.64, P = 0.180) were not. Using the PSA persistence definition of a PSA nadir > or = 0.03 ng/mL, 230 men (26%) had persistence. The independent preoperative predictors of PSA persistence were higher body mass index (BMI, P = 0.002), pathological Gleason score (relative to 2-6: 4 + 3-10, P = 0.001) and preoperative PSA level (P < 0.001). Men with a PSA nadir > or = 0.03 ng/mL after RP were at higher risk for BCR. Using a PSA persistence definition of a PSA nadir > or = 0.03 ng/mL, persistence was predicted by known factors associated with aggressive disease (tumour grade, PSA level and BMI). Validation of the present definition in different populations using later end-points remains necessary to assess its prognostic usefulness.

Modest Amounts of Voluntary Exercise Reduce Pain- and Stress-Related Outcomes in a Rat Model of Persistent Hind Limb Inflammation.

PubMed

Pitcher, Mark H; Tarum, Farid; Rauf, Imran Z; Low, Lucie A; Bushnell, Catherine

2017-06-01

Aerobic exercise improves outcomes in a variety of chronic health conditions, yet the support for exercise-induced effects on chronic pain in humans is mixed. Although many rodent studies have examined the effects of exercise on persistent hypersensitivity, the most used forced exercise paradigms that are known to be highly stressful. Because stress can also produce analgesic effects, we studied how voluntary exercise, known to reduce stress in healthy subjects, alters hypersensitivity, stress, and swelling in a rat model of persistent hind paw inflammation. Our data indicate that voluntary exercise rapidly and effectively reduces hypersensitivity as well as stress-related outcomes without altering swelling. Moreover, the level of exercise is unrelated to the analgesic and stress-reducing effects, suggesting that even modest amounts of exercise may impart significant benefit in persistent inflammatory pain states. Modest levels of voluntary exercise reduce pain- and stress-related outcomes in a rat model of persistent inflammatory pain, independently of the amount of exercise. As such, consistent, self-regulated activity levels may be more relevant to health improvement in persistent pain states than standardized exercise goals. Published by Elsevier Inc.

Mutagenic consequences of a single G-quadruplex demonstrate mitotic inheritance of DNA replication fork barriers

PubMed Central

Lemmens, Bennie; van Schendel, Robin; Tijsterman, Marcel

2015-01-01

Faithful DNA replication is vital to prevent disease-causing mutations, chromosomal aberrations and malignant transformation. However, accuracy conflicts with pace and flexibility and cells rely on specialized polymerases and helicases to ensure effective and timely replication of genomes that contain DNA lesions or secondary structures. If and how cells can tolerate a permanent barrier to replication is, however, unknown. Here we show that a single unresolved G-quadruplexed DNA structure can persist through multiple mitotic divisions without changing conformation. Failed replication across a G-quadruplex causes single-strand DNA gaps that give rise to DNA double-strand breaks in subsequent cell divisions, which are processed by polymerase theta (POLQ)-mediated alternative end joining. Lineage tracing experiments further reveal that persistent G-quadruplexes cause genetic heterogeneity during organ development. Our data demonstrate that a single lesion can cause multiple unique genomic rearrangements, and that alternative end joining enables cells to proliferate in the presence of mitotically inherited replication blocks. PMID:26563448

Mutagenic consequences of a single G-quadruplex demonstrate mitotic inheritance of DNA replication fork barriers.

PubMed

Lemmens, Bennie; van Schendel, Robin; Tijsterman, Marcel

2015-11-13

Faithful DNA replication is vital to prevent disease-causing mutations, chromosomal aberrations and malignant transformation. However, accuracy conflicts with pace and flexibility and cells rely on specialized polymerases and helicases to ensure effective and timely replication of genomes that contain DNA lesions or secondary structures. If and how cells can tolerate a permanent barrier to replication is, however, unknown. Here we show that a single unresolved G-quadruplexed DNA structure can persist through multiple mitotic divisions without changing conformation. Failed replication across a G-quadruplex causes single-strand DNA gaps that give rise to DNA double-strand breaks in subsequent cell divisions, which are processed by polymerase theta (POLQ)-mediated alternative end joining. Lineage tracing experiments further reveal that persistent G-quadruplexes cause genetic heterogeneity during organ development. Our data demonstrate that a single lesion can cause multiple unique genomic rearrangements, and that alternative end joining enables cells to proliferate in the presence of mitotically inherited replication blocks.

Seasonal investigation of trace element contents in commercially valuable fish species from the Black sea, Turkey.

PubMed

Mendil, Durali; Demirci, Zafer; Tuzen, Mustafa; Soylak, Mustafa

2010-03-01

Fish species (Sarda sarda, Mulus barbatus ponticus, Trachurus trachurus and Merlangius merlangus) were collected from the Black sea, Turkey between 2008 and 2009 (spring, summer, autumn and winter). The samples were analyzed using flame and graphite furnace atomic absorption spectrometry after microwave digestion. The maximum metal concentrations were found to be as 25.5-41.4 microg/g (Fe), 17.8-25.7 microg/g (Zn), 0.28-0.64 microg/g (Pb), 0.64-0.99 microg/g (Cr), 1.3-3.6 microg/g (Mn), 1.4-1.9 microg/g (Cu), 0.18-0.35 microg/g (Cd) and 0.25-0.42 microg/g (Co) for fish species. The concentration of trace metals in samples is depended on fish species. Some species is accumulated trace metals at high ratio. Trace element levels in analyzed fish species were acceptable to human consumption at nutritional and toxic levels. The levels of lead and cadmium in fish samples were higher than the recommended legal limits. Copyright (c) 2009 Elsevier Ltd. All rights reserved.

Electrochemical sample matrix elimination for trace-level potentiometric detection with polymeric membrane ion-selective electrodes.

PubMed

Chumbimuni-Torres, Karin Y; Calvo-Marzal, Percy; Wang, Joseph; Bakker, Eric

2008-08-01

Potentiometric sensors are today sufficiently well understood and optimized to reach ultratrace level (subnanomolar) detection limits for numerous ions. In many cases of practical relevance, however, a high electrolyte background hampers the attainable detection limits. A particularly difficult sample matrix for potentiometric detection is seawater, where the high saline concentration forms a major interfering background and reduces the activity of most trace metals by complexation. This paper describes for the first time a hyphenated system for the online electrochemically modulated preconcentration and matrix elimination of trace metals, combined with a downstream potentiometric detection with solid contact polymeric membrane ion-selective microelectrodes. Following the preconcentration at the bismuth-coated electrode, the deposited metals are oxidized and released to a medium favorable to potentiometric detection, in this case calcium nitrate. Matrix interferences arising from the saline sample medium are thus circumvented. This concept is successfully evaluated with cadmium as a model trace element and offers potentiometric detection down to low parts per billion levels in samples containing 0.5 M NaCl background electrolyte.

Distribution of trace levels of therapeutic gallium in bone as mapped by synchrotron x-ray microscopy.

PubMed Central

Bockman, R S; Repo, M A; Warrell, R P; Pounds, J G; Schidlovsky, G; Gordon, B M; Jones, K W

1990-01-01

Gallium nitrate, a drug that inhibits calcium release from bone, has been proven a safe and effective treatment for the accelerated bone resorption associated with cancer. Though bone is a target organ for gallium, the kinetics, sites, and effects of gallium accumulation in bone are not known. We have used synchrotron x-ray microscopy to map the distribution of trace levels of gallium in bone. After short-term in vivo administration of gallium nitrate to rats, trace (nanogram) amounts of gallium preferentially localized to the metabolically active regions in the metaphysis as well as the endosteal and periosteal surfaces of diaphyseal bone, regions where new bone formation and modeling were occurring. The amounts measured were well below the levels known to be cytotoxic. Iron and zinc, trace elements normally found in bone, were decreased in amount after in vivo administration of gallium. These studies represent a first step toward understanding the mechanism(s) of action of gallium in bone by suggesting the possible cellular, structural, and elemental "targets" of gallium. Images PMID:2349224

The Persistence of Illicit Drug Smoke Residues and their Recovery from Common Household Surfaces

PubMed Central

Bitter, Julie L.

2016-01-01

Third-hand smoke is the residue left remaining on surfaces during smoking events, and is composed of particles and vapors that form upon heating. The phrase “third-hand smoke” is primarily used to describe nicotine and other chemicals from cigarettes, but any residues formed from the smoking of various substances could be classified similarly. There has been an increasing body of research on third-hand smoke from cigarettes in the last decade, but little has been done in regards to understanding the persistence of particles and vapors from illicit drugs. In this work, small samples of cocaine and methamphetamine were volatilized to produce an illicit drug smoke that was collected onto various surface materials and left exposed to ambient conditions over 672 hours (four weeks). Chemical analyses by electrospray ionization-mass spectrometry of residues on silicon, plastic, laminate, and artificial leather surfaces indicated a rapid decrease in recovery of the parent molecule, with varied formation of decomposition products over the first 168 hours of exposure. Measurable amounts of the parent molecule were still present after 672 hours, exhibiting a strong persistence of these drugs on various household materials. This is important in a forensic science context, as third-hand smoke residues could provide a viable source of trace evidence previously not utilized. PMID:27328798

Trace metal contents of selected seeds and vegetables from oil producing areas of Nigeria.

PubMed

Wegwu, Matthew O; Omeodu, Stephen I

2010-07-01

The concentrations of accumulated trace metals in selected seeds and vegetables collected in the oil producing Rivers State of Nigeria were investigated. The values were compared with those of seeds and vegetables cultivated in Owerri, a less industrialized area in Nigeria. The lead (Pb) and cadmium (Cd) contents of the seeds obtained from Rivers State ranged between 0.10 and 0.23 microg/g dry weight, while those of the seeds cultivated in Owerri fell below the detection limit of 0.01 microg/g dry weight. The highest manganese (Mn) level (902 microg/g dry weight) was found in Irvingia garbonesis seeds cultivated in Rivers State. Similarly, the highest nickel (Ni) value (199 microg/g dry weight) was also obtained in I. garbonesis, however, in the seeds sampled in Owerri. The highest copper (Cu), zinc (Zn), and iron (Fe) levels (16.8, 5.27, and 26.2 microg/g dry weight, resp.) were detected in seeds collected in Rivers State. With the exception of Talinum triangulae, Ocinum gratissimum, and Piper guineese, with Pb levels of 0.09, 0.10, and 0.11 microg/g dry weight, respectively, the Pb and Cd levels in the vegetables grown in Owerri fell below the detection limit of 0.01 microg/g dry weight. The trace metal with the highest levels in all the vegetables studied was Mn, followed by Fe. The highest concentrations of Ni and Cu occurred in vegetables collected from Rivers State, while the highest level of Zn was observed in Piper guineese collected in Owerri, with a value of 21.4 microg/g dry weight. Although the trace metal concentrations of the seeds and vegetables collected in Rivers State tended to be higher than those of the seeds and vegetables grown in Owerri, the average levels of trace metals obtained in this study fell far below the WHO specifications for metals in foods.

LIBS and LIFS for rapid detection of Rb traces in blood

NASA Astrophysics Data System (ADS)

Al-Jeffery, Mohammad O.; Telle, Helmut H.

2002-05-01

Tests that can quickly and efficiently detect traces of illegal performance enhancing drugs are becoming essential. Certain performance enhancing drugs lead to an increase in the count of red blood cells. The proportion of blood made up of red cells is normally around 42 percent. At least 90 percent of Rubidium measured in whole blood is located in the red blood cells. If Rubidium Chloride (RbCl) is given to an athlete around 30 minutes before competing and a sample of their blood (a drop on a filter) was subsequently tested for Rubidium content, the test will give a direct indication of the red blood cell count. In this contribution, we describe an efficient and fast test based on spectroscopic techniques that can be used to detect trace levels of Rubidium. Our experiments employed Rubidium nitride (RbNO3) and trace levels down to 0.3 percent were successfully detected.

Trace-elements, methylmercury and metallothionein levels in Magellanic penguin (Spheniscus magellanicus) found stranded on the Southern Brazilian coast.

PubMed

Kehrig, Helena A; Hauser-Davis, Rachel A; Seixas, Tércia G; Fillmann, Gilberto

2015-07-15

Magellanic penguins have been reported as good biomonitors for several types of pollutants, including trace-elements. In this context, selenium (Se), total mercury, methylmercury, inorganic mercury (Hg(inorg)), cadmium (Cd) and lead (Pb), as well as metallothionein (MT) levels, were evaluated in the feathers, liver and kidney of juvenile Magellanic penguins found stranded along the coast of Southern Brazil. The highest concentrations of all trace-elements and methylmercury were found in internal organs. Concentrations of Cd and Se in feathers were extremely low in comparison with their concentrations in soft tissues. The results showed that both Se and MT are involved in the detoxification of trace-elements (Cd, Pb and Hg(inorg)) since statistically significant relationships were found in liver. Conversely, hepatic Se was shown to be the only detoxifying agent for methylmercury. Copyright © 2015 Elsevier Ltd. All rights reserved.

Exposure assessment for trace elements from consumption of marine fish in Southeast Asia.

PubMed

Agusa, Tetsuro; Kunito, Takashi; Sudaryanto, Agus; Monirith, In; Kan-Atireklap, Supawat; Iwata, Hisato; Ismail, Ahmad; Sanguansin, Joompol; Muchtar, Muswerry; Tana, Touch Seang; Tanabe, Shinsuke

2007-02-01

Concentrations of 20 trace elements were determined in muscle and liver of 34 species of marine fish collected from coastal areas of Cambodia, Indonesia, Malaysia and Thailand. Large regional difference was observed in the levels of trace elements in liver of one fish family (Carangidae): the highest mean concentration was observed in fish from the Malaysian coastal waters for V, Cr, Zn, Pb and Bi and those from the Java Sea side of Indonesia for Sn and Hg. To assess the health risk to the Southeast Asian populations from consumption of fish, intake rates of trace elements were estimated. Some marine fish showed Hg levels higher than the guideline values by U.S. Environmental Protection Agency and Joint FAO/WHO Expert Committee on Food Additives (JECFA). This suggests that consumption of these fish may be hazardous to the people.

Trace metal concentrations in tropical mangrove sediments, NE Brazil.

PubMed

Miola, Brígida; Morais, Jáder Onofre de; Pinheiro, Lidriana de Souza

2016-01-15

Sediment cores were taken from the mangroves of the Coreaú River estuary off the northeast coast of Brazil. They were analyzed for grain size, CaCO3, organic matter, and trace metal (Cd, Pb, Zn, Cu, Al, and Fe) contents. Mud texture was the predominant texture. Levels of trace metals in surface sediments indicated strong influence of anthropogenic processes, and diagenetic processes controlled the trace metal enrichment of core sediments of this estuary. The positive relationships between trace metals and Al and Fe indicate that Cu, Zn, Pb, and Cd concentrations are associated mainly with Al and Fe oxy-hydroxides and have natural sources. Copyright © 2015 Elsevier Ltd. All rights reserved.

Health and Environmental Hazards of Electronic Waste in India.

PubMed

Borthakur, Anwesha

2016-04-01

Technological waste in the form of electronic waste (e-waste) is a threat to all countries. E-waste impacts health and the environment by entering the food chain in the form of chemical toxicants and exposing the population to deleterious chemicals, mainly in the form of polycyclic aromatic hydrocarbons and persistent organic pollutants. This special report tries to trace the environmental and health implications of e-waste in India. The author concludes that detrimental health and environmental consequences are associated with e-waste and the challenge lies in producing affordable electronics with minimum chemical toxicants.

From birth control to that "fresh feeling": a historical perspective on feminine hygiene in medicine and media.

PubMed

Ferranti, Michelle

2009-12-01

This essay traces the modern history of vaginal douching in the United States from its widespread adoption as the first clinical form of birth control in the nineteenth century, through the marketing success of cosmetic douches in the late twentieth century. Women's changing and often overlapping motivations for douching in the past provide insight into contemporary women's choices about douching. The persistence of the practice today despite its association with adverse health consequences is a troubling phenomenon that can only be fully understood by considering this complex history.

Tropospheric rivers? A pilot study. [of filamentary structures of atmospheric water vapor

NASA Technical Reports Server (NTRS)

Newell, Reginald E.; Newell, Nicholas E.; Zhu, Yong; Scott, Courtney

1992-01-01

Computations of daily global tropospheric water vapor flux values show the presence of a filamentary structure. The filaments, here called rivers, have lengths many times their widths and persist for many days while being translated through the atmosphere. They are present in data analyzed for both 1981 and 1991. The water vapor flux maxima coincide quite closely to reflectivity features (averaged from wavelengths of 380 and 360 nm) as revealed by the Total Ozone Mapping Spectrometer (TOMS). It is suggested that the filamentary structure may also be present in other trace constituents.

Effect of lipid peroxidation, antioxidants, macro minerals and trace elements on eczema.

PubMed

Amin, Mohammad Nurul; Liza, Kaniz Fatema; Sarwar, Md Shahid; Ahmed, Jamiuddin; Adnan, Md Tareek; Chowdhury, Manjurul Islam; Hossain, Mohammad Zahid; Islam, Mohammad Safiqul

2015-09-01

The exact etiology and pathogenesis of eczema are not yet fully understood, although different factors are considered as pathogenic mechanisms in the development of eczema. Our study was designed to determine extent of serum lipid peroxidation, antioxidants, macro minerals and trace elements in patients with eczema, and thereby, find any pathophysiological correlation. The study was conducted as a case-control study with 65 eczema patients as cases and 65 normal healthy individuals as controls. Lipid peroxidation was assessed by measuring the serum level of malondialdehyde (MDA). Antioxidants- vitamin A and E concentration was determined by RP-HPLC method whereas vitamin C was evaluated for serum ascorbic acid by UV spectrophotometric method. Serum macro minerals (Na, K, Ca) and trace elements (Zn, Fe) were determined by Atomic Absorption Spectroscopy (AAS). This study found significantly higher level of MDA (p < 0.001) and lower level of antioxidants (p < 0.05) in patients in comparison to the control subjects. Analysis of serum macro minerals (Na, K and Ca) and trace elements (Zn, Fe) found that the mean values of Na, K, Ca, Zn and Fe were 2771.60 ± 75.64, 66.33 ± 3.03, 48.41 ± 2.50, 0.30 ± 0.02 and 0.29 ± 0.009 mg/L for the patient group and 3284.81 ± 34.51, 162.18 ± 3.72, 87.66 ± 2.10, 0.75 ± 0.06 and 0.87 ± 0.06 mg/L for the control group, accordingly. There was a significant difference for all the minerals between the patients and controls (p < 0.001). This study suggests a strong association between the pathogenesis of eczema with the elevated level of MDA and depleted level of antioxidants, macro minerals, and trace elements.

Elevated serum MDA and depleted non-enzymatic antioxidants, macro-minerals and trace elements are associated with bipolar disorder.

PubMed

Chowdhury, Manjurul Islam; Hasan, Maimuna; Islam, Mohammad Safiqul; Sarwar, Md Shahid; Amin, Mohammad Nurul; Uddin, S M Naim; Rahaman, Md Zahedur; Banik, Sujan; Hussain, Md Saddam; Yokota, Kazushige; Hasnat, Abul

2017-01-01

Genetic and neurobiological factors are considered to be the major causes of mood and mental disorders. However, over the past few years, increased levels of serum malondialdehyde and altered levels of various non-enzymatic antioxidants and essential minerals involved in abnormal functional activity have been identified as major contributing factors to the pathogenesis of several neurological disorders. The aim of this study was to determine the levels of the serum lipid peroxidation product malondialdehyde (MDA), antioxidants (vitamin A, E and C), macro-minerals (calcium, potassium and sodium) and trace elements (zinc, iron and selenium) in patients with bipolar disorder and to explore their role in disease progression. This is a prospective case-control study that evaluated 55 patients with bipolar disorder and 55 healthy volunteers matched by age and sex. Serum MDA levels were determined by UV spectrophotometry as a marker of lipid peroxidation. RP-HPLC was employed to investigate the serum vitamin A and E concentrations, whereas UV spectrophotometry was used to quantify levels of vitamin C. Serum macro-minerals and trace elements were analyzed by atomic absorption spectroscopy (AAS). Statistical analysis was performed with independent sample t-tests and Pearson's correlation test. We found significantly higher concentrations of MDA (p<0.05) and significantly lower concentrations of antioxidants (vitamin A, E and C) (p<0.05) in the patient group compared with control group. Regarding trace elements and macro-minerals, lower concentrations of zinc, calcium, iron, selenium, sodium and potassium were found in the patient group compared with control subjects (p<0.05). Our study suggests that high serum MDA concentrations and low serum concentrations of antioxidants, macro-minerals and trace elements are strongly associated with bipolar disorder. Copyright © 2016 Elsevier GmbH. All rights reserved.

Factors Associated With Persistent Increase in Level of Alanine Aminotransferase in Patients With Chronic Hepatitis B Receiving Oral Antiviral Therapy.

PubMed

Jacobson, Ira M; Washington, Mary K; Buti, Maria; Thompson, Alexander; Afdhal, Nezam; Flisiak, Robert; Akarca, Ulus Salih; Tchernev, Konstantin G; Flaherty, John F; Aguilar Schall, Raul; Myers, Robert P; Subramanian, G Mani; McHutchison, John G; Younossi, Zobair; Marcellin, Patrick; Patel, Keyur

2017-07-01

Despite complete suppression of viral DNA with antiviral agents, in some patients with chronic hepatitis B (CHB), serum levels of alanine aminotransferase (ALT) do not normalize. We investigated factors associated with persistent increases in ALT level in patients with CHB given long-term tenofovir disoproxil fumarate. We analyzed data from 471 hepatitis B e antigen (HBeAg)-positive and HBeAg-negative patients with CHB participating in 2 phase 3 trials. We identified patients with an increased level of ALT (above the upper limit of normal range) after 5 years (240 weeks) of tenofovir disoproxil fumarate therapy. We analyzed findings from liver biopsy specimens collected from 467 patients (99%) at baseline and 339 patients (72%) at year 5 of treatment; biopsy specimens were evaluated by an independent pathologist. We performed stepwise, forward, multivariate regression analyses of specified baseline characteristics and on-treatment response parameters to identify factors associated with persistent increases in ALT level. Of the 471 patients, 87 (18%) still had an increased ALT level at year 5 of treatment. Factors associated significantly with a persistent increase in ALT level were a steatosis score of 5% or greater (grade 1 or more) at baseline (odds ratio [OR], 2.236; 95% confidence interval [CI], 1.031-4.852; P = .042) and at year 5 (OR, 3.392; 95% CI, 1.560 ≥ 7.375; P = .002), HBeAg seropositivity at baseline (OR, 3.297; 95% CI, 1.653-6.576; P < .001), and age 40 years or older (OR, 2.099; 95% CI, 1.014-4.342; P = .046). Of the 42 HBeAg-positive patients with steatosis at baseline, 21 (50%) had an increased ALT level at year 5 of treatment. Patients with persistent increases in ALT level were more likely to have an increase in steatosis at year 5 than those with a normal ALT level. HBeAg seropositivity and hepatic steatosis contribute to persistent increases in ALT level in patients with CHB receiving suppressive antiviral treatment. ClinicalTrials.gov registration numbers: NCT00117676 and NCT00116805. Copyright © 2017 AGA Institute. Published by Elsevier Inc. All rights reserved.

Dietary exposure estimates of twenty-one trace elements from a Total Diet Study carried out in Pavia, Northern Italy.

PubMed

Turconi, Giovanna; Minoia, Claudio; Ronchi, Anna; Roggi, Carla

2009-04-01

The significant role of trace elements in human health is well documented. Trace elements are those compounds that need to be present in the human diet to maintain normal physiological functions. However, some microelements may become harmful at high levels of exposure, or, on the other hand, may give rise to malnutrition, when their exposure is too low. The aim of the present study was to provide a reliable estimate of the dietary exposure of twenty-one trace elements in a Northern Italian area. For this purpose, trace element analyses were undertaken on total diet samples collected from a university cafeteria in Pavia, Northern Italy. The average daily exposure for the adult people was calculated on the basis of food consumption frequency, portion size and trace element levels in foodstuffs. The mean exposure values satisfy the Italian RDA for all the essential trace elements, except for Fe exposure in females, and are well below the Provisional Tolerable Daily Intake for all the toxic compounds, showing that the probability of dietary exposure to health risks is overall small. As far as Fe exposure is concerned, a potential risk of anaemia in the female adult population should be considered, then studies aimed at evaluating the Fe nutritional status of adult Italian women should be addressed. In conclusion, while not excluding the possibility that the daily exposure determined in the present study may not be representative of the population as a whole, this study provides a good estimate of the Italian adult consumer exposure to twenty-one trace elements.

Persistently high psychological well-being predicts better HDL cholesterol and triglyceride levels: findings from the midlife in the U.S. (MIDUS) longitudinal study.

PubMed

Radler, Barry T; Rigotti, Attilio; Ryff, Carol D

2018-01-03

Psychological correlates of blood lipid levels have been previously evaluated mostly in cross sectional studies. However, prospectively measured psychological factors might also predict favorable blood lipid profiles, thereby indicating a healthy mind/body interplay that is associated with less disease, better health and longer lives. This paper examined whether longitudinal profiles of psychological well-being over 9-10 years are predictors of blood lipid profiles. Using the MIDUS (Midlife in the U.S.) biological subsample (n = 1054, aged 34 to 84, 55% female), cross-time trajectories of well-being were linked with three lipid outcomes (i.e., HDL cholesterol, triglycerides, and LDL cholesterol), measured for the first time at the 2nd wave of the study. Most adults showed largely stable profiles of well-being, albeit at different levels. Some showed persistently high well-being over time, while others revealed persistently low or moderate well-being. After adjusting for the effect of demographics, health behaviors, medications, and insulin resistance, adults with persistently high levels of environmental mastery and self-acceptance-two components of psychological well-being-had significantly higher levels of HDL as well as significantly lower levels of triglycerides compared to adults with persistently low levels of well-being. Converging with prior findings, no association was found between well-being and LDL cholesterol. Over 9-10 years, persistently high levels of psychological well-being measures predicted high HDL cholesterol and low triglycerides. These findings add longitudinal evidence to the growing body of research showing that positive psychological factors are linked with better lipoprotein profiles. A better blood lipid profile, particularly higher HDL-C, may be key in mediating how psychological well-being positively impacts health and length of life. Additional research is required to further validate this hypothesis as well as to establish potential underlying mechanisms.

Trace element distribution in waters of the northern catchment area of Lake Linneret, northern Israel

NASA Astrophysics Data System (ADS)

Sandler, A.; Brenner, I. B.; Halicz, L.

1988-02-01

Waters of the northern watershed of Lake Kineret, sampled during the period 1978 1983, were analyzed for their major and trace element contents. The trace element concentrations of the major water sources of the watershed (the Dan and Banias springs) represent background values. After emergence, the waters are subjected to human activity. In crossing the populated and cultivated Hula Basin in man-made canals, the major and trace element contents increase. In comparison to the trace element concentrations, those of the major elements have narrow ranges and small temporal fluctuations. Trace element concentrations varied by 3 orders of magnitude, and temporal variations were large but not neccessarily seasonal. Point sources of trace elements were urban effluents, fish pond wastes, and peat soil drainage. The trace element concentrations decrease in the waters of the last segment of the Jordan River. All measured trace elements were below the criteria levels established by regulatory agencies. Several, however, were of the same order of magnitude. Addition of wastes from enhanced recycling, and morphologic modification of the final course of the Jordan River could result in increase in the trace element concentrations in the water.

[Trace elements in serum of malnourished and well-nourished children living in Lubumbashi and Kawama].

PubMed

Musimwa, Aimée Mudekereza; Kanteng, Gray Wakamb; Kitoko, Hermann Tamubango; Luboya, Oscar Numbi

2016-01-01

The role of trace metals elements in human nutrition can no longer be ignored. Deficiency caused by inadequate dietary intake, secondary deficiencies often under - estimated, and iatrogenic deficiencies lead to pathologies such as infections and others. For this reason their dosages are particularly important to assess disease severity and to facilitate early treatment or improve patient's diet. The aim of this study was to determine trace elements profile in blood (copper, selenium, zinc, iron, chromium, cobalt, etc.) among malnourished and well-nourished children in a mining community in Lubumbashi. Three hundred eleven cases have been collected, 182 malnourished children and 129 well-nourished children in a cross-sectional descriptive study conducted from July 2013 to December 2014. Exhaustive sampling was performed. Metal determination in serum was performed using Inductively Coupled Plasma Spectroscopy (ICP-OES/MS) in the laboratory at Congolese Control Office in Lubumbashi. Essential trace elements (copper, zinc, selenium and iron) were found at very low concentrations in both the malnourished and well-nourished children. Arsenic, cadmium, magnesium and manganese concentrations were normal compared with reference values in well-nourished children Antimony, chromium, lead and cobalt levels were high in both the malnourished and well-nourished children. Nickel level was normal malnourished and well-nourished children. Magnesium, manganese were found in very low levels in malnourished children. Both the malnourished and well-nourished children suffer from deficiencies of essential trace elements associated with trace metals elements This allows to assume that essential micronutrients deficiency promotes the absorption of heavy metals.

Slit Effect of Common Ground Patterns in Affecting Cross-Talk Noise between Two Parallel Signal Traces on Printed Circuit Boards

NASA Astrophysics Data System (ADS)

Maeno, Tsuyoshi; Sakurai, Yukihiko; Unou, Takanori; Ichikawa, Kouji; Fujiwara, Osamu

It is well-known that electromagnetic (EM) disturbances in vehicle-mounted radios are mainly caused by conducted noise currents flowing through wiring-harnesses from vehicle-mounted printed circuit boards (PCBs) with common ground patterns with slits. To evaluate the noise current outflows from the PCBs of this kind, we previously measured noise current outflows from four types of simple three-layer PCBs having two perpendicular signal traces and different ground patterns with/without slits, and showed that slits on a ground pattern allow conducted noise currents to flow out from PCBs, while the levels for the symmetric slits ground type are smaller compared to the case for two asymmetric slits ground types. In the present study, to further investigate the above finding, we fabricated six types of simple two-layer PCBs having two parallel signal traces and different ground patterns with/without slits, and measured the cross-talk noise between the traces. As a result, we found that the ground patterns with the slits perpendicular to the traces increase the cross-talk noise levels, which are larger by 19-42 dB than those for the ground pattern with no slits, while the ground patterns with the slits in parallel with the traces can suppress the noise levels, which are slightly smaller by 2.5-4.5 dB compared to the case for the no-slit ground pattern. These results were confirmed by the FDTD simulation, and were also qualitatively explained from an equivalent bridge circuit model we previously proposed.

Obg and Membrane Depolarization Are Part of a Microbial Bet-Hedging Strategy that Leads to Antibiotic Tolerance.

PubMed

Verstraeten, Natalie; Knapen, Wouter Joris; Kint, Cyrielle Ines; Liebens, Veerle; Van den Bergh, Bram; Dewachter, Liselot; Michiels, Joran Elie; Fu, Qiang; David, Charlotte Claudia; Fierro, Ana Carolina; Marchal, Kathleen; Beirlant, Jan; Versées, Wim; Hofkens, Johan; Jansen, Maarten; Fauvart, Maarten; Michiels, Jan

2015-07-02

Within bacterial populations, a small fraction of persister cells is transiently capable of surviving exposure to lethal doses of antibiotics. As a bet-hedging strategy, persistence levels are determined both by stochastic induction and by environmental stimuli called responsive diversification. Little is known about the mechanisms that link the low frequency of persisters to environmental signals. Our results support a central role for the conserved GTPase Obg in determining persistence in Escherichia coli in response to nutrient starvation. Obg-mediated persistence requires the stringent response alarmone (p)ppGpp and proceeds through transcriptional control of the hokB-sokB type I toxin-antitoxin module. In individual cells, increased Obg levels induce HokB expression, which in turn results in a collapse of the membrane potential, leading to dormancy. Obg also controls persistence in Pseudomonas aeruginosa and thus constitutes a conserved regulator of antibiotic tolerance. Combined, our findings signify an important step toward unraveling shared genetic mechanisms underlying persistence. Copyright © 2015 Elsevier Inc. All rights reserved.

Persistent homology and non-Gaussianity

NASA Astrophysics Data System (ADS)

Cole, Alex; Shiu, Gary

2018-03-01

In this paper, we introduce the topological persistence diagram as a statistic for Cosmic Microwave Background (CMB) temperature anisotropy maps. A central concept in 'Topological Data Analysis' (TDA), the idea of persistence is to represent a data set by a family of topological spaces. One then examines how long topological features 'persist' as the family of spaces is traversed. We compute persistence diagrams for simulated CMB temperature anisotropy maps featuring various levels of primordial non-Gaussianity of local type. Postponing the analysis of observational effects, we show that persistence diagrams are more sensitive to local non-Gaussianity than previous topological statistics including the genus and Betti number curves, and can constrain Δ fNLloc= 35.8 at the 68% confidence level on the simulation set, compared to Δ fNLloc= 60.6 for the Betti number curves. Given the resolution of our simulations, we expect applying persistence diagrams to observational data will give constraints competitive with those of the Minkowski Functionals. This is the first in a series of papers where we plan to apply TDA to different shapes of non-Gaussianity in the CMB and Large Scale Structure.

Role of Prefrontal Persistent Activity in Working Memory

PubMed Central

Riley, Mitchell R.; Constantinidis, Christos

2016-01-01

The prefrontal cortex is activated during working memory, as evidenced by fMRI results in human studies and neurophysiological recordings in animal models. Persistent activity during the delay period of working memory tasks, after the offset of stimuli that subjects are required to remember, has traditionally been thought of as the neural correlate of working memory. In the last few years several findings have cast doubt on the role of this activity. By some accounts, activity in other brain areas, such as the primary visual and posterior parietal cortex, is a better predictor of information maintained in visual working memory and working memory performance; dynamic patterns of activity may convey information without requiring persistent activity at all; and prefrontal neurons may be ill-suited to represent non-spatial information about the features and identity of remembered stimuli. Alternative interpretations about the role of the prefrontal cortex have thus been suggested, such as that it provides a top-down control of information represented in other brain areas, rather than maintaining a working memory trace itself. Here we review evidence for and against the role of prefrontal persistent activity, with a focus on visual neurophysiology. We show that persistent activity predicts behavioral parameters precisely in working memory tasks. We illustrate that prefrontal cortex represents features of stimuli other than their spatial location, and that this information is largely absent from early cortical areas during working memory. We examine memory models not dependent on persistent activity, and conclude that each of those models could mediate only a limited range of memory-dependent behaviors. We review activity decoded from brain areas other than the prefrontal cortex during working memory and demonstrate that these areas alone cannot mediate working memory maintenance, particularly in the presence of distractors. We finally discuss the discrepancy between BOLD activation and spiking activity findings, and point out that fMRI methods do not currently have the spatial resolution necessary to decode information within the prefrontal cortex, which is likely organized at the micrometer scale. Therefore, we make the case that prefrontal persistent activity is both necessary and sufficient for the maintenance of information in working memory. PMID:26778980

Offgassing Characterization of the Columbus Laboratory Module

NASA Technical Reports Server (NTRS)

Rampini, riccardo; Lobascio, Cesare; Perry, Jay L.; Hinderer, Stephan

2005-01-01

Trace gaseous contamination in the cabin environment is a major concern for manned spacecraft, especially those designed for long duration missions, such as the International Space Station (ISS). During the design phase, predicting the European-built Columbus laboratory module s contribution to the ISS s overall trace contaminant load relied on "trace gas budgeting" based on material level and assembled article tests data. In support of the Qualification Review, a final offgassing test has been performed on the complete Columbus module to gain cumulative system offgassing data. Comparison between the results of the predicted offgassing load based on the budgeted material/assembled article-level offgassing rates and the module-level offgassing test is presented. The Columbus module offgassing test results are also compared to results from similar tests conducted for Node 1, U.S. Laboratory, and Airlock modules.

Occupational Exposure to Manganese and Fine Motor Skills in Elderly Men: Results from the Heinz Nixdorf Recall Study.

PubMed

Pesch, Beate; Casjens, Swaantje; Weiss, Tobias; Kendzia, Benjamin; Arendt, Marina; Eisele, Lewin; Behrens, Thomas; Ulrich, Nadin; Pundt, Noreen; Marr, Anja; Robens, Sibylle; Van Thriel, Christoph; Van Gelder, Rainer; Aschner, Michael; Moebus, Susanne; Dragano, Nico; Brüning, Thomas; Jöckel, Karl-Heinz

2017-11-10

Exposure to manganese (Mn) may cause movement disorders, but less is known whether the effects persist after the termination of exposure. This study investigated the association between former exposure to Mn and fine motor deficits in elderly men from an industrial area with steel production. Data on the occupational history and fine motor tests were obtained from the second follow-up of the prospective Heinz Nixdorf Recall Study (2011-2014). The study population included 1232 men (median age 68 years). Mn in blood (MnB) was determined in archived samples (2000-2003). The association between Mn exposure (working as welder or in other at-risk occupations, cumulative exposure to inhalable Mn, MnB) with various motor functions (errors in line tracing, steadiness, or aiming and tapping hits) was investigated with Poisson and logistic regression, adjusted for iron status and other covariates. Odds ratios (ORs) with 95% confidence intervals (CIs) were estimated for substantially impaired dexterity (errors >90th percentile, tapping hits <10th percentile). The median of cumulative exposure to inhalable Mn was 58 µg m-3 years in 322 men who ever worked in at-risk occupations. Although we observed a partly better motor performance of exposed workers at group level, we found fewer tapping hits in men with cumulative Mn exposure >184.8 µg m-3 years (OR 2.15, 95% CI 1.17-3.94). MnB ≥ 15 µg l-1, serum ferritin ≥ 400 µg l-1, and gamma-glutamyl transferase ≥74 U l-1 were associated with a greater number of errors in line tracing. We found evidence that exposure to inhalable Mn may carry a risk for dexterity deficits. Whether these deficits can be exclusively attributed to Mn remains to be elucidated, as airborne Mn is strongly correlated with iron in metal fumes, and high ferritin was also associated with errors in line tracing. Furthermore, hand training effects must be taken into account when testing for fine motor skills. © The Author 2017. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

Trace-element interactions in Rook Corvus frugilegus eggshells along an urbanisation gradient.

PubMed

Orłowski, Grzegorz; Kasprzykowski, Zbigniew; Dobicki, Wojciech; Pokorny, Przemysław; Wuczyński, Andrzej; Polechoński, Ryszard; Mazgajski, Tomasz D

2014-11-01

Concentrations of seven trace elements [arsenic (As), chromium (Cr), nickel (Ni), lead (Pb), copper (Cu), zinc (Zn), and cadmium (Cd)] in the eggshells of Rooks Corvus frugilegus, a focal bird species of Eurasian agricultural environments, are increased above background levels and exceed levels of toxicological concern. The concentrations of Cr, Ni, Pb, Cu, and Zn are greater in eggshells from urban rookeries (large cities) compared with rural areas (small towns and villages) suggesting an urbanisation gradient effect among eggs laid by females. In the present study, the investigators assessed whether the pattern of relationships among the seven trace elements in eggshells change along an urbanisation/pollution gradient. Surprisingly, we found that eggshells with the greatest contaminant burden, i.e., from urban rookeries, showed far fewer significant relationships (n = 4) than eggshells from villages (n = 10), small towns (n = 6), or rural areas (n = 8). In most cases, the relationships were positive. As was an exception: Its concentration was negatively correlated with Ni and Cd levels in eggshells from small town rookeries (where As levels were the highest), whereas eggshells from villages (with a lower As level) showed positive relationships between As and Cd. Our findings suggest that at low to intermediate levels, interactions between the trace elements in Rook eggshells are of a synergistic character and appear to operate as parallel coaccumulation. A habitat-specific excess of some elements (primarily Cr, Ni, Cu, As) suggests their more competitively selective sequestration.

Changes in sediment-associated trace element concentrations in the Seine river basin (1994-2001)

USGS Publications Warehouse

Meybeck, Michel; Horowitz, A.J.; Grosbois, C.; Gueguen, Y.; ,

2003-01-01

In the 1980's, based on the concentrations of particulate-associated Hg, Cd, Pb, Cu and Zn relative to very low natural background levels, the Seine River Basin was one of the most impacted in the world. Over the past 20 years, there has been a general decline in these elevated concentrations that parallels declines in Paris sewage sludge trace element levels. Within the basin, marked differences in spatial and temporal geochemical patterns have been observed: (1) between major tributaries, (2) between trace elements, and (3) with stream order and population density, all of which illustrate the complexity of the geochemical processes ongoing in the basin.

Modeling, Materials, and Metrics: The Three-m Approach to FCS Signature Solutions

DTIC Science & Technology

2002-05-07

calculations. These multiple levels will be incorporated into the MuSES software. The four levels are described as follows: "* Radiosity - Deterministic...view-factor-based, all-diffuse solution. Very fast. Independent of user position. "* Directional Reflectivity - Radiosity with directional incident...target and environment facets (view factor with BRDF). Last ray cast bounce = radiosity solution. "* Multi-bounce path trace - Rays traced from observer

Low serum magnesium levels are associated with increased risk of fractures: a long-term prospective cohort study.

PubMed

Kunutsor, Setor Kwadzo; Whitehouse, Michael Richard; Blom, Ashley William; Laukkanen, Jari Antero

2017-07-01

Magnesium, which is an essential trace element that plays a key role in several cellular processes, is a major component of bone; however, its relationship with risk of major bone fractures is uncertain. We aimed to investigate the association of baseline serum magnesium concentrations with risk of incident fractures. We analyzed data on 2245 men aged 42-61 years in the Kuopio Ischemic Heart Disease prospective cohort study, with the assessment of serum magnesium measurements and dietary intakes made at baseline. Hazard ratios [95% confidence intervals (CI)] for incident total (femoral, humeral, and forearm) and femoral fractures were assessed. During a median follow-up of 25.6 years, 123 total fractures were recorded. Serum magnesium was non-linearly associated with risk of total fractures. In age-adjusted Cox regression analysis, the hazard ratio (HR) (95% CIs) for total fractures in a comparison of the bottom quartile versus top quartile of magnesium concentrations was 2.10 (1.30-3.41), which persisted on adjustment for several established risk factors 1.99 (1.23-3.24). The association remained consistent on further adjustment for renal function, socioeconomic status, total energy intake, and several trace elements 1.80 (1.10-2.94). The corresponding adjusted HRs for femoral fractures were 2.56 (1.38-4.76), 2.43 (1.30-4.53) and 2.13 (1.13-3.99) respectively. There was no evidence of an association of dietary magnesium intake with risk of any fractures. In middle-aged Caucasian men, low serum magnesium is strongly and independently associated with an increased risk of fractures. Further research is needed to assess the potential relevance of serum magnesium in the prevention of fractures.

Chemical structure-based predictive model for the oxidation of trace organic contaminants by sulfate radical.

PubMed

Ye, Tiantian; Wei, Zongsu; Spinney, Richard; Tang, Chong-Jian; Luo, Shuang; Xiao, Ruiyang; Dionysiou, Dionysios D

2017-06-01

Second-order rate constants [Formula: see text] for the reaction of sulfate radical anion (SO 4 •- ) with trace organic contaminants (TrOCs) are of scientific and practical importance for assessing their environmental fate and removal efficiency in water treatment systems. Here, we developed a chemical structure-based model for predicting [Formula: see text] using 32 molecular fragment descriptors, as this type of model provides a quick estimate at low computational cost. The model was constructed using the multiple linear regression (MLR) and artificial neural network (ANN) methods. The MLR method yielded adequate fit for the training set (R training 2 =0.88,n=75) and reasonable predictability for the validation set (R validation 2 =0.62,n=38). In contrast, the ANN method produced a more statistical robustness but rather poor predictability (R training 2 =0.99andR validation 2 =0.42). The reaction mechanisms of SO 4 •- reactivity with TrOCs were elucidated. Our result shows that the coefficients of functional groups reflect their electron donating/withdrawing characters. For example, electron donating groups typically exhibit positive coefficients, indicating enhanced SO 4 •- reactivity. Electron withdrawing groups exhibit negative values, indicating reduced reactivity. With its quick and accurate features, we applied this structure-based model to 55 discrete TrOCs culled from the Contaminant Candidate List 4, and quantitatively compared their removal efficiency with SO 4 •- and OH in the presence of environmental matrices. This high-throughput model helps prioritize TrOCs that are persistent to SO 4 •- based oxidation technologies at the screening level, and provide diagnostics of SO 4 •- reaction mechanisms. Copyright © 2017 Elsevier Ltd. All rights reserved.

PM2.5 levels, chemical composition and health risk assessment in Xinxiang, a seriously air-polluted city in North China.

PubMed

Feng, Jinglan; Yu, Hao; Liu, Shuhui; Su, Xianfa; Li, Yi; Pan, Yuepeng; Sun, Jianhui

2017-10-01

Seventeen PM 2.5 samples were collected at Xinxiang during winter in 2014. Nine water-soluble ions, 19 trace elements and eight fractions of carbonaceous species in PM 2.5 were analyzed. PM 2.5 concentrations and elements species during different periods with different pollution situations were compared. The threat of heavy metals in PM 2.5 was assessed using incremental lifetime cancer risk. During the whole period, serious regional haze pollution persisted, and the averaged concentration of PM 2.5 was 168.5 μg m -3 , with 88.2 % of the daily samples exhibiting higher PM 2.5 concentrations than the national air quality standard II. The high NO 3 - /SO 4 2- ratio suggested that vehicular exhaust made an important contribution to atmospheric pollution. All of organic carbon and elemental carbon ratios in this study were above 2.0 for PM 2.5 , which might reflect the combined contributions from coal combustion, motor vehicle exhaust and biomass burning. Mean 96-h backward trajectory clusters indicated that more serious air pollution occurred when air masses transported from the Hebei, Shanxi and Zhengzhou. The concentrations of the water-soluble ions and trace elements on haze days were 2 and 1.8 times of those on clear days. The heavy metals in PM 2.5 might not cause non-cancerous health issues by exposure through the human respiratory system. However, lifetime cancer risks of heavy metals obviously exceeded the threshold (10 -6 ) and might have a cancer risk for residents in Xinxiang. This study provided detailed composition data and comprehensive analysis of PM 2.5 during the serious haze pollution period and their potential impact on human health in Xinxiang.

Selenium and trace element mobility affected by periodic displacement of stratification in the Great Salt Lake, Utah

USGS Publications Warehouse

Beisner, K.; Naftz, D.L.; Johnson, W.P.; Diaz, X.

2009-01-01

The Great Salt Lake (GSL) is a unique ecosystem in which trace element activity cannot be characterized by standard geochemical parameters due to the high salinity. Movement of selenium and other trace elements present in the lake bed sediments of GSL may occur due to periodic stratification displacement events or lake bed exposure. The water column of GSL is complicated by the presence of a chemocline persistent over annual to decadal time scales. The water below the chemocline is referred to as the deep brine layer (DBL), has a high salinity (16.5 to 22.9%) and is anoxic. The upper brine layer (UBL) resides above the chemocline, has lower salinity (12.6 to 14.7%) and is oxic. Displacement of the DBL may involve trace element movement within the water column due to changes in redox potential. Evidence of stratification displacement in the water column has been observed at two fixed stations on the lake by monitoring vertical water temperature profiles with horizontal and vertical velocity profiles. Stratification displacement events occur over periods of 12 to 24 h and are associated with strong wind events that can produce seiches within the water column. In addition to displacement events, the DBL shrinks and expands in response to changes in the lake surface area over a period of months. Laboratory tests simulating the observed sediment re-suspension were conducted over daily, weekly and monthly time scales to understand the effect of placing anoxic bottom sediments in contact with oxic water, and the associated effect of trace element desorption and (or) dissolution. Results from the laboratory simulations indicate that a small percentage (1%) of selenium associated with anoxic bottom sediments is periodically solubilized into the UBL where it potentially can be incorporated into the biota utilizing the oxic part of GSL.

How Trace Element Levels of Public Drinking Water Affect Body Composition in Turkey.

PubMed

Cetin, Ihsan; Nalbantcilar, Mahmut Tahir; Tosun, Kezban; Nazik, Aydan

2017-02-01

Since waterborne minerals appear in ionic form and are readily absorbed by the gastrointestinal tract, drinking water could be a crucial source of mineral intake. However, no comprehensive research has yet determined how trace elements in drinking water relate to body composition. We aimed to assess the relationship between clinically important trace elements in public drinking water and body composition in average, overweight and obese individuals in Turkey. The study's population consisted of 423 participants: 143 overweight, 138 obese and 142 healthy control individuals, grouped according to clinical cutoff points of body mass index (BMI). We measured levels of lithium (Li), nickel (Ni), lead (Pb), silicon (Si), tin (Sn), strontium (Sr), boron (B), aluminium (Al), barium (Ba) and rubidium (Rb) in samples from wells of municipal water by using inductively coupled plasma mass spectrometry. We gauged all the participants' body composition measurements with a BC-418 body composition analyser. In all the participants, body weight values showed significant positive correlations with Ni levels in drinking water, as did BMI values with Al levels and percentage of obesity with Ni, Si and B levels. In particular, Ni levels showed significant positive correlations with the basal metabolic rate, activity calories, and total activity of participants. Giving findings showing correlations between obesity-related parameters and Al, Si, B and Ni content in drinking water, we hope that these associations will be clarified with further studies including cellular, experimental and clinical studies. Hence, medical practitioners must be aware of trace element levels in drinking water for overweight and obese patients.

Trace-fossil and storm-deposit relationships of San Carlos formation, west Texas

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

Metz, C.L.; Bednarski, S.P.

1986-05-01

Two distinct assemblages of trace fossils are preserved in the storm deposits in delta-front facies of the Upper Cretaceous San Carlos Formation, west Texas. The assemblages represent two widely differing responses to storm deposition and sediment-trace-fossil relationships, indicating that other environmental parameters, probably water depth and oxygen levels, influenced trace-fossil distribution within the San Carlos delta front. Evidence of the storm-deposited nature of the sandstones includes a scoured basal contact, planar to hummocky cross-stratification, and a upper contact that is either ripple marked or is gradational with overlying shales.

Collegiate Athletics: An Investigation into Athletic Persistence of Freshman Student-Athletes Participating in NCAA Division-III Varsity Athletic Programs

ERIC Educational Resources Information Center

Sombito, Lester Jamili

2015-01-01

Understanding of the persistence of student-athletes in athletics at the D-III level is complex. This research study investigated the issue of student-athlete retention by focusing on Division III (D-III) student-athlete persistence in athletics by asking the following research question, "To what extent do freshman student-athletes persist in…

Persistence factors among engineering students at the Polytechnic University of Puerto Rico: Student perceptions and curricular implications

NASA Astrophysics Data System (ADS)

Gonzalez Juarbe, Juan M.

Various persistence studies demonstrate that there is a direct correlation between college or university academic program completion and the amount of students' involvement in the college or university on a social, academic, and institutional level. These studies suggest that, over the course of time, the greater the level of involvement the greater the probability of increased persistence towards program completion. Student persistence among Hispanic engineering students was researched at the Polytechnic University of Puerto Rico during the period of January 2002 to April 2003. Persistence factors lead students to either one of the following behaviors: (1) to re-enroll, (2) to switch to another educational program, or (3) to depart from the institution. Increased student persistence is the result of recurring decisions to re-enroll each trimester. Decreased student persistence is the outcome associated with a decision to either depart or switch to another educational vocation. Early departure at the institution is linked to perceptions formed day-to-day as the student experiences the educational environment. These perceptions inspire behavioral outcomes to either persist or depart the education process. Desirable behavioral outcomes are closely related with educational commitments leading to increased persistence. Likewise, undesirable behavioral outcomes are those resulting in decreased persistence. Satisfactory student experiences in successfully achieving social, academic, and institutional responsibilities set the course towards increased persistence. In the research undertaken, student and faculty educational experiences were analyzed and documented. This was accomplished by the use of a combined quantitative and qualitative research methodology. The volunteer participants in this study included: six full time professors, eight part time professors, eighty-one students at a job fair, and seven individual student participants. Personal data on the participants was kept confidential. A questionnaire based on persistence variable indicators was developed and used as a data collection instrument for a statistical quantitative analysis. Eighty-one students responded to questionnaire items using a Likert scale ranging from one representing disagreement to five representing agreement. This was followed by a qualitative analysis to increase the scope and depth of the quantitative phase. The qualitative analysis involved discussions with full time professors, part time professors, students, and student graduates. Persistence indicators were then classified into social, academic, and institutional classifications to develop a graphic model of student persistence and a persistence interaction formula indicator. Student persistence levels are proportionally correlated to student contentment with educational outcomes.

Disease progression in Chinese chronic hepatitis C patients with persistently normal alanine aminotransaminase levels.

PubMed

Hui, C-K; Zhang, H-Y; Shek, T; Yao, H; Yueng, Y-H; Leung, K-W; Lai, S-T; Lai, J-Y; Leung, N; Lau, G K

2007-06-01

Although chronic hepatitis C virus-infected patients with persistently normal alanine aminotransaminase levels usually have mild liver disease, disease progression can still occur. However, it is uncertain which group of patients is at risk of disease progression. To examine the severity of liver disease on liver biopsy in Chinese patients with persistently normal alanine aminotransaminase levels, and their disease progression over time. Eighty-two patients with persistently normal alanine aminotransaminase levels were followed up longitudinally. The median time of follow-up was 8.1 years. Forty-seven of the 82 patients (57.3%) had a second liver biopsy. At the time of analysis, six of the 82 patients (7.3%) developed decompensated liver cirrhosis. Patients with an initial fibrosis stage F2 or F3 [6/23 (26.1%) vs. 0/59 (0%), P < 0.0001] or inflammatory grade A2 or A3 [5/40 (12.5%) vs. 1/42 (2.4%), P = 0.04] were more likely to develop decompensated liver cirrhosis. On multivariate analysis, initial fibrosis stage F2 or F3 was independently associated with progression to decompensated liver cirrhosis (relative risk 2.3, 95% confidence interval 0.03-2.5, P = 0.02). Chinese chronic hepatitis C virus patients with persistently normal alanine aminotransaminase levels with moderate to severe fibrosis at initial evaluation are more likely to develop decompensated liver cirrhosis.

Selenium status and fungi in the protein-losing enteropathy of persistent diarrhea.

PubMed

Dwipoerwantoro, Pramita G; Lukito, Widjaja; Aulia, Diana; Arnaud, Josiane; Roussel, Anne-Marie

2017-06-01

A vicious cycle of infection, malabsorption, and malnutrition has been implicated in the perpetuation of diarrheal disease. This study examined whether persistent diarrhea is associated with changes in selenium status and stool alpha-1 antitrypsin (AAT) concentration. This cross-sectional study included 30 children aged 1-12 years with persistent diarrhea who were hospitalized in Cipto Mangunkusumo Hospital and Fatmawati Hospital, Jakarta, and 30 apparently healthy children who were matched by age and sex and lived in a rural area of Jakarta. Clinical examinations, blood routine tests, erythrocyte glutathione peroxidase (GPX) activity and plasma selenium levels as well as AAT in fresh stool samples were performed in all the subjects. Of 30 children with persistent diarrhea, 17 had moderate malnutrition and 13 had severe malnutrition. The mean plasma selenium was significantly lower in children with persistent diarrhea than in children without diarrhea (86.0 μg/L [95% CI: 76.1-95.9] vs 110 μg/L [95% CI: 104-116, p<0.0001). The mean stool AAT concentration was significantly higher in children with persistent diarrhea than in those without diarrhea (115 mg/dL [95% CI: 38.5-191] vs 16 mg/dL [95% CI: 4.0-13.5, p<0.0001]). Selenium correlated with AAT (p=0.05). Fecal fungi were persistently present. Although selenium status in both groups was optimal for the obtained plasma GPX activity, children with persistent diarrhea exhibited lower plasma selenium levels. This study suggests that the decrease in the plasma selenium level may be the consequence of protein loss and that fungi may be involved.

Significance and Clinical Management of Persistent Low-Level Viremia and Very-Low-Level Viremia in HIV-1-Infected Patients

PubMed Central

Kelly, Sean; Li, Jonathan Z.; Harrigan, P. Richard; Taiwo, Babafemi

2014-01-01

A goal of HIV therapy is to sustain suppression of the plasma viral load below the detection limits of clinical assays. However, widely followed treatment guidelines diverge in their interpretation and recommended management of persistent viremia of low magnitude, reflecting the limited evidence base for this common clinical finding. Here, we review the incidence, risk factors, and potential consequences of low-level HIV viremia (LLV; defined in this review as a viremia level of 50 to 500 copies/ml) and very-low-level viremia (VLLV; defined as a viremia level of <50 copies/ml detected by clinical assays that have quantification cutoffs of <50 copies/ml). Using this framework, we discuss practical issues related to the diagnosis and management of patients experiencing persistent LLV and VLLV. Compared to viral suppression at <50 or 40 copies/ml, persistent LLV is associated with increased risk of antiretroviral drug resistance and overt virologic failure. Higher immune activation and HIV transmission may be additional undesirable consequences in this population. It is uncertain whether LLV of <200 copies/ml confers independent risks, as this level of viremia may reflect assay-dependent artifacts or biologically meaningful events during suppression. Resistance genotyping should be considered in patients with persistent LLV when feasible, and treatment should be modified if resistance is detected. There is a dearth of clinical evidence to guide management when genotyping is not feasible. Increased availability of genotypic assays for samples with viral loads of <400 copies/ml is needed. PMID:24733471

TraceContract: A Scala DSL for Trace Analysis

NASA Technical Reports Server (NTRS)

Barringer, Howard; Havelund, Klaus

2011-01-01

In this paper we describe TRACECONTRACT, an API for trace analysis, implemented in the SCALA programming language. We argue that for certain forms of trace analysis the best weapon is a high level programming language augmented with constructs for temporal reasoning. A trace is a sequence of events, which may for example be generated by a running program, instrumented appropriately to generate events. The API supports writing properties in a notation that combines an advanced form of data parameterized state machines with temporal logic. The implementation utilizes SCALA's support for defining internal Domain Specific Languages (DSLs). Furthermore SCALA's combination of object oriented and functional programming features, including partial functions and pattern matching, makes it an ideal host language for such an API.

Survivable Software

DTIC Science & Technology

2013-04-01

machine transitions. 2. We developed the TraceContract API for trace analysis in the Scala programming language. TraceContract combines a high-level...DATE (DD-MM-YYYY) 2. REPORT TYPE 3. DATES COVERED (From - To) 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER...awarded within the Software and Systems program . The original Pro- gram Manager was David Luginbuhl. Bob Bonneau took over as PM in March 2011. The award

Unraveling energy conversion modeling in the intrinsic persistent upconverted luminescence of solids: a study of native point defects in antiferromagnetic Er2O3.

PubMed

Huang, Bolong

2016-05-11

We investigated the mechanism of the intrinsic persistent luminescence of Er2O3 in the A-type lattice based on first-principles calculations. We found that the native point defects were engaged in mutual subtle interactions in the form of chemical reactions between different charge states. The release of energy related to lattice distortion facilitates the conversion of energy for electrons to be transported between the valence band and the trap levels or even between the deep trap levels so as to generate persistent luminescence. The defect transitions that take place along the zero-phonon line release energy to enable optical transitions, with the exact amount of negative effective correlation energy determined by the lattice distortions. Our calculations on the thermodynamic transition levels confirm that both the visible and NIR experimentally observed intrinsic persistent luminescence (phosphor or afterglow) are related to the thermodynamic transition levels of oxygen-related defects, and the thermodynamic transition levels within different charge states for these defects are independent of the chemical potentials of the given species. Lattice distortion defects such as anion Frenkel (a-Fr) pair defects play an important role in transporting O-related defects between different lattice sites. To obtain red persistent luminescence that matches the biological therapeutic window, it is suggested to increase the electron transition levels between high-coordinated O vacancies and related metastable a-Fr defects; a close-packed core-shell structure is required to quench low-coordinated O-related defects so as to reduce the green band luminescence. We further established a conversed chain reaction (CCR) model to interpret the energy conversion process of persistent luminescence in terms of the inter-reactions of native point defects between different charge states. It is advantageous to use the study of defect levels combined with formation energies to suggest limits to doping energy and explain photostimulated luminescence in terms of native point defects.

Persistent α-Fetoprotein Elevation in Healthy Adults and Mutational Analysis of α-Fetoprotein Promoter, Enhancer, and Silencer Regions.

PubMed

Jeon, Yejoo; Choi, Yun Suk; Jang, Eun Sun; Kim, Jin Wook; Jeong, Sook-Hyang

2017-01-15

α-Fetoprotein (AFP) is normally <10 ng/mL in adults without malignancy or liver regeneration. However, hereditary or nonhereditary persistence of AFP in healthy adults may be encountered in clinical practice. This study describes four cases of persistent AFP elevation in healthy adults and investigates mutations in key transcription regulatory regions of the AFP gene as potential drivers of AFP overexpression. Four healthy adults with persistently elevated AFP levels (12.1 to 186.1 ng/mL) for >1 year, and 20 controls with low AFP levels (<0.61 to 2.9 ng/mL) were included in the study. AFP levels were collected from the families of two of the patients. We sequenced five regions that are critical for AFP expression: a promoter, two enhancers, and two silencers. One of the two cases in which family information was represented is the first case of hereditary persistence of AFP in South Korea. Mutations related to AFP overexpression were not found in the transcription regulatory regions among the four patients. Persistent AFP elevation is a heterogeneous condition with or without a hereditary pattern and may be caused by factors outside of transcription regulatory region changes. Further research on the mechanism of AFP elevation is needed.

Persistent α-Fetoprotein Elevation in Healthy Adults and Mutational Analysis of α-Fetoprotein Promoter, Enhancer, and Silencer Regions

PubMed Central

Jeon, Yejoo; Choi, Yun Suk; Jang, Eun Sun; Kim, Jin Wook; Jeong, Sook-Hyang

2017-01-01

Background/Aims α-Fetoprotein (AFP) is normally <10 ng/mL in adults without malignancy or liver regeneration. However, hereditary or nonhereditary persistence of AFP in healthy adults may be encountered in clinical practice. This study describes four cases of persistent AFP elevation in healthy adults and investigates mutations in key transcription regulatory regions of the AFP gene as potential drivers of AFP overexpression. Methods Four healthy adults with persistently elevated AFP levels (12.1 to 186.1 ng/mL) for >1 year, and 20 controls with low AFP levels (<0.61 to 2.9 ng/mL) were included in the study. AFP levels were collected from the families of two of the patients. We sequenced five regions that are critical for AFP expression: a promoter, two enhancers, and two silencers. Results One of the two cases in which family information was represented is the first case of hereditary persistence of AFP in South Korea. Mutations related to AFP overexpression were not found in the transcription regulatory regions among the four patients. Conclusions Persistent AFP elevation is a heterogeneous condition with or without a hereditary pattern and may be caused by factors outside of transcription regulatory region changes. Further research on the mechanism of AFP elevation is needed. PMID:27609486

Factors Affecting M-Learners' Course Satisfaction and Learning Persistence

ERIC Educational Resources Information Center

Joo, Young Ju; Joung, Sunyoung; Lim, Eugene; Kim, Hae Jin

2014-01-01

This study investigated whether college students' self-efficacy, level of learning strategy use, academic burnout, and school support predict course satisfaction and learning persistence. To this end, self-efficacy, level of learning strategy use, academic burnout, and school support were used as prediction variables, and course satisfaction and…

Evaluation of the persistence of transformation products from ozonation of trace organic compounds - a critical review.

PubMed

Hübner, Uwe; von Gunten, Urs; Jekel, Martin

2015-01-01

Ozonation is an efficient treatment system to reduce the concentration of trace organic compounds (TrOCs) from technical aquatic systems such as drinking water, wastewater and industrial water, etc. Although it is well established that ozonation generally improves the removal of organic matter in biological post-treatment, little is known about the biodegradability of individual transformation products resulting from ozonation of TrOCs. This publication provides a qualified assessment of the persistence of ozone-induced transformation products based on a review of published product studies and an evaluation of the biodegradability of transformation products with the biodegradability probability program (BIOWIN) and the University of Minnesota Pathway Prediction System (UM-PPS). The oxidation of TrOCs containing the four major ozone-reactive sites (olefins, amines, aromatics and sulfur-containing compounds) follows well described reaction pathways leading to characteristic transformation products. Assessment of biodegradability revealed a high sensitivity to the formed products and hence the ozone-reactive site present in the target compound. Based on BIOWIN, efficient removal can be expected for products from cleavage of olefin groups and aromatic rings. In contrast, estimations and literature indicate that hydroxylamines and N-oxides, the major products from ozonation of secondary and tertiary amines are not necessarily better removed in biological post-treatment. According to UM-PPS, degradation of these products might even occur via reformation of the corresponding amine. Some product studies with sulfide-containing TrOCs showed a stoichiometric formation of sulfoxides from oxygen transfer reactions. However, conclusions on the fate of transformation products in biological post-treatment cannot be drawn based on BIOWIN and UM-PPS.

Use of an ultra-clean sampling technique with inductively coupled plasma-mass spectrometry to determine trace-element concentrations in water from the Kirkwood-Cohansey Aquifer system, coastal plain, New Jersey

USGS Publications Warehouse

Ivahnenko, Tamara; Szabo, Zoltan; Hall, G.S.

1996-01-01

Water samples were collected during 1993 from 22 public supply wells screened in the Kirkwood-Cohansey aquifer system; concentrations of 18 trace elements were determined primarily by using inductively coupled plasma-mass spectrometry (ICP-MS) techniques, though graphite furnace atomic adsorption, hydride generation, and cold- vapor flameless atomic adsorption techniques were used for thallium, arsenic, and mercury, respectively, at the U.S. Geological Survey (USGS) National Water Quality Laboratory (NWQL). In addition, laboratory measurements of alkalinity and turbidity were made. The ground-water samples were collected by using ultra-clean sampling protocols developed by the USGS for collecting ground-water samples in areas with water containing low concentrations of trace elements. This technique is based on recently gained experience in sampling surface water for these elements. Field parameters (water temperature, specific conductance, pH, and dissolved-oxygen concentration) were monitored prior to sample collection. Three equipment blanks were collected to ensure that low-level trace-element contamination did not occur during sample collection. One split sample and a commercially- prepared reference standard were submitted to the NWQL o evaluate laboratory precision and accuracy, respectively. Trace-element concentrations in 10 sample splits and one equipment blank were also determined at the Rutgers University Chemistry Department laboratory. Results of the ICP-MS analyses and cold vapor flameless atomic absorption indicated that five trace elements-- cobalt, copper, lead, mercury, and nickel--were detectable in low concentrations (<0.1-29 mg/L) in most of the samples from the 22 wells, and four elements--aluminum, barium, manganese and zinc--were detected in higher concentrations than the other elements (30-710 mg/L for aluminum; 4-180 mg/L for barium, manganese, and zinc). The remaining nine trace elements were present in concentrations consistently lower than the minimum reporting limit. Turbidity was low (less than 1 nephelometric turbidity unit (NTU)), indicating that the trace-element concentrations were present in the dissolved phase and ideally would be reproducible in the absence of highly variable concentrations of particulates. The concentration of lead in one sample exceeded the U.S. Environmental Protection Agency (USEPA) action level of 15 mg/L; concentrations ranged from <1 to 16 mg/L. Mercury was frequently detected; concentrations ranged from <0.1 to 1.1 mg/L but did not exceed the USEPA maximum contaminant level. Results of analyses of the equipment blanks indicated that samples collected by using the new ultra-clean sampling protocols were free of low-level (< 1mg/L) trace-element contamination. The analysis of the split sample sent to the NWQL had a difference of 5 percent or less for all constituents except aluminum, for which the analysis had a difference of 10 percent. Results of ICP-MS analyses of split water samples sent to the Rutgers University Chemistry Department laboratory were, in general, in good agreement (within 10 percent) with those of the NWQL. Results of the analysis of the commercial standard agreed (within 5 percent) with the known concentrations of the trace elements. The quality-assurance data (three blanks, one split sample, and one standard), although not statistically evaluated because of the small data set, indicate that the measured trace-element concentrations are precise and accurate and that the samples were free of contamination at the microgram-per-liter level of contamination.

[Galectin-3 in Patients With Paroxysmal and Persistent Atrial Fibrillation and Metabolic Syndrome].

PubMed

A, V A; Zaslavskaya, E L; Soboleva, A V; Baranova, E I; Listopad, O V; Nifontov, S E; Nrady, A O; Shlyakhto, E V

2016-06-01

To evaluate serum galectin 3 and to determine the potential clinical value of this parameter in patients with atrial fibrillation - AF (paroxysmal and persistent) and metabolic syndrome (MS). We examined 100 patients with MS (50 with paroxysmal or persistent AF and 50 without arrhythmia) and 50 healthy persons. Serum galectin 3 measured by ELISA method, ECHO cardiography was performed to all examined persons. Galectin 3 in patients with MS and AF was higher, than in patients with MS without arrhythmia and much more higher than galectin 3 in healthy persons 0,72 (0,44;1,36), 0,44 (0,42;1,22) and 0,32 (0,28;0,42) ng/ml (<0,01). In patients with persistent AF levels of galectin 3 is higher than in patients with paroxysmal AF. Positive correlation between the levels of galectin 3 and duration arrhythmia was revealed (r=0,301; p<0,01). Higher level of galectin 3 was revealed in patients with frequent paroxysms of AF and ineffective antiarrhythmic therapy. Marker of myocardial fibrosis serum galectin 3 in patients with atrial fibrillation and metabolic syndrome is higher than in patients with the metabolic syndrome, without this arrhythmia and higher than in healthy controls. In patients with persistent AF level of galectin 3 was higher than in patients with paroxysmal AF.

Trace elements contamination and human health risk assessment in drinking water from Shenzhen, China.

PubMed

Lu, Shao-You; Zhang, Hui-Min; Sojinu, Samuel O; Liu, Gui-Hua; Zhang, Jian-Qing; Ni, Hong-Gang

2015-01-01

The levels of seven essential trace elements (Mn, Co, Ni, Cu, Zn, Se, and Mo) and six non-essential trace elements (Cr, As, Cd, Sb, Hg, and Pb) in a total of 89 drinking water samples collected in Shenzhen, China were determined using inductively coupled plasma mass spectrometry (ICP-MS) in the present study. Both the essential and non-essential trace elements were frequently detectable in the different kinds of drinking waters assessed. Remarkable temporal and spatial variations were observed among most of the trace elements in the tap water collected from two tap water treatment plants. Meanwhile, potential human health risk from these non-essential trace elements in the drinking water for local residents was also assessed. The median values of cancer risks associated with exposure to carcinogenic metals via drinking water consumption were estimated to be 6.1 × 10(-7), 2.1 × 10(-8), and 2.5 × 10(-7) for As, Cd, and Cr, respectively; the median values of incremental lifetime for non-cancer risks were estimated to be 6.1 × 10(-6), 4.4 × 10(-5), and 2.2 × 10(-5) for Hg, Pb, and Sb, respectively. The median value of total incremental lifetime health risk induced by the six non-essential trace elements for the population was 3.5 × 10(-5), indicating that the potential health risks from non-carcinogenic trace elements in drinking water also require some attention. Sensitivity analysis indicates that the most important factor for health risk assessment should be the levels of heavy metal in drinking water.

Molybdenum drawdown during Cretaceous Oceanic Anoxic Event 2

NASA Astrophysics Data System (ADS)

Goldberg, Tatiana; Poulton, Simon W.; Wagner, Thomas; Kolonic, Sadat F.; Rehkämper, Mark

2016-04-01

During the Cretaceous greenhouse, episodes of widespread ocean deoxygenation were associated with globally occurring events of black shale deposition. Possibly the most pronounced of these oceanic anoxic events (OAE's) was the Cenomanian-Turonian OAE2 (∼94 Ma). However, although certain redox sensitive trace metals tend to be preferentially sequestered in sediments deposited under anoxic conditions, with Mo drawdown being specifically prone to euxinic settings, these elements are generally somewhat depleted in sediments deposited during OAE2. To understand the driving factors responsible for this depleted trace metal drawdown, we have studied a low latitude section from the proto-North Atlantic Ocean (Tarfaya S57), where existing biomarker and iron-sulphur data point to a dominantly euxinic water column, with periodic transitions to ferruginous (Fe-rich) water column conditions. We utilise a variety of redox proxies (Fe-speciation, redox sensitive trace metals and Mo isotopes), which, in combination, allows us to evaluate the detailed nature of ocean redox conditions and hence controls on trace metal drawdown. The results suggest that seawater δ98Mo values may have ranged between ∼0.6 and 1.1‰ during OAE2, likely connected to changes in the local Mo reservoir as a consequence of low and probably heterogeneous concentrations of Mo in the ocean. The very low Mo/TOC ratios at Tarfaya and elsewhere in the proto-North Atlantic may support a model in which deep-water circulation was partially restricted within and between the North Atlantic and other ocean basins. We propose that the combination of a low and possibly heterogeneous δ98Mo of seawater Mo, together with low Mo/TOC ratios, points to a large decrease in the global oceanic Mo reservoir during OAE2, reflecting a major global scale increase in Mo drawdown under persistent euxinic conditions.

Environmental Mycobiome Modifiers of Inflammation and Fibrosis in Systemic Sclerosis

DTIC Science & Technology

2016-09-01

TUBB), and ribosomal proteins), while others are considered specific to SSc despite trace level detection in controls. For ex- ample, multiple SSc...Strong re- activity was seen against all five proteins in SSc with only trace levels detected in controls (Fig. 3a), indicating widespread immune...sequences in SSc RNA-seq data was used to detect microbial sequences in human tissues in an unbiased, quantitative manner. Our studies suggest that

Comparison of methods for measurement of organic compounds at ultra-trace level: analytical criteria and application to analysis of amino acids in extraterrestrial samples.

PubMed

Vandenabeele-Trambouze, O; Claeys-Bruno, M; Dobrijevic, M; Rodier, C; Borruat, G; Commeyras, A; Garrelly, L

2005-02-01

The need for criteria to compare different analytical methods for measuring extraterrestrial organic matter at ultra-trace levels in relatively small and unique samples (e.g., fragments of meteorites, micrometeorites, planetary samples) is discussed. We emphasize the need to standardize the description of future analyses, and take the first step toward a proposed international laboratory network for performance testing.

Volatile organic compounds and trace metal level in some beers collected from Romanian market

NASA Astrophysics Data System (ADS)

Voica, Cezara; Kovacs, Melinda; Vadan, Marius

2013-11-01

Beer is one of the most popular beverages at worldwide level. Through this study fifteen different types of beer collected from Romanian market were analysed in order to evaluate their mineral, trace element as well the their organic content. Importance of such characterization of beer samples is supported by the fact that their chemical composition can affect both taste and stability of beer, as well the consumer health. Minerals and trace elements analysis were performed on ICP-MS while organic compounds analysis was done through GC-MS. Through ICP-MS analysis, elements as Ca, Na, K and Mg were evidenced at mgṡkg-1 order while elements as Cr, Ba, Co, Ni were detected at lower level. After GC-MS analysis the major volatile compounds that were detected belong to alcohols namely ethanol, propanol, isobutanol, isoamyl alcohol and linalool. Selected fatty acids and esters were evidenced also in the studied beer samples.

Proton transfer reaction mass spectrometry: on-line trace gas analysis at the ppb level

NASA Astrophysics Data System (ADS)

Hansel, A.; Jordan, A.; Holzinger, R.; Prazeller, P.; Vogel, W.; Lindinger, W.

1995-11-01

A system for trace gas analysis using proton transfer reaction mass spectrometry (PTR-MS) has been developed which allows for on-line measurements of components with concentrations as low as 1 ppb. The method is based on reactions of H3O+ ions, which perform non-dissociative proton transfer to most of the common organic trace constituents but do not react with any of the components present in clean air. Examples of analysis of breath taken from smokers and non-smokers as well as from patients suffering from cirrhosis of the liver, and of air in buildings as well as of ambient air taken at a road crossing demonstrate the wide range of applicability of this method. An enhanced level of acetonitrile in the breath is a most suitable indicator that a person is a smoker. Enhanced levels of propanol strongly indicate that a person has a severe liver deficiency.

Trace element concentrations in feathers and blood of Northern goshawk (Accipiter gentilis) nestlings from Norway and Spain.

PubMed

Dolan, Kevin J; Ciesielski, Tomasz M; Lierhagen, Syverin; Eulaers, Igor; Nygård, Torgeir; Johnsen, Trond V; Gómez-Ramírez, Pilar; García-Fernández, Antonio J; Bustnes, Jan O; Ortiz-Santaliestra, Manuel E; Jaspers, Veerle L B

2017-10-01

Information on trace element pollution in the terrestrial environment and its biota is limited compared to the marine environment. In the present study, we collected body feathers and blood of 37 Northern goshawk (Accipiter gentilis) nestlings from Tromsø (northern Norway), Trondheim (central Norway), and Murcia (southeastern Spain) to study regional exposure, hypothesizing the potential health risks of metals and other trace elements. Blood and body feathers were analyzed by a high resolution inductively coupled plasma mass spectrometer (HR-ICP-MS) for aluminum (Al), nickel (Ni), copper (Cu), zinc (Zn), arsenic (As), selenium (Se), cadmium (Cd), mercury (Hg) and lead (Pb). The influence of regional differences, urbanization and agricultural land usage in proximity to the nesting Northern goshawks was investigated using particular spatial analysis techniques. Most trace elements were detected below literature blood toxicity thresholds, except for elevated concentrations (mean ± SD µgml -1 ww) found for Zn (5.4 ± 1.5), Cd (0.00023 ± 0.0002), and Hg (0.021 ± 0.01). Corresponding mean concentrations in feathers (mean ± SD µgg -1 dw) were 82.0 ± 12.4, 0.0018 ± 0.002, and 0.26 ± 0.2 for Zn, Cd and Hg respectively. Multiple linear regressions indicated region was a significant factor influencing Al, Zn, Se and Hg feather concentrations. Blood Cd and Hg concentrations were significantly influenced by agricultural land cover. Urbanization did not have a significant impact on trace element concentrations in either blood or feathers. Overall metal and trace element levels do not indicate a high risk for toxic effects in the nestlings. Levels of Cd in Tromsø and Hg in Trondheim were however above sub-lethal toxic threshold levels. For holistic risk assessment purposes it is important that the concentrations found in the nestlings of this study indicate that terrestrial raptors are exposed to various trace elements. Copyright © 2017 Elsevier Inc. All rights reserved.

Concentrations of polycyclic aromatic hydrocarbons and trace elements in Arctic soils: A case-study in Svalbard.

PubMed

Marquès, Montse; Sierra, Jordi; Drotikova, Tatiana; Mari, Montse; Nadal, Martí; Domingo, José L

2017-11-01

A combined assessment on the levels and distribution profiles of polycyclic aromatic hydrocarbons (PAHs) and trace elements in soils from Pyramiden (Central Spitsbergen, Svalbard Archipelago) is here reported. As previously stated, long-range atmospheric transport, coal deposits and previous mining extractions, as well as the stack emissions of two operative power plants at this settlement are considered as potential sources of pollution. Eight top-layer soil samples were collected and analysed for the 16 US EPA priority PAHs and for 15 trace elements (As, Be, Cd, Co, Cr, Cu, Hg, Mn, Mo, Ni, Pb, Sn, Tl, V and Zn) during late summer of 2014. The highest levels of PAHs and trace elements were found in sampling sites located near two power plants, and at downwind from these sites. The current PAH concentrations were even higher than typical threshold values. The determination of the pyrogenic molecular diagnostic ratios (MDRs) in most samples revealed that fossil fuel burning might be heavily contributing to the PAHs levels. Two different indices, the Pollution Load Index (PLI) and the Geoaccumulation Index (Igeo), were determined for assessing soil samples with respect to trace elements pollution. Samples collected close to the power plants were found to be slightly and moderately polluted with zinc (Zn) and mercury (Hg), respectively. The Spearman correlation showed significant correlations between the concentrations of 16 PAHs and some trace elements (Pb, V, Hg, Cu, Zn, Sn, Be) with the organic matter content, indicating that soil properties play a key role for pollutant retention in the Arctic soils. Furthermore, the correlations between ∑16 PAHs and some trace elements (e.g., Hg, Pb, Zn and Cu) suggest that the main source of contamination is probably pyrogenic, although the biogenic and petrogenic origin of PAHs should not be disregarded according to the local geology. Copyright © 2017 Elsevier Inc. All rights reserved.

Analysis of Trace Gas Mixtures Using an External Cavity Quantum Cascade Laser Sensor

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

Phillips, Mark C.; Taubman, Matthew S.; Brumfield, Brian E.

2015-07-01

We measure and analyze mixtures of trace gases at ppb-ppm levels using an external cavity quantum cascade laser sensor with a 1-second response time. Accurate spectral fits are obtained in the presence of overlapping spectra.

Trace conditioning in insects—keep the trace!

PubMed Central

Dylla, Kristina V.; Galili, Dana S.; Szyszka, Paul; Lüdke, Alja

2013-01-01

Trace conditioning is a form of associative learning that can be induced by presenting a conditioned stimulus (CS) and an unconditioned stimulus (US) following each other, but separated by a temporal gap. This gap distinguishes trace conditioning from classical delay conditioning, where the CS and US overlap. To bridge the temporal gap between both stimuli and to form an association between CS and US in trace conditioning, the brain must keep a neural representation of the CS after its termination—a stimulus trace. Behavioral and physiological studies on trace and delay conditioning revealed similarities between the two forms of learning, like similar memory decay and similar odor identity perception in invertebrates. On the other hand differences were reported also, like the requirement of distinct brain structures in vertebrates or disparities in molecular mechanisms in both vertebrates and invertebrates. For example, in commonly used vertebrate conditioning paradigms the hippocampus is necessary for trace but not for delay conditioning, and Drosophila delay conditioning requires the Rutabaga adenylyl cyclase (Rut-AC), which is dispensable in trace conditioning. It is still unknown how the brain encodes CS traces and how they are associated with a US in trace conditioning. Insects serve as powerful models to address the mechanisms underlying trace conditioning, due to their simple brain anatomy, behavioral accessibility and established methods of genetic interference. In this review we summarize the recent progress in insect trace conditioning on the behavioral and physiological level and emphasize similarities and differences compared to delay conditioning. Moreover, we examine proposed molecular and computational models and reassess different experimental approaches used for trace conditioning. PMID:23986710

Academic Persistence of International Student-Athletes at NCAA Division I Institutions

ERIC Educational Resources Information Center

Kitsos, Jayne M.

2012-01-01

This study examined academic support programs and personnel that contributed to international student-athlete academic persistence at the National Collegiate Athletics Association (NCAA) Division I level. The purpose of the study was to identify athletic academic personnel's explanations for the academic persistence of NCAA Division I…

Virus-host interactions in persistently FMDV-infected cells derived from bovine pharynx

USDA-ARS?s Scientific Manuscript database

Foot-and-mouth disease virus (FMDV) produces a disease in cattle characterized by vesicular lesions and a persistent infection with asymptomatic low-level production of virus. Here we describe the establishment of a persistently infected primary cell culture derived from bovine pharynx tissue (PBPT)...

Short-Term and Long-Term Biological Effects of Chronic Chemical Contamination on Natural Populations of a Marine Bivalve.

PubMed

Breitwieser, Marine; Viricel, Amélia; Graber, Marianne; Murillo, Laurence; Becquet, Vanessa; Churlaud, Carine; Fruitier-Arnaudin, Ingrid; Huet, Valérie; Lacroix, Camille; Pante, Eric; Le Floch, Stéphane; Thomas-Guyon, Hélène

2016-01-01

Understanding the effects of chronic chemical contamination on natural populations of marine organisms is complex due to the combined effects of different types of pollutants and environmental parameters that can modulate the physiological responses to stress. Here, we present the effects of a chronic contamination in a marine bivalve by combining multiple approaches that provide information on individual and population health. We sampled variegated scallops (Mimachlamys varia) at sites characterized by different contaminants and contamination levels to study the short and long-term (intergenerational) responses of this species to physiological stress. We used biomarkers (SOD, MDA, GST, laccase, citrate synthase and phosphatases) as indicators of oxidative stress, immune system alteration, mitochondrial respiration and general metabolism, and measured population genetic diversity at each site. In parallel, concentration of 14 trace metals and 45 organic contaminants (PAHs, PCBs, pesticides) in tissues were measured. Scallops were collected outside and during their reproductive season to investigate temporal variability in contaminant and biomarker levels. Our analyses revealed that the levels of two biomarkers (Laccase-type phenoloxidase and malondialdehyde) were significantly correlated with Cd concentration. Additionally, we observed significant seasonal differences for four of the five biomarkers, which is likely due to the scallop reproductive status at time of sampling. As a source of concern, a location that was identified as a reference site on the basis of inorganic contaminant levels presented the same level of some persistent organic pollutants (DDT and its metabolites) than more impacted sites. Finally, potential long-term effects of heavy metal contamination were observed for variegated scallops as genetic diversity was depressed in the most polluted sites.

Determination of a No-Observable Effect Level for Endotoxin Following a Single Intravitreal Administration to Dutch Belted Rabbits.

PubMed

Bantseev, Vladimir; Miller, Paul E; Bentley, Ellison; Schuetz, Chris; Streit, Tim M; Christian, Brian J; Farman, Cindy; Booler, Helen; Thackaberry, Evan A

2017-03-01

The purpose of this study was to characterize the inflammatory response and determine a no-observable effect level (NOEL) in rabbit eyes after endotoxin intravitreal (ITV) injection. Fifty-three naïve male Dutch Belted rabbits were treated with a single 50-μL ITV injection ranging from 0.01 to 0.75 endotoxin units/eye (EU/eye) and monitored for up to 42 days post treatment. Ophthalmic examination included slit-lamp biomicroscopy and indirect ophthalmoscopy. Laser flare photometry was performed in a subset of animals. On days 2, 8, 16, and 43, a subset of animals was necropsied and eyes processed for histopathological evaluation. Intravitreal injection of endotoxin at ≥0.05 EU/eye resulted in a dose-related anterior segment inflammation response. No aqueous flare or cell response was noted in the 0.01 EU/eye dose group. A more delayed posterior segment response characterized by vitreal cell response was observed beginning on day 5, peaking on day 9, and decreasing starting on day 16 that persisted at trace to a level of 1+ on day 43. Microscopy findings of infiltrates of minimal mixed inflammatory cells in the vitreous and subconjunctiva and proteinaceous fluid in the anterior chamber and/or vitreous were observed in eyes given ≥0.1 EU/eye. We defined the NOEL for ITV endotoxin to be 0.01 EU/eye, suggesting that the vitreal cavity is more sensitive to the effects of endotoxin than the anterior segment and aqueous chamber. These data highlight the importance of assessing endotoxin level in intravitreal formulations, as levels as low as 0.05 EU/eye may confound the safety evaluations of intravitreal therapeutics in rabbits.

Short-Term and Long-Term Biological Effects of Chronic Chemical Contamination on Natural Populations of a Marine Bivalve

PubMed Central

Graber, Marianne; Murillo, Laurence; Becquet, Vanessa; Churlaud, Carine; Fruitier-Arnaudin, Ingrid; Huet, Valérie; Lacroix, Camille; Pante, Eric; Le Floch, Stéphane; Thomas-Guyon, Hélène

2016-01-01

Understanding the effects of chronic chemical contamination on natural populations of marine organisms is complex due to the combined effects of different types of pollutants and environmental parameters that can modulate the physiological responses to stress. Here, we present the effects of a chronic contamination in a marine bivalve by combining multiple approaches that provide information on individual and population health. We sampled variegated scallops (Mimachlamys varia) at sites characterized by different contaminants and contamination levels to study the short and long-term (intergenerational) responses of this species to physiological stress. We used biomarkers (SOD, MDA, GST, laccase, citrate synthase and phosphatases) as indicators of oxidative stress, immune system alteration, mitochondrial respiration and general metabolism, and measured population genetic diversity at each site. In parallel, concentration of 14 trace metals and 45 organic contaminants (PAHs, PCBs, pesticides) in tissues were measured. Scallops were collected outside and during their reproductive season to investigate temporal variability in contaminant and biomarker levels. Our analyses revealed that the levels of two biomarkers (Laccase-type phenoloxidase and malondialdehyde) were significantly correlated with Cd concentration. Additionally, we observed significant seasonal differences for four of the five biomarkers, which is likely due to the scallop reproductive status at time of sampling. As a source of concern, a location that was identified as a reference site on the basis of inorganic contaminant levels presented the same level of some persistent organic pollutants (DDT and its metabolites) than more impacted sites. Finally, potential long-term effects of heavy metal contamination were observed for variegated scallops as genetic diversity was depressed in the most polluted sites. PMID:26938082

Trace metals and persistent organic pollutants in sediments from river-reservoir systems in Democratic Republic of Congo (DRC): Spatial distribution and potential ecotoxicological effects.

PubMed

Mwanamoki, Paola M; Devarajan, Naresh; Thevenon, Florian; Birane, Niane; de Alencastro, Luiz Felippe; Grandjean, Dominique; Mpiana, Pius T; Prabakar, Kandasamy; Mubedi, Josué I; Kabele, Christophe G; Wildi, Walter; Poté, John

2014-09-01

This paper discusses the occurrence and spatial distribution of metals and persistent organic pollutants (POPs: including organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), Polybrominated diphenyl ethers (PBDEs), and polycyclic aromatic hydrocarbons (PAHs) in sediments from a river-reservoir system. Surface sediments were sampled from thirteen sites of the Congo River Basin and Lake Ma Vallée, both situated in the vicinity of the capital city Kinshasa (Congo Democratic Republic). Sediment qualities were evaluated using toxicity test based on exposing Ostracods to the sediment samples. The highest metal concentrations were observed in sediments subjected to anthropogenic influences, urban runoff and domestic and industrial wastewaters, discharge into the Congo River basin. Ostracods exposed to the sediments resulted in 100% mortality rates after 6d of incubation, indicating the ultimate toxicity of these sediments as well as potential environmental risks. The POPs and PAHs levels in all sediment samples were low, with maximum concentration found in the sediments (area of pool Malebo): OCP value ranged from 0.02 to 2.50 with ∑OCPs: 3.3μgkg(-1); PCB ranged from 0.07 to 0.99 with Total PCBs (∑7×4.3): 15.31μgkg(-1); PAH value ranged from 0.12 to 9.39 with ∑PAHs: 63.89μgkg(-1). Our results indicate that the deterioration of urban river-reservoir water quality result mainly from urban stormwater runoff, untreated industrial effluents which discharge into the river-reservoirs, human activities and uncontrolled urbanization. This study represents useful tools incorporated to evaluate sediment quality in river-reservoir systems which can be applied to similar aquatic environments. Copyright © 2014 Elsevier Ltd. All rights reserved.

The role of the seagrass Posidonia oceanica in the cycling of trace elements

NASA Astrophysics Data System (ADS)

Sanz-Lázaro, C.; Malea, P.; Apostolaki, E. T.; Kalantzi, I.; Marín, A.; Karakassis, I.

2012-03-01

The aim of this work was to study the role of the seagrass Posidonia oceanica on the cycling of a wide set of trace elements (Ag, As, Ba, Bi, Cd, Co, Cr, Cs, Cu, Fe, Ga, Li, Mn, Ni, Pb, Rb, Sr, Tl, V and Zn). We measured the concentration of these trace elements in the different compartments of P. oceanica (leaves, rhizomes, roots and epibiota) in a non-polluted seagrass meadow representative of the Mediterranean and calculated the annual budget from a mass balance. We provide novel data on accumulation dynamics of many trace elements in P. oceanica compartments and demonstrate that trace element accumulation patterns are mainly determined by plant compartment rather than by temporal variability. Epibiota was the compartment which showed the greatest concentrations for most trace elements. Thus, they constitute a key compartment when estimating trace element transfer to higher trophic levels by P. oceanica. For most trace elements, translocation seemed to be low and acropetal. Zn, Cd, Sr and Rb were the trace elements that showed the highest release rate through decomposition of plant detritus, while Cs, Tl and Bi the lowest. P. oceanica acts as a sink of potentially toxic trace elements (Ni, Cr, As and Ag), which can be sequestered, decreasing their bioavailability. P. oceanica may have a relevant role in the cycling of trace elements in the Mediterranean.

The role of the seagrass Posidonia oceanica in the cycling of trace elements

NASA Astrophysics Data System (ADS)

Sanz-Lázaro, C.; Malea, P.; Apostolaki, E. T.; Kalantzi, I.; Marín, A.; Karakassis, I.

2012-07-01

The aim of this study was to investigate the role of the seagrass Posidonia oceanica on the cycling of a wide set of trace elements (Ag, As, Ba, Bi, Cd, Co, Cr, Cs, Cu, Fe, Ga, Li, Mn, Ni, Pb, Rb, Sr, Tl, V and Zn). We measured the concentration of these trace elements in different compartments of P. oceanica (leaves, rhizomes, roots and epiphytes) in a non-polluted seagrass meadow representative of the Mediterranean and calculated the annual budget from a mass balance. We provide novel data on accumulation dynamics of many trace elements in P. oceanica compartments and demonstrate that trace element accumulation patterns are mainly determined by plant compartment rather than by temporal variability. Epiphytes were the compartment, which showed the greatest concentrations for most trace elements. Thus, they constitute a key compartment when estimating trace element transfer to higher trophic levels by P. oceanica. Trace element translocation in P. oceanica seemed to be low and acropetal in most cases. Zn, Cd, Sr and Rb were the trace elements that showed the highest release rate through decomposition of plant detritus, while Cs, Tl and Bi showed the lowest. P. oceanica acts as a sink of potentially toxic trace elements (Ni, Cr, As and Ag), which can be sequestered, decreasing their bioavailability. P. oceanica may have a relevant role in the cycling of trace elements in the Mediterranean.

Advancing neuroscience through epigenetics: molecular mechanisms of learning and memory.

PubMed

Molfese, David L

2011-01-01

Humans share 96% of our 30,000 genes with Chimpanzees. The 1,200 genes that differ appear at first glance insufficient to describe what makes us human and them apes. However, we are now discovering that the mechanisms that regulate how genes are expressed tell a much richer story than our DNA alone. Sections of our DNA are constantly being turned on or off, marked for easy access, or secluded and hidden away, all in response to ongoing cellular activity. In the brain, neurons encode information-in effect memories-at the cellular level. Yet while memories may last a lifetime, neurons are dynamic structures. Every protein in the synapse undergoes some form of turnover, some with half-lives of only hours. How can a memory persist beyond the lifetimes of its constitutive molecular building blocks? Epigenetics-changes in gene expression that do not alter the underlying DNA sequence-may be the answer. In this article, epigenetic mechanisms including DNA methylation and acetylation or methylation of the histone proteins that package DNA are described in the context of animal learning. Through the interaction of these modifications a "histone code" is emerging wherein individual memories leave unique memory traces at the molecular level with distinct time courses. A better understanding of these mechanisms has implications for treatment of memory disorders caused by normal aging or diseases including schizophrenia, Alzheimer's, depression, and drug addiction.

From streets to streams: assessing the toxicity potential of urban sediment by particle size

USGS Publications Warehouse

Corsi, Steven R.; Selbig, William R.; Roger T. Bannerman,; ,

2013-01-01

Urban sediment can act as a transport mechanism for a variety of pollutants to move towards a receiving water body. The concentrations of these pollutants oftentimes exceed levels that are toxic to aquatic organisms. Many treatment structures are designed to capture coarse sediment but do not work well to similarly capture the fines. This study measured concentrations of select trace metals and PAHs in both the silt and sand fractions of urban sediment from four sources: stormwater bed, stormwater suspended, street dirt, and streambed. Concentrations were used to assess the toxic potential of sediment based on published sediment quality guidelines. All sources of sediment showed some level of toxic potential with stormwater bed sediment the highest followed by stormwater suspended, street dirt, and streambed. Both metal and PAH concentration distributions were highly correlated between the four sampling locations suggesting the presence of one or perhaps only a few sources of these pollutants which remain persistent as sediment is transported from street to stream. Comparison to other forms of combustion- and vehicle-related sources of PAHs revealed coal tar sealants to have the strongest correlation, in both the silt and sand fractions, at all four sampling sites. This information is important for environmental managers when selecting the most appropriate Best Management Practice (BMP) as a way to mitigate pollution conveyed in urban stormwater from source to sink.

Role of Stress and Smoking as Modifiable Risk Factors for Nonpersistent and Persistent Back Pain in Women.

PubMed

Schmelzer, Amy C; Salt, Elizabeth; Wiggins, Amanda; Crofford, Leslie J; Bush, Heather; Mannino, David M

2016-03-01

The purpose of this study was to examine the association between smoking and stress with nonpersistent and persistent back pain. Participants included 3703 women who took part in the Kentucky Women's Health Registry in 2008 and 2011. Multivariate logistic regression modeling was used to examine whether smoking status and stress levels were predictive of nonpersistent and persistent back pain, controlling for sociodemographic characteristics. Stress level was associated with both nonpersistent and persistent back pain, whereas smoking was associated with only persistent back pain. Current smokers were 1.5 times more likely to report persistent back pain compared with never smokers, controlling for age, race, body mass index, educational attainment, and employment status. Women experiencing large or overwhelming amounts of stress were 1.8 times more likely to have nonpersistent back pain and 1.6 times more likely to report persistent back pain, compared with women experiencing small amounts of stress. This study further substantiates the findings of prior research that describes a significant relationship between back pain, stress, and smoking. Understanding the role of modifiable risk factors (ie, smoking and stress) and their impact on back pain provides an opportunity to offer a comprehensive and tailored treatment plan.

Persister formation in Staphylococcus aureus is associated with ATP depletion

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

Conlon, Brian P.; Rowe, Sarah E.; Gandt, Autumn Brown

Persisters are dormant phenotypic variants of bacterial cells that are tolerant to killing by antibiotics1. Persisters are associated with chronic bacterial infection and antibiotic treatment failure. In Escherichia coli, toxin/antitoxin (TA) modules are responsible for persister formation. The mechanism of persister formation in Gram positive bacteria is unknown. Staphylococcus aureus is a major human pathogen, responsible for a variety of chronic and relapsing infections such as osteomyelitis, endocarditis and infections of implanted devices. Deleting TA modules in S. aureus did not affect the level of persisters. Here we show that S. aureus persisters are produced due to a stochastic entrancemore » to stationary phase accompanied by a drop in intracellular ATP. Cells expressing stationary state markers are present throughout the growth phase, increasing in frequency with cell density. Cell sorting revealed that expression of stationary markers was associated with a 100-1000 fold increased likelihood of survival to antibiotic challenge. We find that the antibiotic tolerance of these cells is due to a drop in intracellular ATP. The ATP level of the cell is predictive of bactericidal antibiotic efficacy and explains bacterial tolerance to antibiotic treatment.« less

The dynamics of local quantum uncertainty and trace distance discord for two-qubit X states under decoherence: a comparative study

NASA Astrophysics Data System (ADS)

Slaoui, A.; Daoud, M.; Laamara, R. Ahl

2018-07-01

We employ the concepts of local quantum uncertainty and geometric quantum discord based on the trace norm to investigate the environmental effects on quantum correlations of two bipartite quantum systems. The first one concerns a two-qubit system coupled with two independent bosonic reservoirs. We show that the trace discord exhibits frozen phenomenon contrarily to local quantum uncertainty. The second scenario deals with a two-level system, initially prepared in a separable state, interacting with a quantized electromagnetic radiation. Our results show that there exists an exchange of quantum correlations between the two-level system and its surrounding which is responsible for the revival phenomenon of non-classical correlations.

Phytoaccumulation of trace elements by wetland plants. 2: Water hyacinth

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

Zhu, Y.L.; Zayed, A.M.; Qian, J.H.

Wetland plants are being used successfully for the phytoremediation of trace elements in natural and constructed wetlands. This study demonstrates the potential of water hyacinth (Eichhornia crassipes), an aquatic floating plant, for the phytoremediation of six trace elements. The ability of water hyacinth to take up and translocate six trace elements--As(V), Cd(II), Cr(VI), Cu(II), Ni(II), and Se(VI)--was studied under controlled conditions. Water hyacinth accumulated Cd and Cr best, Se and Cu at moderate levels, and was a poor accumulator of As and Ni. The highest levels of Cd found in shoots and roots were 371 and 6103 mg kg[sup [minus]1]more » dry wt., respectively, and those of Cr were 119 and 32951 mg kg[sup [minus]1] dry wt, respectively. Cadmium, Cr, Cu, Ni, and As were more highly accumulated in roots than in shoots. In contrast, Se was accumulated more in shoots than in roots at most external concentrations. Water hyacinth had high trace element bioconcentration factors when supplied with low external concentrations of all six elements, particularly Cd, Cr, and Cu. Therefore, water hyacinth will be very efficient at phytoextracting trace elements from wastewater containing low concentrations of these elements. The authors conclude that water hyacinth is a promising candidate for phytoremediation of wastewater polluted with Cd, Cr, Cu, and Se.« less

Sediment and water chemistry of the San Juan River and Escalante River deltas of Lake Powell, Utah, 2010-2011

USGS Publications Warehouse

Hornewer, Nancy J.

2014-01-01

Recent studies have documented the presence of trace elements, organic compounds including polycyclic aromatic hydrocarbons, and radionuclides in sediment from the Colorado River delta and from sediment in some side canyons in Lake Powell, Utah and Arizona. The fate of many of these contaminants is of significant concern to the resource managers of the National Park Service Glen Canyon National Recreation Area because of potential health impacts to humans and aquatic and terrestrial species. In 2010, the U.S. Geological Survey began a sediment-core sampling and analysis program in the San Juan River and Escalante River deltas in Lake Powell, Utah, to help the National Park Service further document the presence or absence of contaminants in deltaic sediment. Three sediment cores were collected from the San Juan River delta in August 2010 and three sediment cores and an additional replicate core were collected from the Escalante River delta in September 2011. Sediment from the cores was subsampled and composited for analysis of major and trace elements. Fifty-five major and trace elements were analyzed in 116 subsamples and 7 composited samples for the San Juan River delta cores, and in 75 subsamples and 9 composited samples for the Escalante River delta cores. Six composited sediment samples from the San Juan River delta cores and eight from the Escalante River delta cores also were analyzed for 55 low-level organochlorine pesticides and polychlorinated biphenyls, 61 polycyclic aromatic hydrocarbon compounds, gross alpha and gross beta radionuclides, and sediment-particle size. Additionally, water samples were collected from the sediment-water interface overlying each of the three cores collected from the San Juan River and Escalante River deltas. Each water sample was analyzed for 57 major and trace elements. Most of the major and trace elements analyzed were detected at concentrations greater than reporting levels for the sediment-core subsamples and composited samples. Low-level organochlorine pesticides and polychlorinated biphenyls were not detected in any of the samples. Only one polycyclic aromatic hydrocarbon compound was detected at a concentration greater than the reporting level for one San Juan composited sample. Gross alpha and gross beta radionuclides were detected at concentrations greater than reporting levels for all samples. Most of the major and trace elements analyzed were detected at concentrations greater than reporting levels for water samples.

Simple ray tracing of Galileo-observed hectometric attenuation features

NASA Astrophysics Data System (ADS)

Higgins, Charles A.; Thieman, James R.; Fung, Shing F.; Green, James L.; Candey, Robert M.

Observations of persistent structural features within Jovian hectometric (HOM) radio emission have been made with the Galileo spacecraft. Two well-defined sinusoidal-shaped ``band'' features of reduced emission intensity and occurrence probability exist at all Jovian longitudes and nearly cover the entire spectrum of HOM radio emission from ~500 kHz to 3000 kHz. These two sinusoidal lanes have a bandwidth of 200-400 kHz and are 180° out of phase with one another, suggesting that they are a result of HOM radio emission propagation processes from opposite hemispheres. These features become more apparent when presented as intensity or occurrence probability spectrograms added together over multiple Jovian rotations. Enhancements in the HOM intensity and occurrence are seen along the edges of one of the observed sinusoidal lane features which may indicate caustic surfaces due to refraction along the propagation path. We present some simple ray tracing analyses to show that refraction from density enhancements in the Io torus flux tube may explain some of the observations. Using this simple method, we approximate the density enhancements in the Io flux tube to be 100 cm-3.

Persistence of artificial sweeteners in a 15-year-old septic system plume

NASA Astrophysics Data System (ADS)

Robertson, W. D.; Van Stempvoort, D. R.; Solomon, D. K.; Homewood, J.; Brown, S. J.; Spoelstra, J.; Schiff, S. L.

2013-01-01

SummaryGroundwater contamination from constituents such as NO3-, often occurs where multiple sources are present making source identification difficult. This study examines a suite of major ions and trace organic constituents within a well defined septic system plume in southern Ontario, Canada (Long Point site) for their potential use as wastewater tracers. The septic system has been operating for 20 years servicing a large, seasonal-use campground and tritium/helium age dating indicates that the 200 m long monitored section of the plume is about 15 years old. Four parameters are elevated along the entire length of the plume as follows; the mean electrical conductivity value (EC) in the distal plume zone is 926 μS/cm which is 74% of the mean value below the tile bed, Na+ (14.7 mg/L) is 43%, an artificial sweetener, acesulfame (12.1 μg/L) is 23% and Cl- (71.5 mg/L) is 137%. EC and Cl- appear to be affected by dispersive dilution with overlying background groundwater that has lower EC but has locally higher Cl- as result of the use of a dust suppressant (CaCl2) in the campground. Na+, in addition to advective dilution, could be depleted by weak adsorption. Acesulfame, in addition to the above processes could be influenced by increasing consumer use in recent years. Nonetheless, both Na+ and acesulfame remain elevated throughout the plume by factors of more than 100 and 1000 respectively compared to background levels, and are strong indicators of wastewater impact at this site. EC and Cl- are less useful because their contrast with background values is much less (EC) or because other sources are present (Cl-). Nutrients (NO3-, NH4+, PO43-, K+) and pathogens (Escherichia coli) do not persist in the distal plume zone and are less useful as wastewater indicators here. The artificial sweetener, acesulfame, has persisted at high concentrations in the Long Point plume for at least 15 years (and this timing agrees with tritium/helium-3 dating) and this compound likely occurs at uniquely high concentrations in domestic wastewater. As such, it holds considerable promise as a powerful new tracer of wastewater impact in groundwater.

Misconceptions in Optics: Their Persistence at University Level.

ERIC Educational Resources Information Center

Gil Llinas, J.; Suero Lopez, M. I.; Perez Rodriguez, A. L.; Solano Macias, F.

2003-01-01

Presents a study on misconceptions in optics with the objective of checking their persistence over time in spite of the continued academic instruction of students. Involves (n=4000) students of all levels of the Spanish educational system as well as with those at a Spanish university with degrees in medicine, chemical sciences, technical…

Effect of Learning Activity on Students' Motivation, Physical Activity Levels and Effort/Persistence

ERIC Educational Resources Information Center

Gao, Zan; Lee, Amelia M.; Xiang, Ping; Kosma, Maria

2011-01-01

The type of learning activity offered in physical education may influence students' motivational beliefs, physical activity participation and effort/persistence in class. However, most empirical studies have focused on the individual level rather than on the learner-content interactions. Accordingly, the potential effects of learning activities on…

HIGH LEVEL OF PERSISTENCE OF PEDIATRIC BIPOLAR-I DISORDER FROM CHILDHOOD ONTO ADOLESCENT YEARS: A FOUR YEAR PROSPECTIVE LONGITUDINAL FOLLOW-UP STUDY

PubMed Central

Wozniak, Janet; Petty, Carter R.; Schreck, Meghan; Moses, Alana; Faraone, Stephen V.; Biederman, Joseph

2011-01-01

Objective To examine the longitudinal course of pediatric bipolar (BP)-I disorder in youth transitioning from childhood into adolescence. Methods We conducted a four-year prospective follow-up study of 78 youth with BP-I disorder 6-17 years old at ascertainment followed up into adolescent years (13.4±3.9 years). All subjects were comprehensively assessed with structured diagnostic interviews, neuropsychological testing, psychosocial, educational and treatment history assessments. BP disorder was considered persistent if subjects met full criteria for DSM-IV BP-I disorder at follow-up. Results Of 78 BP-I participating youth subjects, 57 (73.1%), continued to meet full diagnostic criteria for BP-I Disorder. Of those with a non-persistent course, only 6.4% (n=5) were euthymic (i.e., syndromatic and symptomatic remission) at the 4-year follow-up and were not receiving pharmacotherapy for the disorder. The other non-persistent cases either continued to have subthreshold BP-I disorder (n=5, 6.4%), met full (n=3, 3.8%) or subthreshold (n=1, 1.3%) criteria for major depression, or were euthymic but were treated for the disorder (n=7, 9.0%). Full persistence was associated with higher rates of major depression and disruptive behavior disorders at the follow-up assessment and higher use of stimulant medicines at the baseline assessment. Non-Peristent BP-I was also characterized by high levels of dysfunction and morbidity. Conclusions This four-year follow-up shows that the majority of BP-I disorder youth continue to experience persistent disorder into their mid and late adolescent years and its persistence is associated with high levels of morbidity and disability. Persistence of subsyndromal forms of bipolar disorder was also associated with dysfunction and morbidity. PMID:21683960

Long term persistence of anti-HBs protective levels in young patients with type 1 diabetes after recombinant hepatitis B vaccine.

PubMed

Marseglia, G; Alibrandi, A; d'Annunzio, G; Gulminetti, R; Avanzini, M A; Marconi, M; Tinelli, C; Lorini, R

2000-11-22

The aim of the present study was to evaluate the persistence of anti-hepatitis B protective levels in young patients with type 1 diabetes, successfully immunised with a recombinant hepatitis B vaccine. We re-evaluated, after a 4 year follow-up, 54 patients and 70 age and sex-matched healthy subjects. Protective antibodies levels were found in 50/54 (92%) patients and in 67/70 (96%) controls. Moreover, anti-HBs levels were similar in diabetic patients and controls (means of log-titre and (sd); 1.95 (0.88) and 2.18 (0.64) patients and controls, respectively; P=0.11). No cases of clinical hepatitis were reported and all patients and controls remained HBc negative. These data demonstrate the persistence of anti-HBs levels in children, adolescents and young patients with type 1 diabetes after recombinant hepatitis B vaccine showing evidence of longterm immunogenity and protective effect.

Lagrangian Photochemical Box-Model Calculations of Asian Pacific Rim Outflow During TRACE-P

NASA Astrophysics Data System (ADS)

Hamlin, A.; Crawford, J.; Olson, J.; Avery, M.; Sachse, G.; Barrick, J.; Blake, D.; Tan, D.; Sandholm, S.; Kondo, Y.; Singh, H.; Eisele, F.; Zondlo, M.; Flocke, F.; Talbot, R.

2006-12-01

NASA's TRACE-P (TRAnsport and Chemical Evolution over the Pacific) mission was conducted over the northwestern Pacific February-April, 2001. During two transit flights across the Pacific, extensive pollution was observed from an Asian outflow event that split into two branches over the central Pacific, one subsiding and moving southward over the central Pacific and the other continuing eastward in the upper troposphere. The subsiding branch was observed as a widespread stagnant pollution layer between 2 and 4 km over the central Pacific during transit flights from Kona, HI to Guam. In this region, high levels of O3 (70 ppbv), CO (217 ppbv), and NOx (114 pptv) were well in excess of typical values observed during TRACE-P along the Asian coast. Evidence suggests that the subsiding branch experienced extensive photochemical processing compared to the branch that remained at altitude. To examine the processes controlling the chemical evolution of ozone and its precursors in this outflow event, data collected during the TRACE-P mission have been combined with lagrangian photochemical box model calculations. One of the largest sources of uncertainty in these calculations was associated with predicted water vapor levels along the transport trajectories calculated using the HYSPLIT model. Water vapor levels predicted by HYSPLIT trajectory calculations in the subsiding layer ranged from 3390 to 4880 ppm, while the median level observed in the pollution layer was only 637 ppm. Simulations of ozone production and associated radical chemistry differed dramatically when using water vapor levels based on trajectory calculations versus observed water vapor levels. Levels of PAN and HO2NO2, NOx reservoir species, are also influenced by uncertainties in temperature along the trajectories. These results highlight the importance of accurately representing the humidification and warming of subsiding air masses in 3-D chemical- transport models.

Milk trace elements in lactating cows environmentally exposed to higher level of lead and cadmium around different industrial units.

PubMed

Patra, R C; Swarup, D; Kumar, P; Nandi, D; Naresh, R; Ali, S L

2008-10-01

The present investigation was carried out to assess the trace mineral profile of milk from lactating cows reared around different industrial units and to examine the effect of blood and milk concentration of lead and cadmium on copper, cobalt, zinc and iron levels in milk. Respective blood and milk samples were collected from a total of 201 apparently healthy lactating cows above 3 years of age including 52 cows reared in areas supposed to be free from pollution. The highest milk lead (0.85+/-0.11 microg/ml) and cadmium (0.23+/-0.02 microg/ml) levels were recorded in lactating cows reared around lead-zinc smelter and steel manufacturing plant, respectively. Significantly (P<0.05) higher concentration of milk copper, cobalt, zinc and iron compared to control animals was recorded in cows around closed lead cum operational zinc smelter. Analysis of correlation between lead and other trace elements in milk from lactating cows with the blood lead level>0.20 microg/ml (n=79) revealed a significant negative correlations between milk iron and milk lead (r=-0.273, P=0.015). However, such trend was not recorded with blood lead level<0.20 microg/ml (n=122). The milk cobalt concentration was significantly correlated (r=0.365, P<0.001) with cadmium level in milk and the highest milk cadmium (>0.10 to 0.39 microg/ml) group had significantly (P<0.05) increased milk cobalt. It is concluded that increased blood and milk lead or cadmium level as a result of natural exposure of lactating cows to these environmental toxicants significantly influences trace minerals composition of milk and such alterations affect the milk quality and nutritional values.

Sensitive Multi-Species Emissions Monitoring: Infrared Laser-Based Detection of Trace-Level Contaminants

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

Steill, Jeffrey D.; Huang, Haifeng; Hoops, Alexandra A.

This report summarizes our development of spectroscopic chemical analysis techniques and spectral modeling for trace-gas measurements of highly-regulated low-concentration species present in flue gas emissions from utility coal boilers such as HCl under conditions of high humidity. Detailed spectral modeling of the spectroscopy of HCl and other important combustion and atmospheric species such as H 2 O, CO 2 , N 2 O, NO 2 , SO 2 , and CH 4 demonstrates that IR-laser spectroscopy is a sensitive multi-component analysis strategy. Experimental measurements from techniques based on IR laser spectroscopy are presented that demonstrate sub-ppm sensitivity levels to thesemore » species. Photoacoustic infrared spectroscopy is used to detect and quantify HCl at ppm levels with extremely high signal-to-noise even under conditions of high relative humidity. Additionally, cavity ring-down IR spectroscopy is used to achieve an extremely high sensitivity to combustion trace gases in this spectral region; ppm level CH 4 is one demonstrated example. The importance of spectral resolution in the sensitivity of a trace-gas measurement is examined by spectral modeling in the mid- and near-IR, and efforts to improve measurement resolution through novel instrument development are described. While previous project reports focused on benefits and complexities of the dual-etalon cavity ring-down infrared spectrometer, here details on steps taken to implement this unique and potentially revolutionary instrument are described. This report also illustrates and critiques the general strategy of IR- laser photodetection of trace gases leading to the conclusion that mid-IR laser spectroscopy techniques provide a promising basis for further instrument development and implementation that will enable cost-effective sensitive detection of multiple key contaminant species simultaneously.« less

Effect of royal jelly on serum trace elements in rats undergoing head and neck irradiation.

PubMed

Cihan, Yasemin Benderli; Cihan, Celaleddin; Mutlu, Hasan; Unal, Dilek

2013-01-01

This study aims to investigate the effects of radiation on serum trace elements and the changes in these elements as induced by royal jelly in rats undergoing head and neck irradiation. Thirty-two Sprague-Dawley male rats at the age of eight weeks with a mean weight of 275±35 g were included in the study. Subjects were divided into four groups with eight rats in each group: group 1: controls (C), group 2: radiation-only (RT), group 3: radiation plus royal jelly 50 mg/kg (RT+RJ50) and group 4: royal jelly 50 mg/kg-only (RJ50). Radiotherapy was applied to the head and neck area by single fraction at a dose of 22 Gy. The royal jelly was given once daily for seven days. The subjects were sacrificed on the seventh day of the study. Trace elements in blood samples were measured using ICP/MS method. When the trace element levels among the groups were compared using ANOVA test, a statistically significant difference was found in Al, As, Ca, Cd, Cr, K, Mg, Pb, Se, and Sn levels (p<0.05). No significant difference was found in the levels of Ag, Ba, Co, Cs, Cu, Fe, Ga, Hg, Mn, Na, Ni, Rb, Sr, Ti, U, V, and Zn (p>0.05). It was observed that oxidative stress was reduced in the radiation plus royal jelly group, compared to the radiation-only group. Our study results suggest that head and neck irradiation increases oxidative stress, leading to some changes in the trace element levels, while royal jelly exhibits a protective effect against the oxidative stress induced by radiation.

Trace elements in early phase type 2 diabetes mellitus-A population-based study. The HUNT study in Norway.

PubMed

Hansen, Ailin Falkmo; Simić, Anica; Åsvold, Bjørn Olav; Romundstad, Pål Richard; Midthjell, Kristian; Syversen, Tore; Flaten, Trond Peder

2017-03-01

Differences in trace elements levels between individuals with type 2 diabetes and controls have been reported in several studies in various body fluids and tissues, but results have been inconsistent. In order to examine trace element levels in the early phase of type 2 diabetes, we investigated the association between whole blood levels of 26 trace elements and the prevalence of previously undiagnosed, screening-detected type 2 diabetes. The study was conducted as a case-control study nested within the third survey of the population-based Nord-Trøndelag Health Study (HUNT3 Survey). Among participants without previously known diabetes, 128 cases of type 2 diabetes were diagnosed in people with a high diabetes risk score (FINDRISC≥15), and frequency-matched for age and sex with 755 controls. Blood samples were analyzed by high resolution inductively coupled plasma mass spectrometry. Associations between trace element levels and the prevalence of previously undiagnosed type 2 diabetes were evaluated with multivariable conditional logistic regression controlling for age, sex, body mass index, waist-to-hip ratio, education, income, smoking and family history of diabetes. The prevalence of previously undiagnosed type 2 diabetes increased across tertiles/quartiles for cadmium, chromium, iron, nickel, silver and zinc, and decreased with increasing quartiles of bromine (P trend <0.05). After corrections for multiple testing, associations for chromium remained significant (Q trend <0.05), while associations for iron and silver were borderline significant. No associations were found for arsenic, boron, calcium, cesium, copper, gallium, gold, indium, lead, magnesium, manganese, mercury, molybdenum, rubidium, selenium, strontium, tantalum, thallium and tin. Our results suggest a possible role of bromine, cadmium, chromium, iron, nickel, silver and zinc in the development of type 2 diabetes. Copyright © 2016 Elsevier GmbH. All rights reserved.

Comparison of elemental composition in two wild and cultured marine fish and potential risks to human health.

PubMed

Marengo, Michel; Durieux, Eric D H; Ternengo, Sonia; Lejeune, Pierre; Degrange, Elise; Pasqualini, Vanina; Gobert, Sylvie

2018-08-30

Among all available species, fish are a powerful model for risk-benefit assessments to study the effects of contaminants on human health. Gilthead seabream (Sparus aurata, Linnaeus 1758) and european seabass (Dicentrarchus labrax, Linnaeus 1758) are two species of great economic importance, representing very large production volumes in the Mediterranean. The objective of this study is (1) to analyze the concentrations of Trace Elements (TE) between wild and cultured seabream and seabass specimens, (2) to compare the determined concentrations with other studies, and (3) to increase the data about the potential risks to human health. Our results point to significant intra- and interspecies-specific differences between wild and cultured fish for several trace elements. Several strong and moderate inter-elemental correlations in fish muscle were observed through correlation analysis. In our study, the mean levels of trace elements were still below the standard safety values for fish intended for human consumption. The same results were reached for all the parameters analyzed (international legal limits, estimated weekly intake, provisional tolerable weekly intake, target hazard quotient, target cancer risk), with trace element levels in fish below those that could pose a risk to human health. Consequently, these fish can be considered safe for human consumption. A better understanding of the levels of trace elements in fish would also better inform consumers about the potential risks of exposure to contaminants. Copyright © 2018 Elsevier Inc. All rights reserved.

Associations between trace elements and clinical health parameters in the North Pacific loggerhead sea turtle (Caretta caretta) from Baja California Sur, Mexico.

PubMed

Ley-Quiñónez, César Paúl; Rossi-Lafferriere, Natalia Alejandra; Espinoza-Carreon, Teresa Leticia; Hart, Catherine Edwina; Peckham, Sherwood Hoyt; Aguirre, Alfredo Alonso; Zavala-Norzagaray, Alan Alfredo

2017-04-01

This study investigated selected trace elements toxicity in sea turtles Caretta caretta population from Baja California Sur (BCS), Mexico, by analyzing associations among Zn, Se, Cu, As, Cd, Ni, Mn, Pb, and Hg with various biochemical parameters (packed cell volume, leukocytes, and selected blood parameters), and whether their concentrations could have an impact on the health status of sea turtles. Blood samples from 22 loggerhead (C. caretta) sea turtles from BCS, Mexico, were collected for trace elements on biochemistry parameter analyses. Significant associations among trace element levels and the biochemistry parameters were found: Cd vs ALP (R 2  = 0.874, p ˂ 0.001), As vs ALP (R 2  = 0.656, p ˂ 0.001), Mn vs ALP (R 2  = 0.834, p ˂ 0.001), and Ni vs LDH (R 2  = 0.587, p ˂ 0.001). This study is the first report of the biochemical parameters of the North Pacific loggerhead sea turtle (C. caretta) from Baja California Sur, Mexico, and it is the first to observe several associations with toxic and essential trace elements. Our study reinforces the usefulness of blood for the monitoring of the levels of contaminating elements and the results suggest that, based on the associations with health clinical parameters, high levels of Cd and As could be representing a risk to the North Pacific loggerhead population health.

Evaluation of inflammatory markers interleukin-6 (IL-6) and matrix metalloproteinase-9 (MMP-9) in asthma.

PubMed

Naik, Srilata Puru; P A, Mahesh; B S, Jayaraj; Madhunapantula, SubbaRao V; Jahromi, Sarah Raeiszadeh; Yadav, Manish Kumar

2017-08-01

Even though IL-6 and MMP-9 are associated with airway inflammation in asthma, there is paucity of data in Indian population. To determine the levels of IL-6 and MMP-9 in the serum of patients suffering from asthma, and correlate with (a) disease severity, as per GINA guidelines; (b) clinical phenotypes; and (c) response to treatment. The levels of IL-6 and MMP-9 were compared between moderate persistent asthma (n = 25), severe persistent asthma (n = 25) and normal controls (n = 30). IL-6 and MMP-9 were measured by ELISA (R&D Systems Inc., USA and Canada) and compared between controls and asthmatics and between groups of different asthma severity, clinical variables, spirometry, and allergen sensitization. Spirometry was repeated after 2 months of ICS+LABA to assess response to treatment in relation to baseline IL-6 and MMP-9 levels. We observed a significant difference in both IL-6 and MMP-9 levels among asthmatics versus controls (p < 0.001), moderate versus severe persistent asthma (p < 0.001). A significant negative correlation was observed between MMP-9 and pre-bronchodilator FEV 1 and FVC, but not with IL-6. There was no association between IL-6 and MMP-9 with asthma duration, total IgE, AEC, number of allergens sensitized and degree of sensitization. No significant correlation (p > 0.5) was observed with IL-6 and MMP-9 levels and FEV 1 improvement after 2 months of ICS+LABA. Higher levels of IL-6 and MMP-9 were observed in asthmatics as compared to controls and in severe persistent asthma as compared to moderate persistent asthma, higher levels of MMP-9 was associated with lower lung functions.

Pituitary origin of persistently elevated human chorionic gonadotropin in a patient with gonadal failure.

PubMed

Merhi, Zaher; Pollack, Staci E

2013-01-01

To report a case of persistently elevated low levels of hCG to increase awareness of pituitary origin of persistently elevated hCG in patients with gonadal failure. Case report and literature review. Large university-affiliated infertility practice. A 16-year-old patient with primary amenorrhea, normal secondary sex characteristics, ovarian failure, and a 46,XY karyotype. Her past medical history was significant for focal segmental glomerulosclerosis, leading to a diagnosis of Frasier syndrome. At age 31 years, she desired pregnancy by oocyte donation and was found to have persistently elevated low levels of hCG (>35 mIU/mL). Pituitary hCG. Both serum free β-hCG and hyperglycosylated hCG were undetectable. Total serum hCG diluted appropriately was not blocked by blocking agent and was detected in the urine. Subsequent treatment with exogenous E(2), in preparation of a donor oocyte cycle, suppressed her hCG levels (down to 8 mIU/mL). These results indicated a pituitary source of the serum hCG. This report reinforces the need to consider pituitary hCG as the origin of persistently elevated hCG levels in patients with gonadal failure. Although levels of hCG <14 mIU/mL have been considered normal in postmenopausal women, our case suggests that patients with gonadal failure at younger ages might have a higher pituitary output of hCG. Copyright © 2013 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

A survey of trace metals in vegetation, soil and lower animal along some selected major roads in metropolitan city of Lagos.

PubMed

Awofolu, O R

2005-06-01

The concentration of trace metals (Cd, Cu, Pb and Zn) in a total of 144 samples of grass, soil and lower animal (earthworm, Lybrodrilus violaceous) were collected and analysed for their metallic content. Levels of cadmium ranged from 0.01-0.07 microg g(-1); 0.01-0.12 microg g(-1) and from trace-0.05 microg g(-1) dry weight for plant, soil and animal samples respectively. Mean concentration of copper ranged 0.10-1.48 microg g(-1); 0.10-2.90 microg g(-1) and 0.01-0.08 microg g(-1) for samples in similar order as above. The levels of Pb varied from 0.01-0.14 microg g(-1); 0.02-0.23 microg g(-1) and from trace-0.07 microg (g-1) while that of Zn ranged from 0.19-1.80 microg g(-1); 0.51-3.35 microg g(-1) and 0.01-0.08 microg g(-1) also in the same order of samples as mentioned above. Levels of metals in soil samples were higher than the background levels with the exception of Zn but lower than European Union (EU) limits. The results generally revealed the presence of metals in plant and animal samples and metal dynamics up the food chain is highly possible. Acceptable recoveries of the spiking experiment validate the experimental protocol.

Relationships of Polychlorinated Biphenyls and Dichlorodiphenyldichloroethylene (p,p’-DDE) with Testosterone Levels in Adolescent Males

PubMed Central

Gallo, Mia V.; Deane, Glenn D.; Nelder, Kyrie R.; DeCaprio, Anthony P.; Jacobs, Agnes

2013-01-01

Background: Concern persists over endocrine-disrupting effects of persistent organic pollutants (POPs) on human growth and sexual maturation. Potential effects of toxicant exposures on testosterone levels during puberty are not well characterized. Objectives: In this study we evaluated the relationship between toxicants [polychlorinated biphenyls (PCBs), dichlorodiphenyldichloroethylene (p,p´-DDE), hexachlorobenzene (HCB), and lead] and testosterone levels among 127 Akwesasne Mohawk males 10 to < 17 years of age with documented toxicant exposures. Methods: Data were collected between February 1996 and January 2000. Fasting blood specimens were collected before breakfast by trained Akwesasne Mohawk staff. Multivariable regression models were used to estimates associations between toxicants and serum testosterone, adjusted for other toxicants, Tanner stage, and potential confounders. Results: The sum of 16 PCB congeners (Σ16PCBs) that were detected in ≥ 50% of the population was significantly and negatively associated with serum testosterone levels, such that a 10% change in exposure was associated with a 5.6% decrease in testosterone (95% CI: –10.8, –0.5%). Of the 16 congeners, the more persistent ones (Σ8PerPCBs) were related to testosterone, whereas the less persistent ones, possibly reflecting more recent exposure, were not. When PCB congeners were subgrouped, the association was significant for the sum of eight more persistent PCBs (5.7% decrease; 95% CI: –11, –0.4%), and stronger than the sum of six less persistent congeners (3.1% decrease; 95% CI: –7.2, 0.9%). p,p´-DDE was positively but not significantly associated with serum testosterone (5.2% increase with a 10% increase in exposure; 95% CI: –0.5, 10.9%). Neither lead nor HCB was significantly associated with testosterone levels. Conclusions: Exposure to PCBs, particularly the more highly persistent congeners, may negatively influence testosterone levels among adolescent males. The positive relationship between p,p´-DDE and testosterone indicates that not all POPs act similarly. Citation: Schell LM, Gallo MV, Deane GD, Nelder KR, DeCaprio AP, Jacobs A; Akwesasne Task Force on the Environment. 2014. Relationships of polychlorinated biphenyls and dichlorodiphenyldichloroethylene (p,p´-DDE) with testosterone levels in adolescent males. Environ Health Perspect 122:304–309; http://dx.doi.org/10.1289/ehp.1205984 PMID:24398050

Correlation between bone mineral density and serum trace elements in response to supervised aerobic training in older adults.

PubMed

Alghadir, Ahmad H; Gabr, Sami A; Al-Eisa, Einas S; Alghadir, Muaz H

2016-01-01

Life style and physical activity play a pivotal role in prevention and treatment of osteoporosis. The mechanism for better bone metabolism and improvement of physical disorders is not clear yet. Trace minerals such as Ca, Mn, Cu, and Zn are essential precursors for most vital biological process, especially those of bone health. The main target of this study was evaluating the effective role of supervised aerobic exercise for 1 hour/day, 3 days/week for 12 weeks in the functions of trace elements in bone health through measuring bone mineral density (BMD), osteoporosis (T-score), bone markers, and trace element concentrations in healthy subjects aged 30-60 years with age average of 41.2±4.9. A total of 100 healthy subjects (47 males, 53 females; age range 30-60 years) were recruited for this study. Based on dual-energy x-ray absorptiometry (DEXA) scan analysis, the participants were classified into three groups: normal (n=30), osteopenic (n=40), and osteoporotic (n=30). Following, 12 weeks of moderate aerobic exercise, bone-specific alkaline phosphatase (BAP), BMD, T-score, and trace elements such as Ca, Mn, Cu, and Zn were assessed at baseline and post-intervention. Significant improvement in serum BAP level, T-score, and BMD were observed in all participants following 12 weeks of moderate exercise. Participants with osteopenia and osteoporosis showed significant increase in serum Ca and Mn, along with decrease in serum Cu and Zn levels following 12 weeks of aerobic training. In control group, the improvements in serum trace elements and body mass index were significantly linked with the enhancement in the levels of BAP, BMD hip, and BMD spine. These results supported the preventive effects of moderate exercise in healthy subjects against osteoporosis. In both sexes, the changes in serum trace elements significantly correlated (P<0.05) with the improvement in BAP, BMD hip, BMD spine, and body mass index in all groups. The observed changes in the levels of Ca, Mn, Cu, and Zn were shown to be positively correlated with improved bone mass density among control and osteoporosis subjects of both sexes. These results demonstrate that aerobic exercise of moderate intensity might protect bone and cartilage by regulation of body trace elements which are involved in the biosynthesis of bone matrix structures and inhibition of bone resorption process via a proposed anti-free radical mechanism.

A numerical investigation of wind accretion in persistent supergiant X-ray binaries - I. Structure of the flow at the orbital scale

NASA Astrophysics Data System (ADS)

El Mellah, I.; Casse, F.

2017-05-01

Classical supergiant X-ray binaries host a neutron star orbiting a supergiant OB star and display persistent X-ray luminosities of 1035-1037 erg s-1. The stellar wind from the massive companion is believed to be the main source of matter accreted by the compact object. With this first paper, we introduce a ballistic model to evaluate the influence of the orbital effects on the structure of the accelerating winds that participate to the accretion process. Thanks to the parametrization we retained the numerical pipeline we designed, we can investigate the supersonic flow and the subsequent observables as a function of a reduced set of characteristic numbers and scales. We show that the shape of the permanent flow is entirely determined by the mass ratio, the filling factor, the Eddington factor and the α-force multiplier that drives the stellar wind acceleration. Provided scales such as the orbital period are known, we can trace back the observables to evaluate the mass accretion rates, the accretion mechanism, the shearing of the inflow and the stellar parameters. We discuss the likelihood of wind-formed accretion discs around the accretors in each case and confront our model to three persistent supergiant X-ray binaries (Vela X-1, IGR J18027-2016, XTE J1855-026).

Oxidation of contaminative methane traces with radio-frequency discharge

NASA Technical Reports Server (NTRS)

Flamm, D. L.; Wydeven, T. L.

1976-01-01

An 11.8 MHz glow discharge was used to oxidize trace levels of methane in oxygen. The concentration of methane can be reduced by three orders of magnitude. The effects of power (0-400 W), flow rate (10-1000 cc-STP/min) and concentration (70-8000 ppm) were investigated at pressures ranging from 50 torr to almost 1 atm. No organic reaction products were detected in the treated gas stream. The process may prove useful for the removal of atmospheric trace contaminants at ambient pressure.

Emergent oscillations assist obstacle negotiation during ant cooperative transport.

PubMed

Gelblum, Aviram; Pinkoviezky, Itai; Fonio, Ehud; Gov, Nir S; Feinerman, Ofer

2016-12-20

Collective motion by animal groups is affected by internal interactions, external constraints, and the influx of information. A quantitative understanding of how these different factors give rise to different modes of collective motion is, at present, lacking. Here, we study how ants that cooperatively transport a large food item react to an obstacle blocking their path. Combining experiments with a statistical physics model of mechanically coupled active agents, we show that the constraint induces a deterministic collective oscillatory mode that facilitates obstacle circumvention. We provide direct experimental evidence, backed by theory, that this motion is an emergent group effect that does not require any behavioral changes at the individual level. We trace these relaxation oscillations to the interplay between two forces; informed ants pull the load toward the nest whereas uninformed ants contribute to the motion's persistence along the tangential direction. The model's predictions that oscillations appear above a critical system size, that the group can spontaneously transition into its ordered phase, and that the system can exhibit complete rotations are all verified experimentally. We expect that similar oscillatory modes emerge in collective motion scenarios where the structure of the environment imposes conflicts between individually held information and the group's tendency for cohesiveness.

Development of Polymorphic Microsatellite Loci for Potato Wart from Next-Generation Sequence Data.

PubMed

Gagnon, Marie-Claude; van der Lee, Theo A J; Bonants, Peter J M; Smith, Donna S; Li, Xiang; Lévesque, C André; Bilodeau, Guillaume J

2016-06-01

Synchytrium endobioticum is the fungal agent causing potato wart disease. Because of its severity and persistence, quarantine measures are enforced worldwide to avoid the spread of this disease. Molecular markers exist for species-specific detection of this pathogen, yet markers to study the intraspecific genetic diversity of S. endobioticum were not available. Whole-genome sequence data from Dutch pathotype 1 isolate MB42 of S. endobioticum were mined for perfect microsatellite motifs. Of the 62 selected microsatellites, 21 could be amplified successfully and displayed moderate levels of polymorphism in 22 S. endobioticum isolates from different countries. Nineteen multilocus genotypes were observed, with only three isolates from Canada displaying identical profiles. The majority of isolates from Canada clustered genetically. In contrast, most isolates collected in Europe show no genetic clustering associated with their geographic origin. S. endobioticum isolates with the same pathotype displayed highly variable genotypes and none of the microsatellite markers correlated with a specific pathotype. The markers developed in this study can be used to assess intraspecific genetic diversity of S. endobioticum and allow track and trace of genotypes that will generate a better understanding of the migration and spread of this important fungal pathogen and support management of this disease.

Searching for Extraterrestrial Amino Acids in a Contaminated Meteorite: Amino Acid Analyses of the Canakkale L6 Chondrite

NASA Technical Reports Server (NTRS)

Burton, A. S.; Elsila, J. E.; Glavin, D. P.; Dworkin, J. P.; Ornek, C. Y.; Esenoglu, H. H.; Unsalan, O.; Ozturk, B.

2016-01-01

Amino acids can serve as important markers of cosmochemistry, as their abundances and isomeric and isotopic compositions have been found to vary predictably with changes in parent body chemistry and alteration processes. Amino acids are also of astrobiological interest because they are essential for life on Earth. Analyses of a range of meteorites, including all groups of carbonaceous chondrites, along with H, R, and LL chondrites, ureilites, and a martian shergottite, have revealed that amino acids of plausible extraterrestrial origin can be formed in and persist after a wide range of parent body conditions. However, amino acid analyses of L6 chondrites to date have not provided evidence for indigenous amino acids. In the present study, we performed amino acid analysis on larger samples of a different L6 chondite, Canakkale, to determine whether or not trace levels of indigenous amino acids could be found. The Canakkale meteor was an observed fall in late July, 1964, near Canakkale, Turkey. The meteorite samples (1.36 and 1.09 g) analyzed in this study were allocated by C. Y. Ornek, along with a soil sample (1.5 g) collected near the Canakkale recovery site.

Science Identity's Influence on Community College Students' Engagement, Persistence, and Performance in Biology

NASA Astrophysics Data System (ADS)

Riccitelli, Melinda

In the United States (U.S.), student engagement, persistence, and academic performance levels in college science, technology, engineering, and mathematics (STEM) programs have been unsatisfactory over the last decade. Low student engagement, persistence, and academic performance in STEM disciplines have been identified as major obstacles to U.S. economic goals and U.S. science education objectives. The central and salient science identity a college student claims can influence his engagement, persistence, and academic achievement in college science. While science identity studies have been conducted on four-year college populations there is a gap in the literature concerning community college students' science identity and science performance. The purpose of this quantitative correlational study was to examine the relationship between community college students claimed science identities and engagement, persistence, and academic performance. A census sample of 264 community college students enrolled in biology during the summer of 2015 was used to study this relationship. Science identity and engagement levels were calculated using the Science Identity Centrality Scale and the Biology Motivation Questionnaire II, respectively. Persistence and final grade data were collected from institutional and instructor records. Engagement significantly correlated to, r =.534, p = .01, and varied by science identity, p < .001. Percent final grade also varied by science identity (p < .005), but this relationship was weaker (r = .208, p = .01). Results for science identity and engagement and final grade were consistent with the identity literature. Persistence did not vary by science identity in this student sample (chi2 =2.815, p = .421). This result was inconsistent with the literature on science identity and persistence. Quantitative results from this study present a mixed picture of science identity status at the community college level. It is suggested, based on the findings, that community college curriculum workers in biology consider student's science identity in terms of improving engagement and final grade, but not persistence. Additionally, as results were mixed, it is recommended that this study be repeated to examine these relationships further.

Application of ray-traced tropospheric slant delays to geodetic VLBI analysis

NASA Astrophysics Data System (ADS)

Hofmeister, Armin; Böhm, Johannes

2017-08-01

The correction of tropospheric influences via so-called path delays is critical for the analysis of observations from space geodetic techniques like the very long baseline interferometry (VLBI). In standard VLBI analysis, the a priori slant path delays are determined using the concept of zenith delays, mapping functions and gradients. The a priori use of ray-traced delays, i.e., tropospheric slant path delays determined with the technique of ray-tracing through the meteorological data of numerical weather models (NWM), serves as an alternative way of correcting the influences of the troposphere on the VLBI observations within the analysis. In the presented research, the application of ray-traced delays to the VLBI analysis of sessions in a time span of 16.5 years is investigated. Ray-traced delays have been determined with program RADIATE (see Hofmeister in Ph.D. thesis, Department of Geodesy and Geophysics, Faculty of Mathematics and Geoinformation, Technische Universität Wien. http://resolver.obvsg.at/urn:nbn:at:at-ubtuw:1-3444, 2016) utilizing meteorological data provided by NWM of the European Centre for Medium-Range Weather Forecasts (ECMWF). In comparison with a standard VLBI analysis, which includes the tropospheric gradient estimation, the application of the ray-traced delays to an analysis, which uses the same parameterization except for the a priori slant path delay handling and the used wet mapping factors for the zenith wet delay (ZWD) estimation, improves the baseline length repeatability (BLR) at 55.9% of the baselines at sub-mm level. If no tropospheric gradients are estimated within the compared analyses, 90.6% of all baselines benefit from the application of the ray-traced delays, which leads to an average improvement of the BLR of 1 mm. The effects of the ray-traced delays on the terrestrial reference frame are also investigated. A separate assessment of the RADIATE ray-traced delays is carried out by comparison to the ray-traced delays from the National Aeronautics and Space Administration Goddard Space Flight Center (NASA GSFC) (Eriksson and MacMillan in http://lacerta.gsfc.nasa.gov/tropodelays, 2016) with respect to the analysis performances in terms of BLR results. If tropospheric gradient estimation is included in the analysis, 51.3% of the baselines benefit from the RADIATE ray-traced delays at sub-mm difference level. If no tropospheric gradients are estimated within the analysis, the RADIATE ray-traced delays deliver a better BLR at 63% of the baselines compared to the NASA GSFC ray-traced delays.

The impact of adipogenic diet on rats' tissue trace elements content.

PubMed

Tinkov, A A; Gatiatulina, E R; Popova, E V; Polyakova, V S; Skalvaya, A A; Agletdinov, E F; Nikonorov, A A; Radysh, I V; Kkarganov, M Yu; Skalny, A V

2016-01-01

The influence of high-fat diet (HFD) on trace elements status, adipokine level, and markers of carbohydrate and lipid metabolism in weanling Wistar rats was investigated. A total of 20 male 1-months-old Wistar rats divided into two equal groups were used in the present study. The first group of animals obtained a standard diet (STD), whereas animals from the second group (NAFLD) were maintained on high-fat diet containing 10 and 31.6% of total calories from fat, respectively, during 1 month. Fat diet (HFD). Trace element status (using inductively coupled plasma mass spectrometry), serum levels of insulin, adiponectin, and leptin (using enzyme-linked immunosorbent assay), total cholesterol (TC), triglycerides (TG), low density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), glucose (spectrophotometrically), apolipoprotein A1 (ApoA1) and B (ApoB) (using immunoturbidimetric method) were assessed. It was shown that 1-month HFD feeding resulted in significant increase of EDAT, RPAT, total adipose tissue mass, and adipocyte area. HFD-fed animals were also characterized by a significant increase in circulating leptin levels and leptin-to-adiponectin ratio as compared to the control ones. No significant HFD-related difference in serum lipid spectrum, adiponectin, apolipoproteins, glucose, insulin, and HOMA-IR were revealed. Liver Cu, I, Mn, Se, Zn; EDAT Cr, V, Co, Cu, Fe,I, and RPAT Co, Cu, I, Cr, V, Fe, and Zn were significantly decreased in HFD-fed rats in comparison with the control group levels. Hair Co, Mn, Si, and V levels significantly exceeded the respective control values, whereas Se and I content were decreased in studied animals. At the same time, only serum Cu was significantly decreased in HFD-fed rats. The interplay between the impaired trace elements metabolism of HFD-fed weanling Wistar rats and disorder of adipokine balance was demonstrated. It is supposed that the altered trace elements status is primary and precedes other metabolic obesity-related disturbances.

Low zinc levels may contribute to gynecomastia in puberty.

PubMed

Erkekoglu, Pinar; Durmaz, Erdem; Kızılgün, Murat; Özmert, Elif N; Derman, Orhan; Yurdakök, Kadriye; Kocer-Gumusel, Belma

2017-12-01

This study aimed to determine whether there were any differences in trace element levels between adolescent boys with gynecomastia and control boys and to determine the correlations between the levels of trace elements and body mass index (BMI) and sex hormones. The pubertal gynecomastia group comprised of 41 patients (mean age=13.2 ±0.9 years), who were admitted to Hacettepe University İhsan Doğramacı Children's Hospital in Ankara. Control group comprised of 21 healthy male children. Analyses of trace element levels were performed atomic absorption spectrometry. The mean zinc level of control group was 101.33±16.87μg/dL and the mean zinc level of gynecomastia group was 81.36±17,43μg/dL (20% lower in gynecomastia patients, p=0.0001). However, the mean copper and manganese levels of gynecomastia patients were not statistically different than the control group. There were significant positive correlations between plasma zinc and total testosterone levels in gynecomastia group (r=0.592; p<0.05). There was a significant negative correlation between plasma zinc levels and BMI (r=-0.311; p<0.05). These results indicate that zinc deficiency might be one of the underlying factors of gynecomastia, the importance of which needs to be further elucidated. Copyright © 2017 Elsevier GmbH. All rights reserved.

Assisting Parents and In-Laws: Gender, Type of Assistance, and Couples' Employment

ERIC Educational Resources Information Center

Chesley, Noelle; Poppie, Kyle

2009-01-01

We use 1995 MIDUS data (n = 2,085) to assess whether the gender gap in help persists across different types of help (unpaid task assistance, emotional support, financial assistance) to parents and in-laws. We also examine whether joint employment patterns influence levels of help. Persistent gender differences are identified in levels of emotional…

Comparative, Population-Level Analysis of Social Networks in Organizations

ERIC Educational Resources Information Center

Jacobs, Abigail Z.

2017-01-01

As social behavior moves increasingly online, the study of social behavior has followed. Online traces of social systems, whether to study online behavior directly or the online traces of offline activity, have made possible previously unavailable empirical analyses of people, groups and organizations. However, practically observing any social…

Cognitive Processing in Oral and Silent Reading Comprehension.

ERIC Educational Resources Information Center

Salasoo, Aita

1986-01-01

Reading rates and comprehension measures that probed recognition of various levels of text structure were collected for passages read orally and silently by 16 college students. Results showed that memory traces of text microstructure created in oral reading were accessed faster during memory-based comprehension tasks than traces established by…

Selenium, Vanadium, and Chromium as Micronutrients to Improve Metabolic Syndrome.

PubMed

Panchal, Sunil K; Wanyonyi, Stephen; Brown, Lindsay

2017-03-01

Trace metals play an important role in the proper functioning of carbohydrate and lipid metabolism. Some of the trace metals are thus essential for maintaining homeostasis, while deficiency of these trace metals can cause disorders with metabolic and physiological imbalances. This article concentrates on three trace metals (selenium, vanadium, and chromium) that may play crucial roles in controlling blood glucose concentrations possibly through their insulin-mimetic effects. For these trace metals, the level of evidence available for their health effects as supplements is weak. Thus, their potential is not fully exploited for the target of metabolic syndrome, a constellation that increases the risk for cardiovascular disease and type 2 diabetes. Given that the prevalence of metabolic syndrome is increasing throughout the world, a simpler option of interventions with food supplemented with well-studied trace metals could serve as an answer to this problem. The oxidation state and coordination chemistry play crucial roles in defining the responses to these trace metals, so further research is warranted to understand fully their metabolic and cardiovascular effects in human metabolic syndrome.

Gas chromatographic analysis of trace impurities in chlorine trifluoride.

PubMed

Laurens, J B; Swinley, J M; de Coning, J P

2000-03-24

The gas chromatographic determination of trace gaseous impurities in highly reactive fluorinated gaseous matrices presents unique requirements to both equipment and techniques. Especially problematic are the gases normally present in ambient air namely oxygen and nitrogen. Analysing these gases at the low microl/l (ppm) level requires special equipment and this publication describes a custom-designed system utilising backflush column switching to protect the columns and detectors. A thermal conductivity detector with nickel filaments was used to determine ppm levels of impurities in ClF3.

Comparing Postsecondary Enrollment and Persistence among Rural and Nonrural Students in Oregon. REL 2015-076

ERIC Educational Resources Information Center

Pierson, Ashley; Hanson, Havala

2015-01-01

This REL Northwest study examined whether rural students at all achievement levels were less likely than their nonrural counterparts to enroll in college and persist to the second year. The researchers analyzed college enrollment patterns and persistence among rural and nonrural Oregon high school students, as well as variations among different…

Mutation in West Nile Virus Structural Protein prM during Human Infection.

PubMed

Lustig, Yaniv; Lanciotti, Robert S; Hindiyeh, Musa; Keller, Nathan; Milo, Ron; Mayan, Shlomo; Mendelson, Ella

2016-09-01

A mutation leading to substitution of a key amino acid in the prM protein of West Nile virus (WNV) occurred during persistent infection of an immunocompetent patient. WNV RNA persisted in the patient's urine and serum in the presence of low-level neutralizing antibodies. This case demonstrates active replication of WNV during persistent infection.

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

Aschengrau, A.; Zierler, S.; Cohen, A.

To investigate the relationship between community drinking water quality and spontaneous abortion, we compared trace element levels in the drinking water of 286 women having a spontaneous abortion through 27 wk gestation with that of 1,391 women having live births. Trace element levels were gathered from analyses of public tap water supplies from the communities where the women resided during pregnancy. After adjustment for potential confounders, an increase in the frequency of spontaneous abortion was associated with detectable levels of mercury; high levels of arsenic, potassium, and silica; moderately hard water, and surface water. In contrast, a decrease in themore » frequency of spontaneous abortion was associated with high levels of alkalinity and sulfate, and any detectable level of nitrate. These results require further corroboration because there is a paucity of data investigating this issue.« less

Hydrochemical profiles in urban groundwater systems: New insights into contaminant sources and pathways in the subsurface from legacy and emerging contaminants.

PubMed

White, D; Lapworth, D J; Stuart, M E; Williams, P J

2016-08-15

It has long been known that groundwaters beneath urban areas carry a fingerprint from urban activities but finding a consistent tracer for anthropogenic influence has proved elusive. The varied sources of urban contaminants means that a single consistent and inexpensive means of tracing the fate of urban contaminants is not generally possible and multiple tracers are often required to understand the contaminant sources and pathways in these complex systems. This study has utilized a combination of micro-organic (MO) contaminants and inorganic hydrochemistry to trace recharge pathways and quantify the variability of groundwater quality in multi-level piezometers in the city of Doncaster, UK. A total of 23 MOs were detected during this study, with more compounds consistently detected during higher groundwater table conditions highlighting the importance of sampling under different hydrological conditions. Four of the compounds detected are EU Water Framework Directive priority substances: atrazine, simazine, naphthalene and DEHP, with a maximum concentration of 0.18, 0.03, 0.2, 16μg/l respectively. Our study shows that the burden of the banned pesticide atrazine persists in the Sherwood Sandstone and is detected at two of the three study sites. Emerging contaminants are seen throughout the borehole profiles and provide insights into transient pathways for contaminant migration in the sub-surface. Long term changes in inorganic hydrochemistry show possible changes in contaminant input or the dissolution of minerals. Nitrate was detected above 50mg/l but on the whole nitrate concentrations have declined in the intervening years either due to a reduction of nitrate application at the surface or a migration of peak nitrate concentrations laterally or to greater depth. This study shows that multiple tracers together with multi-level piezometers can give a better resolution of contaminant pathways and variable flow regimes within the relatively uncomplicated aquifer of the Sherwood Sandstone compared with single long screened wells. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

Trace fossils of microbial colonization on Mars: Criteria for search and for sample return

NASA Technical Reports Server (NTRS)

Friedmann, E. I.

1988-01-01

The recent discovery of microbial trace-fossil formation in the frigid Ross Desert of Antarctica suggests that early primitive life on Mars may have left behind similar signatures. These trace fossils are apparent as chemical or physical changes in rock (or sediment) structure (or chemistry) caused by the activity of organisms. Life on Mars, if it ever existed, almost certainly did not evolve above the level of microorganisms, and this should be considered in search for fossil life. For the reasons detailed here, microbial trace fossils seem to be a better and more realistic target for search than would be true microbial fossils (remnants of cellular structures).

Representability of algebraic topology for biomolecules in machine learning based scoring and virtual screening

PubMed Central

Mu, Lin

2018-01-01

This work introduces a number of algebraic topology approaches, including multi-component persistent homology, multi-level persistent homology, and electrostatic persistence for the representation, characterization, and description of small molecules and biomolecular complexes. In contrast to the conventional persistent homology, multi-component persistent homology retains critical chemical and biological information during the topological simplification of biomolecular geometric complexity. Multi-level persistent homology enables a tailored topological description of inter- and/or intra-molecular interactions of interest. Electrostatic persistence incorporates partial charge information into topological invariants. These topological methods are paired with Wasserstein distance to characterize similarities between molecules and are further integrated with a variety of machine learning algorithms, including k-nearest neighbors, ensemble of trees, and deep convolutional neural networks, to manifest their descriptive and predictive powers for protein-ligand binding analysis and virtual screening of small molecules. Extensive numerical experiments involving 4,414 protein-ligand complexes from the PDBBind database and 128,374 ligand-target and decoy-target pairs in the DUD database are performed to test respectively the scoring power and the discriminatory power of the proposed topological learning strategies. It is demonstrated that the present topological learning outperforms other existing methods in protein-ligand binding affinity prediction and ligand-decoy discrimination. PMID:29309403

Lactase non-persistence is directed by DNA variation-dependent epigenetic aging

PubMed Central

Labrie, Viviane; Buske, Orion J; Oh, Edward; Jeremian, Richie; Ptak, Carolyn; Gasiūnas, Giedrius; Maleckas, Almantas; Petereit, Rūta; Žvirbliene, Aida; Adamonis, Kęstutis; Kriukienė, Edita; Koncevičius, Karolis; Gordevičius, Juozas; Nair, Akhil; Zhang, Aiping; Ebrahimi, Sasha; Oh, Gabriel; Šikšnys, Virginijus; Kupčinskas, Limas; Brudno, Michael; Petronis, Arturas

2016-01-01

Inability to digest lactose due to lactase non-persistence is a common trait in adult mammals, with the exception of certain human populations that exhibit lactase persistence. It is not clear how the lactase gene can be dramatically downregulated with age in most individuals, but remains active in some. We performed a comprehensive epigenetic study of the human and mouse intestine using chromosome-wide DNA modification profiling and targeted bisulfite sequencing. Epigenetically-controlled regulatory elements were found to account for the differences in lactase mRNA levels between individuals, intestinal cell types and species. The importance of these regulatory elements in modulating lactase mRNA levels was confirmed by CRISPR-Cas9-induced deletions. Genetic factors contribute to epigenetic changes occurring with age at the regulatory elements, as lactase persistence- and non-persistence-DNA haplotypes demonstrated markedly different epigenetic aging. Thus, genetic factors facilitate a gradual accumulation of epigenetic changes with age to affect phenotypic outcome. PMID:27159559

Assessment of essential and nonessential dietary exposure to trace elements from homegrown foodstuffs in a polluted area in Makedonska Kamenica and the Kočani region (FYRM).

PubMed

Vrhovnik, Petra; Dolenec, Matej; Serafimovski, Todor; Tasev, Goran; Arrebola, Juan P

2016-07-15

The main purpose of the present study is to assess human dietary exposure to essential and non-essential trace elements via consumption of selected homegrown foodstuffs. Twelve essential and non-essential trace elements (Cd, Co, Cu, Cr, Hg, Mo, Ni, Pb, Sb, Se, Zn and As) were detected in various homegrown foodstuffs. Detailed questionnaires were also applied among a sample of the local population to collect information on sociodemographic characteristics. The results of the present study clearly indicate that the majority of the trace elements are at highly elevated levels in the studied foodstuffs, in comparison to international recommendations. The maximum measured levels of ETE and NETE are as follows [μgkg(-1)]: Cd 873, Co 1370, Cu 21700, Cr 59633, Hg 26, Mo 6460, Ni14.5, Pb 11100, Sb 181, Se 0.30, Zn 102 and As 693. Additionally, age, body mass index and gender were significantly associated with levels of dietary exposure. Further research is warranted on the potential health implication of this exposure. The study merges the accumulation of ETE and NETE in home-grown foodstuffs and reflects considerably high health risks for inhabitants. Copyright © 2016 Elsevier B.V. All rights reserved.

Trace metal determination in natural waters by automated solid phase extraction system and ICP-MS: the influence of low level Mg and Ca.

PubMed

Wang, Bo-Shian; Lee, Chih-Ping; Ho, Tung-Yuan

2014-10-01

A fully automated high pressure pretreatment system with Nobias Chelate-PA1 resin (PA1) was developed for trace metal determination by ICP-MS in natural waters. By varying the concentrations of Mg and Ca to mimic the concentrations in the eluate obtained by PA1 or iminodiacetate type resins, the overall analytical performance of the system was assessed for the determination of Al, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Cd, Ag, Pb and REE. Comparing with the low mM level Mg and Ca (both ranging from 1 to 4mM) eluted by iminodiacetate type resins, the eluate obtained by PA1 contains sub-μM level Mg and Ca, which remarkably decrease matrix effect in ICP-MS analysis and significantly improve the analytical performance. With recovery better than 90% for most the trace metals examined, the accuracy was further verified through the analysis of five natural water reference materials with salinity spanning from 0 to 35‰. We have successfully applied the pretreatment system to determine trace metals in the seawater samples collected in the Western Philippine Sea through Taiwan GEOTRACES cruise. Copyright © 2014 Elsevier B.V. All rights reserved.

Trace elements and organic compounds in streambed sediment and aquatic biota from the Sacramento River Basin, California, October and November 1995

USGS Publications Warehouse

MacCoy, Dorene E.; Domagalski, Joseph L.

1999-01-01

Elevated levels of trace elements and hydrophobic organic compounds were detected in streambed sediments and aquatic biota [Asiatic clam (Corbicula fluminea) or bottom-feeding fish] of the Sacramento River Basin, California, during October and November 1995. Trace elements detected included cadmium, copper, mercury, lead, and zinc. Elevated levels of cadmium, copper, and zinc in the upper Sacramento River are attributed to a mining land use, and elevated levels of zinc and lead in an urban stream, and possibly in the lower Sacramento River, are attributed to urban runoff processes. Elevated levels of mercury in streambed sediment are attributed to either past mercury mining or to the use of mercury in past gold mining operations. Mercury mining was an important land use within the Coast Ranges in the past and gold mining was an important land use of the Sierra Nevada in the past. Mercury was the only trace element found in elevated levels in the tissue of aquatic biota, and those levels also could be attributed to either mining or urban runoff. Hydrophobic organic compounds also were detected in streambed sediments and aquatic biota. The most frequently detected compounds were DDT and its breakdown products, dieldrin, oxychlordane, and toxaphene. Differences were found in the types of compounds detected at agricultural sites and the urban site. Although both types of sites had measurable concentrations of DDT or its breakdown products, the urban site also had measurable concentrations of pesticides used for household pest control. Few semivolatile compounds were detected in the streambed sediments of any site. The semivolatile compound p-cresol, a coal-tar derivative associated with road maintenance, was found in the highest concentration.

Hair toxic and essential trace elements in children with autism spectrum disorder.

PubMed

Skalny, Anatoly V; Simashkova, Natalia V; Klyushnik, Tatiana P; Grabeklis, Andrei R; Bjørklund, Geir; Skalnaya, Margarita G; Nikonorov, Alexandr A; Tinkov, Alexey A

2017-02-01

The objective of the study was to investigate hair trace elements content in children suffering from autism spectrum disorder (ASD). A total of 74 ASD children and 74 sex- and age-matched controls divided into two age groups (2-4 and 5-9 years) were investigated. Hair trace elements content was assessed using inductively coupled plasma mass spectrometry. A general cohort of ASD children was characterized by 29 %, 41 %, and 24 % lower hair levels of chromium (Cr), iodine (I), and vanadium (V), respectively, whereas the level of selenium (Se) exceeded the respective control values by 31 %. In ASD children aged 2-4 years hair Cr, I and V content was 68 %, 36 % and 41 % lower than in the controls. Older ASD children were characterized by 45 % increase in hair Se levels. In a general cohort of ASD children hair beryllium (Be) and tin (Sn) levels were 50 % and 34 % lower than the control values. In the first age group (2-4 years) of ASD children 34 %, 42 %, and 73 % lower levels of arsenic (As), boron (B), and Be were detected. In the second age group of ASD children only a nearly significant 25 % decrease in hair lead (Pb) was detected. Surprisingly, no significant group difference in hair mercury (Hg), zinc (Zn), and copper (Cu) content was detected. Generally, the results of the present study demonstrate that children with ASD are characterized by lower values in hair of not only essential but also toxic trace elements.

Effects of electromagnetic pulse on serum element levels in rat.

PubMed

Li, Kangchu; Ma, Shirong; Ren, Dongqing; Li, Yurong; Ding, Guirong; Liu, Junye; Guo, Yao; Guo, Guozhen

2014-04-01

Electromagnetic pulse (EMP) was a potentially harmful factor to the human body, and a biological dosimetry to evaluate effects of EMP is necessary. Little is known about effects of EMP on concentration of macro and trace elements in serum so far. In this study, Sprague-Dawley rats were randomly divided into 50-kV/m EMP-exposed group (n = 10), 100-kV/m EMP-exposed group (n = 10), 200-kV/m EMP-exposed group (n = 40), and the sham-exposed group (n = 20). The macro and trace element concentrations in serum were examined at 6, 12, 24, and 48 h after EMP exposure at different electric field intensities. Compared with the sham-exposed groups, the concentration of sodium (Na), potassium (K), magnesium (Mg), calcium (Ca), zinc (Zn), copper (Cu), iron (Fe), selenium (Se), and manganese (Mn) in rat serum was not changed significantly within 48 h after 200 pulses of EMP exposure at electric field intensity of 50, 100, and 200 kV/m although the K level was decreased and the Ca level was increased with the electric field intensity of EMP increasing. In addition, there was a tendency that the Zn level was decreased with the time going on within 48 h after EMP exposure. Under our experimental conditions, EMP exposure cannot affect the concentration of macro and trace elements in rat serum. There was no time-effect or dose-effect relationship between EMP exposure and serum element levels. The macro and trace elements in serum are not suitable endpoints of biological dosimetry of EMP.

Trace metal contamination in surface sediments of intertidal zone from Qinhuangdao, China, revealed by geochemical and magnetic approaches: Distribution, sources, and health risk assessment.

PubMed

Zhu, Zongmin; Xue, Junhui; Deng, Yuzhen; Chen, Lin; Liu, Jiangfeng

2016-04-15

Based on geochemical and magnetic approaches, the distribution, sources, and health risk of trace metals in surface sediments from a seashore tourist city were investigated. A significant correlation was found between magnetic susceptibility (χ) and trace metals, which suggested that levels of trace metals in the sediments can be effectively depicted by the magnetic approach. The spatial distribution of χ and trace metals matched well with the city layout with relatively higher values being found in the port and busy tourist areas. This result, together with enrichment factors (EFs) and Tomlinson pollution load index (PLI) of metals, suggested that the influence of human activities on the coastal environment was noticeable. Principal component analysis (PCA) indicated that trace metals in the sediments were derived from both anthropogenic and natural sources. Noncarcinogenic risk assessment showed that there was no potential health risk of exposure to metals by means of ingestion or inhalation. Copyright © 2016 Elsevier Ltd. All rights reserved.

Dispersion model on PM₂.₅ fugitive dust and trace metals levels in Kuwait Governorates.

PubMed

Bu-Olayan, A H; Thomas, B V

2012-03-01

Frequent dust storms and recent environmental changes were found to affect the human health especially in residents of arid countries. Investigations on the PM(2.5) fugitive dust in six Kuwait Governorate areas using dispersion Gaussian plume modeling revealed significant relationship between low rate of pollutant emission, low wind velocity, and stable weather conditions' matrix causing high rate of dust deposition in summer than in winter. The rate of dust deposition and trace metals levels in PM(2.5) were in the sequence of G-VI > G-I > G-II > G-V > G-III > G-IV. Trace metals were observed in the sequence of Al > Fe > Zn > Ni > Pb > Cd irrespective of the Governorate areas and the two seasons. The high rate of dust deposition and trace metals in PM(2.5) was reflected by the vast open area, wind velocity, and rapid industrialization besides natural and anthropogenic sources. A combination of air dispersion modeling and nephalometric and gravimetric studies of this kind not only determines the seasonal qualitative and quantitative analyses on the PM(2.5) dust deposition besides trace metals apportionment in six Kuwait Governorate areas, but also characterizes air pollution factors that could be used by environmentalist to deduce preventive measures.

Pathogenic mycobacteria achieve cellular persistence by inhibiting the Niemann-Pick Type C disease cellular pathway.

PubMed

Fineran, Paul; Lloyd-Evans, Emyr; Lack, Nathan A; Platt, Nick; Davis, Lianne C; Morgan, Anthony J; Höglinger, Doris; Tatituri, Raju Venkata V; Clark, Simon; Williams, Ian M; Tynan, Patricia; Al Eisa, Nada; Nazarova, Evgeniya; Williams, Ann; Galione, Antony; Ory, Daniel S; Besra, Gurdyal S; Russell, David G; Brenner, Michael B; Sim, Edith; Platt, Frances M

2016-11-18

Tuberculosis remains a major global health concern. The ability to prevent phagosome-lysosome fusion is a key mechanism by which intracellular mycobacteria, including Mycobacterium tuberculosis , achieve long-term persistence within host cells. The mechanisms underpinning this key intracellular pro-survival strategy remain incompletely understood. Host macrophages infected with persistent mycobacteria share phenotypic similarities with cells taken from patients suffering from Niemann-Pick Disease Type C (NPC), a rare lysosomal storage disease in which endocytic trafficking defects and lipid accumulation within the lysosome lead to cell dysfunction and cell death. We investigated whether these shared phenotypes reflected an underlying mechanistic connection between mycobacterial intracellular persistence and the host cell pathway dysfunctional in NPC. The induction of NPC phenotypes in macrophages from wild-type mice or obtained from healthy human donors was assessed via infection with mycobacteria and subsequent measurement of lipid levels and intracellular calcium homeostasis. The effect of NPC therapeutics on intracellular mycobacterial load was also assessed. Macrophages infected with persistent intracellular mycobacteria phenocopied NPC cells, exhibiting accumulation of multiple lipid types, reduced lysosomal Ca 2+ levels, and defects in intracellular trafficking. These NPC phenotypes could also be induced using only lipids/glycomycolates from the mycobacterial cell wall. These data suggest that persistent intracellular mycobacteria inhibit the NPC pathway, likely via inhibition of the NPC1 protein, and subsequently induce altered acidic store Ca 2+ homeostasis. Reduced lysosomal calcium levels may provide a mechanistic explanation for the reduced levels of phagosome-lysosome fusion in mycobacterial infection. Treatments capable of correcting defects in NPC mutant cells via modulation of host cell calcium were of benefit in promoting clearance of mycobacteria from infected host cells. These findings provide a novel mechanistic explanation for mycobacterial intracellular persistence, and suggest that targeting interactions between the mycobacteria and host cell pathways may provide a novel avenue for development of anti-TB therapies.

Characteristics of Men Who Report Persistent Sexual Symptoms After Finasteride Use for Hair Loss.

PubMed

Basaria, Shehzad; Jasuja, Ravi; Huang, Grace; Wharton, Whitney; Pan, Hong; Pencina, Karol; Li, Zhuoying; Travison, Thomas G; Bhawan, Jag; Gonthier, Renaud; Labrie, Fernand; Dury, Alain Y; Serra, Carlo; Papazian, Allen; O'Leary, Michael; Amr, Sami; Storer, Thomas W; Stern, Emily; Bhasin, Shalender

2016-12-01

Some men who use finasteride for hair loss report persistent sexual and other symptoms after discontinuing finasteride therapy. To determine whether these persistent symptoms after discontinuation of finasteride use are due to androgen deficiency, decreased peripheral androgen action, or persistent inhibition of steroid 5α-reductase (SRD5A) enzymes. Finasteride users, who reported persistent sexual symptoms after discontinuing finasteride (group 1); age-matched finasteride users who did not report sexual symptoms (group 2); and healthy men who had never used finasteride (group 3). Sexual function, mood, affect, cognition, hormone levels, body composition, functional magnetic resonance imaging (fMRI) response to sexually and affectively valenced stimuli, nucleotide sequences of androgen receptor (AR), SRD5A1, and SRD5A2; expression levels of androgen-dependent genes in skin. Academic medical center. Symptomatic finasteride users were similar in body composition, strength, and nucleotide sequences of AR, SRD5A1, and SRD5A2 genes to asymptomatic finasteride users and nonusers. Symptomatic finasteride users had impaired sexual function, higher depression scores, a more negative affectivity balance, and more cognitive complaints than men in groups 2 and 3 but had normal objectively assessed cognitive function. Testosterone, dihydrotestosterone, 5α-androstane-3α,17β-diol-glucuronide, testosterone to dihydrotestosterone and androsterone glucuronide to etiocholanolone glucuronide ratios, and markers of peripheral androgen action and expression levels of AR-dependent genes in skin did not differ among groups. fMRI blood oxygen level-dependent responses to erotic and nonerotic stimuli revealed abnormal function in brain circuitry linked to sexual arousal and major depression. We found no evidence of androgen deficiency, decreased peripheral androgen action, or persistent peripheral inhibition of SRD5A in men with persistent sexual symptoms after finasteride use. Symptomatic finasteride users revealed depressed mood and fMRI findings consistent with those observed in depression.

Characteristics of Men Who Report Persistent Sexual Symptoms After Finasteride Use for Hair Loss

PubMed Central

Basaria, Shehzad; Jasuja, Ravi; Huang, Grace; Wharton, Whitney; Pan, Hong; Pencina, Karol; Li, Zhuoying; Travison, Thomas G.; Bhawan, Jag; Gonthier, Renaud; Labrie, Fernand; Dury, Alain Y.; Serra, Carlo; Papazian, Allen; O'Leary, Michael; Amr, Sami; Storer, Thomas W.; Stern, Emily

2016-01-01

Context: Some men who use finasteride for hair loss report persistent sexual and other symptoms after discontinuing finasteride therapy. Objective: To determine whether these persistent symptoms after discontinuation of finasteride use are due to androgen deficiency, decreased peripheral androgen action, or persistent inhibition of steroid 5α-reductase (SRD5A) enzymes. Participants: Finasteride users, who reported persistent sexual symptoms after discontinuing finasteride (group 1); age-matched finasteride users who did not report sexual symptoms (group 2); and healthy men who had never used finasteride (group 3). Outcomes: Sexual function, mood, affect, cognition, hormone levels, body composition, functional magnetic resonance imaging (fMRI) response to sexually and affectively valenced stimuli, nucleotide sequences of androgen receptor (AR), SRD5A1, and SRD5A2; expression levels of androgen-dependent genes in skin. Setting: Academic medical center. Results: Symptomatic finasteride users were similar in body composition, strength, and nucleotide sequences of AR, SRD5A1, and SRD5A2 genes to asymptomatic finasteride users and nonusers. Symptomatic finasteride users had impaired sexual function, higher depression scores, a more negative affectivity balance, and more cognitive complaints than men in groups 2 and 3 but had normal objectively assessed cognitive function. Testosterone, dihydrotestosterone, 5α-androstane-3α,17β-diol-glucuronide, testosterone to dihydrotestosterone and androsterone glucuronide to etiocholanolone glucuronide ratios, and markers of peripheral androgen action and expression levels of AR-dependent genes in skin did not differ among groups. fMRI blood oxygen level-dependent responses to erotic and nonerotic stimuli revealed abnormal function in brain circuitry linked to sexual arousal and major depression. Conclusions: We found no evidence of androgen deficiency, decreased peripheral androgen action, or persistent peripheral inhibition of SRD5A in men with persistent sexual symptoms after finasteride use. Symptomatic finasteride users revealed depressed mood and fMRI findings consistent with those observed in depression. PMID:27662439

Clinical Integration and How It Affects Student Retention in Undergraduate Athletic Training Programs

PubMed Central

Young, Allison; Klossner, Joanne; Docherty, Carrie L; Dodge, Thomas M; Mensch, James M

2013-01-01

Context A better understanding of why students leave an undergraduate athletic training education program (ATEP), as well as why they persist, is critical in determining the future membership of our profession. Objective To better understand how clinical experiences affect student retention in undergraduate ATEPs. Design Survey-based research using a quantitative and qualitative mixed-methods approach. Setting Three-year undergraduate ATEPs across District 4 of the National Athletic Trainers' Association. Patients or Other Participants Seventy-one persistent students and 23 students who left the ATEP prematurely. Data Collection and Analysis Data were collected using a modified version of the Athletic Training Education Program Student Retention Questionnaire. Multivariate analysis of variance was performed on the quantitative data, followed by a univariate analysis of variance on any significant findings. The qualitative data were analyzed through inductive content analysis. Results A difference was identified between the persister and dropout groups (Pillai trace = 0.42, F1,92 = 12.95, P = .01). The follow-up analysis of variance revealed that the persister and dropout groups differed on the anticipatory factors (F1,92 = 4.29, P = .04), clinical integration (F1,92 = 6.99, P = .01), and motivation (F1,92 = 43.12, P = .01) scales. Several themes emerged in the qualitative data, including networks of support, authentic experiential learning, role identity, time commitment, and major or career change. Conclusions A perceived difference exists in how athletic training students are integrated into their clinical experiences between those students who leave an ATEP and those who stay. Educators may improve retention by emphasizing authentic experiential learning opportunities rather than hours worked, by allowing students to take on more responsibility, and by facilitating networks of support within clinical education experiences. PMID:23672327

Clinical integration and how it affects student retention in undergraduate athletic training programs.

PubMed

Young, Allison; Klossner, Joanne; Docherty, Carrie L; Dodge, Thomas M; Mensch, James M

2013-01-01

A better understanding of why students leave an undergraduate athletic training education program (ATEP), as well as why they persist, is critical in determining the future membership of our profession. To better understand how clinical experiences affect student retention in undergraduate ATEPs. Survey-based research using a quantitative and qualitative mixed-methods approach. Three-year undergraduate ATEPs across District 4 of the National Athletic Trainers' Association. Seventy-one persistent students and 23 students who left the ATEP prematurely. Data were collected using a modified version of the Athletic Training Education Program Student Retention Questionnaire. Multivariate analysis of variance was performed on the quantitative data, followed by a univariate analysis of variance on any significant findings. The qualitative data were analyzed through inductive content analysis. A difference was identified between the persister and dropout groups (Pillai trace = 0.42, F(1,92) = 12.95, P = .01). The follow-up analysis of variance revealed that the persister and dropout groups differed on the anticipatory factors (F(1,92) = 4.29, P = .04), clinical integration (F(1,92) = 6.99, P = .01), and motivation (F(1,92) = 43.12, P = .01) scales. Several themes emerged in the qualitative data, including networks of support, authentic experiential learning, role identity, time commitment, and major or career change. A perceived difference exists in how athletic training students are integrated into their clinical experiences between those students who leave an ATEP and those who stay. Educators may improve retention by emphasizing authentic experiential learning opportunities rather than hours worked, by allowing students to take on more responsibility, and by facilitating networks of support within clinical education experiences.

Modeling Microbial Processes in EPIC to Estimate Greenhouse Gas Emissions from soils

NASA Astrophysics Data System (ADS)

Schwab, D. E.; Izaurralde, R. C.; McGill, W. B.; Williams, J. R.; Schmid, E.

2009-12-01

Emissions of trace gases (CO2, N2O and CH4) to the atmosphere from managed terrestrial ecosystems have been contributing significantly to the warming of Earth. Trace gas production is dominated by biospheric processes. An improved knowledge of the soil-plant-atmosphere interface is of key importance for understanding trace gas dynamics. In soils, microbial metabolism plays a key role in the release or uptake of trace gases. Here we present work on the biophysical and biogeochemical model EPIC (Environmental Policy/Integrated Climate) to extend its capabilities to simulate CO2 and N2O fluxes in managed and unmanaged ecosystems. Emphasis will be given to recently developed, microbially-based, denitrification and nitrification modules. The soil-atmosphere exchange of trace gases can be measured by using various equipments, but often these measurements exhibit extreme space-time variability. We use hourly time steps to account for the variability induced by small changes in environmental conditions. Soils are often studied as macroscopic systems, although their functions are predominantly controlled at a microscopic level; i.e. the level of the microorganisms. We include these processes to the extent that these are known and can be quantitatively described. We represent soil dynamics mathematically with routines for gas diffusion, Michael Menten processes, electron budgeting and other processes such as uptake and transformations. We hypothesize that maximization of energy capture form scarce substrates using energetic favorable reactions drives evolution and that competitive advantage can result by depriving a competitor from a substrate. This Microbe Model changes concepts of production of N-containing trace gases; it unifies understanding of N oxidation and reduction, predicts production and evolution of trace gases and is consistent with observations of anaerobic ammonium oxidation.

Aspergillus flavus Infection and Aflatoxin Production in Corn: Influence of Trace Elements

PubMed Central

Lillehoj, E. B.; Garcia, W. J.; Lambrow, M.

1974-01-01

Distribution of trace element levels in corn germ fractions from kernels naturally infected with Aspergillus flavus and from kernels free of the fungus demonstrated an association between the presence of A. flavus and higher levels of metals. A. flavus production of aflatoxin on various autoclaved corn media showed that ground, whole corn was an excellent substrate; similar high levels of toxin were observed on full-fat corn germ but endosperm and defatted corn germ supported reduced yields. The influence of trace elements and their availability in defatted corn germ to A. flavus-mediated aflatoxin biosynthesis were measured. Enrichment of the substrate with 5 to 10 μg of manganese, copper, cadmium, or chromium per g of germ increased toxin yields. Addition of lead or zinc (50 to 250 μg/g) also enhanced toxin accumulation. Aflatoxin elaboration was reduced by the addition of 25 μg of cadmium per g or 500 μg of copper per g of germ. PMID:4216287

Levels of HIV-1 persistence on antiretroviral therapy are not associated with markers of inflammation or activation

PubMed Central

Bosch, Ronald J.; Macatangay, Bernard J.; Rinaldo, Charles R.; Riddler, Sharon A.; Mellors, John W.

2017-01-01

Antiretroviral therapy (ART) reduces levels of HIV-1 and immune activation but both can persist despite clinically effective ART. The relationships among pre-ART and on-ART levels of HIV-1 and activation are incompletely understood, in part because prior studies have been small or cross-sectional. To address these limitations, we evaluated measures of HIV-1 persistence, inflammation, T cell activation and T cell cycling in a longitudinal cohort of 101 participants who initiated ART and had well-documented sustained suppression of plasma viremia for a median of 7 years. During the first 4 years following ART initiation, HIV-1 DNA declined by 15-fold (93%) whereas cell-associated HIV-1 RNA (CA-RNA) fell 525-fold (>99%). Thereafter, HIV-1 DNA levels continued to decline slowly (5% per year) with a half-life of 13 years. Participants who had higher HIV-1 DNA and CA-RNA before starting treatment had higher levels while on ART, despite suppression of plasma viremia for many years. Markers of inflammation and T cell activation were associated with plasma HIV-1 RNA levels before ART was initiated but there were no consistent associations between these markers and HIV-1 DNA or CA-RNA during long-term ART, suggesting that HIV-1 persistence is not driving or driven by inflammation or activation. Higher levels of inflammation, T cell activation and cycling before ART were associated with higher levels during ART, indicating that immunologic events that occurred well before ART initiation had long-lasting effects despite sustained virologic suppression. These findings should stimulate studies of viral and host factors that affect virologic, inflammatory and immunologic set points prior to ART initiation and should inform the design of strategies to reduce HIV-1 reservoirs and dampen immune activation that persists despite ART. PMID:28426825

Geologic and paleoseismic study of the Lavic Lake fault at Lavic Lake Playa, Mojave Desert, Southern California

USGS Publications Warehouse

Rymer, M.J.; Seitz, G.G.; Weaver, K.D.; Orgil, A.; Faneros, G.; Hamilton, J.C.; Goetz, C.

2002-01-01

Paleoseismic investigations of the Lavic Lake fault at Lavic Lake playa place constraints on the timing of a possible earlier earthquake along the 1999 Hector Mine rupture trace and reveal evidence of the timing of the penultimate earthquake on a strand of the Lavic Lake fault that did not rupture in 1999. Three of our four trenches, trenches A, B, and C, were excavated across the 1999 Hector Mine rupture; a fourth trench, D, was excavated across a vegetation lineament that had only minor slip at its southern end in 1999. Trenches A-C exposed strata that are broken only by the 1999 rupture; trench D exposed horizontal bedding that is locally warped and offset by faults. Stratigraphic evidence for the timing of an earlier earthquake along the 1999 rupture across Lavic Lake playa was not exposed. Thus, an earlier event, if there was one along that rupture trace, predates the lowest stratigraphic level exposed in our trenches. Radiocarbon dating of strata near the bottom of trenches constrains a possible earlier event to some time earlier than about 4950 B.C. Buried faults revealed in trench D are below a vegetation lineament at the ground surface. A depositional contact about 80 cm below the ground surface acts as the upward termination of fault breaks in trench D. Thus, this contact may be the event horizon for a surface-rupturing earthquake prior to 1999-the penultimate earthquake on the Lavic Lake fault. Radiocarbon ages of detrital charcoal samples from immediately below the event horizon indicate that the earthquake associated with the faulting occurred later than A.D. 260. An approximately 1300-year age difference between two samples at about the same stratigraphic level below the event horizon suggests the potential for a long residence time of detrital charcoal in the area. Coupled with a lack of bioturbation that could introduce young organic material into the stratigraphic section, the charcoal ages provide only a maximum bounding age; thus, the recognized event may be younger. There is abundant, subtle evidence for pre-1999 activity of the Lavic Lake fault in the playa area, even though the fault was not mapped near the playa prior to the Hector Mine earthquake. The most notable indicators for long-term presence of the fault are pronounced, persistent vegetation lineaments and uplifted basalt exposures. Primary and secondary slip occurred in 1999 on two southern vegetation lineaments, and minor slip locally formed on a northern lineament; trench exposures across the northern vegetation lineament revealed the post-A.D. 260 earthquake, and a geomorphic trough extends northward into alluvial fan deposits in line with this lineament. The presence of two basalt exposures in Lavic lake playa indicates the presence of persistent compressional steps and uplift along the fault. Fault-line scarps are additional geomorphic markers of repeated slip events in basalt exposures.

Chemical speciation of heavy metals by surface-enhanced Raman scattering spectroscopy: identification and quantification of inorganic- and methyl-mercury in water

NASA Astrophysics Data System (ADS)

Guerrini, Luca; Rodriguez-Loureiro, Ignacio; Correa-Duarte, Miguel A.; Lee, Yih Hong; Ling, Xing Yi; García de Abajo, F. Javier; Alvarez-Puebla, Ramon A.

2014-06-01

Chemical speciation of heavy metals has become extremely important in environmental and analytical research because of the strong dependence that toxicity, environmental mobility, persistence and bioavailability of these pollutants have on their specific chemical forms. Novel nano-optical-based detection strategies, capable of overcoming the intrinsic limitations of well-established analytic methods for the quantification of total metal ion content, have been reported, but the speciation of different chemical forms has not yet been achieved. Here, we report the first example of a SERS-based sensor for chemical speciation of toxic metal ions in water at trace levels. Specifically, the inorganic Hg2+ and the more toxicologically relevant methylmercury (CH3Hg+) are selected as analytical targets. The sensing platform consists of a self-assembled monolayer of 4-mercaptopyridine (MPY) on highly SERS-active and robust hybrid plasmonic materials formed by a dense layer of interacting gold nanoparticles anchored onto polystyrene microbeads. The co-ordination of Hg2+ and CH3Hg+ to the nitrogen atom of the MPY ring yields characteristic changes in the vibrational SERS spectra of the organic chemoreceptor that can be qualitatively and quantitatively correlated to the presence of the two different mercury forms.Chemical speciation of heavy metals has become extremely important in environmental and analytical research because of the strong dependence that toxicity, environmental mobility, persistence and bioavailability of these pollutants have on their specific chemical forms. Novel nano-optical-based detection strategies, capable of overcoming the intrinsic limitations of well-established analytic methods for the quantification of total metal ion content, have been reported, but the speciation of different chemical forms has not yet been achieved. Here, we report the first example of a SERS-based sensor for chemical speciation of toxic metal ions in water at trace levels. Specifically, the inorganic Hg2+ and the more toxicologically relevant methylmercury (CH3Hg+) are selected as analytical targets. The sensing platform consists of a self-assembled monolayer of 4-mercaptopyridine (MPY) on highly SERS-active and robust hybrid plasmonic materials formed by a dense layer of interacting gold nanoparticles anchored onto polystyrene microbeads. The co-ordination of Hg2+ and CH3Hg+ to the nitrogen atom of the MPY ring yields characteristic changes in the vibrational SERS spectra of the organic chemoreceptor that can be qualitatively and quantitatively correlated to the presence of the two different mercury forms. Electronic supplementary information (ESI) available: Representative TEM and ESEM images of AuNPs and PS@Au particles. Optical extinction spectra of AuNPs and PS@Au suspensions. SERS spectra of unmodified PS@Au suspension before and after the addition of CH3Hg+. SERS spectra of PS@Au-MPY upon addition of several metal solutions. Detailed SERS study of the MPY response to high concentration of CH3Hg+. See DOI: 10.1039/c4nr01464b

Bifurcation of potential vorticity gradients across the Southern Hemisphere stratospheric polar vortex

NASA Astrophysics Data System (ADS)

Conway, Jonathan; Bodeker, Greg; Cameron, Chris

2018-06-01

The wintertime stratospheric westerly winds circling the Antarctic continent, also known as the Southern Hemisphere polar vortex, create a barrier to mixing of air between middle and high latitudes. This dynamical isolation has important consequences for export of ozone-depleted air from the Antarctic stratosphere to lower latitudes. The prevailing view of this dynamical barrier has been an annulus compromising steep gradients of potential vorticity (PV) that create a single semi-permeable barrier to mixing. Analyses presented here show that this barrier often displays a bifurcated structure where a double-walled barrier exists. The bifurcated structure manifests as enhanced gradients of PV at two distinct latitudes - usually on the inside and outside flanks of the region of highest wind speed. Metrics that quantify the bifurcated nature of the vortex have been developed and their variation in space and time has been analysed. At most isentropic levels between 395 and 850 K, bifurcation is strongest in mid-winter and decreases dramatically during spring. From August onwards a distinct structure emerges, where elevated bifurcation remains between 475 and 600 K, and a mostly single-walled barrier occurs at other levels. While bifurcation at a given level evolves from month to month, and does not always persist through a season, interannual variations in the strength of bifurcation display coherence across multiple levels in any given month. Accounting for bifurcation allows the region of reduced mixing to be better characterised. These results suggest that improved understanding of cross-vortex mixing requires consideration of the polar vortex not as a single mixing barrier but as a barrier with internal structure that is likely to manifest as more complex gradients in trace gas concentrations across the vortex barrier region.

West Nile virus nucleic acid persistence in whole blood months after clearance in plasma: implication for transfusion and transplantation safety

PubMed Central

Lanteri, Marion C.; Lee, Tzong-Hae; Wen, Li; Kaidarova, Zhanna; Bravo, Marjorie D.; Kiely, Nancy E.; Kamel, Hany T.; Tobler, Leslie H.; Norris, Philip J.; Busch, Michael P.

2014-01-01

BACKGROUND Previous reports of WNV RNA persistence in blood compartments have raised concerns around the remaining risk of WNV transfusion-transmission. This study characterized the dynamics of WNV viremia in blood compartments in a longitudinal cohort of 54 WNV-infected blood donors. STUDY DESIGN AND METHODS Blood samples were collected throughout the year after WNV RNA+ blood donation (index) and characterized for anti-WNV IgM and IgG antibodies and for WNV RNA by real-time reverse-transcription polymerase chain reaction. WNV viral loads were compared in plasma and whole blood samples and correlated with blood groups and clinical outcomes. RESULTS WNV RNA persisted in the red blood cell (RBC) compartment up to three months post-index in 42% of the donors. Donors with the highest WNV RNA levels in plasma at index maintained the highest WNV RNA levels in whole blood over the three months post-index. Blood group A donors maintained higher post-index WNV viral load in whole blood than blood group O individuals (P=0.027). Despite a trend for WNV RNA to persist longer in whole blood from symptomatic subjects, no significant association was found between WNV RNA levels in whole blood and disease outcome. CONCLUSION This study confirmed that WNV RNA persists in the RBC fraction in whole blood and further suggested that the level of persistence in whole blood may be a reflection of initial viral burden in plasma. The association with blood groups suggests that WNV adherence to RBCs may be mediated by molecules overrepresented at the surface of blood group A RBCs. PMID:24965017

[Contents of macromineral and trace elements in spirulina (Arthrospira platensis) from France, Chad, Togo, Niger, Mali, Burkina-Faso and Central African Republic].

PubMed

Vicat, Jean-Paul; Doumnang Mbaigane, Jean-Claude; Bellion, Yves

2014-01-01

Data on mineral elements in spirulinas being limited, we analyzed macrominerals and trace elements of samples from France and Africa. Spirulinas cultivated in France have a composition in macromineral elements similar to those of the literature. The entire contents of trace elements are low. Unlike marine cyanobacteria, they do not concentrate rare-earth elements. Spirulina harvested in Chad has high levels in macrominerals and trace elements, due to traditional drying and harvesting methods. Rare-earth element levels are attributed to this pollution and not to their concentration in spirulinas, because rare-earth element normalized profiles of spirulina are strictly parallel to those of ouadis mud and very different from those of ouadis water. Despite the sometimes high content of total As, normal water consumption in Chad presents no health problems. Spirulinas grown in Togo, Niger, Mali, Burkina-Faso and Central African Republic have chemical compositions similar to those of Chad spirulinas, but with a lower content of macromineral and trace elements, reflecting a lower mineral pollution. Rare-earth element normalized patterns dismiss an aeolian pollution and the pollution is rather of pedological origin. They show no toxicity problem except spirulinas from Burkina-Faso, whose Pb content is too high. The variability of composition of spirulinas can be largely attributed to the mineral pollution of the samples. Significant levels of rare-earth elements sometimes found in the literature reflect this pollution. Copyright © 2013 Académie des sciences. Published by Elsevier SAS. All rights reserved.

Enduring Poverty: Explanations for the Persistence of Minority Poverty in Vietnam

DTIC Science & Technology

2017-03-01

ethnic groups contribute more to the persistence of minority poverty than geography and agricultural livelihoods. When prosperity levels are compared...between the ethnic majority and minority groups, between ethnic groups in similar geographic regions, and between ethnic groups with agricultural ...poverty than geography and agricultural livelihoods. When prosperity levels are compared between the ethnic majority and minority groups, between

Predicting For-Profit Student Persistence Using the Student Satisfaction Inventory

ERIC Educational Resources Information Center

Edens, David

2012-01-01

For-profit colleges are under scrutiny with questions about quality of curriculum, quality of faculty and instruction, and the value of the degree for the high-priced tuition. The high debt-load and low levels of persistence among students who enter for-profit institutions raise the level of concern for these students, many of whom are older and…

Are Persistent Early Onset Child Conduct Problems Predicted by the Trajectories and Initial Levels of Discipline Practices?

ERIC Educational Resources Information Center

Lorber, Michael F.; Slep, Amy M. Smith

2015-01-01

In the present investigation we focused on 2 broad sets of questions: Do parental overreactivity, laxness, and corporal punishment show evidence of normative change in early to middle childhood? Are persistently elevated child conduct problems (CPs) associated with deviations from normative changes in, as well as high initial levels of, discipline…

The persistent clustering of adult body mass index by school attended in adolescence.

PubMed

Evans, Clare Rosenfeld; Lippert, Adam M; Subramanian, S V

2016-03-01

It is well known that adolescent body mass index (BMI) shows school-level clustering. We explore whether school-level clustering of BMI persists into adulthood. Multilevel models nesting young adults in schools they attended as adolescents are fit for 3 outcomes: adolescent BMI, self-report adult BMI and measured adult BMI. Sex-stratified and race/ethnicity-stratified (black, Hispanic, white, other) analyses were also conducted. School-level clustering (wave 1 intraclass correlation coefficient (ICC)=1.3%) persists over time (wave 4 ICC=2%), and results are comparable across stratified analyses of both sexes and all racial/ethnic groups (except for Hispanics when measured BMIs are used). Controlling for BMI in adolescence partially attenuates this effect. School-level clustering of BMI persists into young adulthood. Possible explanations include the salience of school environments in establishing behaviours and trajectories, the selection of adult social networks that resemble adolescent networks and reinforce previous behaviours, and characteristics of school catchment areas associated with BMI. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Elevation of CSF tumor necrosis factor alpha levels in new daily persistent headache and treatment refractory chronic migraine.

PubMed

Rozen, Todd; Swidan, Sahar Z

2007-01-01

To determine if patients with new daily persistent headache (NDPH) have elevated levels of tumor necrosis factor alpha (TNF alpha) in the CSF. NDPH is considered one of the most treatment resistant of all headache syndromes. This reflects a lack of understanding of its pathogenesis. As a certain percentage of NDPH patients have their headaches start after an infection, the possibility of a persistent state of systemic or CNS inflammation comes into question. TNF alpha is a proinflammatory cytokine involved in brain immune and inflammatory activities, as well as in pain initiation. The goal of this study was to look at TNF alpha levels in the CSF of NDPH patients, to determine if CNS inflammation may play some role in the pathogenesis of this condition. CSF TNF alpha levels were studied in 38 patients: 20 with NDPH and a control population of 16 patients with chronic migraine (CM), and 2 with post-traumatic headache (PT). CSF TNF alpha levels were elevated in 19 of 20 NDPH patients, 16 of 16 CM patients, and both PT patients. Serum TNF alpha levels were normal in most of the study subjects. An elevation of CSF TNF alpha levels was found in almost all NDPH patients and suggest a role for TNF alpha in the pathogenesis of this condition. Surprisingly, all CM and PT patients tested had elevated CSF TNF alpha levels. In most patients with elevated CSF levels, serum TNF alpha levels were normal. All of these syndromes may be manifestations of CNS inflammation. As most of the positive-tested patients showed minimal to no improvement during aggressive inpatient treatment, persistent elevation of CSF TNF alpha levels may be one of the causes of treatment refractory CDH.

Has irrigated water from Mahaweli River contributed to the kidney disease of uncertain etiology in the dry zone of Sri Lanka?

PubMed

Diyabalanage, Saranga; Abekoon, Sumith; Watanabe, Izumi; Watai, Chie; Ono, Yuko; Wijesekara, Saman; Guruge, Keerthi S; Chandrajith, Rohana

2016-06-01

The Mahaweli is the largest river basin in Sri Lanka that provides water to the dry zone region through multipurpose irrigation schemes . Selenium, arsenic, cadmium, and other bioimportant trace elements in surface waters of the upper Mahaweli River were measured using ICP-MS. Trace element levels were then compared with water from two other rivers (Maha Oya, Kalu Ganga) and from six dry zone irrigation reservoirs. Results showed that the trace metal concentrations in the Mahaweli upper catchment were detected in the order of Fe > Cu > Zn > Se > Cr > Mn > As > Ni > Co > Mo. Remarkably high levels of Ca, Cr, Co, Ni, Cu, As, and Se were observed in the Mahaweli Basin compared to other study rivers. Considerably high levels of Cr, Mn, Fe, Co, Ni, Cu, Zn, As, and Se were found in upstream tributaries of the Mahaweli River. Such metals possibly originated from phosphate and organic fertilizers that are heavily applied for tea and vegetable cultivations within the drainage basin. Cadmium that is often attributed to the etiology of unknown chronic kidney diseases in certain parts of the dry zone is much lower than previously reported levels. Decrease in these metals in the lower part of the Mahaweli River could be due to adsorption of trace metals onto sediment and consequent deposition in reservoirs.

Soil-based systemic delivery and phyllosphere in vivo propagation of bacteriophages: Two possible strategies for improving bacteriophage persistence for plant disease control.

PubMed

Iriarte, Fanny B; Obradović, Aleksa; Wernsing, Mine H; Jackson, Lee E; Balogh, Botond; Hong, Jason A; Momol, M Timur; Jones, Jeffrey B; Vallad, Gary E

2012-10-01

Soil-based root applications and attenuated bacterial strains were evaluated as means to enhance bacteriophage persistence on plants for bacterial disease control. In addition, the systemic nature of phage applied to tomato roots was also evaluated. Several experiments were conducted applying either single phages or phage mixtures specific for Ralstonia solanacearum , Xanthomonas perforans or X. euvesicatoria to soil surrounding tomato plants and measuring the persistence and translocation of the phages over time. In general, all phages persisted in the roots of treated plants and were detected in stems and leaves; although phage level varied and persistence in stems and leaves was at a much lower level compared with persistence in roots. Bacterial wilt control was typically best if the phage or phage mixtures were applied to the soil surrounding tomatoes at the time of inoculation, less effective if applied 3 days before inoculation, and ineffective if applied 3 days after inoculation. The use of an attenuated X. perforans strain was also evaluated to improve the persistence of phage populations on tomato leaf surfaces. In greenhouse and field experiments, foliar applications of an attenuated mutant X. perforans 91-118:∆ OPGH strain prior to phage applications significantly improved phage persistence on tomato foliage compared with untreated tomato foliage. Both the soil-based bacteriophage delivery and the use of attenuated bacterial strains improved bacteriophage persistence on respective root and foliar tissues, with evidence of translocation with soil-based bacteriophage applications. Both strategies could lead to improved control of bacterial pathogens on plants.

Robust Requirements Tracing via Internet Search Technology: Improving an IV and V Technique. Phase 2

NASA Technical Reports Server (NTRS)

Hayes, Jane; Dekhtyar, Alex

2004-01-01

There are three major objectives to this phase of the work. (1) Improvement of Information Retrieval (IR) methods for Independent Verification and Validation (IV&V) requirements tracing. Information Retrieval methods are typically developed for very large (order of millions - tens of millions and more documents) document collections and therefore, most successfully used methods somewhat sacrifice precision and recall in order to achieve efficiency. At the same time typical IR systems treat all user queries as independent of each other and assume that relevance of documents to queries is subjective for each user. The IV&V requirements tracing problem has a much smaller data set to operate on, even for large software development projects; the set of queries is predetermined by the high-level specification document and individual requirements considered as query input to IR methods are not necessarily independent from each other. Namely, knowledge about the links for one requirement may be helpful in determining the links of another requirement. Finally, while the final decision on the exact form of the traceability matrix still belongs to the IV&V analyst, his/her decisions are much less arbitrary than those of an Internet search engine user. All this suggests that the information available to us in the framework of the IV&V tracing problem can be successfully leveraged to enhance standard IR techniques, which in turn would lead to increased recall and precision. We developed several new methods during Phase II; (2) IV&V requirements tracing IR toolkit. Based on the methods developed in Phase I and their improvements developed in Phase II, we built a toolkit of IR methods for IV&V requirements tracing. The toolkit has been integrated, at the data level, with SAIC's SuperTracePlus (STP) tool; (3) Toolkit testing. We tested the methods included in the IV&V requirements tracing IR toolkit on a number of projects.

Serum trace elements in obese Egyptian children: a case–control study

PubMed Central

2014-01-01

Background To date, only a few studies on child obesity concerned Trace Elements (TE). TE is involved in the pathogenesis of obesity and obesity related diseases. We tried to assess trace elements status [zinc (Zn), copper (Cu), selenium (Se), iron (Fe), and chromium (Cr)] in obese Egyptian children and their relationships with serum leptin and metabolic risk factors of obesity. Methods This was a case–control study performed with 80 obese children (BMI ≥ 95thcentile for age and gender) and 80 healthy non-obese children with comparable age and gender as the control group. For all subjects, serum Zn, Cu, Se, Fe, ferritin and Cr as well as biochemical parameters including lipid profile, serum glucose and homeostasis model assessment of insulin resistance (HOMA-IR) were assessed. Levels of serum leptin were measured by (enzyme-linked immunosorbent assay [ELISA] method), and serum insulin was measured by an electrochemiluminesce immunoassay. Results Compared to the control group, serum Zn, Se, and Fe levels were significantly lower (all P < 0.01) and serum Cu level was significantly higher (P < 0.01) in the obese children. Meanwhile, no significant differences were observed in serum ferritin or Cr levels (P > 0.05). A significant negative correlation was found between serum leptin and zinc levels in the obese children (r = −0.746; P < 0.01). Further, serum Zn showed significant negative correlations with total cholesterol TC levels (P < 0.05) and were positively correlated with high density lipoprotein- cholesterol HDL-C levels (P < 0.01) in the obese children. In addition, serum Se levels showed significant positive correlations with HOMA-IR values in the obese children (P < 0.01). Conclusion The obese children may be at a greater risk of developing imbalance (mainly deficiency) of trace elements which may be playing an important role in the pathogenesis of obesity and related metabolic risk factors. PMID:24555483

Content and persistence of extracellular DNA in native soils

NASA Astrophysics Data System (ADS)

Blagodatskaya, Evgenia; Blagodatsky, Sergey; Anderson, Traute-Heidi; Kuzyakov, Yakov

2014-05-01

The long-term persistence of soil extracellular DNA is questionable because of high potential activity of nucleases produced by soil microorganisms. By the other hand, the relative persistence of DNA-like biopolymers could be due to their adsorption on clay minerals and humus substances in soil. High-specific and ultra sensitive reagent PicoGreenTM (Molecular Probes) permits the quantitative assessment of microbial dsDNA in diluted soil extracts giving a good tool for tracing the DNA fate in soil. Our goal was to determine intracellular and extracellular DNA content in cambisol (loamy sand) and in chernozem (silty loam) soils and to investigate the possible adsorption and degradation of extracellular DNA in soil. Optimized procedure of mechanical and enzymatic destruction of cell walls was used for direct extraction of microbial DNA with Tris-EDTA buffer (Blagodatskaya et al., 2003). Extracellular dsDNA was determined in distilled water and in Tris-EDTA extracts without enzymatic or mechanical treatments. DNA content was determined after addition of PicoGreen to diluted soil extracts. Degradation of extracellular DNA was traced during 24 h incubation of 2 µg lambda-phage DNA in soil. Possible DNA adsorption to soil matrix was determined by recovery of lambda -phage DNA added to autoclaved soil. Extracellular dsDNA was absent in water extracts of both soils. The content of extracellular dsDNA extracted by Tris-EDTA buffer was 0.46 µg/g in chernozem and 1.59 µg/g in cambisol amounting 0.43 and 2.8% of total dsDNA content in these soils, respectively. 100% and 64.8% of added extracellular lambda -phage dsDNA was found in cambisol and chernozem soils, respectively, in 5 h after application. 39% and 73.5% of added DNA disappeared in cambisol and in chernozem, respectively, during 24 h incubation. Degradation rate of extracellular DNA depended on microbial biomass content, which was 2.5 times higher in chernozem as compared to cambisol. Maximum adsorption of DNA by soils was observed in cambisol and reached 2.7% of added amount. We speculate that probability of gene transfer could be rather high in soils, taking into account possible increase of extracellular DNA content after transient environmental events (i.e. drying - rewetting and freezing - thawing).

Quantitative Ultrasound-Assisted Extraction for Trace-Metal Determination: An Experiment for Analytical Chemistry

ERIC Educational Resources Information Center

Lavilla, Isela; Costas, Marta; Pena-Pereira, Francisco; Gil, Sandra; Bendicho, Carlos

2011-01-01

Ultrasound-assisted extraction (UAE) is introduced to upper-level analytical chemistry students as a simple strategy focused on sample preparation for trace-metal determination in biological tissues. Nickel extraction in seafood samples and quantification by electrothermal atomic absorption spectrometry (ETAAS) are carried out by a team of four…

Hyperthyroidism as a cause of persistent vomiting.

PubMed

Hoogendoorn, E H; Cools, B M

2004-09-01

A 32-year-old woman presented with persistent vomiting, epigastric pain and weight loss. A sinus tachycardia was the clue to the diagnosis of hyperthyroidism due to Graves' disease. On treatment with propylthiouracil and a beta-blocking agent, her symptoms resolved within one day, even though her free thyroxine level was still high. Hyperthyroidism is an uncommon, but previously reported cause of persistent vomiting.

Profiles of Persisting Fourth-Year STEM Majors. ACT Research Report Series 2016 (5)

ERIC Educational Resources Information Center

Westrick, Paul

2016-01-01

Using date from 120,612 students at 26 four-year institutions, this report provides a description of STEM majors entering four-year postsecondary institutions and those who persist through four years of study. The results indicate that persisting STEM majors enter college with very high levels of pre-college academic achievement as measured by the…

African American Female Community College Graduates: A Phenomenological Study of Motivation and Success Strategies for Persistence in Minnesota

ERIC Educational Resources Information Center

Mattison, Tamara D.

2013-01-01

African American females at the community level have low persistence rates and the literature regarding motivation and success strategies for those who persist to graduation is limited. This study was designed to identify the motivation and success strategies used by African American females to graduate from community colleges in Minnesota.…

Trace elements in seminal plasma of men from infertile couples.

PubMed

Guzikowski, Wojciech; Szynkowska, Małgorzata I; Motak-Pochrzęst, Hanna; Pawlaczyk, Aleksandra; Sypniewski, Stanisław

2015-06-19

An analysis of lead, zinc, cadmium and other trace elements in semen of men from infertile couples was performed to determine the association between abnormal semen parameters and enviromental or occupational exposure to some trace metals. Presence of manganese, cobalt, nickel, copper, zinc, molybdenum, cadmium, tin and lead was measured in seminal plasma of 34 men from infertile couples using spectrometry with time-of-flight analysis. Correlations among sperm parameters and trace metals were determined using cluster analysis and Pearson's correlation coefficient. Abnormally high concentrations of lead, cadmium, zinc and cobalt were found in 23 seminal plasma of men from infertile couples. The most consistent evidence was determined for an association between high cadmium concentration in seminal plasma and sperm count, motility and morphology below reference limits (p < 0.01). A correlation of significantly increased tin level and reduced sperm count in semen of men with limited fertility potential was observed (p = 0.04). In our study we observed a correlation of tin level with sperm count in semen of men with limited fertility potential.

Baseline Levels and Trimestral Variation of Triiodothyronine and Thyroxine and Their Association with Mortality in Maintenance Hemodialysis Patients

PubMed Central

Meuwese, Christiaan L.; Dekker, Friedo W.; Lindholm, Bengt; Qureshi, Abdul R.; Heimburger, Olof; Barany, Peter; Stenvinkel, Peter; Carrero, Juan J.

2012-01-01

Summary Background and objectives Conflicting evidence exists with regard to the association of thyroid hormones and mortality in dialysis patients. This study assesses the association between basal and trimestral variation of thyroid stimulating hormone, triiodothyronine, and thyroxine and mortality. Design, setting, participants, & measurements In 210 prevalent hemodialysis patients, serum triiodothyronine, thyroxine, thyroid stimulating hormone, and interleukin-6 were measured 3 months apart. Cardiovascular and non-cardiovascular deaths were registered during follow-up. Based on fluctuations along tertiles of distribution, four trimestral patterns were defined for each thyroid hormone: persistently low, decrease, increase, and persistently high. The association of baseline levels and trimestral variation with mortality was investigated with Kaplan–Meier curves and Cox proportional hazard models. Results During follow-up, 103 deaths occurred. Thyroid stimulating hormone levels did not associate with mortality. Patients with relatively low basal triiodothyronine concentrations had higher hazards of dying than patients with high levels. Longitudinally, patients with persistently low levels of triiodothyronine during the 3-month period had higher mortality hazards than those having persistently high levels. These associations were mainly attributable to cardiovascular-related mortality. The association between thyroxine and mortality was not altered after adjustment for triiodothyronine. Conclusions Hemodialysis patients with reduced triiodothyronine or thyroxine levels bear an increased mortality risk, especially due to cardiovascular causes. This was true when considering both baseline measurements and trimestral variation patterns. Our longitudinal design adds observational evidence supporting the hypothesis that the link may underlie a causal effect. PMID:22246282

Baseline levels and trimestral variation of triiodothyronine and thyroxine and their association with mortality in maintenance hemodialysis patients.

PubMed

Meuwese, Christiaan L; Dekker, Friedo W; Lindholm, Bengt; Qureshi, Abdul R; Heimburger, Olof; Barany, Peter; Stenvinkel, Peter; Carrero, Juan J

2012-01-01

Conflicting evidence exists with regard to the association of thyroid hormones and mortality in dialysis patients. This study assesses the association between basal and trimestral variation of thyroid stimulating hormone, triiodothyronine, and thyroxine and mortality. In 210 prevalent hemodialysis patients, serum triiodothyronine, thyroxine, thyroid stimulating hormone, and interleukin-6 were measured 3 months apart. Cardiovascular and non-cardiovascular deaths were registered during follow-up. Based on fluctuations along tertiles of distribution, four trimestral patterns were defined for each thyroid hormone: persistently low, decrease, increase, and persistently high. The association of baseline levels and trimestral variation with mortality was investigated with Kaplan-Meier curves and Cox proportional hazard models. During follow-up, 103 deaths occurred. Thyroid stimulating hormone levels did not associate with mortality. Patients with relatively low basal triiodothyronine concentrations had higher hazards of dying than patients with high levels. Longitudinally, patients with persistently low levels of triiodothyronine during the 3-month period had higher mortality hazards than those having persistently high levels. These associations were mainly attributable to cardiovascular-related mortality. The association between thyroxine and mortality was not altered after adjustment for triiodothyronine. Hemodialysis patients with reduced triiodothyronine or thyroxine levels bear an increased mortality risk, especially due to cardiovascular causes. This was true when considering both baseline measurements and trimestral variation patterns. Our longitudinal design adds observational evidence supporting the hypothesis that the link may underlie a causal effect.

Estimation of TiO₂ nanoparticle-induced genotoxicity persistence and possible chronic gastritis-induction in mice.

PubMed

Mohamed, Hanan Ramadan Hamad

2015-09-01

Titanium dioxide (TiO2) nanoparticles are widely used as a food additive and coloring agent in many consumer products however limited data is available on the nano-TiO2 induced genotoxicity persistence. Thus, this study investigated the persistence of nano-TiO2 induced genotoxicity and possible induction of chronic gastritis in mice. The mice were orally administered 5, 50 or 500 mg/kg body weight nano-TiO2 for five consecutive days, and then mice from each dosage group were sacrificed 24 h or one or two weeks after the last treatment. The administration of nano-TiO2 resulted in persistent apoptotic DNA fragmentation and mutations in p53 exons (5-8) as well as significant persistent elevations in malondialdehyde and nitric oxide levels and decreases in the reduced glutathione level and catalase activity compared with the control mice in a dose- and time-dependent manner. Necrosis and inflammation were evident upon histological examination. These findings could be attributed to the persistent accumulation of nano-TiO2 at the tested doses at all three time points. Based on these findings, we conclude that the administration of nano-TiO2, even at low doses, leads to persistent accumulation of nano-TiO2 in mice, resulting in persistent inflammation, apoptosis and oxidative stress, ultimately leading to the induction of chronic gastritis. Copyright © 2015 Elsevier Ltd. All rights reserved.

Stratospheric H2O and HNO3 profiles derived from solar occultation measurements

NASA Technical Reports Server (NTRS)

Fischer, H.; Fergg, F.; Rabus, D.; Burkert, P.

1985-01-01

Compact two-channel radiometers for solar occultation experiments have been constructed in order to measure stratospheric trace gases. The instruments can be used as filter- or correlation-type radiometers, depending on the trace gas under investigation. Within the LIMS correlative measurement program, balloon flights were performed with a payload of up to four of these two-channel radiometers. From the filter-type measurements, profiles of the trace gases H2O and HNO3 are inferred for the height region between the tropopause and the balloon float level. The data evaluation also includes a comprehensive analysis of the error sources and their effect on the accuracy of the trace gas profiles. The derived H2O and HNO3 profiles are assessed against the observations of other authors and are discussed in the light of the trace gas distributions calcualted from photochemical models.

Trace Mineral Micronutrients and Chronic Periodontitis-a Review.

PubMed

Gaur, Sumit; Agnihotri, Rupali

2017-04-01

Trace mineral micronutrients are imperative for optimum host response. Populations worldwide are prone to their insufficiency owing to lifestyle changes or poor nutritional intake. Balanced levels of trace minerals like iron (Fe), zinc (Zn), selenium (Se) and copper (Cu) are essential to prevent progression of chronic conditions like periodontitis. Their excess as well as deficiency is detrimental to periodontal health. This is specifically true in relation to Fe. Furthermore, some trace elements, e.g. Se, Zn and Cu are integral components of antioxidant enzymes and prevent reactive oxygen species induced destruction of tissues. Their deficiency can worsen periodontitis associated with systemic conditions like diabetes mellitus. With this background, the present review first focusses on the role of four trace minerals, namely, Fe, Zn, Se and Cu in periodontal health followed by an appraisal of the data from case control studies related to their association with chronic periodontitis.

TRACE ELEMENT ANALYSES OF URANIUM MATERIALS

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

Beals, D; Charles Shick, C

The Savannah River National Laboratory (SRNL) has developed an analytical method to measure many trace elements in a variety of uranium materials at the high part-per-billion (ppb) to low part-per-million (ppm) levels using matrix removal and analysis by quadrapole ICP-MS. Over 35 elements were measured in uranium oxides, acetate, ore and metal. Replicate analyses of samples did provide precise results however none of the materials was certified for trace element content thus no measure of the accuracy could be made. The DOE New Brunswick Laboratory (NBL) does provide a Certified Reference Material (CRM) that has provisional values for a seriesmore » of trace elements. The NBL CRM were purchased and analyzed to determine the accuracy of the method for the analysis of trace elements in uranium oxide. These results are presented and discussed in the following paper.« less

Neural population-level memory traces in the mouse hippocampus.

PubMed

Chen, Guifen; Wang, L Phillip; Tsien, Joe Z

2009-12-16

One of the fundamental goals in neurosciences is to elucidate the formation and retrieval of brain's associative memory traces in real-time. Here, we describe real-time neural ensemble transient dynamics in the mouse hippocampal CA1 region and demonstrate their relationships with behavioral performances during both learning and recall. We employed the classic trace fear conditioning paradigm involving a neutral tone followed by a mild foot-shock 20 seconds later. Our large-scale recording and decoding methods revealed that conditioned tone responses and tone-shock association patterns were not present in CA1 during the first pairing, but emerged quickly after multiple pairings. These encoding patterns showed increased immediate-replay, correlating tightly with increased immediate-freezing during learning. Moreover, during contextual recall, these patterns reappeared in tandem six-to-fourteen times per minute, again correlating tightly with behavioral recall. Upon traced tone recall, while various fear memories were retrieved, the shock traces exhibited a unique recall-peak around the 20-second trace interval, further signifying the memory of time for the expected shock. Therefore, our study has revealed various real-time associative memory traces during learning and recall in CA1, and demonstrates that real-time memory traces can be decoded on a moment-to-moment basis over any single trial.

Associations between toxic and essential trace elements in maternal blood and fetal congenital heart defects.

PubMed

Ou, Yanqiu; Bloom, Michael S; Nie, Zhiqiang; Han, Fengzhen; Mai, Jinzhuang; Chen, Jimei; Lin, Shao; Liu, Xiaoqing; Zhuang, Jian

2017-09-01

Prenatal exposure to toxic trace elements, including heavy metals, is an important public health concern. Few studies have assessed if individual and multiple trace elements simultaneously affect cardiac development. The current study evaluated the association between maternal blood lead (Pb), cadmium (Cd), chromium (Cr), copper (Cu), mercury (Hg), and selenium (Se) levels and congenital heart defects (CHDs) in offspring. This hospital-based case-control study included 112 case and 107 control infants. Maternal peripheral blood draw was made during gestational weeks 17-40 and used to determine trace element levels by inductively coupled plasma mass spectrometry. Multivariable logistic regression was used to assess associations and interactions between individual and multiple trace elements and fetal CHDs, adjusted for maternal age, parity, education, newborn gender, migrant, folic acid or multivitamin intake, cigarette smoking, maternal prepregnancy body mass index, and time of sample collection. Control participants had medians of 2.61μg/dL Pb, 1.76μg/L Cd, 3.57μg/L Cr, 896.56μg/L Cu, 4.17μg/L Hg, and 186.47μg/L Se in blood. In a model including all measured trace elements and adjusted for confounders, high levels of maternal Pb (OR=12.09, 95% CI: 2.81, 51.97) and Se (OR=0.25, 95% CI: 0.08, 0.77) were harmful and protective predictors of CHDs, respectively, with positive and negative interactions suggested for Cd with Pb and Se with Pb, respectively. Similar associations were detected for subgroups of CHDs, including conotruncal defects, septal defects, and right ventricle outflow tract obstruction. Our results suggest that even under the current standard for protecting human health (10μg/dL), Pb exposure poses an important health threat. These data can be used for developing interventions and identifying high-risk pregnancies. Copyright © 2017. Published by Elsevier Ltd.

Role of long-range transport and local meteorology in seasonal variation of surface ozone and its precursors at an urban site in India

NASA Astrophysics Data System (ADS)

Yadav, Ravi; Sahu, L. K.; Beig, G.; Jaaffrey, S. N. A.

2016-07-01

This study is based on the continuous measurements of ozone (O3), carbon monoxide (CO) and nitrogen oxides (NOx) at a semi-arid urban site in Udaipur, India during the years 2011-2012. The mixing ratios of trace gases show strong and weak diurnal variations during the winter and monsoon seasons, respectively. The temporal changes in local emission and PBL depth play an important role in the diurnal variation of trace gases. The daily means of O3, CO and NOx were in the ranges of 5-53 ppbv, 121-842 ppbv and 3-29 ppbv, respectively. The mixing ratios of trace gases were highest and lowest during the winter/pre-monsoon and monsoon seasons, respectively. In the winter season, the lowest of O3 during night-morning hours was caused by the efficient loss due to titration and deposition compared to other seasons. During the winter to the pre-monsoon period, higher levels of trace gases were due to regional biomass burning and long-range transport of continental pollutants. However, strong convection, rainfall and transport of oceanic air resulted in the lowest concentrations of trace gases during the monsoon season. The O3min values tend to increase slightly with increasing values of Tmin while COmax and NOxmax decrease rapidly with increasing values of Tmin. The levels of CO and NOx decreased with increasing wind speed, while O3 tends to increase with wind speed. The rates of change of O3 (dO3/dt) were about 3.7 ppbv h- 1 and - 4.5 ppbv h- 1 during the morning and evening hours, respectively. Exceptionally high levels of trace gases during the Diwali (festival) period were due to extensive use of firecrackers from evening till morning hours. The enhancements of O3, CO and NOx compared to normal days were about 61%, 62% and 23%, respectively.

Persistence of undergraduate women in STEM fields

NASA Astrophysics Data System (ADS)

Pedone, Maggie Helene

The underrepresentation of women in science, technology, engineering, and mathematics (STEM) is a complex problem that continues to persist at the postsecondary level, particularly in computer science and engineering fields. This dissertation explored the pre-college and college level factors that influenced undergraduate women's persistence in STEM. This study also examined and compared the characteristics of undergraduate women who entered STEM fields and non-STEM fields in 2003-2004. The nationally representative Beginning Postsecondary Students Longitudinal Study (BPS:04/09) data set was used for analysis. BPS:04/09 study respondents were surveyed three times (NPSAS:04, BPS:04/06, BPS:04/09) over a six-year period, which enabled me to explore factors related to long-term persistence. Astin's Input-Environment-Output (I-E-O) model was used as the framework to examine student inputs and college environmental factors that predict female student persistence (output) in STEM. Chi-square tests revealed significant differences between undergraduate women who entered STEM and non-STEM fields in 2003-2004. Differences in student demographics, prior academic achievement, high school course-taking patterns, and student involvement in college such as participation in study groups and school clubs were found. Notably, inferential statistics showed that a significantly higher proportion of female minority students entered STEM fields than non-STEM fields. These findings challenge the myth that underrepresented female minorities are less inclined to enter STEM fields. Logistic regression analyses revealed thirteen significant predictors of persistence for undergraduate women in STEM. Findings showed that undergraduate women who were younger, more academically prepared, and academically and socially involved in college (e.g., lived on campus, interacted with faculty, participated in study groups, fine arts activities, and school sports) were more likely to persist in STEM fields. This longitudinal study showed that both pre-college and college level factors influenced undergraduate women's persistence in STEM. The research findings offer important implications for policy and practice initiatives in higher education that focus on the recruitment and retention of women in postsecondary STEM fields.

Trace-metal concentrations, waters from selected sky lakes, streams and springs, northern Shawangunk Mountains, New York: geologic and ecologic implications

USGS Publications Warehouse

Friedman, J.D.; Huth, P.C.; Smiley, D.

1990-01-01

Reconnaissance sampling and chemical analysis of water from selected lakes, streams and springs of the northern Shawangunk Mountains in 1987 to 1988 to determine the influence of lithology on trace-metal concentrations in surface water, and to establish a base level of concentration of 27 selected metals by ICP-AES and Hg by cold-vapor AAS methods, for geochemical exploration, ecologic, acid-rain, and climatic-change studies, have yielded trace-metal concentrations greater than detection limits for 10 metallic elements. Eighteen additional metallic elements were also present in trace quantities below the quantitative detection limit. Two distinct geochemical populations are related to source lithology and pH. -from Authors

Electric discharge for treatment of trace contaminants

NASA Technical Reports Server (NTRS)

Flamm, D. L.; Wydeven, T. J. (Inventor)

1978-01-01

A radio frequency glow discharge reactor is described for removing trace oxidizable contaminants from an oxygen bearing atmosphere. The reaction chamber is defined by an inner metal electrode facing a dielectric backed by an outer conductive electrode. In one embodiment, a conductive liquid forms the conductor of an outer electrode and cools the dielectric. A resonator coupled to a variable radio frequency source generates the high voltages for creating a glow discharge in the chamber at a predetermined pressure whereby the trace contaminants are oxidized into a few simple non-toxic products that may be easily recovered. The corresponding process for removal of trace contaminants from an oxygen-bearing atmosphere with high efficiency independent of the concentration level is also disclosed.

Groundwater monitoring in the Savannah River Plant Low Level Waste Burial Ground

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

Carlton, W.H.

1983-12-31

This document describes chemical mechanisms that may affect trace-level radionuclide migration through acidic sandy clay soils in a humid environment, and summarizes the extensive chemical and radiochemical analyses of the groundwater directly below the SRP Low-Level Waste (LLW) Burial Ground (643-G). Anomalies were identified in the chemistry of individual wells which appear to be related to small amounts of fission product activity that have reached the water table. The chemical properties which were statistically related to trace level transport of Cs-137 and Sr-90 were iron, potassium, sodium and calcium. Concentrations on the order of 100 ppM appear sufficient to affectmore » nuclide migration. Several complexation mechanisms for plutonium migration were investigated.« less

The Struggle to Succeed: Factors Associated with the Persistence of Part-Time Adult Students Seeking a Master's Degree

ERIC Educational Resources Information Center

Cohen, Marian A. O.; Greenberg, Scott

2011-01-01

Studies of student persistence at the undergraduate level are numerous and well known to those in the field, but at the graduate level, they are far more limited. The latter generally focus on doctoral candidates or those enrolled in professional programs. Master's-degree candidates, especially those who pursue a degree on a part-time basis at a…

Mediators, Moderators, and Tests for Mediation.

DTIC Science & Technology

1983-12-09

relation between level of poor performance and degree of intended persistence for high self - esteem individuals, and (b) ability attributions mediate...the relation between level of poor performance and degree of intended persistence for low self - esteem individuals. The proposed causal models are shown...in Figure Ia. Individuals are first given a self - esteem ouestionnaire and then blocked (subgrouped) into high self - esteems or lcw self - esteems , the

Testing Our Assumptions: The Role of First Course Grade and Course Level in Mathematics and English

ERIC Educational Resources Information Center

Callahan, Janet; Belcheir, Marcia

2017-01-01

Methods that provide an early indicator of factors that affect student persistence are important to colleges and universities. This quantitative research focused on the role of level of entry mathematics and English and also on grades earned in those classes, as they relate to persistence after 1 year. The research showed that by far, the variable…

Trace-element concentrations in streambed sediment across the conterminous United States

USGS Publications Warehouse

Rice, Karen C.

1999-01-01

Trace-element concentrations in 541 streambed-sediment samples collected from 20 study areas across the conterminous United States were examined as part of the National Water-Quality Assessment Program of the U.S. Geological Survey. Sediment samples were sieved and the <63-μm fraction was retained for determination of total concentrations of trace elements. Aluminum, iron, titanium, and organic carbon were weakly or not at all correlated with the nine trace elements examined:  arsenic, cadmium, chromium, copper, lead, mercury, nickel, selenium, and zinc. Four different methods of accounting for background/baseline concentrations were examined; however, normalization was not required because field sieving removed most of the background differences between samples. The sum of concentrations of trace elements characteristic of urban settings - copper, mercury, lead, and zinc - was well correlated with population density, nationwide. Median concentrations of seven trace elements (all nine examined except arsenic and selenium) were enriched in samples collected from urban settings relative to agricultural or forested settings. Forty-nine percent of the sites sampled in urban settings had concentrations of one or more trace elements that exceeded levels at which adverse biological effects could occur in aquatic biota.

New insights into trace element wet deposition in the Himalayas: amounts, seasonal patterns, and implications.

PubMed

Cong, Zhiyuan; Kang, Shichang; Zhang, Yulan; Gao, Shaopeng; Wang, Zhongyan; Liu, Bin; Wan, Xin

2015-02-01

Our research provides the first complete year-long dataset of wet deposition of trace elements in the high Himalayas based on a total of 42 wet deposition events on the northern slope of Mt. Qomolangma (Everest). Except for typical crustal elements (Al, Fe, and Mn), the concentration level of most trace elements (Sc, V, Cr, Co, Ni, Cu, Zn, As, Mo, Cd, Sn, Cs, Pb, Bi, and U) are generally comparable to those preserved in snow pits and ice cores from the nearby East Rongbuk Glacier. Cadmium was the element most affected by anthropogenic emissions. No pronounced seasonal variations are observed for most trace elements despite different transport pathways. In our study, the composition of wet precipitation reflects a regional background condition and is not clearly related to specific source regions. For the trace element record from ice cores and snow pits in the Himalayas, it could be deduced that the pronounced seasonal patterns were caused by the dry deposition of trace elements (aerosols) during their long exposure to the atmosphere after precipitation events. Our findings are of value for the understanding of the trace element deposition mechanisms in the Himalayas.

Distribution and partitioning of trace metals in sediments of the lower reaches of the New Calabar River, Port Harcourt, Nigeria.

PubMed

Horsfall, M; Spiff, A I

2002-09-01

The distribution of trace metals in sediments of the lower reaches of the New Calabar River, Nigeria was evaluated together with the partitioning of their chemical species between five geochemical phases. Samplings were made in five zones at the lower reaches of the New Calaber River. All the trace metals were determined by AAS after selective chemical extractions and concentrations given in microg gm(-1) (dry weight basis). The average total concentrations found for trace metals in the sediment were ( mean +/- rsd.) Pb: 41.6 +/- 0.29, Zn: 31.60 +/- 0.42, Cd: 12.80 +/- 0.92, Co: 92 +/- 0.25, Cu: 25.5 +/- 0.65 and Ni: 3.2 +/- 0.25. Maxima and minima concentrations are inconsistent with previous studies in other rivers of this region. Spatial distribution revealed that the sources of trace metals into the river appeared to be of non-point. Five contamination indices were applied in studying the partitioning of the trace metals in the sediment. These indices provided bases for ascertaining the potential environmental risk of trace metals in the river system. The results denote high partition levels in the more mobile and more dangerous phases.

The role of high-energy synchrotron radiation in biomedical trace element research

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

Pounds, J.G.; Long, G.J.; Kwiatek, W.M.

1987-01-01

This paper will present the results of an investigation of the distribution of essential elements in the normal hepatic lobule. the liver is the organ responsible for metabolism and storage of most trace elements. Although parenchymal hepatocytes are rather uniform histologically, morphometry, histochemistry, immunohistochemistry, and microdissection with microchemical investigations have revealed marked heterogeneity on a functional and biochemical level. Hepatocytes from the periportal and perivenous zones of the liver parrenchyma differ in oxidative energy metabolism, glucose uptake and output, unreagenesis, biotransformation, bile acid secretion, and palsma protein synthesis and secretion. Although trace elements are intimately involved in the regulation andmore » maintenance of these functions, little is known regarding the heterogeneity of trace element localization of the liver parenchyma. Histochemical techniques for trace elements generally give high spatial resolution, but lack specificity and stoichiometry. Microdissection has been of marginal usefulness for trace element analyses due to the very small size of the dissected parenchyma. The characteristics of the high-energy x-ray microscope provide an effective approach for elucidating the trace element content of these small biological structures or regions. 5 refs., 1 fig., 1 tab.« less

Invited: Advances Toward Practical Detection of Trace Chemical Hazards with Solid State Microarray Devices

NASA Astrophysics Data System (ADS)

Raman, Barani; Meier, Douglas; Shenoy, Rupa; Benkstein, Kurt; Semancik, Steve

2011-09-01

We describe progress on an array-based microsensor approach employed for detecting trace levels of toxic industrial chemicals (TICs) in air-based backgrounds with varied levels of humidity, and with occasional introduction of aggressive interferents. Our MEMS microhotplate arrays are populated with multiple chemiresistive sensing materials, and all elements are programmed to go through extensive temperature cycling over repetitive cycles with lengths of approximately 20 s. Under such operation, analytically-rich data streams are produced containing the required information for target recognition.

MiRNA-124 is a link between measles virus persistent infection and cell division of human neuroblastoma cells.

PubMed

Naaman, Hila; Rall, Glenn; Matullo, Christine; Veksler-Lublinsky, Isana; Shemer-Avni, Yonat; Gopas, Jacob

2017-01-01

Measles virus (MV) infects a variety of lymphoid and non-lymphoid peripheral organs. However, in rare cases, the virus can persistently infect cells within the central nervous system. Although some of the factors that allow MV to persist are known, the contribution of host cell-encoded microRNAs (miRNA) have not been described. MiRNAs are a class of noncoding RNAs transcribed from genomes of all multicellular organisms and some viruses, which regulate gene expression in a sequence-specific manner. We have studied the contribution of host cell-encoded miRNAs to the establishment of MV persistent infection in human neuroblastoma cells. Persistent MV infection was accompanied by differences in the expression profile and levels of several host cell-encoded microRNAs as compared to uninfected cells. MV persistence infection of a human neuroblastoma cell line (UKF-NB-MV), exhibit high miRNA-124 expression, and reduced expression of cyclin dependent kinase 6 (CDK6), a known target of miRNA-124, resulting in slower cell division but not cell death. By contrast, acute MV infection of UKF-NB cells did not result in increased miRNA-124 levels or CDK6 reduction. Ectopic overexpression of miRNA-124 affected cell viability only in UKF-NB-MV cells, causing cell death; implying that miRNA-124 over expression can sensitize cells to death only in the presence of MV persistent infection. To determine if miRNA-124 directly contributes to the establishment of MV persistence, UKF-NB cells overexpressing miRNA-124 were acutely infected, resulting in establishment of persistently infected colonies. We propose that miRNA-124 triggers a CDK6-dependent decrease in cell proliferation, which facilitates the establishment of MV persistence in neuroblastoma cells. To our knowledge, this is the first report to describe the role of a specific miRNA in MV persistence.

Ancient DNA Analysis Reveals High Frequency of European Lactase Persistence Allele (T-13910) in Medieval Central Europe

PubMed Central

Akgül, Gülfirde; Della Casa, Philippe; Rühli, Frank; Warinner, Christina

2014-01-01

Ruminant milk and dairy products are important food resources in many European, African, and Middle Eastern societies. These regions are also associated with derived genetic variants for lactase persistence. In mammals, lactase, the enzyme that hydrolyzes the milk sugar lactose, is normally down-regulated after weaning, but at least five human populations around the world have independently evolved mutations regulating the expression of the lactase-phlorizin-hydrolase gene. These mutations result in a dominant lactase persistence phenotype and continued lactase tolerance in adulthood. A single nucleotide polymorphism (SNP) at C/T-13910 is responsible for most lactase persistence in European populations, but when and where the T-13910 polymorphism originated and the evolutionary processes by which it rose to high frequency in Europe have been the subject of strong debate. A history of dairying is presumed to be a prerequisite, but archaeological evidence is lacking. In this study, DNA was extracted from the dentine of 36 individuals excavated at a medieval cemetery in Dalheim, Germany. Eighteen individuals were successfully genotyped for the C/T-13910 SNP by molecular cloning and sequencing, of which 13 (72%) exhibited a European lactase persistence genotype: 44% CT, 28% TT. Previous ancient DNA-based studies found that lactase persistence genotypes fall below detection levels in most regions of Neolithic Europe. Our research shows that by AD 1200, lactase persistence frequency had risen to over 70% in this community in western Central Europe. Given that lactase persistence genotype frequency in present-day Germany and Austria is estimated at 71–80%, our results suggest that genetic lactase persistence likely reached modern levels before the historic population declines associated with the Black Death, thus excluding plague-associated evolutionary forces in the rise of lactase persistence in this region. This new evidence sheds light on the dynamic evolutionary history of the European lactase persistence trait and its global cultural implications. PMID:24465990

Emotion Causes Targeted Forgetting of Established Memories

PubMed Central

Strange, Bryan A.; Kroes, Marijn C. W.; Fan, Judith E.; Dolan, Raymond J.

2010-01-01

Reconsolidation postulates that reactivation of a memory trace renders it susceptible to disruption by treatments similar to those that impair initial memory consolidation. Despite evidence that implicit, or non-declarative, human memories can be disrupted at retrieval, a convincing demonstration of selective impairment in retrieval of target episodic memories following reactivation is lacking. In human subjects, we demonstrate that if reactivation of a verbal memory, through successful retrieval, is immediately followed by an emotionally aversive stimulus, a significant impairment is evident in its later recall. This effect is time-dependent and persists for at least 6 days. Thus, in line with a reconsolidation hypothesis, established human episodic memories can be selectively impaired following their retrieval. PMID:21191439

Spontaneous breaking of discrete symmetries in QCD on a small volume

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

Lucini, B.; Patella, A.; Pica, C.

2007-11-20

In a compact space with non-trivial cycles, for sufficiently small values of the compact dimensions, charge conjugation (C), spatial reflection (P) and time reversal (J) are spontaneously broken in QCD. The order parameter for the symmetry breaking is the trace of the Wilson line wrapping around the compact dimension, which acquires an imaginary part in the broken phase. We show that a physical signature for the symmetry breaking is a persistent baryonic current wrapping in the compact directions. The existence of such a current is derived analytically at first order in perturbation theory and confirmed in the non-perturbative regime bymore » lattice simulations.« less

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

Rabin, S.A.; Lotts, A.L.; Hammond, J.P.

Uranium --molybdenum alloy rods containing from 10 to 15 wt% Mo and 1/16- in. in diameter were successfully fabricated by hot rotary swaging, followed by machining to remove the protective sheathing (Inconel with molybdenum barrier). Structurally strong rods with densities greater than 95% of theoretical were produced from both calciumreduced uranium mixed with hydrogen-reduced molybdenum and acid-cleaned, prealloyed shot when reduced in area about 55% at 1050 or 1100 deg C. Alloy homogeneity was good with prealloyed powders; however, traces of molybdenum -rich, gamma phase persisted in the elemental uranium -molybdenum material after swaging at 1100 deg C. Swagings embodyingmore » hydride uranium or oxide- contaminated prealloyed shot were unsatisfactory because of insufficient consolidation or poor interparticle bonding. (auth)« less

Reporter Concerns in 300 Mode-Related Incident Reports from NASA's Aviation Safety Reporting System

NASA Technical Reports Server (NTRS)

McGreevy, Michael W.

1996-01-01

A model has been developed which represents prominent reporter concerns expressed in the narratives of 300 mode-related incident reports from NASA's Aviation Safety Reporting System (ASRS). The model objectively quantifies the structure of concerns which persist across situations and reporters. These concerns are described and illustrated using verbatim sentences from the original narratives. Report accession numbers are included with each sentence so that concerns can be traced back to the original reports. The results also include an inventory of mode names mentioned in the narratives, and a comparison of individual and joint concerns. The method is based on a proximity-weighted co-occurrence metric and object-oriented complexity reduction.

Emotion causes targeted forgetting of established memories.

PubMed

Strange, Bryan A; Kroes, Marijn C W; Fan, Judith E; Dolan, Raymond J

2010-01-01

Reconsolidation postulates that reactivation of a memory trace renders it susceptible to disruption by treatments similar to those that impair initial memory consolidation. Despite evidence that implicit, or non-declarative, human memories can be disrupted at retrieval, a convincing demonstration of selective impairment in retrieval of target episodic memories following reactivation is lacking. In human subjects, we demonstrate that if reactivation of a verbal memory, through successful retrieval, is immediately followed by an emotionally aversive stimulus, a significant impairment is evident in its later recall. This effect is time-dependent and persists for at least 6 days. Thus, in line with a reconsolidation hypothesis, established human episodic memories can be selectively impaired following their retrieval.

Addressing inequity in health and health care in Mexico.

PubMed

Barraza-Lloréns, Mariana; Bertozzi, Stefano; González-Pier, Eduardo; Gutiérrez, Juan Pablo

2002-01-01

Despite the fact that life expectancy at birth in Mexico has improved from forty-two years in 1940 to seventy-three in 2000, major inequalities persist in health and access to health care. The Mexican health care system has evolved into a series of disjointed subsystems that are incapable of delivering universal health insurance. Without greatly restructuring the way health care is financed, performance with respect to equity will remain poor. This paper presents the inequities of the system and describes how the current system contributes to the status quo rather than redressing the situation. After tracing the origins of the present system, we discuss policy initiatives for moving toward universal health insurance.

Reassessing the Role of Type II Toxin-Antitoxin Systems in Formation of Escherichia coli Type II Persister Cells.

PubMed

Goormaghtigh, Frédéric; Fraikin, Nathan; Putrinš, Marta; Hallaert, Thibaut; Hauryliuk, Vasili; Garcia-Pino, Abel; Sjödin, Andreas; Kasvandik, Sergo; Udekwu, Klas; Tenson, Tanel; Kaldalu, Niilo; Van Melderen, Laurence

2018-06-12

Persistence is a reversible and low-frequency phenomenon allowing a subpopulation of a clonal bacterial population to survive antibiotic treatments. Upon removal of the antibiotic, persister cells resume growth and give rise to viable progeny. Type II toxin-antitoxin (TA) systems were assumed to play a key role in the formation of persister cells in Escherichia coli based on the observation that successive deletions of TA systems decreased persistence frequency. In addition, the model proposed that stochastic fluctuations of (p)ppGpp levels are the basis for triggering activation of TA systems. Cells in which TA systems are activated are thought to enter a dormancy state and therefore survive the antibiotic treatment. Using independently constructed strains and newly designed fluorescent reporters, we reassessed the roles of TA modules in persistence both at the population and single-cell levels. Our data confirm that the deletion of 10 TA systems does not affect persistence to ofloxacin or ampicillin. Moreover, microfluidic experiments performed with a strain reporting the induction of the yefM-yoeB TA system allowed the observation of a small number of type II persister cells that resume growth after removal of ampicillin. However, we were unable to establish a correlation between high fluorescence and persistence, since the fluorescence of persister cells was comparable to that of the bulk of the population and none of the cells showing high fluorescence were able to resume growth upon removal of the antibiotic. Altogether, these data show that there is no direct link between induction of TA systems and persistence to antibiotics. IMPORTANCE Within a growing bacterial population, a small subpopulation of cells is able to survive antibiotic treatment by entering a transient state of dormancy referred to as persistence. Persistence is thought to be the cause of relapsing bacterial infections and is a major public health concern. Type II toxin-antitoxin systems are small modules composed of a toxic protein and an antitoxin protein counteracting the toxin activity. These systems were thought to be pivotal players in persistence until recent developments in the field. Our results demonstrate that previous influential reports had technical flaws and that there is no direct link between induction of TA systems and persistence to antibiotics. Copyright © 2018 Goormaghtigh et al.

Variations in trace element geochemistry in the Seine River Basin based on floodplain deposits and bed sediments

USGS Publications Warehouse

Horowitz, A.J.; Meybeck, Michel; Idlafkih, Z.; Biger, E.

1999-01-01

Between 1990 and 1995 a series of bed sediment, suspended sediment and fresh floodplain samples were collected within the Seine River Basin, in France, to evaluate variations in trace element geochemistry. Average background trace element levels for the basin were determined from the collection and subsequent analyses of bed sediment samples from small rural watersheds and from a prehistoric (5000 BP) site in Paris. Concentrations are relatively low, and similar to those observed for fine-grained bed sediments from unaffected areas in the United States and Canada. However, the concentrations are somewhat higher than the reference levels presently adopted by French water authorities for areas north of the Seine Basin, which have similar bedrock lithologies. Downstream trace element variations were monitored in 1994 and 1995 using fresh surficial floodplain samples that were collected either as dried deposits a few days after peak discharge, or immediately after peak discharge (under ??? 30 cm of water). Chemical comparisons between fresh floodplain deposits, and actual suspended sediments collected during flood events, indicate that, with some caveats, the former can be used as surrogates for the latter. The floodplain sediment chemical data indicate that within the Seine Basin, from the relatively unaffected headwaters through heavily affected urban streams, trace element concentrations vary by as much as three orders of magnitude. These trace element changes appear to be the result of both increases in population as well as concomitant increases in industrial activity. This article is a US government work and is in the public domain in the United States.

Influences of different dietary contents of macrominerals on the availability of trace elements in horses.

PubMed

Neustädter, L-T; Kamphues, J; Ratert, C

2018-04-01

In this study, influences of a reduced macromineral intake on the trace element metabolism in horses at maintenance were investigated. Background of this study is the revised recommendation on the macromineral supply for horses (GfE ). Balance studies on three adult pony geldings with body weights of 405 / 348 / 384 kg were performed to obtain data on apparent digestibility (aD), retention and serum concentrations of different trace elements (Cu, Zn, Se) at different dietary macromineral levels. A mineral supplement or a complementary feed-with a reduced macromineral content-was added to a hay-based diet (daily 5.5 kg hay per animal, split in three servings a day), beside distilled water was offered. The diets were offered one after the other in a way that all ponies had the same sequence of treatments. The native macromineral contents of the daily offered amount of hay already surpassed the new recommendations whereas dietary trace elements needed to be supplemented. There were no statistically significant differences (p ≤ .05) concerning the aD of copper, zinc and selenium comparing the diets with and without macromineral supplementation. Serum levels of these three trace elements were not affected by the different macromineral content of the diet. Results of this study, based on a 22-day feeding period for each treatment, indicate that a macromineral supplementation of a hay-based diet for adult horses at maintenance was not necessary. However, no negative effects of added macrominerals on the trace element metabolism occurred in this study. © 2017 Blackwell Verlag GmbH.

Raman Laser Spectrometer internal Optical Head current status: opto-mechanical redesign to minimize the excitation laser trace

NASA Astrophysics Data System (ADS)

Sanz, Miguel; Ramos, Gonzalo; Moral, Andoni; Pérez, Carlos; Belenguer, Tomás; del Rosario Canchal, María; Zuluaga, Pablo; Rodriguez, Jose Antonio; Santiago, Amaia; Rull, Fernando; Instituto Nacional de Técnica Aeroespacial (INTA); Ingeniería de Sistemas para la Defesa de España S.A. (ISDEFE)

2016-10-01

Raman Laser Spectrometer (RLS) is the Pasteur Payload instruments of the ExoMars mission, within the ESA's Aurora Exploration Programme, that will perform for the first time in an out planetary mission Raman spectroscopy. RLS is composed by SPU (Spectrometer Unit), iOH (Internal Optical Head), and ICEU (Instrument Control and Excitation Unit). iOH focuses the excitation laser on the samples (excitation path), and collects the Raman emission from the sample (collection path, composed on collimation system and filtering system). The original design presented a high laser trace reaching to the detector, and although a certain level of laser trace was required for calibration purposes, the high level degrades the Signal to Noise Ratio confounding some Raman peaks.The investigation revealing that the laser trace was not properly filtered as well as the iOH opto-mechanical redesign are reported on. After the study of the Long Pass Filters Optical Density (OD) as a function of the filtering stage to the detector distance, a new set of filters (Notch filters) was decided to be evaluated. Finally, and in order to minimize the laser trace, a new collection path design (mainly consisting on that the collimation and filtering stages are now separated in two barrels, and on the kind of filters to be used) was required. Distance between filters and collimation stage first lens was increased, increasing the OD. With this new design and using two Notch filters, the laser trace was reduced to assumable values, as can be observed in the functional test comparison also reported on this paper.