16,414 research outputs found
Natural mineral particles are cytotoxic to rainbow trout gill epithelial cells in vitro
No full textWorldwide increases in fluvial fine sediment are a threat to aquatic animal health. Fluvial fine sediment is always a mixture of particles whose mineralogical composition differs depending on the sediment source and catchment area geology.Nonetheless, whether particle impact in aquatic organisms differs between mineral species remains to be investigated. This study applied an in vitro approach to evaluate cytotoxicity and uptake of four common fluvial mineral particles (quartz, feldspar, mica, and kaolin; concentrations: 10, 50, 250 mg L21) in the rainbow trout epithelial gill cell line RTgill-W1. Cells were exposed for 24, 48, 72, and 96 h. Cytotoxicity assays for cell membrane integrity (propidium iodide assay), oxidative stress (H2DCF-DA assay), and metabolic activity (MTT assay) were applied. These assays were complemented with cellcounts and transmission electron microscopy. Regardless of mineral species, particles #2 mm in diameter were taken up by the cells, suggesting that particles of all mineral species came into contact and interacted with the cells. Not all particles, however, caused strong cytotoxicity: Among all assays the tectosilicates quartz and feldspar caused sporadic maximum changes of 0.8–1.2-fold compared to controls. In contrast, cytotoxicity of the clay particles was distinctly stronger and even differed between the two particle types: mica induced concentration-dependent increases in free radicals, with consistent1.6–1.8-fold-changes at the 250 mg L21 concentration, and a dilated endoplasmic reticulum. Kaolin caused concentrationdependent increases in cell membrane damage, with consistent 1.3–1.6-fold increases at the 250 mg L21 concentration. All effects occurred in the presence or absence of 10% fetal bovine serum. Cell numbers per se were marginally affected. Results indicate that (i.) natural mineral particles can be cytotoxic to gill epithelial cells, (ii.) their cytotoxic potential differs between mineral species, with clay particles being more cytotoxic, and (iii.) some clays might induce effects comparable to engineered nanoparticles
White Mouse or Hi-tun-ka-ska or Ilun-Pola-ka, Ogalala Sioux
No full textPortraits taken by Gill while working for Smithsonian's Bureau of Ethnology in Washington D.C.Original is 6" x 7 1/2
A Low SWaP-C Radar Altimeter Transceiver Design for Small Satellites
No full textThis paper discusses the design details of a high resolution, low "Size, Weight, Power and Cost" (SWaP-C) radar altimeter (RA) system. Operating frequency of the radar is chosen within the Ka-band to achieve the desired size and weight requirements, that are highly demanded for the small satellite missions in a cost-efficient way. We propose a system design such that, an intended radar altimeter can be built by using the Commercial off the Shelf (COTS) components. The simulation results show that the proposed RA has high potentiality for realization.Accepted author manuscriptMicrowave Sensing, Signals & SystemsAtmospheric Remote SensingMathematical Geodesy and Positionin
Detection of QTL with effects on osmoregulation capacities in the rainbow trout (Oncorhynchus mykiss)
No full textBackground
There is increasing evidence that the ability to adapt to seawater in teleost fish is modulated by genetic factors. Most studies have involved the comparison of species or strains and little is known about the genetic architecture of the trait. To address this question, we searched for
QTL affecting osmoregulation capacities after transfer to saline water in a nonmigratory captive-bred population of rainbow trout.
Results
A QTL design (5 full-sib families, about 200 F2 progeny each) was produced from a cross between F0 grand-parents previously selected during two generations for a high or a low cortisol response after a standardized confinement stress. When fish were about 18 months old (204 g body weight), individual progeny were submitted to two successive hyper-osmotic challenges (30g of salt/L) at a 14 d interval. Plasma chloride and sodium concentrations were
recorded 24h after each transfer. After the second challenge, fish were sacrificed and gill index (weight of total gill arches corrected for body weight) was recorded. The genome scan was performed using 200 microsatellites and 88 SNP markers. Unitrait and multitrait QTL analyses evidenced a total of 15 and 7 different QTL (P<0.10) for plasma ion concentrations and gill index respectively. Among the most significant QTL, three affected concentrations of both chloride and sodium during both challenges, two were specific to either chloride or
sodium concentrations, three QTL were specific to gill index, and three affected both gill index and ionic concentrations in plasma. Altogether, allelic effects were consistent for QTL affecting chloride and sodium concentrations but inconsistent for QTL affecting ionic
concentrations and gill morphology. There was no systematic lineage effect (grand-parental origin of QTL alleles) on the recorded traits.
Conclusions
For the first time, genomic loci associated with effects on major physiological components of osmotic adaptation to seawater in a nonmigratory fish were revealed. The results pave the way for further deciphering of the complex regulatory mechanisms underlying seawater adaptation
and genes involved in osmoregulatory physiology in rainbow trout and other euryhaline fishes
To-ka-kin Uyaya or Runs the Enemy, Dakota: Two Kettle
No full textPortraits taken by Gill while working for Smithsonian's Bureau of Ethnology in Washington D.C.Original is 6" x 7 1/2
Variability of the gill rakers in common perch (Perca fluviatilis): A comparison between colored and clear-water lakes
No full textBakalaureusetöö
Kalanduse ja rakendusökoloogia õppekavalKäesolev töö käsitleb hariliku ahvena (Perca fluviatilis) bioloogiat, keskendudes peamiselt
lõpuspiide morfoloogiale ja nende võimalikule asümmeetriale erinevate järvetüüpide lõikes.
Uuringu peamised eesmärgid olid hinnata lõpuspiide sümmeetriat populatsioonide siseselt,
samuti võrrelda lõpuspiide arvu selgeveeliste ja tumedaveeliste järvede ahvenate vahel ning
välja selgitada, kas lõpuspiide arv on ka sugude vahel erinev. Kokku analüüsiti 153 ahvenat
kuuest järvest (kolm selgeveelist ja kolm tumedaveelist). Iga kala mõlema lõpuskaare
lõpuspiide arvud loendati kolmes korduses. Tulemused näitasid, et lõpuspiide arv nii
populatsioonide siseselt kui ka kogu andmestiku lõikes oli sümmeetriline ning olulisi erinevusi
selgeveeliste ja tumedaveeliste järvede ahvenate vahel ei täheldatud. Siiski leiti statistiliselt
oluline erinevus isaste ja emaste ahvenate keskmise lõpuspiide arvu vahel. Käesolev töö aitab
paremini mõista, kuidas keskkonnategurid ja bioloogilised erinevused võivad mõjutada
hariliku ahvena lõpuspiide morfoloogiat emaste ja isaste kalade vahel ning lisaks
populatsioonide siseselt kui ka nende vahel.This study examines the biology of the European perch (Perca fluviatilis), with a specific
focus on gill raker morphology and its potential asymmetry based on the characteristics of
different lake types. The primary objectives were to assess the symmetry of gill rakers within
populations, compare gill raker counts between perch from clear-water and colored lakes, and
determine if gender affects the gill raker number. A total of 153 perch from six lakes (three
clear-water and three colored) were analyzed. Gill raker counts were meticulously recorded
from both the left and right gill arches of each fish. Statistical analysis was employed to
evaluate symmetry and differences across lake types and gender. Results indicated a high
degree of symmetry in gill raker counts within individual fish, with no significant difference
between perch from clear-water and colored lakes. However, slight but statistically important
variations were observed between male and female perch. This research contributes to
understanding how environmental factors and biological differences influence gill raker
morphology in European perch
Una interpretación de a-ka-na-jo ( a3-ka-na-jo)
No full textThe author studies the word a-ka-na-jo in the PY Cn 328 tablet and taking into account some factors she proposes αγναιος as the reading of this word.The author studies the word a-ka-na-jo in the PY Cn 328 tablet and taking into account some factors she proposes αγναιος as the reading of this word
Environmental influences over the last 16 ka on compound-specific δ13C variations of leaf wax n-alkanes in the Hani peat deposit from northeast China
No full textCompound-specific carbon isotope ratios (δ13C) of leaf wax n-alkanes (C21-C33 odd carbon numbered n-alkanes) were measured in the Hani peat sequence from northeast China. These data were compared with lipid biomarker compositions to assess changes in local vegetation and paleoclimate for the last 16 ka The δ13C values of n-alkanes range between -36.6 and -30.7‰, showing that the compounds originate from C3 plants. Much larger variations (∼5.4‰) in the n-alkane δ13C values than those of atmospheric CO2 during the last 16 ka (< 0.5‰) indicate that the isotopic values were affected by environmental factors in addition to the postglacial δ13C variations in the atmospheric reservoir. The stratigraphic records of δ13C reveal decoupled fluctuations among the individual n-alkanes, particularly between 15.5 to 11.4 ka. Synchronous excursions in the δ13C offsets among individual n-alkanes (Δδ13C) and lipid biomarker paleoplant proxies (Paq, and C23/C31 and C27/C31) from 14.9 to 13.2 ka and 12.7 to 11.6 ka suggest that vegetational changes are the most likely causes for the decoupled δ13C variations. Parallel fluctuations of the δ13C values of terrestrial higher plant-derived C29 and C31 n-alkanes and the n-alkane average chain-length (ACL) from 11 to 6 ka indicate that the δ13C variations responded to net evaporation changes. Negative shifts in the n-alkane δ13C values coinciding with the ACL decreases at 10.5-9.3 ka and 8.1 ka indicate the short-term onset and fluctuations of the summer monsoon strength in eastern China during the early Holocene
NRF2 and chemoprevention: signaling, epigenetics and role in intestinal carcinogensis
No full textPrevention is better than cure. The carcinogenesis could take as long as 20 to 30 years to develop from initiated cells to malignant tumor, therefore providing us various opportunities to prevent the appearance of tumors with the use of chemopreventive compounds in the early stage. Chemoprevention becomes an increasing important concept and has led to the intense research about the mechanisms of actions of various chemopreventive compounds. They can be generally classified into blocking agents and suppressing agents. The chemopreventive compounds usually prevent or slow progression of cancer by maintaining a low oxidative stress and inflammatory environment in cells. This is brought about by the activation of Nrf2, the key protein being investigated in our lab. In this dissertation, I will be discussing the use of compounds as suppressing agents and blocking agents, how compounds activates Nrf2 signaling, how novel Nrf2 interaction partner IQGAP1 mediates Nrf2-Keap1 signaling axis, how expression level of Nrf2 could be regulated epigenetically, apart from the well-known post-translational control by Keap1-Ubiquitinase-Protesome axis and finally how loss of Nrf2 could enhance intestinal tumorigenesis in Apc(min/+) mice.Ph.D.Includes bibliographical referencesIncludes vitaby Ka Lung Cheun
Weathering of zinc (Zn)-bearing mine wastes in a neutral mine drainage setting, Gunnerside Gill, Yorkshire.
No full textNumerous areas throughout the world are affected by circum-neutral pH, low iron (Fe) drainage with high concentrations of zinc (Zn) arising from discharges from, and weathering of, mine wastes. Gunnerside Gill, a small upland tributary in the headwaters of the River Swale in Yorkshire, is such a site affected by historic lead and zinc mining. The aim of the study is to assess the controls on Zn mobilisation from the mine tailings and floodplain sediments to the river water through a column leaching experiment. Sphalerite has been identified as the primary Zn mineral in the bedrock within Gunnerside Gill. However, there is more evidence of secondary phases of Zn were including Fe oxides and phosphates present within the samples and the BCR data suggests it is these phases that appear to be undergoing the majority of the Zn dissolution
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