Removal of radiation damage by subpopulations of plateau-phase Chinese hamster ovary cells

International Nuclear Information System (INIS)

Nelson, J.M.; Metting, N.F.; Braby, L.A.; Roesch, W.C.

1987-01-01

Specific cellular radiobiology studies are often required to test aspects of the mathematical models developed in the Radiation Dosimetry program. These studies are designed to determine whether specific mathematical expressions, which characterize the expected effect of biochemical mechanisms on observable biological responses, are consistent with the behavior of selected cell lines. Since these tests place stringent requirements on the cellular system, special techniques and culture conditions are required to minimize biological variability. The use of specialized cell populations is providing data on the extent of repair following low doses, and on the changes in the types of damage that can be repaired as the cell progresses toward mitosis. The stationary-phase Chinese hamster ovary (CHO) cells are composed primarily of G(1)-phase cells (83%), with the remainder comprising both G(2) and S phases. Removal of radiation damage by cells was studied in split-dose experiments. To date, we have observed no significant differences in cellular repair rate. This suggests, therefore, that each of the repair processes found in stationary-phase cells is cell-age independent. However, cellular radiation sensitivity does change rapidly and considerably as the cells progress from one phase to the next through the cell cycle. Since the rate of damage removal appears invariant, the change in survival must reflect the efficiency of producing that damage. The experimental data suggest that production of one or another sort of damage probably dominates during specific phases of the cell cycle, while the capacity for removal of all types of damage remains relatively constant

Cell cycle phase of nondividing cells in aging human cell cultures determined by DNA content and chromosomal constitution

International Nuclear Information System (INIS)

Yanishevsky, R.M.

1975-01-01

Human diploid cell cultures, strain WI-38, have a finite proliferative capacity and have been proposed as a model of biological aging. To identify the cell cycle phase of the nondividing cells, cultures of various ages were exposed to 3 Hdt for 48 hours to label dividing cells, then the cycle phase was identified for individual cells by one of two methods, and finally, the proliferative status of the same cells was scored by autoradiographic evidence of 3 HdT uptake. The methods to identify the cycle phase were: determination of DNA strain content by Feulgen scanning cytophotometry, and determination of chromosome constitution by the technique of premature chromosome condensation (PCC). Preliminary experiments showed the effect of continuous exposure to various levels of 3 HdT on cell growth. High levels of 3 HdT inhibited cell cycle traverse: the cell number and labeling index curves reached a plateau; the cell volume increased; the cells accumulated with 4C DNA contents and it appeared that they blocked in G 2 phase. This pattern is consistent with a radiation effect. (U.S.)

Comparison of time/phase lags in the hard state and plateau state of GRS 1915+105

Energy Technology Data Exchange (ETDEWEB)

Pahari, Mayukh; Yadav, J. S. [Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai, India (MP) (India); Neilsen, Joseph [Boston University, Boston, MA 02215 (United States); Misra, Ranjeev [Inter University Center for Astronomy and Astrophysics, Pune (India); Uttley, Phil, E-mail: mp@tifr.res.in [Astronomical Institute, " Anton Pannekoek," University of Amsterdam, Science Park 904, 1098-XH Amsterdam (Netherlands)

2013-12-01

We investigate the complex behavior of energy- and frequency-dependent time/phase lags in the plateau state and the radio-quiet hard (χ) state of GRS 1915+105. In our timing analysis, we find that when the source is faint in the radio, quasi-periodic oscillations (QPOs) are observed above 2 Hz and typically exhibit soft lags (soft photons lag hard photons), whereas QPOs in the radio-bright plateau state are found below 2.2 Hz and consistently show hard lags. The phase lag at the QPO frequency is strongly anti-correlated with that frequency, changing sign at 2.2 Hz. However, the phase lag at the frequency of the first harmonic is positive and nearly independent of that frequency at ∼0.172 rad, regardless of the radio emission. The lag energy dependence at the first harmonic is also independent of radio flux. However, the lags at the QPO frequency are negative at all energies during the radio-quiet state, but lags at the QPO frequency during the plateau state are positive at all energies and show a 'reflection-type' evolution of the lag energy spectra with respect to the radio-quiet state. The lag energy dependence is roughly logarithmic, but there is some evidence for a break around 4-6 keV. Finally, the Fourier-frequency-dependent phase lag spectra are fairly flat during the plateau state, but increase from negative to positive during the radio-quiet state. We discuss the implications of our results in light of some generic models.

Phased uplift of the northeastern Tibetan Plateau inferred from a pollen record from Yinchuan Basin, northwestern China.

Science.gov (United States)

Li, Xinling; Hao, Qingzhen; Wei, Mingjian; Andreev, Andrei A; Wang, Junping; Tian, Yanyan; Li, Xiaolei; Cai, Maotang; Hu, Jianmin; Shi, Wei

2017-12-21

The uplift of the Tibetan Plateau (TP) significantly affected both regional and global climates. Although there is evidence that the Tibetan Plateau experienced uplift during the Quaternary, the timing and amplitude are poorly constrained. However, the increased availability of long sedimentary records of vegetation change provides an opportunity to reconstruct the timing of the uplift. Here, we present a well-dated, high-resolution pollen record for the last 2.6 Ma from the Yinchuan Basin, which was incised by the Yellow River with its source in the northeastern Tibetan Plateau. Variations in the Artemisia/Chenopodiaceae (A/C) ratio of the reveal changes in moisture conditions in the Yinchuan Basin during glacial-interglacial cycles, as well as a gradual long-term aridification trend which is consistent with progressive global cooling. However, fluctuations in the percentages of Picea and Abies differ from those of the A/C ratio and we propose that they reflect changes in the vegetation and environment of high elevation areas. The Picea and Abies records reveal two phases of increased representation, at 2.1 and 1.2 Ma, which may indicate phases in the uplift of the northeastern Tibetan Plateau. Thus, they provide independent evidence for the timing of the uplift of the Tibetan Plateau during the Quaternary.

5-Fluorouracil-radiation interactions in human colon adenocarcinoma cells

International Nuclear Information System (INIS)

Buchholz, Daniel J.; Lepek, Katherine J.; Rich, Tyvin A.; Murray, David

1995-01-01

Purpose: To determine the effect of cellular proliferation and cell cycle stage on the ability of postirradiation 5-fluorouracil (5-FU) to radiosensitize cultured human colon adenocarcinoma Clone A cells. Methods and Materials: Cell survival curves were generated for irradiated: (a) log- and plateau-phase Clone A cells; and (b) Clone A cells separated by centrifugal elutriation into the various phases of the cell cycle; with and without postirradiation treatment with 100 μg/ml 5-FU. Results: Postirradiation treatment with 5-FU sensitized proliferating cells to a greater degree than it sensitized cells growing in plateau phase. The β component of cell kill in log-phase cells was increased by a factor of 1.5 with a sensitizer enhancement ratio of 1.21 at the 0.01 survival level. Plateau-phase cells showed less radiosensitization (sensitizer enhancement ratio of 1.13 at the 0.01 survival level); however, there was a mild increase in both α and β kill in plateau-phase cells. Elutriated G 1 cells were the most radiosensitive, independent of treatment with 5-FU. The phase of the cell cycle had little effect on the ability of fluorouracil to radiosensitize Clone A cells. Conclusion: Proliferating cells are more susceptible to radiosensitization with 5-FU than plateau-phase cells are, but this effect appears to be independent of the phase of the cell cycle

Spiny Neurons of Amygdala, Striatum and Cortex Use Dendritic Plateau Potentials to Detect Network UP States

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Katerina D Oikonomou

2014-09-01

Full Text Available Spiny neurons of amygdala, striatum, and cerebral cortex share four interesting features: [1] they are the most abundant cell type within their respective brain area, [2] covered by thousands of thorny protrusions (dendritic spines, [3] possess high levels of dendritic NMDA conductances, and [4] experience sustained somatic depolarizations in vivo and in vitro (UP states. In all spiny neurons of the forebrain, adequate glutamatergic inputs generate dendritic plateau potentials (dendritic UP states characterized by (i fast rise, (ii plateau phase lasting several hundred milliseconds and (iii abrupt decline at the end of the plateau phase. The dendritic plateau potential propagates towards the cell body decrementally to induce a long-lasting (longer than 100 ms, most often 200 – 800 ms steady depolarization (~20 mV amplitude, which resembles a neuronal UP state. Based on voltage-sensitive dye imaging, the plateau depolarization in the soma is precisely time-locked to the regenerative plateau potential taking place in the dendrite. The somatic plateau rises after the onset of the dendritic voltage transient and collapses with the breakdown of the dendritic plateau depolarization. We hypothesize that neuronal UP states in vivo reflect the occurrence of dendritic plateau potentials (dendritic UP states. We propose that the somatic voltage waveform during a neuronal UP state is determined by dendritic plateau potentials. A mammalian spiny neuron uses dendritic plateau potentials to detect and transform coherent network activity into a ubiquitous neuronal UP state. The biophysical properties of dendritic plateau potentials allow neurons to quickly attune to the ongoing network activity, as well as secure the stable amplitudes of successive UP states.

CENTRAL PLATEAU REMEDIATION

International Nuclear Information System (INIS)

ROMINE, L.D.

2006-01-01

A systematic approach to closure planning is being implemented at the Hanford Site's Central Plateau to help achieve the goal of closure by the year 2035. The overall objective of Central Plateau remediation is to protect human health and the environment from the significant quantity of contaminated material that resulted from decades of plutonium production in support of the nation's defense. This goal will be achieved either by removing contaminants or placing the residual contaminated materials in a secure configuration that minimizes further migration to the groundwater and reduces the potential for inadvertent intrusion into contaminated sites. The approach to Central Plateau cleanup used three key concepts--closure zones, closure elements, and closure process steps--to create an organized picture of actions required to complete remediation. These actions were merged with logic ties, constraints, and required resources to produce an integrated time-phased schedule and cost profile for Central Plateau closure. Programmatic risks associated with implementation of Central Plateau closure were identified and analyzed. Actions to mitigate the most significant risks are underway while high priority remediation projects continue to make progress

Comparison of DNA double-strand break rejoining as measured by pulsed field gel electrophoresis, neutral sucrose gradient centrifugation and non-unwinding filter elution in irradiated plateau-phase CHO cells

International Nuclear Information System (INIS)

Iliakis, G.; Metzger, L.; Pantelias, G.

1991-01-01

The initial (up to 30 min) rate of DNA double-strand break (dsb) rejoining was measured in irradiated plateau-phase CHO cells, in a set of parallel experiments using the same cell suspension, by means of non-unwinding filter elution, neutral sucrose gradient centrifugation, and two pulsed-field gel electrophoresis assays: asymmetric field inversion gel electrophoresis (AFIGE) and clamped homogeneous electric field (CHEF) gel electrophoresis. The rate of DNA dsb rejoining was compared to the rate of rejoining of chromatin breaks measured, also in the same cell population, using the technique of premature chromosome condensation (PCC). Two radiation exposures, 25 Gy and/or 50 Gy, were used and applied to the individual parts of the experiments according to the sensitivity of the assay under investigation. The results suggest all major techniques currently used for assaying rejoining of DNA dsb give similar results, and indicate that more information is required before a direct correlation between rejoining of DNA dsb and rejoining of chromatin breaks can be established. (author)

On the inward drift of runaway electrons during the plateau phase of runaway current

Energy Technology Data Exchange (ETDEWEB)

Hu, Di, E-mail: hudi-2@pku.edu.cn [School of Physics, Peking University, Beijing 100871 (China); Qin, Hong [Princeton Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08540 (United States); School of Nuclear Science and Technology and Department of Modern Physics, University of Science and Technology of China, Hefei 230026 (China)

2016-03-15

The well observed inward drift of current carrying runaway electrons during runaway plateau phase after disruption is studied by considering the phase space dynamic of runaways in a large aspect ratio toroidal system. We consider the case where the toroidal field is unperturbed and the toroidal symmetry of the system is preserved. The balance between the change in canonical angular momentum and the input of mechanical angular momentum in such a system requires runaways to drift horizontally in configuration space for any given change in momentum space. The dynamic of this drift can be obtained by integrating the modified Euler-Lagrange equation over one bounce time. It is then found that runaway electrons will always drift inward as long as they are decelerating. This drift motion is essentially non-linear, since the current is carried by runaways themselves, and any runaway drift relative to the magnetic axis will cause further displacement of the axis itself. A simplified analytical model is constructed to describe such inward drift both in the ideal wall case and no wall case, and the runaway current center displacement as a function of parallel momentum variation is obtained. The time scale of such displacement is estimated by considering effective radiation drag, which shows reasonable agreement with the observed displacement time scale. This indicates that the phase space dynamic studied here plays a major role in the horizontal displacement of runaway electrons during plateau phase.

Dose-rate effects on mammalian cells exposed to ionizing radiation

International Nuclear Information System (INIS)

Mitchell, J.B.

1978-01-01

The effect of irradiation on the life cycle and on cell survival was studied for a range of different dose rates. Log phase, plateau phase and synchronized cultures of different mammalian cells were used. Cell cycle redistribution during the radiation exposure was found to be a very important factor in determining the overall dose-rate effect for log phase and synchronized cells. In fact, cell cycle redistribution during the exposure, in some instances, resulted in a lower dose rate being more effective in cell killing per unit dose than a higher dose rate. For plateau phase cultures, where cell cycle times are greatly lengthened, the effects of redistribution in regard to cell killing was virtually eliminated. Both fed and unfed plateau phase cultures exhibited a dose-rate effect, but it was found that below dose rates of 154 rad/h there is no further loss in effectiveness

Comparison of Time/Phase Lags in the Hard State and Plateau State of GRS 1915+105

NARCIS (Netherlands)

Pahari, M.; Neilsen, J.; Yadav, J.S.; Misra, R.; Uttley, P.

2013-01-01

We investigate the complex behavior of energy- and frequency-dependent time/phase lags in the plateau state and the radio-quiet hard (χ) state of GRS 1915+105. In our timing analysis, we find that when the source is faint in the radio, quasi-periodic oscillations (QPOs) are observed above 2 Hz and

Regrowth and radiation sensitivity of quiescent cells isolated from EMT6/Ro-fed plateau monolayers

International Nuclear Information System (INIS)

Luk, C.K.; Keng, P.C.; Sutherland, R.M.

1985-01-01

A quiescent [denoted as Q(G0/G1)] subpopulation was isolated from EMT6/Ro-fed plateau monolayers by centrifugal elutriation. The median Coulter volume of these cells was significantly smaller than that of the original population from which they were elutriated. Using two-step acridine orange staining and dual parameter flow cytometric analysis, over 95% of quiescent cells were found to have G1 DNA content, and 80% of the cells had a decreased RNA content as compared to rapidly proliferating exponential G1 cells. After labeling for 24 hr (two doubling times) with [ 3 H]thymidine, less than 2% of the quiescent cells incorporated [3H]thymidine as measured by autoradiography. The colony-forming efficiency of these cells was not significantly different from that of exponential cells. When such Q(G0/G1) cells were replated in fresh medium at a lower density, there was a lag time of 30 hr before any increase in cell number was detected, after which the cell-doubling rate matched that of exponential culture. Results obtained from the radiation dose-response curves showed that quiescent (G0/G1) cells were more radiosensitive than exponential G1 or unseparated fed plateau cells

The Supercritical Pile Gamma-Ray Burst Model: The GRB Afterglow Steep Decline and Plateau Phase

Science.gov (United States)

Sultana, Joseph; Kazanas, D.; Mastichiadis, A.

2013-01-01

We present a process that accounts for the steep decline and plateau phase of the Swift X-Ray Telescope (XRT) light curves, vexing features of gamma-ray burst (GRB) phenomenology. This process is an integral part of the "supercritical pile" GRB model, proposed a few years ago to account for the conversion of the GRB kinetic energy into radiation with a spectral peak at E(sub pk) is approx. m(sub e)C(exp 2). We compute the evolution of the relativistic blast wave (RBW) Lorentz factor Gamma to show that the radiation-reaction force due to the GRB emission can produce an abrupt, small (approx. 25%) decrease in Gamma at a radius that is smaller (depending on conditions) than the deceleration radius R(sub D). Because of this reduction, the kinematic criticality criterion of the "supercritical pile" is no longer fulfilled. Transfer of the proton energy into electrons ceases and the GRB enters abruptly the afterglow phase at a luminosity smaller by approx. m(sub p)/m(sub e) than that of the prompt emission. If the radius at which this slow-down occurs is significantly smaller than R(sub D), the RBW internal energy continues to drive the RBW expansion at a constant (new) Gamma and its X-ray luminosity remains constant until R(sub D) is reached, at which point it resumes its more conventional decay, thereby completing the "unexpected" XRT light curve phase. If this transition occurs at R is approx. equal to R(sub D), the steep decline is followed by a flux decrease instead of a "plateau," consistent with the conventional afterglow declines. Besides providing an account of these peculiarities, the model suggests that the afterglow phase may in fact begin before the RBW reaches R is approx. equal to R(sub D), thus providing novel insights into GRB phenomenology.

Effects of hyperthermia on growth kinetics of Chinese hamster ovarian carcinoma cells

International Nuclear Information System (INIS)

Leeper, D.B.; Bobyock, S.B.

1987-01-01

The effects of hyperthermia on growth rate, cell volume, and density at plateau phase were studied in OvCa cells in monolayer culture in McCoy's 5a + 10% FCS. At 37 0 C, T/sub G/=9.3 hr, cell density at plateau was 32 x 10/sup 4//cm/sup 2/, and mean cell volume decreased from 1200 μ/sup 3/ at the onset of exponential growth to 850 μ/sup 3/ in plateau phase. Cells were acutely heated for 60' at 43 0 ,30' at 44 0 , or 15' at 45 0 (S.F.=20%) and incubated at 37 0 ; or were chronically heated for up to 80 hr at 39-42 0 . Acute heating at 43-45 0 delayed cell division for appx 13 hr after which growth resumed with a T/sub G/=18 hr. Incubation at 39-40 0 had no effect on T/sub G/, but temperatures of 40.5-42 0 increased T/sub G/ at ΔH=176 kcal/mole. Increasing incubation temperature decreased cell density at plateau phase and altered cell volume kinetics. Cell density in plateau phase was 20 x 10/sup 4//cm/sup 2/ at 39 0 , 13 x 10/sup 4//cm/sup 2/ at 40 0 , 5x10/sup 4//cm/sup 2/ at 41 0 . Growth was greatly reduced at 42 0 (T/sub G/=55 hr) and doubling did not occur before onset of cell lysis. The decrease in cell volume with growth of the culture was unaffected at 39 0 . However, at temperatures ≥40 0 cell volume transiently increase, and the rate of decrease in volume that normally occurred with growth at 37-39 0 was less such that at 41 0 there was no decrease in volume at all before cells entered plateau phase. The authors' hypothesis is that the effects of heat on growth kinetics are related to alterations in rates of protein synthesis. This is currently being tested

Seismic observation of a sharp post-garnet phase transition within the Farallon crust: Evidence for oceanic plateau subduction

Science.gov (United States)

Maguire, R.; Ritsema, J.

2017-12-01

The tectonic evolution of North America over the past 150 million years was heavily influenced by the complex subduction history of the Farallon plate. In particular, Laramide mountain building may have been triggered by the initiation of flat slab subduction in the late Cretaceous. While it has been proposed that the cause of slab flattening is related to the subduction of an oceanic plateau[1], direct geophysical evidence of a subducted oceanic plateau is lacking. Here, using P-to-S receiver functions, we detect a sharp seismic discontinuity at 720-km depth beneath the southeastern United States and Gulf of Mexico. We interpret this discontinuity as a garnet-to-bridgmanite phase transition occurring within a thickened Farallon crust. Our results are consistent with a subducted oceanic plateau (likely the conjugate half of the Hess rise) which is foundering below the base of the mantle transition zone. Additionally, we find a strong 520-km discontinuity beneath the southeastern United States which may indicate a hydrous transition zone due to the release of H2O from the Farallon slab. These results provide insight into the dynamics of flat slab subduction as well as the tectonic history of North America. [1] Livaccari, R. F., Burke, K., & Şengör, A. M. C. (1981). Was the Laramide orogeny related to subduction of an oceanic plateau? Nature, v. 289, p. 276-278, doi: 10.1038/289276a0

Effects of proliferation on the decay of thermotolerance in Chinese hamster cells.

Science.gov (United States)

Armour, E P; Li, G C; Hahn, G M

1985-09-01

Development and decay of thermotolerance were observed in Chinese hamster HA-1 cells. The thermotolerance kinetics of exponentially growing and fed plateau-phase cells were compared. Following a 10-min heat exposure at 45 degrees C, cells in both growth states had similar rates of development of tolerance to a subsequent 45-min exposure at 45 degrees C. This thermotolerant state started to decay between 12 and 24 hr after the initial heat exposure. The decay appeared to initiate slightly sooner in the exponentially growing cells when compared to the fed plateau-phase cells. During the decay phase, the rate of thermotolerance decay was similar in the two growth conditions. In other experiments, cells were induced to divide at a slower rate by chronic growth (3 months) in a low concentration of fetal calf serum. Under these low serum conditions cells became more sensitive to heat and the rate of decay of thermotolerance remained the same for exponentially growing cells. Plateau-phase cells were also more sensitive, but thermotolerance decayed more rapidly in these cells. Although dramatic cell cycle perturbations were seen in the exponentially growing cells, these changes appeared not to be related to thermotolerance kinetics.

Adaption to High Altitude: An Evaluation of the Storage Quality of Suspended Red Blood Cells Prepared from the Whole Blood of Tibetan Plateau Migrants.

Science.gov (United States)

Zhong, Rui; Liu, Hua; Wang, Hong; Li, Xiaojuan; He, Zeng; Gangla, Meiduo; Zhang, Jingdan; Han, Dingding; Liu, Jiaxin

2015-01-01

Hypoxia has been reported to cause the significant enhancement of hemoglobin (Hb) and hematocrit (Hct), which stabilizes at relatively high levels after an individual ascends to a high altitude. However, the quality of the suspended red blood cells (SRBCs) obtained from individuals at high altitudes such as Tibetan plateau migrants after storage has not been studied. In this study, we compared the storage quality of SRBCs prepared from Tibetan plateau and Deyang lowland populations by adding a normal volume of mannitol-adenine-phosphate (MAP), which is a common additive solution used in blood storage in Asian countries. The storage cell characteristics were examined on days 1, 7, 14 and 35.We found higher Hct and Hb levels and viscosity in the high altitude samples. The metabolic rates, including those for electrolytes and lactate, were higher in plateau SRBCs than in lowland SRBCs; these findings were consistent with the higher osmotic fragility and hemolysis of plateau SRBCs throughout the entire storage period. In addition, the reduction rates of 2,3-diphosphoglycerate (2,3-DPG) and oxygen tension to attain 50% oxygen saturation of Hb (P50) in plateau SRBCs were higher than those in lowland SRBCs, and the oxygen delivering capacity in plateau SRBCs was weaker than that in lowland SRBCs. We concluded that the storage quality of plateau SRBCs was inferior to that of lowland SRBCs when using the same concentration of MAP. We suggested that the optimal formula, including the MAP concentration or even a new additive solution, to store the plateau SRBCs must be assessed and regulated.

Adaption to High Altitude: An Evaluation of the Storage Quality of Suspended Red Blood Cells Prepared from the Whole Blood of Tibetan Plateau Migrants

Science.gov (United States)

Wang, Hong; Li, Xiaojuan; He, Zeng; Gangla, Meiduo; Zhang, Jingdan; Han, Dingding; Liu, Jiaxin

2015-01-01

Hypoxia has been reported to cause the significant enhancement of hemoglobin (Hb) and hematocrit (Hct), which stabilizes at relatively high levels after an individual ascends to a high altitude. However, the quality of the suspended red blood cells (SRBCs) obtained from individuals at high altitudes such as Tibetan plateau migrants after storage has not been studied. In this study, we compared the storage quality of SRBCs prepared from Tibetan plateau and Deyang lowland populations by adding a normal volume of mannitol-adenine-phosphate (MAP), which is a common additive solution used in blood storage in Asian countries. The storage cell characteristics were examined on days1, 7, 14 and 35.We found higher Hct and Hb levels and viscosity in the high altitude samples. The metabolic rates, including those for electrolytes and lactate, were higher in plateau SRBCs than in lowland SRBCs; these findings were consistent with the higher osmotic fragility and hemolysis of plateau SRBCs throughout the entire storage period. In addition, the reduction rates of 2,3-diphosphoglycerate (2,3-DPG) and oxygen tension to attain 50% oxygen saturation of Hb (P50) in plateau SRBCs were higher than those in lowland SRBCs, and the oxygen delivering capacity in plateau SRBCs was weaker than that in lowland SRBCs. We concluded that the storage quality of plateau SRBCs was inferior to that of lowland SRBCs when using the same concentration of MAP. We suggested that the optimal formula, including the MAP concentration or even a new additive solution, to store the plateau SRBCs must be assessed and regulated. PMID:26637115

Adaption to High Altitude: An Evaluation of the Storage Quality of Suspended Red Blood Cells Prepared from the Whole Blood of Tibetan Plateau Migrants.

Directory of Open Access Journals (Sweden)

Rui Zhong

Full Text Available Hypoxia has been reported to cause the significant enhancement of hemoglobin (Hb and hematocrit (Hct, which stabilizes at relatively high levels after an individual ascends to a high altitude. However, the quality of the suspended red blood cells (SRBCs obtained from individuals at high altitudes such as Tibetan plateau migrants after storage has not been studied. In this study, we compared the storage quality of SRBCs prepared from Tibetan plateau and Deyang lowland populations by adding a normal volume of mannitol-adenine-phosphate (MAP, which is a common additive solution used in blood storage in Asian countries. The storage cell characteristics were examined on days 1, 7, 14 and 35.We found higher Hct and Hb levels and viscosity in the high altitude samples. The metabolic rates, including those for electrolytes and lactate, were higher in plateau SRBCs than in lowland SRBCs; these findings were consistent with the higher osmotic fragility and hemolysis of plateau SRBCs throughout the entire storage period. In addition, the reduction rates of 2,3-diphosphoglycerate (2,3-DPG and oxygen tension to attain 50% oxygen saturation of Hb (P50 in plateau SRBCs were higher than those in lowland SRBCs, and the oxygen delivering capacity in plateau SRBCs was weaker than that in lowland SRBCs. We concluded that the storage quality of plateau SRBCs was inferior to that of lowland SRBCs when using the same concentration of MAP. We suggested that the optimal formula, including the MAP concentration or even a new additive solution, to store the plateau SRBCs must be assessed and regulated.

The radiation response of cells recovering after chronic hypoxia

International Nuclear Information System (INIS)

Kwok, T.T.; Sutherland, R.M.

1989-01-01

Experiments were performed to study the influence of hypoxic pretreatment on the radiation response of A431 human squamous carcinoma cells. Reaeration for 10 min after chronic hypoxia (greater than 2 h) was found to enhance the radiosensitivity of A431 cells, and the maximal effect was seen for those cells reaerated after 12 h of hypoxia. The radiosensitivity enhancement for reaerated cells after 12 h of hypoxia was maximized by 5 min after the return to aerobic conditions and reached the control level by 12 h of reaeration. This enhanced radiosensitive state was characterized by a reduced shoulder region and increased slope of the radiation dose-response curve for cells in both the exponential and plateau phases of growth. There was a slight increase in the number of G1 and decrease in the number of S and G2 + M cells for both exponential- and plateau-phase cultures following 12 h hypoxic treatment. Although growth inhibition induced by 12 h of hypoxia was seen for cells in the exponential phase, there was no cell number change in the plateau-phase culture after hypoxia. Plating efficiency (PE) of cells in both growth phases was reduced by 30% after hypoxia. Furthermore, in the exponential-phase culture, the extent of reduction in PE after hypoxia was similar among cells in different phases of the cell cycle. Although S-phase cells in exponentially growing cultures were relatively more resistant to radiation than G1 and G2 + M cells, the cell age-response pattern was the same whether the cells had been aerobic or hypoxic before reaeration and irradiation. Furthermore, the enhancement ratio associated with reaeration after 12 h of hypoxia for these three subpopulations of cells was 1.3. Our results indicate that the increase in radiosensitivity due to reaeration after chronic hypoxia is unlikely to be related to the changes of cell cycle stage and growth phase during hypoxic treatment

Toward Quantitative Understanding of the Atmospheric Heating over the Tibetan Plateau (Invited)

Science.gov (United States)

Koike, T.; Tamura, T.; Rasmy, M.; Seto, R.

2010-12-01

There are different ideas on the atmospheric heating over the Tibetan Plateau. Yanai et al. (1992) and Yanai and Li (1994) concluded this sensible heat flux from the surface is the major source of heating on the plateau before the summer rain commences. On the other hand, Ueda et al. (2003) also showed the importance of condensation heating in the heat balance during the pre-onset-phase of the summer monsoon over the western part of the Tibetan Plateau. The first intensive in situ observation in early spring was implemented on the plateau in April 2004 under the framework of the Coordinated Enhanced Observing Period (CEOP) (Koike, 2004). Taniguchi and Koike (2007) revealed the importance of cumulus activity in atmospheric temperature increases in the upper troposphere even in April by in situ and satellite observations and numerical simulations. They concluded that sensible heat transfer by dry convection is insufficient to warm the upper layer over the plateau and that the development of cloud convection is indispensable for atmospheric heating in the upper troposphere over the plateau during early spring. Then, Taniguchi and Koike (2008) investigated the seasonal variation in the cloud activity over the eastern part of the Tibetan Plateau, and the vertical profile of the atmosphere and moist condition causing the cloud. They showed cumulus convections easily occur under the adiabatically neutral condition of the first phase of the active convections in April. During a resting phase before the second active phase, the atmosphere is conditionally unstable but an unsaturated condition restrains cloud activity, while during second phase, the atmosphere is inclined to be saturated and cloud activity begins again. From early May to mid June, there is a resting period of cumulus convective activity. However, the tropospheric temperature at 200 hPa increases rapidly from late April. Such rapid tropospheric warming without significant cumulus convective activity is

Observation of the Zero Hall Plateau in a Quantum Anomalous Hall Insulator

Energy Technology Data Exchange (ETDEWEB)

Feng, Yang; Feng, Xiao; Ou, Yunbo; Wang, Jing; Liu, Chang; Zhang, Liguo; Zhao, Dongyang; Jiang, Gaoyuan; Zhang, Shou-Cheng; He, Ke; Ma, Xucun; Xue, Qi-Kun; Wang, Yayu

2015-09-16

We report experimental investigations on the quantum phase transition between the two opposite Hall plateaus of a quantum anomalous Hall insulator. We observe a well-defined plateau with zero Hall conductivity over a range of magnetic field around coercivity when the magnetization reverses. The features of the zero Hall plateau are shown to be closely related to that of the quantum anomalous Hall effect, but its temperature evolution exhibits a significant difference from the network model for a conventional quantum Hall plateau transition. We propose that the chiral edge states residing at the magnetic domain boundaries, which are unique to a quantum anomalous Hall insulator, are responsible for the novel features of the zero Hall plateau.

Solid phases limiting the concentration of dissolved constituents in basalt aquifers of the Columbia Plateau in eastern Washington

International Nuclear Information System (INIS)

Deutsch, W.J.; Jenne, E.A.; Krupka, K.M.

1981-01-01

The purposes of this study were: (1) to provide information on the solid phases which are in apparent equilibrium with ground waters of basalt aquifers, and (2) to further develop the capability of geochemical modeling to support solute transport studies and performance assessments of nuclear waste repositories. The basalt aquifers of the Columbia Plateau in eastern Washington were chosen as the study area because: (1) regional ground-water analyses are readily available, (2) these basalts are a potential medium for a nuclear-waste repository, and (3) mineralogical analyses from local site studies are available

Radiobiological properties of radiosensitive XR-1 Chinese hamster cells and hybrids from these and human A-T cells

International Nuclear Information System (INIS)

Bahari, I.B.

1989-01-01

Results indicate that XR-1 cells were very radiosensitive to gamma-irradiation compared to its parental type, and that this radiosensitivity is cell cycle dependent. Irradiating the cells the G 1 or plateau phase did not induce any delay entering S-phase but mitotic delays were observed in both XR-1 and the wild-type cells. The delays per unit dose were much longer for XR-1. A delay in subculture from plateau phase reduced the mitotic delay in both cell lines. Unlike the wild-type cells which expressed virtually all chromosome-type aberrations after irradiation of G 1 cells, the XR-1 cells expressed both chromatid- as well as chromosome-type aberrations. There was a one-to-one correlation between total aberrations induced and lethality for both cells. Many of these radiobiological properties of XR-1 cells relative to the wild-type cells, mimic the response of A-T cells relative to the normal human cells. However, the restoration of radioresistance and cytogenetic response in the XR1/AT5BI(4) hybrid cells suggest that the XR-1 and A-T cells have different defects because of the complementation in the hybrids. It also appears that this genetic defect is recessive in nature

Precipitation phase separation schemes in the Naqu River basin, eastern Tibetan plateau

Science.gov (United States)

Liu, Shaohua; Yan, Denghua; Qin, Tianling; Weng, Baisha; Lu, Yajing; Dong, Guoqiang; Gong, Boya

2018-01-01

Precipitation phase has a profound influence on the hydrological processes in the Naqu River basin, eastern Tibetan plateau. However, there are only six meteorological stations with precipitation phase (rainfall/snowfall/sleet) before 1979 within and around the basin. In order to separate snowfall from precipitation, a new separation scheme with S-shaped curve of snowfall proportion as an exponential function of daily mean temperature was developed. The determinations of critical temperatures in the single/two temperature threshold (STT/TTT2) methods were explored accordingly, and the temperature corresponding to the 50 % snowfall proportion (SP50 temperature) is an efficiently critical temperature for the STT, and two critical temperatures in TTT2 can be determined based on the exponential function and SP50 temperature. Then, different separation schemes were evaluated in separating snowfall from precipitation in the Naqu River basin. The results show that the S-shaped curve methods outperform other separation schemes. Although the STT and TTT2 slightly underestimate and overestimate the snowfall when the temperature is higher and colder than SP50 temperature respectively, the monthly and annual separation snowfalls are generally consistent with the observed snowfalls. On the whole, S-shaped curve methods, STT, and TTT2 perform well in separating snowfall from precipitation with the Pearson correlation coefficient of annual separation snowfall above 0.8 and provide possible approaches to separate the snowfall from precipitation for hydrological modelling.

Synchronous drought and flooding in southern Chinese Loess Plateau in phase with the variation of global temperature

Science.gov (United States)

Yu, X.; Kang, Z.

2017-12-01

Drought and flooding, usually occurring in the catchment scale, are the main natural threats to human livelihood due to the extreme variation of precipitation in spatiotemporal scales. Within the context of global warming, the risk of flood and drought tends to increase in different regions. Understanding the mechanism of the regional occurrence of flood and drought is of enormous importance for the predicting studies and taking corresponding measures. However, the instrumental records are too short to conduct a prediction. Here, we present a historical-archive-based high-resolution dataset of drought and flooding back to AD 1646 in the southern Chinese Loess Plateau. This sequence, integrated with the modern meteorological observation data, shows that the frequency of drought and flooding in the study region is synchronous on a decadal scale, and they are in phase with the increase in both global and regional temperature. During the warm period, the ENSO activity was found to be increase, resulting in the anomaly distribution of precipitation in different seasons in southern Chinese Loess Plateau, which is the reason for the temperature dependence of flooding and drought in this region. If global temperature continues to rise in the future, the risk of both drought and flooding in the study area would also increase.

Potentially lethal damage repair in cell lines of radioresistant human tumours and normal skin fibroblasts

International Nuclear Information System (INIS)

Marchese, M.J.; Minarik, L.; Hall, E.J.; Zaider, M.

1985-01-01

Radiation cell survival data were obtained in vitro for three cell lines isolated from human tumours traditionally considered to be radioresistant-two melanomas and one osteosarcoma-as well as from a diploid skin fibroblast cell line. One melanoma cell line was much more radioresistant than the other, while the osteosarcoma and fibroblast cell lines were more radiosensitive than either. For cells growing exponentially, little potentially lethal damage repair (PLDR) could be demonstrated by comparing survival data for cells in which subculture was delayed by 6 h with those sub-cultured immediately after treatment. For the malignant cells in plateau phase, which in these cells might be better termed 'slowed growth phase', since an appreciable fraction of the cells are still cycling, a small amount of PLDR was observed, but not as much as reported by other investigators in the literature. The normal fibroblasts, which achieved a truer plateau phase in terms of noncycling cells, showed a significantly larger amount of PLDR than the tumour cells. (author)

Changes in sensitivity to radiation and to bleomycin occurring during the life history of monolayer cultures of a mouse tumour cell line

International Nuclear Information System (INIS)

Twentyman, P.R.; Bleehen, N.M.

1975-01-01

The response to X-radiation and to bleomycin has been measured at a number of times during the life of monolayer cultures of EMT6 mouse tumour cells. Little change in radiation sensitivity was seen at any time and no loss of the shoulder to the survival curve occurred. Cultures in early plateau phase (where a considerable amount of cell proliferation is balanced by cell loss) showed a reduced sensitivity to bleomycin when compared with cells in exponential growth. However, after a longer period in plateau phase, when proliferation had virtually ceased, the sensitivity became greater than that of exponential phase cells. These findings are discussed with reference to the conflicting results of other workers. (author)

Evidence for the induction of two types of potentially lethal damage after exposure of plateau phase Chinese hamster V79 cells to γ-rays

International Nuclear Information System (INIS)

Iliakis, G.

1985-01-01

The fixation of γ-rays induced potentially damage (PLD) caused after treatment either with β-araA or in medium made hypertonic by the addition of sodium chloride was studied in plateauphase chinese hamster V79 cells. Treatment with β-araA was found to affect a sector of PLD, the fixation of which specifically reduced the shoulder width of the survival curve. The effect was maximized when cell survival reached levels corresponding to an exponential line, with a slope similar to the final slope of the survival curve of untreated cells. This effect was achieved by a four hour treatment with β-araA at concentrations above 150 μM. Longer treatment times or incubation at higher β-araA concentrations did not significantly enhance the effect. Treatment in hypertonic medium, on the other hand, enhanced cell killing in a concentration dependent (NaCl-concentration) way and the survival reached values much lower than those corresponding to an exponential line. No indication for a plateau in the effect, indicating complete fixation of the sector of PLD that reacts sensitively to this treatment, was obtained. Boht the slope and the shoulder width of the survival curve were affected, the slope first being increaseed after short treatment times (up to 10 min), followed by a decrease in the shoulder width after longer treatment times (longer than 10 min). (orig./WL)

Preparation and thermal properties of Glauber’s salt-based phase-change materials for Qinghai-Tibet Plateau solar greenhouses

Science.gov (United States)

Jiang, Zipeng; Tie, Shengnian

2017-07-01

This paper reports the preparation and characterization of eutectic Glauber’s salt-based composite, phase-change materials (G-PCMs). PCMs were prepared using industrial-grade sodium sulfate decahydrate (Na2SO4 ṡ 10H2O) as the basic material. Other salts were added to obtain the eutectic Glauber’s salt-based PCMs with phase-change temperatures of 25∘C, 15∘C and 10∘C. The modification of the G-PCMs was designed using the same experimental method to select the efficient nucleating, thickening and thermal conductive agents. The results show that borax can be an effective nucleating agent, sodium carboxymethyl cellulose is an excellent thickener and carbon powder is a good thermal conductive agent. The phase-change temperature, latent heat and thermal conductivity of the three different PCMs are 23.9∘C, 15.4∘C and 9.5∘C; 179.6, 129 and 116.2 J/g; and 1.02, 1.10 and 1.23 W/(m K), respectively. These PCMs possess suitable phase-change temperature, high latent heat and good thermal conductivity, and can be used in Qinghai-Tibet Plateau agricultural solar greenhouses.

Genetic diversity and sex-bias dispersal of plateau pika in Tibetan plateau.

Science.gov (United States)

Zhang, Liangzhi; Qu, Jiapeng; Li, Kexin; Li, Wenjing; Yang, Min; Zhang, Yanming

2017-10-01

Dispersal is an important aspect in organism's life history which could influence the rate and outcome of evolution of organism. Plateau pika is the keystone species in community of grasslands in Tibetan Plateau. In this study, we combine genetic and field data to character the population genetic pattern and dispersal dynamics in plateau pika ( Ochotona curzoniae ). Totally, 1,352 individual samples were collected, and 10 microsatellite loci were analyzed. Results revealed that plateau pika possessed high genetic diversity and inbreeding coefficient in a fine-scale population. Dispersal distance is short and restricted in about 20 m. An effective sex-biased dispersal strategy is employed by plateau pika: males disperse in breeding period for mating while females do it after reproduction for offspring and resource. Inbreeding avoiding was shown as the common driving force of dispersal, together with the other two factors, environment and resource. In addition, natal dispersal is female biased. More detailed genetic analyzes are needed to confirm the role of inbreeding avoidance and resource competition as ultimate cause of dispersal patterns in plateau pika.

Slow growth of the Rayleigh-Plateau instability in aqueous two phase systems

NARCIS (Netherlands)

Geschiere, S.D.; Ziemecka, I.; Van Steijn, V.; Koper, G.J.M.; Van Esch, J.H.; Kreutzer, M.T.

2012-01-01

This paper studies the Rayleigh-Plateau instability for co-flowing immiscible aqueous polymer solutions in a microfluidic channel. Careful vibration-free experiments with controlled actuation of the flow allowed direct measurement of the growth rate of this instability. Experiments for the

Tibial Plateau Fractures

DEFF Research Database (Denmark)

Elsøe, Rasmus

This PhD thesis reported an incidence of tibial plateau fractures of 10.3/100,000/year in a complete Danish regional population. The results reported that patients treated for a lateral tibial plateau fracture with bone tamp reduction and percutaneous screw fixation achieved a satisfactory level...... with only the subgroup Sport significantly below the age matched reference population. The thesis reports a level of health related quality of life (Eq5d) and disability (KOOS) significantly below established reference populations for patients with bicondylar tibial plateau fracture treated with a ring...... fixator, both during treatment and at 19 months following injury. In general, the thesis demonstrates that the treatment of tibial plateau fractures are challenging and that some disabilities following these fractures must be expected. Moreover, the need for further research in the area, both with regard...

Radiosensitive xrs-5 and parental CHO cells show identical DNA neutral filter elution dose-response: implications for a relationship between cell radiosensitivity and induction of DNA double-strand breaks

International Nuclear Information System (INIS)

Iliakis, George; Okayasu, Ryuichi; Seaner, Robert

1988-01-01

The purpose of this work was to investigate a possible correlation between DNA elution dose-response and cell radiosensitivity. For this purpose neutral (pH 9.6) DNA filter elution dose-response curves were measured with radiosensitive xrs-5 and the parental Chinese hamster ovary (CHO) cells in the logarithmic and plateau phase of growth. No difference was observed between the two cell types in the DNA elution dose-response curves either in logarithmic or plateau phase, despite the dramatic differences in cell radiosensitivity. This observation indicates that the shape of the DNA elution dose-response curve and the shape of the cell survival curve are not causally related. It is proposed that the shoulder observed in the DNA elution dose-response curve reflects either partial release of DNA from chromatin, or cell cycle-specific alterations in the physicochemical properties of the DNA. (author)

PLATEAU IRIS SYNDROME--CASE SERIES.

Science.gov (United States)

Feraru, Crenguta Ioana; Pantalon, Anca Delia; Chiselita, Dorin; Branisteanu, Daniel

2015-01-01

Plateau iris is characterized by closing the anterior chamber angle due to a large ciliary body or due to its anterior insertion that alters the position of iris periphery in respect to the trabecular meshwork. There are two aspects that need to be differentiated: plateau iris configuration and plateau iris syndrome. The first describes a situation when the iris root is flat and the anterior chamber is not shallow, the latter refers to a post laser iridotomy condition in which a patent iridotomy has removed the relative pupillary block, but goniscopically confirmed angle closure recurs without central shallowing of the anterior chamber. Isolated plateau iris syndrome is rare compared to plateau iris configuration. We hereby present two case reports of plateau iris syndrome in young patients who came to an ophthalmologic consult by chance.

Cell-cycle phase specificity of chloroethylnitrosoureas

International Nuclear Information System (INIS)

Linfoot, P.A.

1986-01-01

Although the cancer chemotherapeutic agent 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) is considered a non-cell cycle phase specific drug, it has been shown to produce differential cell killing in G 1 , S, and G 2 /M phase cells, with S phase cells appearing relatively resistant. Studies of cell cycle phase specific cell killing produced by nitrosoureas with different chemical reactivities, clearly indicated that the ability of compounds to cross-link DNA was important in determining their phase specificity. Cells that lacked guanine O 6 -alkytransferase activity showed similar patterns of BCNU phase specificity regardless of their intrinsic sensitivity to BCNU. DNA inter-strand cross-linking, as measured by alkaline elution, was similar in cells exposed to BCNU in G 1 or S phase. 3 H [1-chloroethyl-1nitrosourea] binding to DNA was the same in G 1 , S and G 2 /M phase cells indicating that phase-specific differences in drug uptake and intracellular drug dose were not responsible for phase specific cell kill. These studies suggest that cross-link lesions, other than DNA inter-strand cross-links, and/or effects on DNA repair, other than guanine O 6 -alkyltransferase, are additional important determinants of BCNU phase specific cell killing

Irreversible altering of crystalline phase of phase-change Ge-Sb thin films

International Nuclear Information System (INIS)

Krusin-Elbaum, L.; Shakhvorostov, D.; Cabral, C. Jr.; Raoux, S.; Jordan-Sweet, J. L.

2010-01-01

The stability of the crystalline phase of binary phase-change Ge x Sb 1-x films is investigated over a wide range of Ge content. From Raman spectroscopy we find the Ge-Sb crystalline structure irreversibly altered after exposure to a laser beam. We show that with increasing beam intensity/temperature Ge agglomerates and precipitates out in the amount growing with x. A simple empirical relation links Ge precipitation temperature T Ge p to the rate of change dT cryst /dx of crystallization, with the precipitation easiest on the mid-range x plateau, where T cryst is nearly constant. Our findings point to a preferable 15% < or approx. x < 50% window, that may achieve the desired cycling/archival properties of a phase-change cell.

Dose-rate evidence for two kinds of radiation damage in stationary-phase mammalian cells

International Nuclear Information System (INIS)

Metting, N.F.; Braby, L.A.; Roesch, W.C.; Nelson, J.M.

1985-01-01

Survival based on colony formation was measured for starved plateau-phase Chinese hamster ovary (CHO) cells exposed to 250 kVp X rays at dose rates of 0.0031, 0.025, 0.18, 0.31, and 1.00 Gy/min. A large dose-rate effect was demonstrated. Delayed plating experiments and dose response experiments following a conditioning dose, both using a dose rate of 1.00 Gy/min and plating delays of up to 48 hr, were also used to investigate the alternative repair hypotheses. There is clearly a greater change in survival in dose-rate experiments than in the other experiments. Thus the authors believe that a process which depends on the square of the concentration of initial damage, and which alters the effect of initial damage on cell survival is being observed. They have applied the damage accumulation model to separate the single-event damage from this concentration-dependent form and estimate the repair rate for the latter type to be 70 min for their CHO cells

Molecular identification of Taenia mustelae cysts in subterranean rodent plateau zokors (Eospalax baileyi).

Science.gov (United States)

Zhao, Fang; Ma, Jun-Ying; Cai, Hui-Xia; Su, Jian-Ping; Hou, Zhi-Bin; Zhang, Tong-Zuo; Lin, Gong-Hua

2014-07-01

Cestode larvae spend one phase of their two-phase life cycle in the viscera of rodents, but cases of cestodes infecting subterranean rodents have only been rarely observed. To experimentally gain some insight into this phenomenon, we captured approximately 300 plateau zokors (Eospalax baileyi), a typical subterranean rodent inhabiting the Qinghai-Tibet Plateau, and examined their livers for the presence of cysts. Totally, we collected five cysts, and using a mitochondrial gene (cox1) and two nuclear genes (pepck and pold) as genetic markers, we were able to analyze the taxonomy of the cysts. Both the maximum likelihood and Bayesian methods showed that the cysts share a monophyly with Taenia mustelae, while Kimura 2-parameter distances and number of different sites between our sequences and T. mustelae were far less than those found between the examined sequences and other Taeniidae species. These results, alongside supporting paraffin section histology, imply that the cysts found in plateau zokors can be regarded as larvae of T. mustelae, illustrating that zokors are a newly discovered intermediate host record of this parasite.

Scale-Up Information for Gas-Phase Ammonia Treatment of Uranium in the Vadose Zone at the Hanford Site Central Plateau

Energy Technology Data Exchange (ETDEWEB)

Truex, Michael J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Szecsody, James E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Zhong, Lirong [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Thomle, Jonathan N. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Johnson, Timothy C. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

2014-09-01

Uranium is present in the vadose zone at the Hanford Central Plateau and is of concern for protection of groundwater. The Deep Vadose Zone Treatability Test Plan for the Hanford Central Plateau identified gas-phase treatment and geochemical manipulation as potentially effective treatment approaches for uranium and technetium in the Hanford Central Plateau vadose zone. Based on laboratory evaluation, use of ammonia vapor was selected as the most promising uranium treatment candidate for further development and field testing. While laboratory tests have shown that ammonia treatment effectively reduces the mobility of uranium, additional information is needed to enable deployment of this technology for remediation. Of importance for field applications are aspects of the technology associated with effective distribution of ammonia to a targeted treatment zone, understanding the fate of injected ammonia and its impact on subsurface conditions, and identifying effective monitoring approaches. In addition, information is needed to select equipment and operational parameters for a field design. As part of development efforts for the ammonia technology for remediation of vadose zone uranium contamination, field scale-up issues were identified and have been addressed through a series of laboratory and modeling efforts. This report presents a conceptual description for field application of the ammonia treatment process, engineering calculations to support treatment design, ammonia transport information, field application monitoring approaches, and a discussion of processes affecting the fate of ammonia in the subsurface. The report compiles this information from previous publications and from recent research and development activities. The intent of this report is to provide technical information about these scale-up elements to support the design and operation of a field test for the ammonia treatment technology.

PLATEAU IRIS--DIAGNOSIS AND TREATMENT.

Science.gov (United States)

Stefan, Cornel; Iliescu, Daniela Adriana; Batras, Mehdi; Timaru, Cristina Mihaela; De Simone, Algerino

2015-01-01

The objective of our study was to review the current knowledge on the diagnosis and treatment options of plateau iris configuration and syndrome. Relevant publications on plateau iris that were published until 2014. Plateau iris syndrome is a form of primary angle closure glaucoma caused by a large or anteriorly positioned ciliary body that leads to mechanical obstruction of trabecular meshwork. This condition is most often found in younger patients. Plateau iris has been considered an abnormal anatomic variant of the iris that can be diagnosed on ultrasound biomicroscopy or optical coherence tomography of anterior segment. Patients with plateau iris syndrome can be recognized by the lack of response in angle opening after iridotomy. The treatment of choice in these cases is argon laser peripheral iridoplasty.

Maximum recovery potential of human tumor cells may predict clinical outcome in radiotherapy

International Nuclear Information System (INIS)

Weichselbaum, R.R.; Beckett, M.

1987-01-01

We studied inherent radiosensitivity/resistance (D0), ability to accumulate sublethal damage (n) and repair of potentially lethal damage (PLDR) in established human tumor cell lines as well as early passage human tumor cell lines derived from patients with known outcome following radiotherapy. Survival 24 hrs after treatment of human tumor cells with X rays in plateau phase cultures is a function of initial damage (D0, n), as well as recovery over 24 hrs (PLDR). A surviving fraction greater than .1 24 hrs following treatment with 7 Gy in plateau phase cultures is associated with tumor cell types (melanoma, osteosarcoma) with a high probability of radiotherapy failure or tumor cells derived from patients who actually failed radiotherapy. Therefore, total cellular recovery following radiation may be an important determinant of radiocurability. Accurate assays of radiotherapy outcome may need to account for all these radiobiological parameters

Eocene to Miocene Out-of-Sequence Deformation in the Eastern Tibetan Plateau: Insights From Shortening Structures in the Sichuan Basin

Science.gov (United States)

Tian, Yuntao; Kohn, Barry P.; Qiu, Nansheng; Yuan, Yusong; Hu, Shengbiao; Gleadow, Andrew J. W.; Zhang, Peizhen

2018-02-01

A distinctive NNE trending belt of shortening structures dominates the topography and deformation of the eastern Sichuan Basin, 300 km east of the Tibetan Plateau. Debate continues as to whether the structures resulted from Cenozoic eastward growth of the Tibetan Plateau. A low-temperature thermochronology (AFT and AHe) data set from four deep boreholes and adjacent outcrops intersecting a branch of the shortening structures indicates distinctive differential cooling at 35-28 Ma across the structure, where stratigraphy has been offset vertically by 0.8-1.3 km. This result forms the first quantitative evidence for the existence of a late Eocene-Oligocene phase of shortening in the eastern Sichuan Basin, synchronous with the early phase of eastward growth and extrusion of the Tibetan Plateau. Further, a compilation of regional Cenozoic structures reveals a Miocene retreat of deformation from the foreland basin to the hinterland areas. Such a tectonic reorganization indicates that Eocene to Miocene deformation in the eastern Tibetan Plateau is out-of-sequence and was probably triggered by enhanced erosion in the eastern Tibetan Plateau.

Freshwater Biogeography and Limnological Evolution of the Tibetan Plateau - Insights from a Plateau-Wide Distributed Gastropod Taxon (Radix spp.)

Science.gov (United States)

von Oheimb, Parm Viktor; Albrecht, Christian; Riedel, Frank; Du, Lina; Yang, Junxing; Aldridge, David C.; Bößneck, Ulrich; Zhang, Hucai; Wilke, Thomas

2011-01-01

Background The Tibetan Plateau is not only the highest and largest plateau on earth; it is also home to numerous freshwater lakes potentially harbouring endemic faunal elements. As it remains largely unknown whether these lakes have continuously existed during the Last Glacial Maximum (LGM), questions arise as to whether taxa have been able to exist on the plateau since before the latest Pleistocene, from where and how often the plateau was colonized, and by which mechanisms organisms conquered remote high altitude lentic freshwater systems. In this study, species of the plateau-wide distributed freshwater gastropod genus Radix are used to answer these biogeographical questions. Methodology/Principal Findings Based on a broad spatial sampling of Radix spp. on the Tibetan Plateau, and phylogenetic analyses of mtDNA sequence data, three probably endemic and one widespread major Radix clade could be identified on the plateau. Two of the endemic clades show a remarkably high genetic diversity, indicating a relatively great phylogenetic age. Phylogeographical analyses of individuals belonging to the most widely distributed clade indicate that intra-plateau distribution cannot be explained by drainage-related dispersal alone. Conclusions/Significance Our study reveals that Radix spp. persisted throughout the LGM on the Tibetan Plateau. Therefore, we assume the continuous existence of suitable water bodies during that time. The extant Radix diversity on the plateau might have been caused by multiple colonization events combined with a relatively long intra-plateau evolution. At least one colonization event has a Palaearctic origin. In contrast to freshwater fishes, passive dispersal, probably by water birds, might be an important mechanism for conquering remote areas on the plateau. Patterns found in Radix spp. are shared with some terrestrial plateau taxa, indicating that Radix may be a suitable model taxon for inferring general patterns of biotic origin, dispersal and

High-Resolution Regional Phase Attenuation Models of the Iranian Plateau and Surrounding Regions

Science.gov (United States)

2014-03-03

crustal structure or sediment thickness across much of the Iranian plateau. The lone exception is the region between the central Zagros and the Lut block...L11303, 2007. Meunier, P., N. Hovius, and J. A. Haines, Topographic site effects and the location of earthquake induced landslides, Earth Planet . Sci

New Hf-Nd evidence supports a heterogeneous plume source for the Caribbean Plateau

International Nuclear Information System (INIS)

Thompson, P.M.E; Kempton, P.D; White, R.V; Kerr, A.C; Tarney, J.; Sauders, A.D

2001-01-01

Hf-Nd systematics provide us with a valuable tool for tracing mantle sources and signatures in ancient or altered rocks. Hf and Nd are amongst the most resistant of all elements to secondary alteration processes (Pearce et al., 1999) and hence can give us insights into the source compositions of altered plateau basalts that other isotopic systems will not. Here we use Hf-Nd systematics to probe the depths of the Cretaceous Caribbean Plateau, in order to characterise its isotope systematics, and hence determine the geochemical nature of the mantle plume responsible for its formation. Much of the plateau is already well characterised in terms of trace elements and isotopes such as Sr, Nd, Pb and Os (Kerr et al., 1997; White et al., 1999; Walker et al., 1999). Unfortunately, isotope system resetting due to sub- solidus alteration, amongst other factors, has ensured that these isotopes have been inconclusive in resolving many important issues, such as whether the Caribbean plateau is a product of an earlier Galapagos plume phase, and how the apparently unique Gorgona komatiites relate to the rest of the Caribbean plateau. We present new Hf-Nd isotopic data which reveal that the Caribbean plume must have been compositionally heterogeneous, comprising at least three different source components. We then compare this 'Caribbean plume' to other present-day plumes, (e.g. Galapagos) and from this speculate whether initial magmatism from the Galapagos plume could indeed have been responsible for the formation of the Caribbean Plateau (au)

Effects of temperature anisotropy on neoclassical transport in the plateau and banana-plateau regimes

International Nuclear Information System (INIS)

Taguchi, Masayoshi

1999-01-01

The neoclassical transport theory in a presence of temperature anisotropy is investigated in the low to the intermediate collision frequency regimes for a large aspect-ratio tokamak plasma. The standard procedure for an isotropic plasma in the plateau regime is extended to an anisotropic plasma, and the neoclassical transport coefficients in this regime are explicitly calculated. By interpolating the results in the plateau regime and the previously obtained ones in the banana regime, the expressions for the neoclassical transport coefficients which are continuously valid from the banana to the plateau regimes are presented. (author)

PLATEAU IRIS – DIAGNOSIS AND TREATMENT

Science.gov (United States)

Stefan, Cornel; Iliescu, Daniela Adriana; Batras, Mehdi; Timaru, Cristina Mihaela; De Simone, Algerino

2015-01-01

Objectives: The objective of our study was to review the current knowledge on the diagnosis and treatment options of plateau iris configuration and syndrome. Systematic review methodology: Relevant publications on plateau iris that were published until 2014. Conclusions: Plateau iris syndrome is a form of primary angle closure glaucoma caused by a large or anteriorly positioned ciliary body that leads to mechanical obstruction of trabecular meshwork. This condition is most often found in younger patients. Plateau iris has been considered an abnormal anatomic variant of the iris that can be diagnosed on ultrasound biomicroscopy or optical coherence tomography of anterior segment. Patients with plateau iris syndrome can be recognized by the lack of response in angle opening after iridotomy. The treatment of choice in these cases is argon laser peripheral iridoplasty PMID:27373109

Collision-induced post-plateau volcanism: Evidence from a seamount on Ontong Java Plateau

Science.gov (United States)

Hanyu, Takeshi; Tejada, Maria Luisa G.; Shimizu, Kenji; Ishizuka, Osamu; Fujii, Toshiyuki; Kimura, Jun-Ichi; Chang, Qing; Senda, Ryoko; Miyazaki, Takashi; Hirahara, Yuka; Vaglarov, Bogdan S.; Goto, Kosuke T.; Ishikawa, Akira

2017-12-01

Many seamounts on the Ontong Java Plateau (OJP) occur near the Stewart Arch, a topographic high that extends parallel to the North Solomon Trench along the southern margins of the plateau. Despite the thick sediment cover, several volcanic cones with strong acoustic reflection were discovered on the submarine flank of the Nuugurigia Seamount. From such volcanic cones, basalts were successfully sampled by dredging. Radiometric dating of basalts and ferromanganese encrustation indicate eruption age of 20-25 Ma, significantly younger than the 122 Ma main OJP plateau and post-plateau basalts. The age range coincides with the collision of the OJP with the Solomon Arc. The Nuugurigia basalts geochemically differ from any other rocks sampled on the OJP so far. They are alkali basalts with elevated Sr, low Zr and Hf, and Enriched Mantle-I (EMI)-like isotopic composition. Parental magmas of these alkali basalts may have formed by small-degree melting of peridotitic mantle impregnated with recycled pyroxenite material having enriched geochemical composition in the OJP's mantle root. We conclude that small-volume alkali basalts from the enriched mantle root migrated through faults or fractures caused by the collision along the Stewart Arch to form the seamount. Our results suggest that the collision of the OJP with the Solomon arc played an important role in the origin of similar post-plateau seamounts along the Stewart Arch.

Prevalence of sickle cell disease among children attending plateau specialist hospital, Jos, Nigeria

Directory of Open Access Journals (Sweden)

Nanbur Stephen

2018-01-01

Full Text Available Background: An estimate of 250,000 children are born annually with sickle cell disease (SCD worldwide and 75%–85% of the affected children are born in Africa; where mortality rates for those under age 5 years range from 50% to 80%. Objective: The present study was conducted to estimate the prevalence of SCD among children in Plateau State Specialist Hospital (PSSH, Jos, Nigeria. Methodology: Ethical approval was obtained from the Health Research Ethics Committee of the Hospital. Secondary data on age, gender, and region from the case notes of infants, children and/or adolescents; who received medical care in PSSH from 2012 to 2014 were used. Data were analyzed using frequency tables and Chi-square statistics. Results: The findings revealed that the prevalence of SCD in PSSH, Jos from 2012 to 2014 was 26.9/1000 population of pediatric patients. There was a gradual increase in the prevalence rate from 25.8/1000 in 2012 to 26.8/1000 in 2013 and 28.1/1000 in 2014. However, the case fatality rate of SCD gradually decreased from 15.4% in 2012 to 11.1% in 2013 and 10.3% in 2014. Chi-square test shows that the prevalence of the disease in relation to sex, age, and residence was not statistically significant (P > 0.05. Even though the case fatality rate of the disease decreased, its prevalence increased during the study. Conclusion: Therefore, preventive measure for SCD such as premarital genetic screening and counseling should be emphasized, especially in the southern and central geopolitical zones of Plateau state, where the prevalence was found to be higher.

Paleocene Pacific Plate reorganization mirrored in formation of the Suvarov Trough, Manihiki Plateau

Science.gov (United States)

Pietsch, Ricarda; Uenzelmann-Neben, Gabriele

2016-10-01

The Suvarov Trough is a graben structure that deviates from the Danger Islands Troughs within the Manihiki Plateau, a Large Igneous Province (LIP) located in the Central Pacific. New high-resolution seismic reflection data provide evidence that the graben formed in two phases during the Paleocene (65-45 Ma). In a first phase extension occurred in southwestward direction, pulling apart the northern part of the Suvarov Trough and a parallel trending unnamed trough. In a second phase a change of extensional force direction occurred from southwest to west-northwest, forming the southern part of the Suvarov Trough that extends onto the High Plateau. The formation of the Suvarov Trough is accompanied by a series of normal fault systems that apparently formed simultaneously. Comparing the seismic results to existing Pacific paleo strain reconstructions, the timing of increased strain and local deformation direction fits well to our findings. We thus suggest that the multiple strike directions of the Suvarov Trough represent an extensional structure that was caused by the major, stepwise Pacific Plate reorganization during the Paleocene.

Cyprininae phylogeny revealed independent origins of the Tibetan Plateau endemic polyploid cyprinids and their diversifications related to the Neogene uplift of the plateau.

Science.gov (United States)

Wang, Xuzhen; Gan, Xiaoni; Li, Junbing; Chen, Yiyu; He, Shunping

2016-11-01

Origin and diversification of the Tibetan polyploid cyprinids (schizothoracins) may help us to explore relationships between diversification of the cyprinids and the Tibetan Plateau uplift. Cyprininae phylogeny was analyzed using mitochondrial and nuclear DNA sequences to trace origins of polyploidy and diversifications of schizothoracins. Ancestral states reconstruction for ploidy levels indicated that the Cyprininae was diploid origin and the schizothoracin clades tetraploid origins. There were two diversification rate shifts along with diversification of the cyprinine fishes in response to the Tibetan uplift. The unusual diversification shifts were located to branches subtending the clades of Tibetan polyploid cyprinids. Our analyses suggested that (i) phylogeny of Cyprininae recovered two independent origins of the Tibetan polyploidy schizothoracins; (ii) diversifications of the schizothoracins were closely related to the Neogene uplift of the Tibetan plateau in the following ways: the relatively ancient Late Oligocene-Middle Miocene adaptive radiation may be associated with the uplift of the southern Tibet and Himalaya; the Middle Miocene-Early Pleistocene lineage-specific diversification broadly coincident with major phase of the Neogene Tibetan uplift; and the most recent Pleistocene diversification shift in Schizothorax closely coincident with the successive Kunlun-Huanghe and Gonghe movements of the Tibetan uplift and the glaciation-induced climate oscillations on the plateau.

Cenozoic uplift of the Tibetan Plateau: Evidence from the tectonic–sedimentary evolution of the western Qaidam Basin

Directory of Open Access Journals (Sweden)

Yadong Wang

2012-03-01

Full Text Available Geologists agree that the collision of the Indian and Asian plates caused uplift of the Tibet Plateau. However, controversy still exists regarding the modes and mechanisms of the Tibetan Plateau uplift. Geology has recorded this uplift well in the Qaidam Basin. This paper analyzes the tectonic and sedimentary evolution of the western Qaidam Basin using sub-surface seismic and drill data. The Cenozoic intensity and history of deformation in the Qaidam Basin have been reconstructed based on the tectonic developments, faults growth index, sedimentary facies variations, and the migration of the depositional depressions. The changes in the sedimentary facies show that lakes in the western Qaidam Basin had gone from inflow to still water deposition to withdrawal. Tectonic movements controlled deposition in various depressions, and the depressions gradually shifted southeastward. In addition, the morphology of the surface structures in the western Qaidam Basin shows that the Cenozoic tectonic movements controlled the evolution of the Basin and divided it into (a the southern fault terrace zone, (b a central Yingxiongling orogenic belt, and (c the northern fold-thrust belt; divided by the XI fault (Youshi fault and Youbei fault, respectively. The field data indicate that the western Qaidam Basin formed in a Cenozoic compressive tectonic environment caused by the India–Asia plate collision. Further, the Basin experienced two phases of intensive tectonic deformation. The first phase occurred during the Middle Eocene–Early Miocene (Xia Ganchaigou Fm. and Shang Ganchaigou Fm., 43.8–22 Ma, and peaked in the Early Oligocene (Upper Xia Ganchaigou Fm., 31.5 Ma. The second phase occurred between the Middle Miocene and the Present (Shang Youshashan Fm. and Qigequan Fm., 14.9–0 Ma, and was stronger than the first phase. The tectonic–sedimentary evolution and the orientation of surface structures in the western Qaidam Basin resulted from the Tibetan

PLATEAUING COSMIC RAY DETECTORS TO ACHIEVE OPTIMUM OPERATING VOLTAGE

Energy Technology Data Exchange (ETDEWEB)

Knoff, E.N.; Peterson, R.S.

2008-01-01

Through QuarkNet, students across the country have access to cosmic ray detectors in their high school classrooms. These detectors operate using a scintillator material and a photomultiplier tube (PMT). A data acquisition (DAQ) board counts cosmic ray hits from the counters. Through an online e-Lab, students can analyze and share their data. In order to collect viable data, the PMTs should operate at their plateau voltages. In these plateau ranges, the number of counts per minute remains relatively constant with small changes in PMT voltage. We sought to plateau the counters in the test array and to clarify the plateauing procedure itself. In order to most effectively plateau the counters, the counters should be stacked and programmed to record the number of coincident hits as well as their singles rates. We also changed the threshold value that a signal must exceed in order to record a hit and replateaued the counters. For counter 1, counter 2, and counter 3, we found plateau voltages around 1V. The singles rate plateau was very small, while the coincidence plateau was very long. The plateau voltages corresponded to a singles rate of 700–850 counts per minute. We found very little effect of changing the threshold voltages. Our chosen plateau voltages produced good performance studies on the e-Lab. Keeping in mind the nature of the experiments conducted by the high school students, we recommend a streamlined plateauing process. Because changing the threshold did not drastically affect the plateau voltage or the performance study, students should choose a threshold value, construct plateau graphs, and analyze their data using a performance study. Even if the counters operate slightly off their plateau voltage, they should deliver good performance studies and return reliable results.

Neoclassical resonant-plateau transport in the noncircular equipotential surface of a tandem mirror

International Nuclear Information System (INIS)

Katanuma, I.; Kiwamoto, Y.; Ishii, K.; Yatsu, K.; Miyoshi, S.

1989-01-01

Neoclassical resonant-plateau transport in a minimum-B anchored tandem mirror is calculated in an experimentally observed case where a flux tube of equipotential contours is not circular at the central cell

Control of electron localization to isolate and enhance molecular harmonic plateau in asymmetric HeH2+ system

International Nuclear Information System (INIS)

Lu, Ruifeng; Yu, Chao; Wang, Yunhui; Shi, Qi; Zhang, Yadong

2014-01-01

High-order harmonic generation from the asymmetric molecular ion HeH 2+ exposed to intense laser fields was investigated by quantum wave packet calculations in which the initial wave packet of HeH 2+ was prepared in the first excited 2pσ state. The calculated molecular harmonic plateau at low frequencies was effectively isolated and enhanced by adjusting the carrier-envelope phase (CEP) of the laser field. Furthermore, double-well model, time-dependent electronic density, electronic state population, and time-frequency analyses were presented to explain the underlying mechanism of the efficient isolated molecular plateau. By taking advantage of the CEP effect to control the electronic dynamics, this isolated molecular plateau can be used to generate high-intensity single attosecond pulses.

Modification of potentially lethal damage in irradiated Chinese hamster V79 cells after incorporation of halogenated pyrimidines

NARCIS (Netherlands)

Franken, N. A.; van Bree, C. V.; Kipp, J. B.; Barendsen, G. W.

1997-01-01

Radiosensitization of exponentially growing and plateau phase Chinese hamster V79 cells by incorporation of halogenated pyrimidines (HP) was investigated for different culture conditions that influenced repair. For this purpose cells were grown for 72 h with 0, 1, 2 and 4 microM of chloro-(CldUrd),

Cell cycle phases in the unequal mother/daughter cell cycles of Saccharomyces cerevisiae.

Science.gov (United States)

Brewer, B J; Chlebowicz-Sledziewska, E; Fangman, W L

1984-11-01

During cell division in the yeast Saccharomyces cerevisiae mother cells produce buds (daughter cells) which are smaller and have longer cell cycles. We performed experiments to compare the lengths of cell cycle phases in mothers and daughters. As anticipated from earlier indirect observations, the longer cell cycle time of daughter cells is accounted for by a longer G1 interval. The S-phase and the G2-phase are of the same duration in mother and daughter cells. An analysis of five isogenic strains shows that cell cycle phase lengths are independent of cell ploidy and mating type.

Quantum critical behaviour of the plateau-insulator transition in the quantum Hall regime

International Nuclear Information System (INIS)

Visser, A de; Ponomarenko, L A; Galistu, G; Lang, D T N de; Pruisken, A M M; Zeitler, U; Maude, D

2006-01-01

High-field magnetotransport experiments provide an excellent tool to investigate the plateau-insulator phase transition in the integral quantum Hall effect. Here we review recent low-temperature high-field magnetotransport studies carried out on several InGaAs/InP heterostructures and an InGaAs/GaAs quantum well. We find that the longitudinal resistivity ρ xx near the critical filling factor ν c ∼ 0.5 follows the universal scaling law ρ xx (ν, T) ∝ exp(-Δν/(T/T 0 ) κ ), where Δν = ν-ν c . The critical exponent κ equals 0.56 ± 0.02, which indicates that the plateau-insulator transition falls in a non-Fermi liquid universality class

Vertebrate Fossils Imply Paleo-elevations of the Tibetan Plateau

Science.gov (United States)

Deng, T.; Wang, X.; Li, Q.; Wu, F.; Wang, S.; Hou, S.

2017-12-01

The uplift of the Tibetan Plateau remains unclear, and its paleo-elevation reconstructions are crucial to interpret the geodynamic evolution and to understand the climatic changes in Asia. Uplift histories of the Tibetan Plateau based on different proxies differ considerably, and two viewpoints are pointedly opposing on the paleo-elevation estimations of the Tibetan Plateau. One viewpoint is that the Tibetan Plateau did not strongly uplift to reach its modern elevation until the Late Miocene, but another one, mainly based on stable isotopes, argues that the Tibetan Plateau formed early during the Indo-Asian collision and reached its modern elevation in the Paleogene or by the Middle Miocene. In 1839, Hugh Falconer firstly reported some rhinocerotid fossils collected from the Zanda Basin in Tibet, China and indicated that the Himalayas have uplifted by more than 2,000 m since several million years ago. In recent years, the vertebrate fossils discovered from the Tibetan Plateau and its surrounding areas implied a high plateau since the late Early Miocene. During the Oligocene, giant rhinos lived in northwestern China to the north of the Tibetan Plateau, while they were also distributed in the Indo-Pakistan subcontinent to the south of this plateau, which indicates that the elevation of the Tibetan Plateau was not too high to prevent exchanges of large mammals; giant rhinos, the rhinocerotid Aprotodon, and chalicotheres still dispersed north and south of "Tibetan Plateau". A tropical-subtropical lowland fish fauna was also present in the central part of this plateau during the Late Oligocene, in which Eoanabas thibetana was inferred to be closely related to extant climbing perches from South Asia and Sub-Saharan Africa. In contrast, during the Middle Miocene, the shovel-tusked elephant Platybelodon was found from many localities north of the Tibetan Plateau, while its trace was absent in the Siwaliks of the subcontinent, which implies that the Tibetan Plateau had

Neoclassical resonant-plateau transport in the noncircular equipotential surface of a tandem mirror

International Nuclear Information System (INIS)

Katanuma, I.; Kiwamoto, Y.; Ishii, K.; Yatsu, K.; Miyoshi, S.

1988-07-01

Neoclassical resonant-plateau transport in a minimum-B anchored tandem mirror is calculated in an experimentally observed case that a magnetic flux tube of an equipotential contours is not circular at the central cell. (author)

Prehistoric human settling on the Tibetan Plateau

Science.gov (United States)

Chen, F.; Zhang, D.; Dong, G.; Xia, H.

2017-12-01

When and where did human first settle down on the Tibetan Plateau is under hot debate among archaeologist, anthropologists, geneticist and paleo-geographers. Based on systematic archaeological, chronological and archaeo-botanical studies of 53 sites in Northeastern Tibetan Plateau, we propose that agriculture facilitated human permanent settlement on the Tibetan Plateau initially since 5200 years ago below 2500 masl and since 3600 years ago up to around 4000 masl, possibly assisted by domesticated animals (Chen et al. 2015). By redating the age of hand- and footprints in Chusang site in Tibet, Meyer et al. (2017) argue that hunter-gatherers permanently occupied central Tibetan Plateau in early Holocene (before 7.4 ka) without the help of agriculture. Except for the possible problem of dating, however, the limited hand- and footprints could only indicate the presence of prehistoric hunter-gatherers on the remote central Tibetan Plateau in the early Holocene, unable to support the permanent inhabitation assertion (Zhang et al., 2017). To better understand how human spread to, settle on and adapt to the Tibetan Plateau, we are closely working together with anthropologists, archaeologists and geneticists to do system Paleolithic surveys, full excavations, and genetic analysis of ancient and modern human, animals and plants. Our preliminary study show that human migrated to the Tibetan Plateau from the last Deglacial period to late Holocene mainly from North China via Yellow River valley and its tributary valleys in the Northeastern Tibetan Plateau (NETP). This migration is constituted of four stages (Upper Paleolithic, Epi-Paleolithic, Neolithic and Bronze Age) with different adaptation strategies, including microlithic technology, millet and barley farming, and sheep herding and so on (Zhang et al., 2016). In addition, our new finds in Tibet indicate that there are probably more migration routes from southeast and southwest Tibetan Plateau in the late Pleistocene or

PLD-Repair after ''holding'' of rodent cell cultures: A critical annotation

International Nuclear Information System (INIS)

Stevenson, A.F.G.; Lange, C.S.

1987-01-01

The radiosensitivity of cells in vitro has been reported to be influenced by culture-conditions both before and after exposure to ionising radiations. The effect of ''Stationary-Holding'' and/or delayed plating on the repair of potentially lethal damage (PLDR) are such examples. The so-called Stationary or Plateau-Phase of commonly used cell lines like the V79 are often quiescent (non-mitotic). The authors analysis of the V79 ''Plateau-Phase'' (S-phase cytocide through VrUdR incorporation with FuDR block and light exposure) reveals that the cultures have merely reached a state of maximal permissible density and are, in fact, in kinetic equilibrium with at least half the population of cells, even in densely confluent cultures, going through cycle. Attempts at holding the cells from cycling (through nutrient-depletion and serum-privation) were unsuccessful, although the turn-over-rate was reduced. Their assays for X-irradiated clonogenic survivors after attempted holding combined with delayed plating (DP) showed differences in the survival curves for exponentially growing (Log) and confluent cultures, Although DP improved survival in general, it abolished the shoulder in Log cultures. These observations may explain why most PLDR is seen in the second and lower survival-decades. The significance of the persistent cycling fraction in the interpretation of PLDR after delayed plating must be considered

Orogenic plateau growth: Expansion of the Turkish-Iranian Plateau across the Zagros fold-and-thrust belt

Science.gov (United States)

Allen, M. B.; Saville, C.; Blanc, E. J.-P.; Talebian, M.; Nissen, E.

2013-03-01

This paper shows how the Turkish-Iranian Plateau grows laterally by incrementally incorporating adjacent parts of the Zagros fold-and-thrust belt. The limit of significant, seismogenic, thrusting in the Zagros (Mw > 5) occurs close to the regional 1250 m elevation contour. The seismicity cutoff is not a significant bedrock geology boundary. Elevations increase northward, toward regional plateau elevations of 2 km, implying that another process produced the extra elevation. Between the seismogenic limit of thrusting and the suture, this process is a plausibly ductile thickening of the basement, suggesting depth-dependent strain during compression. Similar depth-dependant crustal strain may explain why the Tibetan plateau has regional elevations 1500 m greater than the elevation limit of seismogenic thrusting at its margins. We estimate 68 km shortening across the Zagros Simply Folded Belt in the Fars region, and 120 km total shortening of the Arabian plate. The Dezful Embayment is a low strain zone in the western Zagros. Deformation is more intense to its northeast, in the Bakhtyari Culmination. The orogenic taper (across strike topographic gradient) across the Dezful Embayment is 0.0004, and across the Bakhtyari Culmination, 0.022. Lateral plateau growth is more pronounced farther east (Fars), where a more uniform structure has a taper of 0.010 up to elevations of 1750 m. A >100 km wide region of the Zagros further northeast has a taper of 0.002 and is effectively part of the Turkish-Iranian Plateau. Internal drainage enhances plateau development but is not a pre-requisite. Aspects of the seismicity, structure, and geomorphology of the Zagros do not support critical taper models for fold-and-thrust belts.

CENTRAL PLATEAU REMEDIATION OPTIMIZATION STUDY

Energy Technology Data Exchange (ETDEWEB)

BERGMAN, T. B.; STEFANSKI, L. D.; SEELEY, P. N.; ZINSLI, L. C.; CUSACK, L. J.

2012-09-19

THE CENTRAL PLATEAU REMEDIATION OPTIMIZATION STUDY WAS CONDUCTED TO DEVELOP AN OPTIMAL SEQUENCE OF REMEDIATION ACTIVITIES IMPLEMENTING THE CERCLA DECISION ON THE CENTRAL PLATEAU. THE STUDY DEFINES A SEQUENCE OF ACTIVITIES THAT RESULT IN AN EFFECTIVE USE OF RESOURCES FROM A STRATEGIC PERSPECTIVE WHEN CONSIDERING EQUIPMENT PROCUREMENT AND STAGING, WORKFORCE MOBILIZATION/DEMOBILIZATION, WORKFORCE LEVELING, WORKFORCE SKILL-MIX, AND OTHER REMEDIATION/DISPOSITION PROJECT EXECUTION PARAMETERS.

Functional-trait ecology of the plateau pika Ochotona curzoniae (Hodgson, 1858) in the Qinghai-Tibetan Plateau ecosystem.

Science.gov (United States)

Smith, Andrew T; Badingqiuying; Wilson, Maxwell C; Hogan, Brigitte W

2018-01-09

Understanding a species' functional traits allows for a directed and productive perspective on the role a species plays in nature, thus its relative importance to conservation planning. The functional trait ecology of the plateau pika Ochotona curzoniae (Hodgson, 1858) is examined to better understand the resilience and sustainability of the high alpine grasslands of the Qinghai-Tibetan Plateau (QTP). The key functional traits of plateau pikas are their abundance and behavior of digging extensive burrow systems. Plateau pikas have been poisoned over a significant part of their original geographic distribution across the QTP, allowing comparison of ecological communities with and without pikas. Nearly all mammalian and avian carnivores, most of which are obligate predators on pikas, have been lost in regions where pikas have been poisoned. Most endemic birds on the QTP nest in pika burrows; when pikas are poisoned, burrows collapse, and these birds are greatly reduced in number. Due to the biopedturbation resulting from their burrows, regional plant species richness is higher in areas with pikas than without. The presence of pika burrows allows higher rates of infiltration during heavy monsoon rains compared to poisoned areas, possibly mitigating runoff and the potential for serious downslope erosion and flooding. Thus the functional traits of plateau pikas enhance native biodiversity and other important ecosystem functions; these traits are irreplaceable. As plateau pikas are not natural colonizers, active re-introduction programs are needed to restore pikas to areas from which they have been poisoned to restore the important functional ecological traits of pikas. This article is protected by copyright. All rights reserved.

The Hikurangi Plateau: Tectonic Ricochet and Accretion

Science.gov (United States)

Willis, David; Moresi, Louis; Betts, Peter; Whittaker, Joanne

2015-04-01

80 million years between interactions with different subduction systems provided time for the Hikurangi Plateau and Pacific Ocean lithosphere to cool, densify and strengthen. Neogene subduction of the Hikurangi Plateau occurring orthogonal to its Cretaceous predecessor, provides a unique opportunity to explore how changes to the physical properties of oceanic lithosphere affect subduction dynamics. We used Underworld to build mechanically consistent collision models to understand the dynamics of the two Hikurangi collisions. The Hikurangi Plateau is a ~112 Ma, 15km thick oceanic plateau that has been entrained by subduction zones immediately preceding the final break-up of Eastern Gondwana and currently within the active Hikurangi Margin. We explore why attempted subduction of the plateau has resulted in vastly different dynamics on two separate occasions. Slab break-off occured during the collision with Gondwana, currently there is apparent subduction of the plateau underneath New Zealand. At ~100Ma the young, hot Hikurangi Plateau, positively buoyant with respect to the underlying mantle, impacted a Gondwana Margin under rapid extension after the subduction of an mid-ocean ridge 10-15Ma earlier. Modelling of plateaus within young oceanic crust indicates that subduction of the thickened crust was unlikely to occur. Frontal accretion of the plateau and accompanying slab break-off is expected to have occured rapidly after its arrival. The weak, young slab was susceptible to lateral propagation of the ~1500 km window opened by the collision, and break-off would have progressed along the subduction zone inhibiting the "step-back" of the trench seen in older plates. Slab break-off coincided with a world-wide reorganisation of plate velocites, and orogenic collapse along the Gondwana margin characterised by rapid extension and thinning of the over-riding continental plate from ~60 to 30km. Following extension, Zealandia migrated to the NW until the Miocene allowing the

Heat flow in the north-central Colorado Plateau

International Nuclear Information System (INIS)

Bodell, J.M.; Chapman, D.S.

1982-01-01

We report new heat flow measurements at 25 evenly distributed sites in the north-central Colorado Plateau. Heat flow values computed for these new sites and one previously published site range from 43 to 116 mW m -2 but fall into the following district subsets related to physiographic and tectonic elements within the Plateau: (1) heat flow of 51 mW m -2 (12 sites; s.d. 6) in the San Rafael Swell and Green River Desert which constitute the core of the Colorado Plateau at this latitude, (2) heat flows of 69 mW m -2 (5 sites; s.d. 10) in successive parallel north-south bands approaching the Wasatch Plateau to the west but still 80 km east of the Basin and Range physiographic boundary, (3) heat flow of 64 mW m -2 (5 sites; s.d. 2) along the Salt Anticline trend which strikes northwest in the region of Moab, Utah. Heat flow results for the entire Colorado Plateau have been reexamined in view of our new results, and the overall pattern supports the concept of a low heat flow 'thermal interior' for the plateau surrounded by a periphery some 100 km wide having substantially higher heat flow. Average heat flow in the thermal interior is about 60 mW m -2 compared to 80--90 mW m -2 in the periphery. This regional heat flow pattern supports a model of tertiary lithospheric thinning under the Colorado Plateau whereby the plateau is still in transient thermal response and a 15--20 m.y. lag between uplift and corresponding surface heat flow anomaly is to be expected. The position of the heat flow transition between our interior and peripheral regions in the northwest plateau is roughly consistent with lateral warming and weakening of the Colorado Plateau lithosphere initiated at the Basin and Range boundary some 20 m.y. ago

An avifaunal case study of a plateau from Goa, India: an eye opener for conservation of plateau ecosystems

Directory of Open Access Journals (Sweden)

Minal Desai

2012-03-01

Full Text Available The lateritic plateaux typical of the midlands between the Western Ghats and the coastal plains of the Arabian Sea are known to be a unique ecosystem with a sizeable endemic flora. However, there is a total lack of studies on the faunal diversity of these plateaux, which are currently experiencing enormous anthropogenic pressures. We conducted a year-long study on the avifauna of the Taleigao Plateau, Goa. The Taleigao Plateau harbours 114 species of birds, accounting for 37% of the avifaunal diversity of the state. The resident bird population did not vary significantly through the seasons. Among the migrant birds, Rosy Starling Sturnus roseus was particularly partial to the plateau. Besides, five species of larks, grassland specialists were also recorded on the plateau. However, the absence of forest birds like the Malabar Pied Hornbill and the Indian Grey Hornbill (recorded earlier and the predominance of habitat generalists like the House Crow and the Jungle Myna seemed to be the offshoot of heavy anthropogenic pressures on the plateau. It is recommended that at least some plateaux in the belt deserve to be protected from the impact of unsustainable developmental process

In vitro holding and PLD-repair. Pt. 2

International Nuclear Information System (INIS)

Stevenson, A.F.G.; Palackal, T.; Lange, C.S.

1989-01-01

The repair of potentially lethal damage (PLDR) in mammalian cells is expected to be better in quiescent cultures since PLD is supposedly fixed during cycle progression. Plateau phase cultures, therefore, serve as models because of assumed mitotic quiescence. Four established cell lines (V79, CHO, L5178Y and HELA) and one euploid cell strain IMR-90 have been analysed by flow cytometry and electron microscopy to address questions on quiescence in the plateau phase and the effect of holding (induction of quiescence by nutrient privation). In contrast to commonly held views, our results indicate that the quiescent fraction in cultures from transformed cells is exceedingly low (1% or less). Plateau phase cultures of transformed cells are constantly turning over. Euploid cells like the IMR-90 show true quiescence in the plateau phase. Holding causes typical cytopathological changes. These changes have been ultrastructurely characterised. Resistant sub-populations of cells can be selected out under holding-conditions. Such selected cells show completely different radiobiological characteristics, which raise questions on the interpretation of data on PLDR. (orig.)

Effect of neon ions on synchronized Chinese hamster cells

International Nuclear Information System (INIS)

Raju, M.R.; Carpenter, S.G.; Tokita, N.; Howard, J.

1985-01-01

The variation in radiosensitivity across the cell cycle after exposure to neon ions and 60 Co γ-rays is reported for cultured hamster cells. The cells were first synchronized by mitotic selection, then resynchronized in the region of the G 1 /S boundary by treatment with 10 -3 M hydroxyurea. Although the use of hydroxyurea improves the synchrony, it does sensitize cells at the G 1 /S boundary to some degree. The cells were exposed at the plateau and the distal peak position of a neon ion beam modified by a 10 cm wide ridge filter. The results indicate that the variation (ratio of maximum to minimum survival after fixed doses of radiation that are approximately matched to produce similar cell killing) was approximately 80 to 100-fold for 60 Co γ-rays and neon ions at the plateau, and 25-fold for distal peak neon ions. While the r.b.e. of distal peak neon ions decreased rapidly with increasing dose for cells in late S-phase, the r.b.e. is independent of dose for cells at the G 1 /S boundary. (author)

Effect of neon ions on synchronized Chinese hamster cells

Energy Technology Data Exchange (ETDEWEB)

Raju, M.R.; Carpenter, S.G.; Tokita, N. (Los Alamos National Lab., NM (USA)); Howard, J. (Lawrence Berkeley Lab., CA (USA))

1985-08-01

The variation in radiosensitivity across the cell cycle after exposure to neon ions and /sup 60/Co ..gamma..-rays is reported for cultured hamster cells. The cells were first synchronized by mitotic selection, then resynchronized in the region of the G/sub 1//S boundary by treatment with 10/sup -3/ M hydroxyurea. Although the use of hydroxyurea improves the synchrony, it does sensitize cells at the G/sub 1//S boundary to some degree. The cells were exposed at the plateau and the distal peak position of a neon ion beam modified by a 10 cm wide ridge filter. The results indicate that the variation (ratio of maximum to minimum survival after fixed doses of radiation that are approximately matched to produce similar cell killing) was approximately 80 to 100-fold for /sup 60/Co ..gamma..-rays and neon ions at the plateau, and 25-fold for distal peak neon ions. While the r.b.e. of distal peak neon ions decreased rapidly with increasing dose for cells in late S-phase, the r.b.e. is independent of dose for cells at the G/sub 1//S boundary.

Radiation biophysical studies with mammalian cells and a modulated carbon ion beam

International Nuclear Information System (INIS)

Chapman, J.D.; Blakely, E.A.; Smith, K.C.; Urtasun, R.C.; Lyman, J.T.; Tobias, C.A.

1978-01-01

Chinese hamster (V-79) and human kidney (T-1) cells were irradiated in stirred suspensions placed at various positions in the plateau and extended Bragg peak of a 400-MeV/amu carbon ion beam. The range of the ions was modulated by a lead (translational) ridge filter and a brass (spiral) ridge filter designed to produce extended peaks of approximately 4 and 10 cm, respectively. Stationary-phase and G 1 -phase populations of Chinese hamster cells were found to have different absolute radiosensitivities which, in turn, were different from that of asynchronous human kidney cells. The increase in relative biological effectiveness (RBE) observed as carbon ions were slowed down and stopped in water was similar for the three cell populations at doses greater than 400 rad. At lower doses the RBE was greater for the hamster cell populations than for the human kidney cells. The gain in RBE (at the 50% survival level) between the plateaus and the middle region of the extended peaks was approximately 2.0 and 1.7 for the 4- and 10-cm extended peaks, respectively. Oxygen enhancement ratios (OER) were determined at the 10% survival levels with stationary-phase populations of hamster cells. Values of 2.8, 2.65, and 1.65 were obtained for the OER of 220-kV x rays, plateau carbon, and the middle region of the 4-cm carbon peak, respectively. Across the 10-cm carbon peak the OER was found to vary between values of 2.4 to 1.55 from the proximal to distal positions

Colorado Plateau magmatism and uplift by warming of heterogeneous lithosphere.

Science.gov (United States)

Roy, Mousumi; Jordan, Thomas H; Pederson, Joel

2009-06-18

The forces that drove rock uplift of the low-relief, high-elevation, tectonically stable Colorado Plateau are the subject of long-standing debate. While the adjacent Basin and Range province and Rio Grande rift province underwent Cenozoic shortening followed by extension, the plateau experienced approximately 2 km of rock uplift without significant internal deformation. Here we propose that warming of the thicker, more iron-depleted Colorado Plateau lithosphere over 35-40 Myr following mid-Cenozoic removal of the Farallon plate from beneath North America is the primary mechanism driving rock uplift. In our model, conductive re-equilibration not only explains the rock uplift of the plateau, but also provides a robust geodynamic interpretation of observed contrasts between the Colorado Plateau margins and the plateau interior. In particular, the model matches the encroachment of Cenozoic magmatism from the margins towards the plateau interior at rates of 3-6 km Myr(-1) and is consistent with lower seismic velocities and more negative Bouguer gravity at the margins than in the plateau interior. We suggest that warming of heterogeneous lithosphere is a powerful mechanism for driving epeirogenic rock uplift of the Colorado Plateau and may be of general importance in plate-interior settings.

Computed tomography of tibial plateau fractures

International Nuclear Information System (INIS)

Rafii, M.; Firooznia, H.; Golimbu, C.; Bonamo, J.

1984-01-01

Twenty patients with tibial plateau fractures were studied by conventional tomography and computed tomography (CT) in order to determine the role and feasibility of CT in management of such patients. CT resulted in less discomfort to the patient and provided optimal visualization of the plateau defect and the split fragments. It proved more accurate than conventional tomography in assessing depressed and split fractures when they involved the anterior or posterior border of the plateau and in demonstrating the extent of fracture comminution. Split fragments with an oblique plane of fracture also were seen better by CT. The degree of fracture depression and separation as measured by the computerized technique was often more accurate than measurements obtained from conventional tomograms

Susceptibility of Hep3B cells in different phases of cell cycle to tBid.

Science.gov (United States)

Ma, Shi-Hong; Chen, George G; Ye, Caiguo; Leung, Billy C S; Ho, Rocky L K; Lai, Paul B S

2011-01-01

tBid is a pro-apoptotic molecule. Apoptosis inducers usually act in a cell cycle-specific fashion. The aim of this study was to elucidate whether effect of tBid on hepatocellular carcinoma (HCC) Hep3B cells was cell cycle phase specific. We synchronized Hep3B cells at G0/G1, S or G2/M phases by chemicals or flow sorting and tested the susceptibility of the cells to recombinant tBid. Cell viability was measured by MTT assay and apoptosis by TUNEL. The results revealed that tBid primarily targeted the cells at G0/G1 phase of cell cycle, and it also increased the cells at the G2/M phase. 5-Fluorouracil (5-FU), on the other hand, arrested Hep3B cells at the G0/G1 phase, but significantly reduced cells at G2/M phase. The levels of cell cycle-related proteins and caspases were altered in line with the change in the cell cycle. The combination of tBid with 5-FU caused more cells to be apoptotic than either agent alone. Therefore, the complementary effect of tBid and 5-FU on different phases of the cell cycle may explain their synergistric effect on Hep3B cells. The elucidation of the phase-specific effect of tBid points to a possible therapeutic option that combines different phase specific agents to overcome resistance of HCC. Copyright © 2010 Elsevier B.V. All rights reserved.

Modeling and analysis of LiFePO4/Carbon battery considering two-phase transition during galvanostatic charging/discharging

International Nuclear Information System (INIS)

Li, Xueyan; Xiao, Meng; Choe, Song-Yul; Joe, Won Tae

2015-01-01

Highlights: • Reduced order model for LiFePO 4 particles considering two-phase transition • Model validation with experimental results of current and voltage • Analysis of two-phase transition and path dependence - Abstract: Batteries with lithium iron phosphate (LFP) cathode and carbon anode have shown various advantages over those with other chemistries, but the plateau and path dependence caused by the two-phase transition taking place during charging and discharging make it difficult to estimate the states of battery. Thus, based on electrochemical principles we propose a new reduced order model that has been validated against experimental data obtained during galvanostatic charging/discharging. The mechanism of the two-phase transition during lithiation and delithiation in LFP particles is approximated using a shrinking corewith a moving interface between the two phases and is described by modified diffusion equations that take into account multiple layers formed within LFP particles. The shrinking core model is integrated into a cell model developed previously, which is used to analyze the path dependence at different load profiles. The results show that the model is capable of representing the characteristics of the plateau and path dependence. Particularly, the available charge at a certain State of Charge (SOC) varies dependent upon paths to reach the SOC. When an initial SOC is reached by discharging, the cell can accept more charges during charging, while when an initial SOC is reached by charging, more charge will be available during discharging

Intracontinental Deformation in the NW Iranian Plateau and Comparisons with the Northern Margin of the Tibetan Plateau

Science.gov (United States)

Chen, L.; Jiang, M.; Talebian, M.; Wan, B.; Ai, Y.; Ghods, A.; Sobouti, F.; Xiao, W.; Zhu, R.

2017-12-01

This study investigates the intracontinental deformation and its relationship with the structure of the crust and uppermost mantle in the NW Iranian plateau by combining new seismic and geological observations, to understand how this part of the plateau deformed to accommodate the Arabia-Eurasia plate collision and how the property of the lithosphere controls the deformation pattern. In contrast to the adjacent Anatolian block that exhibits westward large-scale extrusion, the northwesternmost part of the Iranian plateau shows dispersed intracontinental deformations with the development of numerous small-scale and discontinuous right-lateral strike-slip faults. The dispersed surface structures and deformation pattern correspond well to the active volcanism and seismically slow crust and uppermost mantle, and hence a weak lithosphere of the area. Further to the southeast are the western part of the Alborz Mountains and the southern Caspian Sea, both of which are characterized by stronger and more rigid lithosphere with relatively fast crust and uppermost mantle and absence of Quaternary volcanoes. A sharp Moho offset of 18 km has been imaged at the border of the Alborz and southern Caspian Sea using teleseismic receiver function data from a dense seismic array deployed under a collaborative project named "China-Iran Geological and Geophysical Survey in the Iranian Plateau (CIGSIP)". The sharp Moho offset and the minor undulations of the Moho on both sides indicate insignificant intracrustal deformation but mainly relative crustal movements between the Alborz Mountains and southern Caspian Sea, a behavior consistent with the relatively rigid nature of the lithosphere. Similar Moho offsets and lithospheric structures have been reported at the borders between the Kunlun Mountains and Qaidam or Tarim Basins in the northern margin of the Tibetan plateau, suggesting the occurrence of relative crustal movements with the effects of rigid continental lithosphere in the region

Loess Thickness Variations Across the Loess Plateau of China

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Zhu, Yuanjun; Jia, Xiaoxu; Shao, Mingan

2018-01-01

The soil thickness is very important for investigating and modeling soil-water processes, especially on the Loess Plateau of China with its deep loess deposit and limited water resources. A digital elevation map (DEM) of the Loess Plateau and neighborhood analysis in ArcGIS software were used to generate a map of loess thickness, which was then validated by 162 observations across the plateau. The generated loess thickness map has a high resolution of 100 m × 100 m. The map indicates that loess is thick in the central part of the plateau and becomes gradually shallower in the southeast and northwest directions. The areas near mountains and river basins have the shallowest loess deposit. The mean loess thickness is the deepest in the zones with 400-600-mm precipitation and decreases gradually as precipitation varies beyond this range. Our validation indicates that the map just slightly overestimates loess thickness and is reliable. The loess thickness is mostly between 0 and 350 m in the Loess Plateau region. The calculated mean loess thickness is 105.7 m, with the calibrated value being 92.2 m over the plateau exclusive of the mountain areas. Our findings provide very basic data of loess thickness and demonstrate great progress in mapping the loess thickness distribution for the plateau, which are valuable for a better study of soil-water processes and for more accurate estimations of soil water, carbon, and solute reservoirs in the Loess Plateau of China.

Happily Ever After: Plateauing as a Means for Long-Term Career Satisfaction.

Science.gov (United States)

Montgomery, Denise L.

2002-01-01

Discusses plateauing as a means for long-term career satisfaction, Highlights include a literature review; what plateauing is and why it occurs, including career-based plateauing and life plateauing; some solutions to plateauing for librarians, including management changes and individual changes; and personal examples. (LRW)

Brain blood flow studies with single photon emission computed tomography in patients with plateau waves

International Nuclear Information System (INIS)

Hayashi, Minoru; Kobayashi, Hidenori; Kawano, Hirokazu; Handa, Yuji; Noguchi, Yoshiyuki; Shirasaki, Naoki; Hirose, Satoshi

1986-01-01

The authors studied brain blood flow with single photon emission computed tomography (SPECT) in two patients with plateau waves. The intracranial pressure and blood pressure were also monitored continuously in these patients. They included one patient with brain-tumor (rt. sphenoid ridge meningioma) and another with hydrocephalus after subarachnoid hemorrhage due to rupture of lt. internal carotid aneurysm. The intracranial pressure was monitored through an indwelling ventricular catheter attached to a pressure transducer. The blood pressure was recorded through an intraarterial catheter placed in the dorsalis pedis artery. Brain blood flow was studied with Headtome SET-011 (manufactured by Shimazu Co., Ltd.). For this flow measurement study, an intravenous injection of Xenon-133 of about 30 mCi was given via an antecubital vein. The position of the slice for the SPECT was selected so as to obtain information not only from the cerebral hemisphere but also from the brain stem : a cross section 25 deg over the orbito-meatal line, passing through the inferior aspect of the frontal horn, the basal ganglia, the lower recessus of the third ventricle and the brain stem. The results indicated that, in the cerebral hemisphere, plateau waves were accompanied by a decrease in blood flow, whereas, in the brain stem, the blood flow showed little change during plateau waves as compared with the interval phase between two plateau waves. These observations may explain why there is no rise in the blood pressure and why patients are often alert during plateau waves. (author)

Technetium-99m labeled antisense probes uptake in vascular smooth muscle cells

International Nuclear Information System (INIS)

Zhang, Y.X.; Qin, G.M.; An, R.; Cao, G.X.; Cao, W.; Gao, Z.R.

2002-01-01

In the arterial wall, smooth muscle cells (SMC) normally exist in a quiescent, differentiated state, representing the contractile phenotype. During the development of atherosclerosis SMC change towards the synthetic phenotype going along with proliferation, chemotactic response and increased monocyte binding. The Fas/Fas ligand/caspase death-signaling pathway, Bcl-2 protein family/mitochondria, the tumor suppressive gene p53, and the proto-oncogene c-myc may be activated in atherosclerotic lesions, and mediates vascular apoptosis during the development of atherosclerosis. The atherosclerotic plaques contained 3-4 fold more c-myc mRNA than those in the normal aortic arteries, while increased Bax and Bak coupled with lack/paucity of Bcl-2 and Bcl-xL are associated with SMC apoptosis in advanced lesions. Methods: 1 Oligonucleotide Conjugation: A solution of single stranded amine-derivatized DNA (100-1000μg) was prepared at a concentration of 2 mg/ml in 0.25M sodium bicarbonate, 1 M sodium chloride, 1mM EDTA, pH8.5. Cell uptake studies: 99m Tc- MAG 3 -DNA radioactivity incorporation into porcine coronary smooth muscle cells in the log and plateau phases, respectively, was determined after different times of incubation at 37. The influence of extracellular 99m Tc- MAG 3 -DNA concentration on SMC uptake was also analyzed. [Results] Essentially complete conjugation was achieved by reverse-phase Sep-Pak C18 chromatography analysis. The MAG 3 -DNA was labeled with 99m Tc at room temperature and neutral pH, with a mean labeling efficiency of 80.11%(s.d=2.96%,n=4). The labeled antisense DNA still remained the ability to hybridize with its complementary DNA. After labeling, the stability of the DNA in saline or serum was retained as determined by reverse-phase Sep-Pak C18 chromatography analysis, except a shift at 30 min in serum incubation that suggesting a short time serum protein binding. 99m Tc-MAG 3 -c-myc uptake plateaued at 60 min and was directly proportional to the

Angular-dependent light scattering from cancer cells in different phases of the cell cycle.

Science.gov (United States)

Lin, Xiaogang; Wan, Nan; Weng, Lingdong; Zhou, Yong

2017-10-10

Cancer cells in different phases of the cell cycle result in significant differences in light scattering properties. In order to harvest cancer cells in particular phases of the cell cycle, we cultured cancer cells through the process of synchronization. Flow cytometric analysis was applied to check the results of cell synchronization and prepare for light scattering measurements. Angular-dependent light scattering measurements of cancer cells arrested in the G1, S, and G2 phases have been performed. Based on integral calculations for scattering intensities from 5° to 10° and from 110° to 150°, conclusions have been reached. Clearly, the sizes of the cancer cells in different phases of the cell cycle dominated the forward scatter. Accompanying the increase of cell size with the progression of the cell cycle, the forward scattering intensity also increased. Meanwhile, the DNA content of cancer cells in every phase of the cell cycle is responsible for light scattering at large scatter angles. The higher the DNA content of cancer cells was, the greater the positive effect on the high-scattering intensity. As expected, understanding the relationships between the light scattering from cancer cells and cell cycles will aid in the development of cancer diagnoses. Also, it may assist in the guidance of antineoplastic drugs clinically.

Shiga Toxin-Producing Escherichia coli in Plateau Pika (Ochotona curzoniae) on the Qinghai-Tibetan Plateau, China.

Science.gov (United States)

Bai, Xiangning; Zhang, Wang; Tang, Xinyuan; Xin, Youquan; Xu, Yanmei; Sun, Hui; Luo, Xuelian; Pu, Ji; Xu, Jianguo; Xiong, Yanwen; Lu, Shan

2016-01-01

Shiga toxin-producing Escherichia coli (STEC) are an emerging group of zoonotic pathogens. Ruminants are the natural reservoir of STEC. In this study we determined the prevalence and characteristics of the STEC in plateau pika (Ochotona curzoniae) on the Qinghai-Tibetan Plateau, China. A total of 1116 pika samples, including 294 intestinal contents samples, 317 fecal samples, and 505 intestinal contents samples, were collected from May to August in the years 2012, 2013, and 2015, respectively. Twenty-one samples (1.88%) yielded at least one STEC isolate; in total, 22 STEC isolates were recovered. Thirteen different O serogroups and 14 serotypes were identified. One stx 1 subtype (stx 1a) and three stx 2 subtypes (stx 2a, stx 2b, and stx 2d) were present in the STEC isolates. Fifteen, fourteen, and three STEC isolates harbored the virulence genes ehxA, subA, and astA, respectively. Adherence-associated genes iha and saa were, respectively, present in 72.73 and 68.18% of the STEC isolates. Twenty antibiotics were active against all the STEC isolates; all strains were resistant to penicillin G, and some to cephalothin or streptomycin. The 22 STEC isolates were divided into 16 pulsed-field gel electrophoresis patterns and 12 sequence types. Plateau pikas may play a role in the ongoing circulation of STEC in the Qinghai-Tibetan plateau. This study provides the first report on STEC in plateau pikas and new information about STEC reservoirs in wildlife. Based on the serotypes, virulence gene profiles and multi-locus sequence typing (MLST) analysis, the majority of these pika STECs may pose a low public health risk.

Chemical erosion and hydrologic budget for the Susure karst plateau

Directory of Open Access Journals (Sweden)

Nikić Zoran

2010-01-01

Full Text Available The karst plateau of Susure, about 4.5 km2 in surface area, is situated on the Jadovnik eastern offset, western Serbia. The plateau is a morphologic unit higher 15 m to 30 m than the surrounding terrain. The unit consists of crushed and karstified Middle Triassic limestones. Numerous hydrogeological and geomorphologic features of the plateau are attractive for visitors in this economically underdeveloped country. Rocks building up the surrounding terrain are largely peridotites. Surface streams flow neither into nor off the plateau. Atmospheric precipitations discharge to evapotanspiration and filtration underground. More than eighteen constant springs at the limestone/peridotite tectonic contact drain fracture aquifers on the karst plateau border. Measured precipitations and springflows were the input and output data for accounting water budget of an aquifer of Middle Triassic limestones in the Susure plateau.

The Evolution of Eastern Himalayan Syntaxis of Tibetan Plateau

Science.gov (United States)

Zhang, S.; Wu, T.; Li, M.; Zhang, Y.; Hua, Y.; Zhang, B.

2017-12-01

Indian plate has been colliding with Eurasian plate since 50Ma years ago, resulting in the Tethys extinction, crust shortening and Tibetan plateau uplift. But it is still a debate how the Tibetan Plateau material escaped. This study tries to invert the distributions of dispersion phase velocity and anisotropy in Eastern Himalayan Syntaxis (EHS) based on the seismic data. We focused on the seven sub-blocks around EHS region. Sub-block "EHS" represents EHS corner with high velocity anomalies, significantly compressed in the axle and strike directions. Sub-blocks "LSD", "QTB" and "SP-GZB" are located at its northern areas with compressions also, and connected with low-velocity anomalies in both crustal and upper mantle rocks. Sub-block "ICB" is located at its southern area with low velocity anomaly, and connected with Tengchong volcano. Sub-blocks "SYDB" and "YZB" are located at its eastern areas with high velocity anomalies in both crustal and upper mantle rocks. Our results demonstrated that significant azimuthal anisotropy of crust (t£30s) and upper mantle (30s£t£60s). Crustal anisotropy indicates the orogenic belt matched well with the direction of fast propagation, and upper mantle anisotropy represents the lattic-preferred orientation (LPO) of mantle minerals (e.g. olivine and basalt), indicating the features of subducting Indian plate. Besides, Red River fault is a dextral strike fault, controlling the crustal and mantle migration. There is a narrow zone to be the channel flow of Tibetan crustal materials escaping toward Yunnan area. The evolution of EHS seems constrained by gravity isostatic mechanism. Keywords: Tibetan Plateau; Eastern Himalayan Syntaxis; Red River fault; crustal flow; surface wave; anisotropy

A preliminary study of the heating effect of the Tibetan Plateau.

Directory of Open Access Journals (Sweden)

Yonghui Yao

Full Text Available The immense and towering Tibetan Plateau acts as a heating source and, thus, deeply shapes the climate of the Eurasian continent and even the whole world. However, due to the scarcity of meteorological observation stations and very limited climatic data, little is quantitatively known about the heating effect of the plateau and its implications. This paper firstly collects climate data (2001-2007 from 109 observation stations and MODIS-based estimated monthly mean temperature data in the plateau and the neighboring Sichuan Basin, and conducts correlation and simple linear regression to reveal the altitudinal pattern of temperature. Then, according to the linear relationships of temperature and altitude for each month, it compares air temperature differences on the same elevation between the main plateau and surrounding mountains and the Sichuan Basin so as to quantify the heating effect and discuss its implication on timberline of the plateau. The results show that: 1 the heating effect of the plateau is significant. The temperature of the main plateau area was higher than that of free air on the same elevation above the neighboring areas; on the elevation of 4500 m (the main plateau, temperature is 1-6°C higher in the main Plateau than over the Sichuan Basin for different months and 5.9-10.7°C higher than in the Qilian Mountains in the northeastern corner of the plateau. 2 Even at altitudes of 5000-6000 m in the main Plateau, there are 4 months with a mean temperature above 0°C. The mean temperature of the warmest month (July can reach 10°C at about 4600-4700 m. This may help explain why the highest timberline in the northern hemisphere is on the southeastern Tibetan Plateau.

The Pajarito Plateau: A bibliography

Science.gov (United States)

Mathien, Frances Joan; Steen, Charlie R.; Allen, Craig D.

1993-01-01

This bibliography is the result of two initially independent projects. As the consulting archaeologist at Los Alamos National Laboratory (LANL), Charlie R. Steen collected entries at the suggestion of the staff of the Environmental Surveillance Group of the Health, Safety, and Environmental Division, HSE-8. The primary purpose was to aid the staff in evaluating cultural resources on LANL lands. In addition to works that related to the archaeology and history of the area, Steen included notations of a few books and articles in other fields such as geology and natural history. It was hoped that they also would be of value to other organizations and to students of past human activities on the Pajarito Plateau.At the same time, the National Park Service (NPS) was planning a major survey of Bandelier National Monument (BNM). As part of this plan, the author was asked to prepare a background document that described research previously carried out in the area, including an annotated bibliography. Although the survey would be limited to the park boundaries, the larger Pajarito Plateau is a more logical study area from physiographic, environmental, and cultural perspectives; hence the focus was on this larger region. Mathien (1986) also included some references to natural resources studies, particularly those initiated by NPS within Bandelier National Monument.Both bibliographies were made available to Colleen Olinger and Beverly Larson of the Health and Environmental Services Group at Los Alamos. They realized that while neither was complete, each included entries missing from the other. Larson suggested the two bibliographies be combined. (At this time, Craig Allen was studying the landscape of the Jemez Mountains [Allen 1984c, 1989]. His investigations included much detailed information on natural resource studies and were added in 1991 and 1992.)To limit the scope of their work, Steen and Mathien had chosen their parameter: the Pajarito Plateau. Geographically, the

Expression of radiation damage in two tumor subpopulations obtained from a heterogeneous human colon carcinoma as a function of growth state

International Nuclear Information System (INIS)

Arundel, C.M.; Leith, J.T.

1984-01-01

The authors have defined changes in intrinsic x-ray (100 kVp) radiation sensitivity that occur when human tumor cells are grown either exponentially, or as plateau (both fed and unfed) phase cultures in vitro. Two subpopulations of a human colon carcinoma were studied (clones A and D), and values for single hit, multitarget inactivation were obtained. For clone A the n, D/sub o/ (Gy), and D/sub q/ (Gy) values for exponential cells were 8.2, 1.06, and 2.23. For clone D, these values were 5.8, 1.08, and 2.23. For fed plateau phase cultures the clone A values were 18.4, 0.86, and 2.52, while for fed clone D cells these values were 16.1, 0.80, and 2.24. For unfed plateau phase cultures the clone A values were 28.5, 0.71, and 2.40, while for unfed clone D cells these values were 15.5, 0.76, and 2.10. These data indicate that the major change in intrinsic radiation sensitivity of these heterogeneous tumor subpopulations is the increase in the number of lesions per unit dose produced in plateau phase cells. Complete studies of repair of potentially lethal damage in these 2 tumor lines are being done to fully define radiation responses in plateau phase cultures

Backup pathways of NHEJ in cells of higher eukaryotes: Cell cycle dependence

International Nuclear Information System (INIS)

Iliakis, George

2009-01-01

DNA double-strand breaks (DSBs) induced by ionizing radiation (IR) in cells of higher eukaryotes are predominantly repaired by a pathway of non-homologous end joining (NHEJ) utilizing Ku, DNA-PKcs, DNA ligase IV, XRCC4 and XLF/Cernunnos (D-NHEJ) as central components. Work carried out in our laboratory and elsewhere shows that when this pathway is chemically or genetically compromised, cells do not shunt DSBs to homologous recombination repair (HRR) but instead use another form of NHEJ operating as a backup (B-NHEJ). Here I review our efforts to characterize this repair pathway and discuss its dependence on the cell cycle as well as on the growth conditions. I present evidence that B-NHEJ utilizes ligase III, PARP-1 and histone H1. When B-NHEJ is examined throughout the cell cycle, significantly higher activity is observed in G2 phase that cannot be attributed to HRR. Furthermore, the activity of B-NHEJ is compromised when cells enter the plateau phase of growth. Together, these observations uncover a repair pathway with unexpected biochemical constitution and interesting cell cycle and growth factor regulation. They generate a framework for investigating the mechanistic basis of HRR contribution to DSB repair.

Modeling two-phase flow in PEM fuel cell channels

Energy Technology Data Exchange (ETDEWEB)

Wang, Yun; Basu, Suman; Wang, Chao-Yang [Electrochemical Engine Center (ECEC), and Department of Mechanical and Nuclear Engineering, The Pennsylvania State University, University Park, PA 16802 (United States)

2008-05-01

This paper is concerned with the simultaneous flow of liquid water and gaseous reactants in mini-channels of a proton exchange membrane (PEM) fuel cell. Envisaging the mini-channels as structured and ordered porous media, we develop a continuum model of two-phase channel flow based on two-phase Darcy's law and the M{sup 2} formalism, which allow estimate of the parameters key to fuel cell operation such as overall pressure drop and liquid saturation profiles along the axial flow direction. Analytical solutions of liquid water saturation and species concentrations along the channel are derived to explore the dependences of these physical variables vital to cell performance on operating parameters such as flow stoichiometric ratio and relative humility. The two-phase channel model is further implemented for three-dimensional numerical simulations of two-phase, multi-component transport in a single fuel-cell channel. Three issues critical to optimizing channel design and mitigating channel flooding in PEM fuel cells are fully discussed: liquid water buildup towards the fuel cell outlet, saturation spike in the vicinity of flow cross-sectional heterogeneity, and two-phase pressure drop. Both the two-phase model and analytical solutions presented in this paper may be applicable to more general two-phase flow phenomena through mini- and micro-channels. (author)

Parhelic-like circle from light scattering in Plateau borders

Energy Technology Data Exchange (ETDEWEB)

Tufaile, A., E-mail: tufaile@usp.br; Tufaile, A.P.B.

2015-03-06

We are reporting a new simple optical element to generate halos. We have observed interesting patterns of light scattering in Plateau borders in foams. In analogy to the atmospheric phenomena known as parhelic circle, sun dogs, and sun pillars, we have named the features of the patterns observed as parlaseric circle, laser dogs, and laser pillars. The triangular symmetry of the Plateau borders is analogous to the hexagonal symmetry of ice crystals which produce these atmospheric phenomena. Working with one Plateau border at a time, we have observed wave optics phenomena that are not perceived in the atmospheric phenomena, such as diffraction and interference. - Highlights: • We obtained halo formation from light scattering in a Plateau border using an experiment. • We explained halo formation using geometrical theory of diffraction. • An optical element based on a Plateau border is proposed. • We compared some aspects of the parhelic circle with the parlaseric circle.

Intrinsic radiosensitivity and PLD repair in osteosarcoma cell lines

International Nuclear Information System (INIS)

Sugimoto, M.; Toguchida, J.; Kotoura, Y.; Yamamuro, T.; Utsumi, H.

1992-01-01

The response to radiation of seven osteosarcoma cell lines was analysed by in vitro colony-forming assay and compared with that of eight human fibroblast strains. The values of D 0 , the surviving fraction after 2 Gy (S2Gy), and the mean inactivation dose (D-bar) of osteosarcoma cells in log-phase culture were significantly higher than those of fibroblast strains (p<0.01). PLD (potentially lethal damage) repair of osteosarcoma cells evaluated in the plateau phase of growth showed great variation for enhancement of survival, although all of the values were maximised within 12 h after irradiation. In the osteosarcoma, intrinsic radiosensitivity in vitro reflected the clinical response to radiation. However, the capacity for PLD repair might not be a good indicator for predicting the results of radiation therapy. (author)

Future vegetation ecosystem response to warming climate over the Tibetan Plateau

Science.gov (United States)

Bao, Y.; Gao, Y.; Wang, Y.

2017-12-01

The amplified vegetation response to climate variability has been found over the Tibetan Plateau (TP) in recent decades. In this study, the potential impacts of 21st century climate change on the vegetation ecosystem over the TP are assessed based on the dynamic vegetation outputs of models from Coupled Model Intercomparison Project Phase 5 (CMIP5), and the sensitivity of the TP vegetation in response to warming climate was investigated. Models project a continuous and accelerating greening in future, especially in the eastern TP, which closely associates with the plant type upgrade due to the pronouncing warming in growing season.Vegetation leaf area index (LAI) increase well follows the global warming, suggesting the warming climate instead of co2 fertilization controlls the future TP plant growth. The warming spring may advance the start of green-up day and extend the growing season length. More carbon accumulation in vegetation and soil will intensify the TP carbon cycle and will keep it as a carbon sink in future. Keywords: Leaf Area Index (LAI), Climate Change, Global Dynamic Vegetation Models (DGVMs), CMIP5, Tibetan Plateau (TP)

Fate of Glaciers in the Tibetan Plateau by 2100

Science.gov (United States)

Duan, K.

2017-12-01

As the third polar on the Earth, the Tibetan plateau holds more than 40,000 glaciers which have experienced a rapid retreat in recent decades. The variability of equilibrium line altitude (ELA) indicates expansion and wastage of glacier directly. Here we simulated the ELA variability in the Tibetan Plateau based on a full surface energy and mass balance model. The simulation results are agreement with the observations. The ELAs have risen at a rate of 2-8m/a since 1970 throughout the Plateau, especially in the eastern Plateau where the ELAs have risen to or over the top altitude of glacier, indicating the glaciers are accelerating to melting over there. Two glaciers, XD glacier in the center of the Plateau and Qiyi glacier in the Qilian Mountain, are chosen to simulate its future ELA variability in the scenarios of RCP2.6, RCP4.5 and RCP 8.5 given by IPCC. The results show the ELAs will arrive to its maximum in around 2040 in RCP2.6, while the ELAs will be over the top altitude of glaciers in 2035-2045 in RCP4.5 and RCP8.5, suggesting the glaciers in the eastern Plateau will be melting until the disappear of the glaciers by the end of 2100.

Cytotoxic properties of a 4-nitroimidazole (NSC 38087): a radiosensitizer of hypoxic cells in vitro

International Nuclear Information System (INIS)

Stratford, I.J.; Williamson, C.; Hardy, C.

1981-01-01

5-Phenoxysulphonyl-1-methyl-4-nitroimidazole (NSC 38087) can act as a sensitizer of hypoxic mammalian cells to radiation in vitro. The degree of sensitization achieved is greater than would be predicted from the drug's electron affinity. Cytotoxicity studies have shown that 5sub(μM) NSC 38087 can reduce the surviving fraction of log-phase V79 cells in air at 37 0 C to 10 -2 after 2 h exposure. This toxicity is considerably increased by small rises in temperature. In contrast to other nitroheterocyclic radiosensitizers, NSC 38087 and related 5-substituted 4-nitroimidazoles show greater toxicity towards aerobic than to hypoxic cells. Log-phase cells show the highest sensitivity to the toxic action of NSC 38087, with plateau-phase cells, cells with a history of chronic hypoxia, and thermotolerant cells showing greater resistance. These toxicity data are compared to those for the 2-nitroimidazole hypoxic-cell sensitizer misonidazole. (author)

The Low-luminosity Type IIP Supernova 2016bkv with Early-phase Circumstellar Interaction

Science.gov (United States)

Nakaoka, Tatsuya; Kawabata, Koji S.; Maeda, Keiichi; Tanaka, Masaomi; Yamanaka, Masayuki; Moriya, Takashi J.; Tominaga, Nozomu; Morokuma, Tomoki; Takaki, Katsutoshi; Kawabata, Miho; Kawahara, Naoki; Itoh, Ryosuke; Shiki, Kensei; Mori, Hiroki; Hirochi, Jun; Abe, Taisei; Uemura, Makoto; Yoshida, Michitoshi; Akitaya, Hiroshi; Moritani, Yuki; Ueno, Issei; Urano, Takeshi; Isogai, Mizuki; Hanayama, Hidekazu; Nagayama, Takahiro

2018-06-01

We present optical and near-infrared observations of a low-luminosity (LL) Type IIP supernova (SN) 2016bkv from the initial rising phase to the plateau phase. Our observations show that the end of the plateau is extended to ≳140 days since the explosion, indicating that this SN takes one of the longest times to finish the plateau phase among Type IIP SNe (SNe IIP), including LL SNe IIP. The line velocities of various ions at the middle of the plateau phase are as low as 1000–1500 km s‑1, which is the lowest even among LL SNe IIP. These measurements imply that the ejecta mass in SN 2016bkv is larger than that of the well-studied LL IIP SN 2003Z. In the early phase, SN 2016bkv shows a strong bump in the light curve. In addition, the optical spectra in this bump phase exhibit a blue continuum accompanied by a narrow Hα emission line. These features indicate an interaction between the SN ejecta and the circumstellar matter (CSM) as in SNe IIn. Assuming the ejecta–CSM interaction scenario, the mass loss rate is estimated to be ∼ 1.7× {10}-2 {M}ȯ yr‑1 within a few years before the SN explosion. This is comparable to or even larger than the largest mass loss rate observed for the Galactic red supergiants (∼ {10}-3 {M}ȯ yr‑1 for VY CMa). We suggest that the progenitor star of SN 2016bkv experienced a violent mass loss just before the SN explosion.

Induction and repair of lethal and oncogenic lesions and their relationship to cytogenetic changes in UV-irradiated mouse 10T1/2 cells

International Nuclear Information System (INIS)

Chan, G.L.; Nagasawa, H.; Little, J.B.

1979-01-01

While bacterial system is valuable for the pragmatic purpose of screening potential environmental carcinogens, the fundamental difference between prokaryotes and mammalian cells warrant caution against the use of bacterial mutagenic mechanisms to explain the oncogenic process in mammalian cells. The 10 T1/2 cells exposed to UV light in the plateau phase and subcultured immediately to low density to assay for clonogenic survival were extremely resistant to the cytotoxic effect of UV light. Purely physical considerations such as the increased thickness of plateau phase cells and the increased cytoplasmic shielding of UV light from the nuclei were insufficient to account for this unusual resistance. The effect of caffeine on the repair processes in UV-irradiated mammalian cells appears to be exerted during the first DNA synthetic phase after the UV exposure. The daughter DNA synthesized on a UV-irradiated template is of reduced molecular weight. 10 T1/2 cells were exposed in the log phase of growth to UV light, and then they were cultured for the next 48 hours in the complete growth medium containing the specific concentration of caffeine. Parallel experiments were performed, in which cells were exposed for 48 hours to caffeine only with no prior exposure to UV light. It was found that caffeine did not potentiate the transformation by UV light. Caffeine alone induced sister chromatid exchange (SCE), whereas the caffeine given after UV light had no effect. The class of UV-induced lesions which induce SCE also leads to malignant transformation. (Yamashita, S.)

Cytotoxicity and cell-cycle effects of paclitaxel when used as a single agent and in combination with ionizing radiation

International Nuclear Information System (INIS)

Gupta, Nalin; Hu, Lily J.; Deen, Dennis F.

1997-01-01

Purpose: This study aimed to determine the extent of paclitaxel-induced cytotoxicity and cell-cycle perturbations when used alone and in combination with radiation in human glioma cells. Methods and Materials: The effect of paclitaxel alone on three human glioma cells lines--SF-126, U-87 MG, and U-251 MG--was assessed after 24, 48, 72, or 96 h treatment. For experiments in combination with radiation, cells were exposed to either a long (48-h) or short (8-h) duration of paclitaxel treatment prior to irradiation. Cell survival was determined by clonogenic assay. Cell cycle perturbations were assessed by using flow cytometry to measure the proportion of cells in G 1 , S, and G 2 /M phases. Results: When cells were treated with paclitaxel alone for ≥24 h, cytotoxicity increased up to a threshold dose, after which it plateaued. When treatment duration was ≤24 h, cytotoxicity was appreciably greater in U-251 MG cells than in SF-126 and U-87 MG cells. After 24 h of paclitaxel treatment, cells in plateau phase growth had increased survival compared to cells in log phase growth. In contrast, after 8 h paclitaxel treatment, mitotic cells had reduced survival compared to cells from an asynchronous population. Cell-cycle perturbations were consistent with the presence of a mitotic block after paclitaxel treatment, although changes in other cell-cycle phase fractions varied among cell lines. For experiments in combination with radiation, cytotoxicity was increased when cells were irradiated after 48 h of paclitaxel treatment but not after 8 h of treatment. Conclusion: The duration of paclitaxel treatment and the location of cells in the cell cycle modify the degree of radiation cytotoxicity. The mechanisms of paclitaxel cytotoxicity are likely to be multifactorial because varying effects are seen in different cell lines. Furthermore, it is clear that simply increasing the number of cells in G 2 /M is insufficient in itself to increase the response of cells to radiation

Characterization of rapid recovery from γ-ray damage in plateau-phase human diploid fibroblasts

International Nuclear Information System (INIS)

Malcolm, A.W.; Tomkinson, K.N.; Little, J.B.

1982-01-01

Rapid recovery was investigated in density-inhibited, stationary-phase human diploid cells subcultured to low density at various times after a single dose of radiation. The influence of total dose, postirradiation temperature, and cell-to-cell contact on recovery was examined. The cultures were exposed to 60 Co γ rays at a dose rate of 50 rad per second. When the irradiation and postirradiation temperatures were maintained at 25 or 37 0 C, recovery, as manifested by an enhancement in survival, was similar during the first 30 min, whereas it was reduced at later times in the 25 0 C compared with the 37 0 C cultures. This result suggests the existence of different rapidly and slowly acting components to recovery. No recovery was noted at any time with incubation at 4 0 C. The recovery observed in density-inhibited cultures was consistently greater than that in less dense cultures, suggesting an effect of cell-to-cell contact and cell cycle distribution. Following single doses of 200 to 900 rad, progressive enhancement in relative recovery occurred with increasing doses over a period of 2 to 90 min, illustrating the importance of the relationship of the dose to the rapid recovery process

40 CFR 81.162 - Northeast Plateau Intrastate Air Quality Control Region.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 17 2010-07-01 2010-07-01 false Northeast Plateau Intrastate Air... Air Quality Control Regions § 81.162 Northeast Plateau Intrastate Air Quality Control Region. The Northeast Plateau Intrastate Air Quality Control Region (California) consists of the territorial area...

HANFORD SITE CENTRAL PLATEAU CLEANUP COMPLETION STRATEGY

International Nuclear Information System (INIS)

Bergman, T.B.

2011-01-01

Cleanup of the Hanford Site is a complex and challenging undertaking. The U.S. Department of Energy (DOE) has developed a comprehensive vision for completing Hanford's cleanup mission including transition to post-cleanup activities. This vision includes 3 principle components of cleanup: the ∼200 square miles ofland adjacent to the Columbia River, known as the River Corridor; the 75 square miles of land in the center of the Hanford Site, where the majority of the reprocessing and waste management activities have occurred, known as the Central Plateau; and the stored reprocessing wastes in the Central Plateau, the Tank Wastes. Cleanup of the River Corridor is well underway and is progressing towards completion of most cleanup actions by 2015. Tank waste cleanup is progressing on a longer schedule due to the complexity of the mission, with construction of the largest nuclear construction project in the United States, the Waste Treatment Plant, over 50% complete. With the progress on the River Corridor and Tank Waste, it is time to place increased emphasis on moving forward with cleanup of the Central Plateau. Cleanup of the Hanford Site has been proceeding under a framework defmed in the Hanford Federal Facility Agreement and Consent Order (Tri-Party Agreement). In early 2009, the DOE, the State of Washington Department of Ecology, and the U.S. Environmental Protection Agency signed an Agreement in Principle in which the parties recognized the need to develop a more comprehensive strategy for cleanup of the Central Plateau. DOE agreed to develop a Central Plateau Cleanup Completion Strategy as a starting point for discussions. This DOE Strategy was the basis for negotiations between the Parties, discussions with the State of Oregon, the Hanford Advisory Board, and other Stakeholder groups (including open public meetings), and consultation with the Tribal Nations. The change packages to incorporate the Central Plateau Cleanup Completion Strategy were signed by the

Preliminary study of crust-upper mantle structure of the Tibetan Plateau by using broadband teleseismic body waveforms

Science.gov (United States)

Zhu, Lu-Pei; Zeng, Rong-Sheng; Wu, Francis T.; Owens, Thomas J.; Randall, George E.

1993-05-01

As part of a joint Sino-U.S. research project to study the deep structure of the Tibetan Plateau, 11 broadband digital seismic recorders were deployed on the Plateau for one year of passive seismic recording. In this report we use teleseimic P waveforms to study the seismic velocity structure of crust and upper mantle under three stations by receiver function inversion. The receiver function is obtained by first rotating two horizontal components of seismic records into radial and tangential components and then deconvolving the vertical component from them. The receiver function depends only on the structure near the station because the source and path effects have been removed by the deconvolution. To suppress noise, receiver functions calculated from events clustered in a small range of back-azimuths and epicentral distances are stacked. Using a matrix formalism describing the propagation of elastic waves in laterally homogeneous stratified medium, a synthetic receiver function and differential receiver functions for the parameters in each layer can be calculated to establish a linearized inversion for one-dimensional velocity structure. Preliminary results of three stations, Wen-quan, Golmud and Xigatze (Coded as WNDO, TUNL and XIGA), located in central, northern and southern Plateau are given in this paper. The receiver functions of all three stations show clear P-S converted phases. The time delays of these converted phases relative to direct P arrivals are: WNDO 7.9s (for NE direction) and 8.3s (for SE direction), TUNL 8.2s, XIGA 9.0s. Such long time delays indicate the great thickness of crust under the Plateau. The differences between receiver function of these three station shows the tectonic difference between southern and north-central Plateau. The waveforms of the receiver functions for WNDO and TUNL are very simple, while the receiver function of XIGA has an additional midcrustal converted phase. The S wave velocity structures at these three stations

Novel ordered phases in the orthogonal dimer spin system SrCu2(BO3)2

International Nuclear Information System (INIS)

Takigawa, Masashi; Waki, Takeshi; Horvatic, Mladen; Berthier, Claude

2010-01-01

The magnetic properties of SrCu 2 (BO 3 ) 2 , a model spin system on the two-dimensional (2D) Shastry-Sutherland lattice, are reviewed with particular emphasis on the nuclear magnetic resonance (NMR) experiments. SrCu 2 (BO 3 ) 2 has a dimer singlet ground state at zero magnetic field and shows a sequence of magnetization plateaux at high magnetic fields. The plateaux are attributed to the localization of triplets into a superlattice due to mutual repulsion. Such a superstructure has been indeed observed at the 1/8 plateau by NMR experiments. Furthermore, the superstructure persists above the 1/8 plateau, where new phases have been identified by the torque and NMR measurements. SrCu 2 (BO 3 ) 2 also has the anisotropic Dzyaloshinski-Moriya interactions, which significantly change the ground state in magnetic fields. A recent development is the discovery of a new magnetic phase transition under high pressure. At 2.4 GPa, the 11 B NMR spectrum exhibits line splitting as a function of temperature in two steps. A gradual splitting below 30 K indicating loss of four-fold symmetry is followed by a further sudden splitting below 4 K marking a clear magnetic phase transition. The low-T phase has a doubled unit cell, yet with no spontaneous magnetic moment. A new type of valence-bond-solid (VBS) order is proposed. (author)

Does the climate warming hiatus exist over the Tibetan Plateau?

Science.gov (United States)

Duan, Anmin; Xiao, Zhixiang

2015-09-02

The surface air temperature change over the Tibetan Plateau is determined based on historical observations from 1980 to 2013. In contrast to the cooling trend in the rest of China, and the global warming hiatus post-1990s, an accelerated warming trend has appeared over the Tibetan Plateau during 1998-2013 (0.25 °C decade(-1)), compared with that during 1980-1997 (0.21 °C decade(-1)). Further results indicate that, to some degree, such an accelerated warming trend might be attributable to cloud-radiation feedback. The increased nocturnal cloud over the northern Tibetan Plateau would warm the nighttime temperature via enhanced atmospheric back-radiation, while the decreased daytime cloud over the southern Tibetan Plateau would induce the daytime sunshine duration to increase, resulting in surface air temperature warming. Meanwhile, the in situ surface wind speed has recovered gradually since 1998, and thus the energy concentration cannot explain the accelerated warming trend over the Tibetan Plateau after the 1990s. It is suggested that cloud-radiation feedback may play an important role in modulating the recent accelerated warming trend over the Tibetan Plateau.

Geochemical characteristics of the Jos-Plateau Basalts, North ...

African Journals Online (AJOL)

The Jos Plateau basalts, present Zr/Nb ratios (2.4-3.0) comparable to those of the alkali basalts of the lower Benue valley, and of the Cameroon volcanic line, suggesting that they were possibly derived from the same mantle source. Keywords: Jos Plateau, alkali basalt, mantle, partial melting, incompatible elements.

Effect of time intervals between irradiation and chemotherapeutic agents on the normal tissue damage. Comparison between in vivo and in vitro experiments

Energy Technology Data Exchange (ETDEWEB)

Ito, Hisao; Nakayama, Toshitake; Hashimoto, Shozo (Keio Univ., Tokyo (Japan). School of Medicine)

1989-05-01

Experiments have been carried out to determine the effect on the cell survivals at different time intervals between irradiation and chemotherapeutic agents (BLM, cisDDP, ADM and ACNU) in either the in vivo or the in vitro system. The intestinal epithelial assay was applied on the in vivo system. The clonogenic cell survivals of V/sub 79/ cells, both in the proliferative and the plateau phases, were determined in the in vitro system. The V/sub 79/ cells in the plateau phase were more sensitive to BLM, cisDDP and ACNU than those in the proliferative phase, however, the result was reverse with ADM. When BLM, cisDDP or ACNU was combined with irradiation at different time intervals, the response of the plateau phase V/sub 79/ cells to combination therapies were very similar to those of the intestinal epithelial cells. On the other hand, V/sub 79/ cells in the proliferative phase, which were treated with ADM and irradiation, showed the similar response as the intestinal cells. These results suggest that studies of chemo-radiotherapy with cultured cells which are sensitive to chemotherapeutic agents might be suitable to expect the in vivo damage of the normal tissue. (author).

The Colorado Plateau II: biophysical, socioeconomic, and cultural research

Science.gov (United States)

Mattson, David J.; van Riper, Charles

2005-01-01

The publication of The Colorado Plateau: Cultural, Biological, and Physical Research in 2004 marked a timely summation of current research in the Four Corners states. This new volume, derived from the seventh Biennial Conference on the Colorado Plateau in 2003, complements the previous book by focusing on the integration of science into resource management issues. The 32 chapters range in content from measuring human impacts on cultural resources, through grazing and the wildland-urban interface issues, to parameters of climate change on the Plateau. The book also introduces economic perspectives by considering shifting patterns and regional disparities in the Colorado Plateau economy. A series of chapters on mountain lions explores the human-wildland interface. These chapters deal with the entire spectrum of challenges associated with managing this large mammal species in Arizona and on the Colorado Plateau, conveying a wealth of timely information of interest to wildlife managers and enthusiasts. Another provocative set of chapters on biophysical resources explores the management of forest restoration, from the micro scale all the way up to large-scale GIS analyses of ponderosa pine ecosystems on the Colorado Plateau. Given recent concerns for forest health in the wake of fires, severe drought, and bark-beetle infestation, these chapters will prove enlightening for forest service, park service, and land management professionals at both the federal and state level, as well as general readers interested in how forest management practices will ultimately affect their recreation activities. With broad coverage that touches on topics as diverse as movement patterns of rattlesnakes, calculating watersheds, and rescuing looted rockshelters, this volume stands as a compendium of cutting-edge research on the Colorado Plateau that offers a wealth of insights for many scholars.

Segmentation and classification of cell cycle phases in fluorescence imaging.

Science.gov (United States)

Ersoy, Ilker; Bunyak, Filiz; Chagin, Vadim; Cardoso, M Christina; Palaniappan, Kannappan

2009-01-01

Current chemical biology methods for studying spatiotemporal correlation between biochemical networks and cell cycle phase progression in live-cells typically use fluorescence-based imaging of fusion proteins. Stable cell lines expressing fluorescently tagged protein GFP-PCNA produce rich, dynamically varying sub-cellular foci patterns characterizing the cell cycle phases, including the progress during the S-phase. Variable fluorescence patterns, drastic changes in SNR, shape and position changes and abundance of touching cells require sophisticated algorithms for reliable automatic segmentation and cell cycle classification. We extend the recently proposed graph partitioning active contours (GPAC) for fluorescence-based nucleus segmentation using regional density functions and dramatically improve its efficiency, making it scalable for high content microscopy imaging. We utilize surface shape properties of GFP-PCNA intensity field to obtain descriptors of foci patterns and perform automated cell cycle phase classification, and give quantitative performance by comparing our results to manually labeled data.

Polar solvent modification of x ray induced potentially lethal damage in heterogeneous human colon tumor cells in vitro

International Nuclear Information System (INIS)

Arundel, C.M.; Leith, J.T.; Dexter, D.L.; Glicksman, A.S.

1984-01-01

Two subpopulations of tumor cells (clones A and D) obtained from a human colon adenocarcinoma were examined for their sensitivities to x-irradiation as unfed, early plateau phase cultures. Both the single dose survival curves and the kinetics of potentially lethal damage recovery (PLDR) were determined for the two tumor lines. Also, possible modification of PLDR by N,N-dimethylformamide (DMF), which has previously been shown to enhance the radiosensitivity of exponentially growing tumor cells, was investigated by adding DMF (0.8% v/v) to plateau phase cultures immediately after irradiation, and determining effects on the extent of PLDR. For non-DMF treated cells, the survival curve parameters of the diploid (clone D) and aneuploid (clone A) lines were very similar. Using initial survival levels of 3.5% (clone D) or 5.5% (clone A) to investigate PLDR, it was found that the increase in survival for clone D was 2.2, while the SFR for clone A was 1.6. DMF did not change either the kinetics or extent of PLDR in these two tumor lines when added to cultures immediately after irradiation. These results indicate that significant heterogeneity in PLDR exists between these closely related tumor subpopulations

Soil carbon sequestration potential for "grain for green" project in Loess Plateau, China

Science.gov (United States)

Chang, R.; Fu, B.; Liu, Gaisheng; Liu, S.

2011-01-01

Conversion of cropland into perennial vegetation land can increase soil organic carbon (SOC) accumulation, which might be an important mitigation measure to sequester carbon dioxide from the atmosphere. The “Grain for Green” project, one of the most ambitious ecological programmes launched in modern China, aims at transforming the low-yield slope cropland into grassland and woodland. The Loess Plateau in China is the most important target of this project due to its serious soil erosion. The objectives of this study are to answer three questions: (1) what is the rate of the SOC accumulation for this “Grain for Green” project in Loess Plateau? (2) Is there a difference in SOC sequestration among different restoration types, including grassland, shrub and forest? (3) Is the effect of restoration types on SOC accumulation different among northern, middle and southern regions of the Loess Plateau? Based on analysis of the data collected from the literature conducted in the Loess Plateau, we found that SOC increased at a rate of 0.712 TgC/year in the top 20 cm soil layer for 60 years under this project across the entire Loess Plateau. This was a relatively reliable estimation based on current data, although there were some uncertainties. Compared to grassland, forest had a significantly greater effect on SOC accumulation in middle and southern Loess Plateau but had a weaker effect in the northern Loess Plateau. There were no differences found in SOC sequestration between shrub and grassland across the entire Loess Plateau. Grassland had a stronger effect on SOC sequestration in the northern Loess Plateau than in the middle and southern regions. In contrast, forest could increase more SOC in the middle and southern Loess Plateau than in the northern Loess Plateau, whereas shrub had a similar effect on SOC sequestration across the Loess Plateau. Our results suggest that the “Grain for Green” project can significantly increase the SOC storage in Loess Plateau

Medial tibial plateau morphology and stress fracture location: A magnetic resonance imaging study.

Science.gov (United States)

Yukata, Kiminori; Yamanaka, Issei; Ueda, Yuzuru; Nakai, Sho; Ogasa, Hiroyoshi; Oishi, Yosuke; Hamawaki, Jun-Ichi

2017-06-18

To determine the location of medial tibial plateau stress fractures and its relationship with tibial plateau morphology using magnetic resonance imaging (MRI). A retrospective review of patients with a diagnosis of stress fracture of the medial tibial plateau was performed for a 5-year period. Fourteen patients [three female and 11 male, with an average age of 36.4 years (range, 15-50 years)], who underwent knee MRI, were included. The appearance of the tibial plateau stress fracture and the geometry of the tibial plateau were reviewed and measured on MRI. Thirteen of 14 stress fractures were linear, and one of them stellated on MRI images. The location of fractures was classified into three types. Three fractures were located anteromedially (AM type), six posteromedially (PM type), and five posteriorly (P type) at the medial tibial plateau. In addition, tibial posterior slope at the medial tibial plateau tended to be larger when the fracture was located more posteriorly on MRI. We found that MRI showed three different localizations of medial tibial plateau stress fractures, which were associated with tibial posterior slope at the medial tibial plateau.

Multimodal quantitative phase and fluorescence imaging of cell apoptosis

Science.gov (United States)

Fu, Xinye; Zuo, Chao; Yan, Hao

2017-06-01

Fluorescence microscopy, utilizing fluorescence labeling, has the capability to observe intercellular changes which transmitted and reflected light microscopy techniques cannot resolve. However, the parts without fluorescence labeling are not imaged. Hence, the processes simultaneously happen in these parts cannot be revealed. Meanwhile, fluorescence imaging is 2D imaging where information in the depth is missing. Therefore the information in labeling parts is also not complete. On the other hand, quantitative phase imaging is capable to image cells in 3D in real time through phase calculation. However, its resolution is limited by the optical diffraction and cannot observe intercellular changes below 200 nanometers. In this work, fluorescence imaging and quantitative phase imaging are combined to build a multimodal imaging system. Such system has the capability to simultaneously observe the detailed intercellular phenomenon and 3D cell morphology. In this study the proposed multimodal imaging system is used to observe the cell behavior in the cell apoptosis. The aim is to highlight the limitations of fluorescence microscopy and to point out the advantages of multimodal quantitative phase and fluorescence imaging. The proposed multimodal quantitative phase imaging could be further applied in cell related biomedical research, such as tumor.

A Short-Term Advantage for Syngamy in the Origin of Eukaryotic Sex: Effects of Cell Fusion on Cell Cycle Duration and Other Effects Related to the Duration of the Cell Cycle-Relationship between Cell Growth Curve and the Optimal Size of the Species, and Circadian Cell Cycle in Photosynthetic Unicellular Organisms.

Science.gov (United States)

Mancebo Quintana, J M; Mancebo Quintana, S

2012-01-01

The origin of sex is becoming a vexatious issue for Evolutionary Biology. Numerous hypotheses have been proposed, based on the genetic effects of sex, on trophic effects or on the formation of cysts and syncytia. Our approach addresses the change in cell cycle duration which would cause cell fusion. Several results are obtained through graphical and mathematical analysis and computer simulations. (1) In poor environments, cell fusion would be an advantageous strategy, as fusion between cells of different size shortens the cycle of the smaller cell (relative to the asexual cycle), and the majority of mergers would occur between cells of different sizes. (2) The easiest-to-evolve regulation of cell proliferation (sexual/asexual) would be by modifying the checkpoints of the cell cycle. (3) A regulation of this kind would have required the existence of the G2 phase, and sex could thus be the cause of the appearance of this phase. Regarding cell cycle, (4) the exponential curve is the only cell growth curve that has no effect on the optimal cell size in unicellular species; (5) the existence of a plateau with no growth at the end of the cell cycle explains the circadian cell cycle observed in unicellular algae.

A Short-Term Advantage for Syngamy in the Origin of Eukaryotic Sex: Effects of Cell Fusion on Cell Cycle Duration and Other Effects Related to the Duration of the Cell Cycle—Relationship between Cell Growth Curve and the Optimal Size of the Species, and Circadian Cell Cycle in Photosynthetic Unicellular Organisms

Science.gov (United States)

Mancebo Quintana, J. M.; Mancebo Quintana, S.

2012-01-01

The origin of sex is becoming a vexatious issue for Evolutionary Biology. Numerous hypotheses have been proposed, based on the genetic effects of sex, on trophic effects or on the formation of cysts and syncytia. Our approach addresses the change in cell cycle duration which would cause cell fusion. Several results are obtained through graphical and mathematical analysis and computer simulations. (1) In poor environments, cell fusion would be an advantageous strategy, as fusion between cells of different size shortens the cycle of the smaller cell (relative to the asexual cycle), and the majority of mergers would occur between cells of different sizes. (2) The easiest-to-evolve regulation of cell proliferation (sexual/asexual) would be by modifying the checkpoints of the cell cycle. (3) A regulation of this kind would have required the existence of the G2 phase, and sex could thus be the cause of the appearance of this phase. Regarding cell cycle, (4) the exponential curve is the only cell growth curve that has no effect on the optimal cell size in unicellular species; (5) the existence of a plateau with no growth at the end of the cell cycle explains the circadian cell cycle observed in unicellular algae. PMID:22666626

RBE of neutrons for induction of cell reproductive death and chromosome aberrations in three cell lines

International Nuclear Information System (INIS)

Zoetelief, J.; Kuijpers, W.C.; Baten-Wittwer, A.; Barendsen, G.W.

1983-01-01

The authors have compared the RBE values for induction of dicentrics and centric rings with those for cell inactivation and with the mean or effective quality factors (Q) recommended for radiation protection. The induction of cell reproductive death and chromosome aberrations has been investigated in plateau phase cultures of established lines of a rat rhabdomyosarcoma, a rat ureter carcinoma and Chinese hamster cells for single doses of 300 kV X-rays and 0.5, 4.2 and 15 MeV neutrons. The different cell lines show considerable variations in sensitivity and the RBE values obtained are presented in tabular form. The mean RBE values for the rat rhabdomyosarcoma cells are lower than those for the other two relatively resistant cell lines. Those for the Chinese hamster cells extrapolated to levels according to low doses of X-rays are in good agreement with the quoted Q values. (Auth./C.F.)

Radar-derived quantitative precipitation estimation in complex terrain over the eastern Tibetan Plateau

Science.gov (United States)

Gou, Yabin; Ma, Yingzhao; Chen, Haonan; Wen, Yixin

2018-05-01

Quantitative precipitation estimation (QPE) is one of the important applications of weather radars. However, in complex terrain such as Tibetan Plateau, it is a challenging task to obtain an optimal Z-R relation due to the complex spatial and temporal variability in precipitation microphysics. This paper develops two radar QPE schemes respectively based on Reflectivity Threshold (RT) and Storm Cell Identification and Tracking (SCIT) algorithms using observations from 11 Doppler weather radars and 3264 rain gauges over the Eastern Tibetan Plateau (ETP). These two QPE methodologies are evaluated extensively using four precipitation events that are characterized by different meteorological features. Precipitation characteristics of independent storm cells associated with these four events, as well as the storm-scale differences, are investigated using short-term vertical profile of reflectivity (VPR) clusters. Evaluation results show that the SCIT-based rainfall approach performs better than the simple RT-based method for all precipitation events in terms of score comparison using validation gauge measurements as references. It is also found that the SCIT-based approach can effectively mitigate the local error of radar QPE and represent the precipitation spatiotemporal variability better than the RT-based scheme.

Crustal anisotropy from Moho converted Ps wave splitting and geodynamic implications in Northeastern margin of Tibetan Plateau

Science.gov (United States)

Xie, Z.; Wu, Q.; Zhang, R.

2017-12-01

Collision between Indian and Eurasian result in intense deformation and crustal shortening in the Tibetan Plateau. NE margin of Tibetan Plateau experienced complex deformation between Qilian orogen and its adjacent blocks, Alxa Block in the north and Ordos Block in the east. We focus on if there any evidences exist in the NE margin of Tibetan Plateau, which can support crustal channel flow model. China Earthquake Administration had deployed temporary seismic array which is called ChinaArray Phase Ⅱ, dense seismic stations covered NE margin of Tibetan Plateau. Seismic data recorded by 81 seismic stations is applied in this research. We calculated receiver functions with time-domain deconvolution. We selected RFs which have clear Ps phase both in radial and transverse components to measure Ps splitting owing to crustal anisotropy, and 130 pairs of anisotropy parameters of 51 seismic stations were obtained. We would like to discuss about dynamic mechanism of this area using crustal anisotropy associated with the result of SKS-splitting and surface constrains like GPS velocity. The result can be summarized as follows. The large scale of delay time imply that the crustal anisotropy mainly derives from middle to lower crust rather than upper crust. In the southeastern part of the research area, crustal anisotropy is well agree with the result computed form SKS-splitting and GPS velocity directions trending NWW-SEE or E-W direction. This result imply a vertically coherent deformation in the area as the directions of crustal anisotropy trend to be perpendicular to the direction of normal stress. In the middle and north part of the research area, the fast polarization direction of crustal anisotropy is NEE-SWW or E-W direction, parallels with direction of GPS velocity, but differ to the direction of the result of SKS-splitting. This result may imply that decoupled deformation in this area associated with middle to lower crustal flow.

Teaching Rayleigh–Plateau instabilities in the laboratory

International Nuclear Information System (INIS)

Fragkopoulos, A A; Ellis, P W; Fernandez-Nieves, A

2015-01-01

The breakup of a liquid jet into spherical droplets via the Rayleigh–Plateau instability is a common and fundamental part of fluid mechanics. However, teaching this instability in a laboratory setting is challenging, requiring sophisticated methods to generate and study the jet dynamics. Recently, toroidal droplets were shown to break into one or more spherical droplets in the thin-drop limit via the Rayleigh–Plateau instability. We propose a simple experimental setup to generate toroidal droplets that break up on the order of tens of seconds, allowing for easy video capture using a basic CCD camera. With this setup, it is possible to quantify the Rayleigh–Plateau instability in a pedagogical laboratory setting. In addition, the role of curvature on jet breakup can be explored using thick toroidal droplets. We envision this setup as a powerful teaching tool for one of the most fundamental fluid dynamics processes. (paper)

Cell flux through S phase in the mouse duodenal epithelium determined by cell sorting and radioautography

International Nuclear Information System (INIS)

Bjerknes, M.; Cheng, H.

1982-01-01

An accumulation of cells in early S phase was observed in normal mouse duodenal epithelium studied with flow cytometry. To determine if this accumulation of cells was the result of a lower rate of DNA synthesis, animals were given a single injection of 3 H-thymidine and the epithelium collected one hour later. The epithelium was processed for flow cytometry. Seven sort windows were established in different portions of the DNA histogram. Cells from each window were sorted onto glass slides that were then processed for radioautography. The number of silver grains over the nuclei of each sorted population was counted. It was found that cells in early S phase had significantly fewer grains over their nuclei than did mid- or late-S phase cells. We conclude that the accumulation of cells in early S phase is due, at least in part, to a lower rate of DNA synthesis in early than in mid or late S phase

Influence of Western Tibetan Plateau Summer Snow Cover on East Asian Summer Rainfall

Science.gov (United States)

Wang, Zhibiao; Wu, Renguang; Chen, Shangfeng; Huang, Gang; Liu, Ge; Zhu, Lihua

2018-03-01

The influence of boreal winter-spring eastern Tibetan Plateau snow anomalies on the East Asian summer rainfall variability has been the focus of previous studies. The present study documents the impacts of boreal summer western and southern Tibetan Plateau snow cover anomalies on summer rainfall over East Asia. Analysis shows that more snow cover in the western and southern Tibetan Plateau induces anomalous cooling in the overlying atmospheric column. The induced atmospheric circulation changes are different corresponding to more snow cover in the western and southern Tibetan Plateau. The atmospheric circulation changes accompanying the western Plateau snow cover anomalies are more obvious over the midlatitude Asia, whereas those corresponding to the southern Plateau snow cover anomalies are more prominent over the tropics. As such, the western and southern Tibetan Plateau snow cover anomalies influence the East Asian summer circulation and precipitation through different pathways. Nevertheless, the East Asian summer circulation and precipitation anomalies induced by the western and southern Plateau snow cover anomalies tend to display similar distribution so that they are more pronounced when the western and southern Plateau snow cover anomalies work in coherence. Analysis indicates that the summer snow cover anomalies over the Tibetan Plateau may be related to late spring snow anomalies due to the persistence. The late spring snow anomalies are related to an obvious wave train originating from the western North Atlantic that may be partly associated with sea surface temperature anomalies in the North Atlantic Ocean.

Active shortening, intermontane basin formation, and geomorphic evolution in an orogenic plateau: Central Puna Plateau, NW Argentina (24°37'S, 67°03'W)

Science.gov (United States)

Strecker, Manfred R.; Alonso, Ricardo N.; Bookhagen, Bodo; Freymark, Jessica; Pingel, Heiko

2017-04-01

The high-elevation Andean Plateau (Altiplano-Puna; 4km) is a first-order morphotectonic province of the Central Andes and constitutes the world's second largest orogenic plateau. While there are many unifying basin characteristics in this region, including internal drainage, semi-arid to arid climate and associated deposition of evaporites, there are notable differences between the northern and southern parts of the plateau. In contrast to the vast basins of the Altiplano (north) and incipient establishment of fluvial connectivity and sediment transport to the foreland, the Puna (south) comprises numerous smaller basins, bordered by reverse-fault bounded ranges up to 6 km high. The plateau is internally drained and fluvial connectivity with the foreland does not exist leading to thick sedimentary basin fills that comprise continental evaporites, volcanic and clastic deposits, typically between 3 and 5 km thick. However, repeated impacts of climate change and superposed tectonic activity in the southern plateau have resulted in further basin differentiation, abandonment or re-arrangement of fluvial networks and impacts on sediment transport. Here we report evidence for sustained contractional tectonic activity in the Pocitos Basin in the southern plateau. On the western margin of the basin fanning of dipping strata and regraded, steeply inclined gravel-covered pediment surfaces and wind gaps associated with gravel derived from distant sources in the west document late Tertiary to Pleistocene growth of an approximately N-S oriented and N plunging anticline. The growth of the eastern limb of this anticline has caused the isolation of a formerly more extensive basin. In addition, Late Pleistocene and Holocene lake shorelines and lacustrine deposits are tilted eastward along the same structure and InSAR measurements of deformed lake terraces document that the fold is growing. Despite widely reported extensional faulting in the southern Puna, we conclude (1) that the

Effects of X-irradiation on cell-cycle progression, induction of chromosomal aberrations and cell killing in ataxia telangiectasia (AT) fibroblasts

International Nuclear Information System (INIS)

Nagasawa, H.; Little, J.B.; Latt, S.A.; Lalande, M.E.

1985-01-01

Survival, cumulative labeling indices, chromosomal aberrations and cell-cycle distribution by flow microfluorometry (FMF) were studied in fibroblasts from normal and three ataxia telangiectasia (AT) families after X-irradiation during density-inhibition of growth and immediate release by subculture to low density. Homozygotic AT (proband) fibroblasts were very hypersensitive to cell killing by X-irradiation. Fibroblasts from AT heterozygotes (parents) were minimally hypersensitive, with D 0 's slightly lower than those for normal fibroblasts. There were three different response groups for a G 1 phase block induced by 400 rad of X-rays: (1) minimal or no G 1 block was observed in AT homozygote cell strains; (2) 10-20% of the cells were blocked in G 1 in normal cell strains; and (3) 50% or more of the cells were blocked in AT heterozygote strains. FMF profiles and cumulative labeling indices showed that homozygotic AT cells irradiated in plateau phase moved into the S-phase following subculture with no additional delay over non-irradiated controls. Homozygotic AT cells showed not only a 4-5 times higher frequency of X-ray-induced chromosomal aberrations than normal strains, but approximately 30% of these were of the chromatid-type. There were no differences in the frequency or type of X-ray-induced chromosomal aberrations between normal and heterozygotic AT cells. (orig.)

Multi-color phase imaging and sickle cell anemia (Conference Presentation)

Science.gov (United States)

Hosseini, Poorya; Zhou, Renjie; Yaqoob, Zahid; So, Peter T. C.

2016-03-01

Quantitative phase measurements at multiple wavelengths has created an opportunity for exploring new avenues in phase microscopy such as enhancing imaging-depth (1), measuring hemoglobin concentrations in erythrocytes (2), and more recently in tomographic mapping of the refractive index of live cells (3). To this end, quantitative phase imaging has been demonstrated both at few selected spectral points as well as with high spectral resolution (4,5). However, most of these developed techniques compromise imaging speed, field of view, or the spectral resolution to perform interferometric measurements at multiple colors. In the specific application of quantitative phase in studying blood diseases and red blood cells, current techniques lack the required sensitivity to quantify biological properties of interest at individual cell level. Recently, we have set out to develop a stable quantitative interferometric microscope allowing for measurements of such properties for red cells without compromising field of view or speed of the measurements. The feasibility of the approach will be initially demonstrated in measuring dispersion curves of known solutions, followed by measuring biological properties of red cells in sickle cell anemia. References: 1. Mann CJ, Bingham PR, Paquit VC, Tobin KW. Quantitative phase imaging by three-wavelength digital holography. Opt Express. 2008;16(13):9753-64. 2. Park Y, Yamauchi T, Choi W, Dasari R, Feld MS. Spectroscopic phase microscopy for quantifying hemoglobin concentrations in intact red blood cells. Opt Lett. 2009;34(23):3668-70. 3. Hosseini P, Sung Y, Choi Y, Lue N, Yaqoob Z, So P. Scanning color optical tomography (SCOT). Opt Express. 2015;23(15):19752-62. 4. Jung J-H, Jang J, Park Y. Spectro-refractometry of individual microscopic objects using swept-source quantitative phase imaging. Anal Chem. 2013;85(21):10519-25. 5. Rinehart M, Zhu Y, Wax A. Quantitative phase spectroscopy. Biomed Opt Express. 2012;3(5):958-65.

Monuments of the Giza Plateau

Science.gov (United States)

Ruggles, Clive L. N.

The colossal pyramids of the pharaohs Khufu (Cheops), Khafre (Chephren), and Menkaure (Mycerinus) have attracted a huge amount of astronomical interest over the years, both scholarly and popular. Less attention is usually given to the broader context of structures on the Giza Plateau. One of the most notorious ideas connecting the Giza Plateau with astronomy is that the three large pyramids are laid out on the ground so as to reflect the appearance of the three stars of Orion's Belt in the sky. This idea is unsupportable for several reasons but has succeeded in generating huge public interest. Of much greater serious interest is the fact that the three main pyramids were oriented cardinally to extraordinary precision, which raises the questions of why this was important and how it was achieved. Another idea that has attracted serious attention but also some confusion is that the orientations of some narrow shafts within Khufu's pyramid might have been deliberately aligned upon particular stars. The overall layout of monuments on the plateau may certainly have been designed so as to emphasize certain solar phenomena, for symbolic and ideological reasons relating to a dominant sun cult. It is also possible that it formed part of a wider cosmological "master plan" extending to other pyramids and temples up to 20 km distant.

Snow surface microbiome on the High Antarctic Plateau (DOME C).

Science.gov (United States)

Michaud, Luigi; Lo Giudice, Angelina; Mysara, Mohamed; Monsieurs, Pieter; Raffa, Carmela; Leys, Natalie; Amalfitano, Stefano; Van Houdt, Rob

2014-01-01

The cryosphere is an integral part of the global climate system and one of the major habitable ecosystems of Earth's biosphere. These permanently frozen environments harbor diverse, viable and metabolically active microbial populations that represent almost all the major phylogenetic groups. In this study, we investigated the microbial diversity in the surface snow surrounding the Concordia Research Station on the High Antarctic Plateau through a polyphasic approach, including direct prokaryotic quantification by flow cytometry and catalyzed reporter deposition fluorescence in situ hybridization (CARD-FISH), and phylogenetic identification by 16S RNA gene clone library sequencing and 454 16S amplicon pyrosequencing. Although the microbial abundance was low (<10(3) cells/ml of snowmelt), concordant results were obtained with the different techniques. The microbial community was mainly composed of members of the Alpha-proteobacteria class (e.g. Kiloniellaceae and Rhodobacteraceae), which is one of the most well-represented bacterial groups in marine habitats, Bacteroidetes (e.g. Cryomorphaceae and Flavobacteriaceae) and Cyanobacteria. Based on our results, polar microorganisms could not only be considered as deposited airborne particles, but as an active component of the snowpack ecology of the High Antarctic Plateau.

Snow surface microbiome on the High Antarctic Plateau (DOME C.

Directory of Open Access Journals (Sweden)

Luigi Michaud

Full Text Available The cryosphere is an integral part of the global climate system and one of the major habitable ecosystems of Earth's biosphere. These permanently frozen environments harbor diverse, viable and metabolically active microbial populations that represent almost all the major phylogenetic groups. In this study, we investigated the microbial diversity in the surface snow surrounding the Concordia Research Station on the High Antarctic Plateau through a polyphasic approach, including direct prokaryotic quantification by flow cytometry and catalyzed reporter deposition fluorescence in situ hybridization (CARD-FISH, and phylogenetic identification by 16S RNA gene clone library sequencing and 454 16S amplicon pyrosequencing. Although the microbial abundance was low (<10(3 cells/ml of snowmelt, concordant results were obtained with the different techniques. The microbial community was mainly composed of members of the Alpha-proteobacteria class (e.g. Kiloniellaceae and Rhodobacteraceae, which is one of the most well-represented bacterial groups in marine habitats, Bacteroidetes (e.g. Cryomorphaceae and Flavobacteriaceae and Cyanobacteria. Based on our results, polar microorganisms could not only be considered as deposited airborne particles, but as an active component of the snowpack ecology of the High Antarctic Plateau.

Plateau iris secondary to iridociliary cysts.

Science.gov (United States)

Vila-Arteaga, J; Díaz-Céspedes, R A; Suriano, M M

2015-11-01

We present a case of plateau iris and glaucoma due to multiple unilateral iridociliary cysts. The patient was treated with iridotomy Nd: YAG laser and 360° iridoplasty, without achieving pressure control. Phacoemulsification improved the hypertension. Dynamic gonioscopy and OCT of the anterior chamber was also performed before and after treatment. Iridociliary cysts are a benign condition that can cause iris plateau configuration, and can produce a difficult to treat ocular hypertension. Cystotomy, peripheral iridoplasty, and other treatments have been proposed. Copyright © 2014 Sociedad Española de Oftalmología. Published by Elsevier España, S.L.U. All rights reserved.

Hexabromocyclododecane in alpine fish from the Tibetan Plateau, China

International Nuclear Information System (INIS)

Zhu, Nali; Fu, Jianjie; Gao, Yan; Ssebugere, Patrick; Wang, Yawei; Jiang, Guibin

2013-01-01

Hexabromocyclododecanes (HBCDs) has just been listed into Stockholm Convention as a persistent organic pollutant recently. This paper studied the HBCDs in 79 wild fish from high mountain lakes and rivers of the Tibetan Plateau. The ∑HBCDs in fish muscles ranged from non detectable levels to 13.7 ng/g lipid weight (lw) (mean value of 2.12 ng/g lw) with a high detection frequency of 65.8%. α-HBCD dominated among the isomers and accounted for 78.2% of the total burden. Concentrations of ∑HBCDs in the fish were significantly correlated with the lipid content . A decreasing trend was observed between α-HBCD and trophic level. Positive correlation was also noted between the HBCD levels in fish from lakes and the annual precipitation, and this implied the long-range atmospheric transport of HBCDs to the Tibet Plateau. This was the first work to widely explore HBCDs contamination in the aquatic ecosystems of the Tibetan Plateau. -- Highlights: •HBCDs were ubiquitous in fish of the Tibetan Plateau. •α-HBCD showed a negative correlation with TL in the Lhasa River aquatic food web. •Concentrations of ∑HBCD were significantly correlated with lipid contents of fish. -- HBCD was ubiquitous in fish of the Tibetan Plateau, and its concentration was significantly correlated with lipid content

Multi-phase induced inflation in theories with non-minimal coupling to gravity

Energy Technology Data Exchange (ETDEWEB)

Artymowski, Michał [Institute of Physics, Jagiellonian University, Łojasiewicza 11, 30-348 Kraków (Poland); Lalak, Zygmunt; Lewicki, Marek, E-mail: Michal.Artymowski@uj.edu.pl, E-mail: Zygmunt.Lalak@fuw.edu.pl, E-mail: Marek.Lewicki@fuw.edu.pl [Institute of Theoretical Physics, Faculty of Physics, University of Warsaw ul. Hoża 69, 00-681 Warszawa (Poland)

2017-01-01

In this paper we investigate the induced inflation with two flat regions: one Starobinsky-like plateau in strong coupling regime and one shorter plateau around the saddle point of the Einstein frame potential. This multi-phase inflationary scenario can be used to solve problems of classical cosmology as well as the problem of initial conditions for inflation. The inflation at the saddle-point plateau is consistent with the data and can have arbitrarily low scale. The results can be useful in the context of the Higgs-Axion relaxation and in a certain limit they are equivalent to the α-attractors.

Geodynamics of oceanic plateau and plume head accretion and their role in Phanerozoic orogenic systems of China

Directory of Open Access Journals (Sweden)

Peter G. Betts

2015-01-01

Full Text Available We present three 3D numerical models of deep subduction where buoyant material from an oceanic plateau and a plume interact with the overriding plate to assess the influence on subduction dynamics, trench geometry, and mechanisms for plateau accretion and continental growth. Transient instabilities of the convergent margin are produced, resulting in: contorted trench geometry; trench migration parallel with the plate margin; folding of the subducting slab and orocline development at the convergent margin; and transfer of the plateau to the overriding plate. The presence of plume material beneath the oceanic plateau causes flat subduction above the plume, resulting in a “bowed” shaped subducting slab. In plateau-only models, plateau accretion at the edge of the overriding plate results in trench migration around the edge of the plateau before subduction is re-established directly behind the trailing edge of the plateau. The plateau shortens and some plateau material subducts. The presence of buoyant plume material beneath the oceanic plateau has a profound influence on the behaviour of the convergent margin. In the plateau + plume model, plateau accretion causes rapid trench advance. Plate convergence is accommodated by shearing at the base of the plateau and shortening in the overriding plate. The trench migrates around the edge of the plateau and subduction is re-established well behind the trailing edge of the plateau, effectively embedding the plateau into the overriding plate. A slab window forms beneath the accreted plateau and plume material is transferred from the subducting plate to the overriding plate through the window. In all of the models, the subduction zone maintains a relatively stable configuration away from the buoyancy anomalies within the downgoing plate. The models provide a dynamic context for plateau and plume accretion in Phanerozoic accretionary orogenic systems such as the East China Orogen and the Central Asian

Greenhouse gases emissions in rivers of the Tibetan Plateau.

Science.gov (United States)

Qu, Bin; Aho, Kelly Sue; Li, Chaoliu; Kang, Shichang; Sillanpää, Mika; Yan, Fangping; Raymond, Peter A

2017-11-29

Greenhouse gases (GHGs) emissions from streams are important to regional biogeochemical budgets. This study is one of the first to incorporate stream GHGs (CO 2 , CH 4 and N 2 O) concentrations and emissions in rivers of the Tibetan Plateau. With one-time sampling from 32 sites in rivers of the plateau, we found that most of the rivers were supersaturated with CO 2 , CH 4 and N 2 O during the study period. Medians of partial pressures of CO 2 (pCO 2 ), pCH 4 and pN 2 O were presented 864 μatm, 6.3 μatm, and 0.25 μatm respectively. Based on a scaling model of the flux of gas, the calculated fluxes of CO 2 , CH 4 and N 2 O (3,452 mg-C m 2 d -1 , 26.7 mg-C m 2 d -1 and 0.18 mg-N m 2 d -1 , respectively) in rivers of the Tibetan Plateau were found comparable with most other rivers in the world; and it was revealed that the evasion rates of CO 2 and CH 4 in tributaries of the rivers of the plateau were higher than those in the mainstream despite its high altitude. Furthermore, concentrations of GHGs in the studied rivers were related to dissolved carbon and nitrogen, indicating that riverine dissolved components could be used to scale GHGs envision in rivers of the Tibetan Plateau.

Medial tibial plateau morphology and stress fracture location: A magnetic resonance imaging study

OpenAIRE

Yukata, Kiminori; Yamanaka, Issei; Ueda, Yuzuru; Nakai, Sho; Ogasa, Hiroyoshi; Oishi, Yosuke; Hamawaki, Jun-ichi

2017-01-01

AIM To determine the location of medial tibial plateau stress fractures and its relationship with tibial plateau morphology using magnetic resonance imaging (MRI). METHODS A retrospective review of patients with a diagnosis of stress fracture of the medial tibial plateau was performed for a 5-year period. Fourteen patients [three female and 11 male, with an average age of 36.4 years (range, 15-50 years)], who underwent knee MRI, were included. The appearance of the tibial plateau stress fract...

Plateau iris Íris em platô

Directory of Open Access Journals (Sweden)

Alberto Diniz Filho

2008-10-01

Full Text Available The term plateau iris was first coined in 1958 to describe the iris configuration of a patient. Two years later the concept of plateau iris was published. In 1977, the plateau iris configuration was classically defined as presurgical changes of an eye with a relative normal central anterior chamber depth, flat iris by conventional biomicroscopy, but displaying an extremely narrow or closed angle on gonioscopic examination. On the other hand, the plateau iris syndrome was defined as an acute glaucoma crisis in one eye with a relative normal central anterior chamber depth and patent iridotomy on direct examination, presenting angle closure confirmed by gonioscopic examination after mydriasis. In 1992, the anatomic aspects of plateau iris were studied using ultrasound biomicroscopy. Finally, plateau iris has been considered an anatomic variant of iris structure in which the iris periphery angulates sharply forward from its insertion point and then again angulates sharply and centrally backward, along with an anterior positioning of the ciliary processes seen on ultrasound biomicroscopy. The clinical treatment of plateau iris syndrome is carried out with topical use of pilocarpine. However, the definitive treatment should be fulfilled by performing an argon laser peripheral iridoplasty.O termo íris em platô foi primeiramente inventado em 1958 para descrever a configuração da íris de um paciente. Dois anos depois o conceito de íris em platô foi publicado. Em 1977, a configuração de íris em platô foi classicamente definida como alterações pré-cirúrgicas de um olho com uma profundidade de câmara anterior relativamente normal, íris plana pela biomicroscopia convencional, mas mostrando um ângulo extremamente estreito ou fechado pela gonioscopia. Por outro lado, a síndrome de íris em platô foi definida como uma crise de glaucoma agudo em um olho com uma profundidade de câmara anterior relativamente normal e uma iridectomia patente ao

Hydrogen storage performance of Ti-V-based BCC phase alloys with various Fe content

International Nuclear Information System (INIS)

Yu, X.B.; Feng, S.L.; Wu, Z.; Xia, B.J.; Xu, N.X.

2005-01-01

The effect of Fe content on hydrogen storage characteristics of Ti-10Cr-18Mn-(32-x)V-xFe (x = 0, 2, 3, 4, 5) alloys has been investigated at 353 K. The X-ray diffraction (XRD) patterns and scanning electron microscopy (SEM) images of the alloys present BCC and C14 two-phase structures for all of the Fe-containing alloys. With the increasing Fe content, the lattice parameters of the BCC phase decrease, which results in an increase of the hydrogen desorption plateau pressure of the alloys. Among the studied alloys, Ti-10Cr-18Mn-27V-5Fe alloy exhibits the smallest PCT plateau slope and a more suitable plateau pressure (0.1 MPa equ <1 MPa). The maximum and effective capacities of the alloy are 3.32 wt.% and 2.26 wt.%, respectively, which are higher than other reported Fe-containing BCC phase alloys. In addition, the V/Fe ratio in this alloy is close to that of (VFe) alloy, whose cost is much lower than that of pure V

Human occupation and environmental change in Holocene from a case of XDW2 relic site in the Tibetan Plateau at above 4000 meters above sea level.

Science.gov (United States)

Hou, G.; Li, F.; Zhu, Y.

2017-12-01

XDW2 is an important microlithic cultural relics with continuous stratum that is located in the the Tibetan plateau at above 4,000 masl, wich is a window of revealing the evolution of early human activities and the response and adaptation to extreme environmental in the principal part of Tibetan plateau. So it has important research significance. The analysis on human activity indicator(stoneware, potsherds) and environmental indicators(magnetic susceptibility, color, granularity and pollen) showed: the winter wind and dust storm intensity is weak in this area during 7.0-6 cal. Ka BP, pedogenesis is strong, the climate is humid, environment is suitable relatively, when is Holocene Megathermal; the active phase of microlithic human activities occurred during 7.2-6 cal. ka BP, and quickly weakened after 6 cal. ka BP. The number of stone tools reveal that human activities are concentrated before and after 7-6.2 cal. ka BP, charcoal fragmental concentration indicates that microlithic human activity reached the peak at around 6.7 cal. ka BP. Thus relatively suitable environment during Holocene Megathermal is the important motivating factor of active hunter-gatherer activities in the principal part of Tibetan plateau. After 6 cal. ka BP, summer monsoon weakened rapidly, agricultural growers in the Loess Plateau began to expand towards the plateau, under the effect of environmental degradation and new technologies, microlithic hunter-gatherers in the principal part of plateau moved towards the river valley at low altitude, and learnt settlement and plantation, microlithic activity in the main plateau began to decline.

Oxygen-18 in present-day precipitation on the Tibetan Plateau

Institute of Scientific and Technical Information of China (English)

章新平; 姚檀栋; 中尾正义

2001-01-01

The temporal and spatial variations of the δ18O in precipitation on the Tibetan Plateau are analyzed. There is no temperature effect in the southern Tibetan Plateau. Amount effect has been observed at Lhasa station. However, the seasonal variations of the δ18O in precipitation are different from that of precipitation intensity, showing that the precipitation intensity is not a main controlling factor on the stable isotopic compositions in precipitation in the southern Tibetan Plateau. There is notable temperature effect in the middle and northern Tibetan Plateau. The seasonal variations of the δ18O in precipitation are almost consistent with those of air temperature there, indicating that temperature is a main factor controlling the stable isotopic variations in precipitation. A meridional cross-section shows that a notable depletion of the stable isotopic ratio in precipitation takes place in the Himalayas due to very strong rainout of vapor as it rises over the Himalayas, then the δ18O remains basi

Industrialization of Polymer Solar Cells – phase 1

DEFF Research Database (Denmark)

Lauritzen, Hanne; Bork, Jakob; Andersen, Rasmus B.

into more refined products. Such refined products might be self-powered electronic devices designed for easy integration in the customer’s production or solar-powered products for the end-user. A three-phased project with the objective to industrialize DTU’s basic polymer solar cell technology was started...... in the summer of 2009. The technology comprises a specific design of the polymer solar cell and a corresponding roll-to-roll manufacturing process. This basic technology is referred to as ProcessOne in the open literature. The present report relates to the project’s phase 1.The key tasks in phase 1...... to a slot-die printing head manufactured in DTU’s workshop. The line was at the same time adjusted and updated to handle the new production. The very first solar cells produced on this line appeared in July 2010. The line has subse-quently been upgraded on a running basis, and Mekoprint’s operators have...

Selection of G1 Phase Yeast Cells for Synchronous Meiosis and Sporulation.

Science.gov (United States)

Stuart, David T

2017-01-01

Centrifugal elutriation is a procedure that allows the fractionation of cell populations based upon their size and shape. This allows cells in distinct cell cycle stages can be captured from an asynchronous population. The technique is particularly helpful when performing an experiment to monitor the progression of cells through the cell cycle or meiosis. Yeast sporulation like gametogenesis in other eukaryotes initiates from the G1 phase of the cell cycle. Conveniently, S. cerevisiae arrest in G1 phase when starved for nutrients and so withdrawal of nitrogen and glucose allows cells to abandon vegetative growth in G1 phase before initiating the sporulation program. This simple starvation protocol yields a partial synchronization that has been used extensively in studies of progression through meiosis and sporulation. By using centrifugal elutriation it is possible to isolate a homogeneous population of G1 phase cells and induce them to sporulate synchronously, which is beneficial for investigating progression through meiosis and sporulation. An additionally benefit of this protocol is that cell populations can be isolated based upon size and both large and small cell populations can be tested for progression through meiosis and sporulation. Here we present a protocol for purification of G1 phase diploid cells for examining synchronous progression through meiosis and sporulation.

Behavior of Colorado Plateau uranium minerals during oxidation

Science.gov (United States)

Garrels, Robert Minard; Christ, C.L.

1956-01-01

Uranium occurs as U(VI) and U(IV) in minerals of the Colorado Plateau ores. The number of species containing U(VI) is large, but only two U(IV) minerals are known from the Plateau: uraninite, and oxide, and coffinite, a hydroxy-silicate. These oxidize to yield U(VI) before reacting significantly with other mineral constituents. Crystal-structure analysis has shown that U(VI) invariable occurs as uranyl ion, UO2+2. Uranyl ion may form complex carbonate or sulfate ions with resulting soluble compounds, but only in the absence of quinquevalent vanadium, arsenic, or phosphorous. In the presence of these elements in the +5 valence state, the uranyl ion is fixed in insoluble layer compounds formed by union of uranyl ion with orthovanadate, orthophosphate, or orthoarsenate. Under favorable conditions UO2+2 may react to form the relatively insoluble rutherfordine, UO2CO3, or hydrated uranyl hydroxides. These are rarely found on the Colorado Plateau as opposed to their excellent development in other uraniferous areas, a condition which is apparently related to the semiarid climate and low water table of the Plateau. Uranium may also be fixed as uranyl silicate, but little is known about minerals of this kind. In the present study emphasis has been placed on a detailing of the chemical and crystal structural changes which occur in the oxidation paragenetic sequence.

The Caribbean-Colombian cretaceous igneous province: The internal anatomy of an oceanic plateau

Science.gov (United States)

Kerr, Andrew C.; Tarney, John; Marriner, Giselle F.; Nivia, Alvaro; Saunders, Andrew D.

The Late Cretaceous Caribbean—Colombian igneous province is one of the world's best-exposed examples of a plume-derived oceanic plateau. The buoyancy of the plateau (resulting from residual heat and thick crust) kept it from being totally subducted as it moved eastward with the Farallon Plate from its site of generation in the eastern Pacific and encountered a destructive plate margin. In effect, the plateau makes up much of the Caribbean Plate; it is well exposed around its margins, but more so in accreted terranes in western Colombia (including the well-known Gorgona komatiites and Bolívar mafic/ultramafic cumulates). Compositionally, the lavas of the plateau form three groups: (a) basalts, picrites, and komatiites with light-rare-earth-element (LREE)-depleted chondrite-normalised patterns; (b) basalts with LREE-enriched patterns; and (c) basalts with essentially flat REE patterns (the most dominant type) similar to many of the basalts from the Ontong Java Plateau. These three types demonstrate the heterogeneous nature of the mantle plume source region. The picrites and the komatiites seem to lie nearer the base of the plateau than the more homogeneous basalts; thus, the more MgO-rich melts may have been erupted before large magma chambers had a chance to develop. A reconstructed crustal cross section through the plateau consists of dunitic and pyroxenitic cumulates near the base which are overlain by layered olivine-rich gabbros and more isotropic gabbros. The lowermost eruptive sequence comprises compositionally heterogeneous picrites/komatiites overlain by more homogeneous pillow basalts. Spectacular hornblende-plagioclase veins cut the Bolívar assemblage and these may represent local partial melts of the plateau's base as it was thrusted onto the continent. Subduction-related batholiths and extrusive rocks found around the margin of the province are of two distinct ages; one suite represents pre-plateau collision-related volcanism whereas the other suite

[Correlation between morphogical factor of lateral plateau fracture and meniscus injury].

Science.gov (United States)

Bai, L; Zhou, W; Zhang, W T; Huang, W; You, T; Chen, P; Zhang, H L

2016-04-18

To analyze morphological character of lateral tibial plateau fracture fragment, and its correlation to the presence of a meniscus injury in tibial plateau fractures. A total of 79 consecutive patients of the simple lateral tibial plateau fractures from July 2011 to July 2015 were included in this study, with 65 males and 14 females with an average age of (34.3±7.2) years and 22-61 years. According to Schatzker classification, 21 cases were of Type I, 41 cases Type II, and 17 cases Type III. The characteristics of lateral tibial plateau fractures were evaluated by plain X-ray and magnetic resonance imaging (MRI). The type and severity of meniscus injury were diagnosed by MRI scan. Three-dimensional measurements of the lateral fragment width (LFW), the lateral plateau depression (LPD), the coronal angulation of lateral fragment (CALF), and tibial plateau widening (TPW) were measured with Picture Archiving and Communication Systems(PACS) software. The patients with and without meniscus injuries were divided into different groups and analyzed respectively. Comparison of the above measurements between the two groups was analyzed by independent t test. In all the 79 lateral tibial plateau fracture patients, 26 cases (32.9%) of meniscus injuries were detected by MRI. Among all the meniscus injury cases, 3 were of Schatzker I, 16 Schatzker II, and 7 Schatzker III. In meniscus intact group, the average LFW was (22.0±2.8) mm while in meniscus injury group it was (21.3± 3.3) mm (t=-1.008, P=0.317).The average LPD of non meniscus injury group was (5.4±2.8) mm, while in meniscus injury group was (8.7±2.8) mm (t=4.98, P=0.001). The average CALF of the two groups were 9.1°±6.1°and 10.6°± 7.1°, and there was no significant difference between the two groups (t=0.38, P=0.831). The average TPW was (3.0± 1.1) mm, and (4.8±1.7) mm of the two groups. There were significant differences between the two groups (t=5.216, P=0.001). There was no obvious correlation between the

Overcoming the Photovoltage Plateau in Large Bandgap Perovskite Photovoltaics.

Science.gov (United States)

Rajagopal, Adharsh; Stoddard, Ryan J; Jo, Sae Byeok; Hillhouse, Hugh W; Jen, Alex K-Y

2018-05-09

Development of large bandgap (1.80-1.85 eV E g ) perovskite is crucial for perovskite-perovskite tandem solar cells. However, the performance of 1.80-1.85 eV E g perovskite solar cells (PVKSCs) are significantly lagging their counterparts in the 1.60-1.75 eV E g range. This is because the photovoltage ( V oc ) does not proportionally increase with E g due to lower optoelectronic quality of conventional (MA,FA,Cs)Pb(I,Br) 3 and results in a photovoltage plateau ( V oc limited to 80% of the theoretical limit for ∼1.8 eV E g ). Here, we incorporate phenylethylammonium (PEA) in a mixed-halide perovskite composition to solve the inherent material-level challenges in 1.80-1.85 eV E g perovskites. The amount of PEA incorporation governs the topography and optoelectronic properties of resultant films. Detailed structural and spectroscopic characterization reveal the characteristic trends in crystalline size, orientation, and charge carrier recombination dynamics and rationalize the origin of improved material quality with higher luminescence. With careful interface optimization, the improved material characteristics were translated to devices and V oc values of 1.30-1.35 V were achieved, which correspond to 85-87% of the theoretical limit. Using an optimal amount of PEA incorporation to balance the increase in V oc and the decrease in charge collection, a highest power conversion efficiency of 12.2% was realized. Our results clearly overcome the photovoltage plateau in the 1.80-1.85 eV E g range and represent the highest V oc achieved for mixed-halide PVKSCs. This study provides widely translatable insights, an important breakthrough, and a promising platform for next-generation perovskite tandems.

Forced convection heat transfer with slurry of phase change material in circular ducts: A phenomenological approach

International Nuclear Information System (INIS)

Royon, Laurent; Guiffant, Gerard

2008-01-01

A model describing the thermal behaviour of a slurry of phase change material flow in a circular duct is presented. Reactors connected in series are considered for the representation of the circular duct with constant wall temperature. A phenomenological equation is formulated to take account of the heat generation due to phase change in the particles. Results of the simulation present a plateau of temperature along the longitudinal direction, characteristic of the phase change. The effect of different parameters such as the Reynolds number, the weight fraction and the temperature of the cold spring on the length of the plateau is analysed. A correlation resulting from numerical results is proposed for use in the determination of the characteristics of the exchanger for a phase change material slurry

Organizational restructuring and career plateauing

NARCIS (Netherlands)

P. Paffen; Hans Timmermans

2009-01-01

This article describes a flexibility program for plateaued professionals in a technical Dutch firm operating in the consultancy sector we will refer to with the pseudonym Greentree Corp. First, we will discuss the impact reorganization had on job-requirements and career opportunities for technical

Black Carbon Radiative Forcing over the Tibetan Plateau

Energy Technology Data Exchange (ETDEWEB)

He, Cenlin; Li, Qinbin; Liou, K. N.; Takano, Y.; Gu, Yu; Qi, L.; Mao, Yuhao; Leung, Lai-Yung R.

2014-11-28

We estimate the snow albedo forcing and direct radiative forcing (DRF) of black carbon (BC) in the Tibetan Plateau using a global chemical transport model in conjunction with a stochastic snow model and a radiative transfer model. Our best estimate of the annual BC snow albedo forcing in the Plateau is 2.9 W m-2 (uncertainty: 1.5–5.0 W m-226 ). We find that BC-snow internal mixing increases the albedo forcing by 40-60% compared with external mixing and coated BC increases the forcing by 30-50% compared with uncoated BC, whereas Koch snowflakes reduce the forcing by 20-40% relative to spherical snow grains. Our best estimate of the annual BC DRF at the top of the atmosphere is 2.3 W m-2 (uncertainty: 0.7–4.3 W m-230 ) in the Plateau after scaling the modeled BC absorption optical depth to Aerosol Robotic Network (AERONET) observations. The BC forcings are attributed to emissions from different regions.

Into Tibet: An Early Pliocene Dispersal of Fossil Zokor (Rodentia: Spalacidae) from Mongolian Plateau to the Hinterland of Tibetan Plateau.

Science.gov (United States)

Li, Qiang; Wang, Xiaoming

2015-01-01

This paper reports the fossil zokors (Myospalacinae) collected from the lower Pliocene (~4.4 Ma) of Zanda Basin, southwestern Tibet, which is the first record in the hinterland of Tibetan Plateau within the Himalayan Range. Materials include 29 isolated molars belonging to Prosiphneus eriksoni (Schlosser, 1924) by having characters including large size, highly fused roots, upper molars of orthomegodont type, m1 anterior cap small and centrally located, and first pair of m1 reentrants on opposing sides, high crowns, and high value of dentine tract parameters. Based on the cladistics analysis, all seven species of Prosiphneus and P. eriksoni of Zanda form a monophyletic clade. P. eriksoni from Zanda, on the other hand, is nearly the terminal taxon of this clade. The appearance of P. eriksoni in Zanda represents a significant dispersal in the early Pliocene from its center of origin in north China and Mongolian Plateau, possibly via the Hol Xil-Qiangtang hinterland in northern Tibet. The fast evolving zokors are highly adapted to open terrains at a time when regional climates had become increasingly drier in the desert zones north of Tibetan Plateau during the late Miocene to Pliocene. The occurrence of this zokor in Tibet thus suggests a rather open steppe environment. Based on fossils of large mammals, we have formulated an "out of Tibet" hypothesis that suggests earlier and more primitive large mammals from the Pliocene of Tibet giving rise to the Ice Age megafauna. However, fossil records for large mammals are still too poor to evaluate whether they have evolved from lineages endemic to the Tibetan Plateau or were immigrants from outside. The superior record of small mammals is in a better position to address this question. With relatively dense age intervals and numerous localities in much of northern Asia, fossil zokors provide the first example of an "into Tibet" scenario--earlier and more primitive taxa originated from outside of the Tibetan Plateau and the

Plateau inflation in R-parity violating MSSM

Directory of Open Access Journals (Sweden)

Girish Kumar Chakravarty

2016-12-01

Full Text Available Inflation with plateau potentials give the best fit to the CMB observables as they predict tensor to scalar ratio stringently bounded by the observations from Planck and BICEP2/Keck. In supergravity models it is possible to obtain plateau potentials for scalar fields in the Einstein frame which can serve as the inflation potential by considering higher dimensional Planck suppressed operators and by the choice of non-canonical Kähler potentials. We construct a plateau inflation model in MSSM where the inflation occurs along a sneutrino-Higgs flat direction. A hidden sector Polonyi field is used for the breaking of supersymmetry after the end of the inflation. The proper choice of superpotential leads to strong stabilization of the Polonyi field, mZ2≫m3/22, which is required to solve the cosmological moduli problem. Also, the SUSY breaking results in a TeV scale gravitino mass and scalar masses and gives rise to bilinear and trilinear couplings of scalars which can be tested at the LHC. The sneutrino inflation field can be observed at the LHC as a TeV scale diphoton resonance like the one reported by CMS and ATLAS.

Posterior Slope of the Tibia Plateau in Malaysian Patients Undergoing Total Knee Replacement

Directory of Open Access Journals (Sweden)

R Yoga

2009-05-01

Full Text Available The posterior slope of the tibial plateau is an important feature to preserve during knee replacement. The correct slope aids in the amount of flexion and determines if the knee will be loose on flexion. This is a study on the posterior tibial plateau slope based on preoperative and postoperative radiographs of 100 consecutive patients who had total knee replacements. The average posterior slope of the tibia plateau was 10.1 degrees. There is a tendency for patients with higher pre-operative posterior tibial plateau slope to have higher post-operative posterior tibial plate slope.

Easy labeling of proliferative phase and sporogonic phase of microsporidia Nosema bombycis in host cells.

Directory of Open Access Journals (Sweden)

Jie Chen

Full Text Available Microsporidia are eukaryotic, unicellular parasites that have been studied for more than 150 years. These organisms are extraordinary in their ability to invade a wide range of hosts including vertebrates and invertebrates, such as human and commercially important animals. A lack of appropriate labeling methods has limited the research of the cell cycle and protein locations in intracellular stages. In this report, an easy fluorescent labeling method has been developed to mark the proliferative and sporogonic phases of microsporidia Nosema bombycis in host cells. Based on the presence of chitin, Calcofluor White M2R was used to label the sporogonic phase, while β-tubulin antibody coupled with fluorescence secondary antibody were used to label the proliferative phase by immunofluorescence. This method is simple, efficient and can be used on both infected cells and tissue slices, providing a great potential application in microsporidia research.

New polymers for low-gravity purification of cells by phase partitioning

Science.gov (United States)

Harris, J. M.

1983-01-01

A potentially powerful technique for separating different biological cell types is based on the partitioning of these cells between the immiscible aqueous phases formed by solution of certain polymers in water. This process is gravity-limited because cells sediment rather than associate with the phase most favored on the basis of cell-phase interactions. In the present contract we have been involved in the synthesis of new polymers both to aid in understanding the partitioning process and to improve the quality of separations. The prime driving force behind the design of these polymers is to produce materials which will aid in space experiments to separate important cell types and to study the partitioning process in the absence of gravity (i.e., in an equilibrium state).

Neoclassical resonant transport of a mirror cell

International Nuclear Information System (INIS)

Ito, T.; Katanuma, I.

2005-01-01

The neoclassical resonant plateau transport in a mirror cell is studied theoretically. The analytical expression for a non-square-well magnetic field is obtained. The analytical result is applied to the GAMMA10 tandem mirror [T. Cho, M. Yoshida, J. Kohagura et al., Phys. Rev. Lett. 94, 085002-1 (2005)], which consists of several mirror cells in it, and the confinement time due to the neoclassical resonant plateau transport is determined in each mirror cell. It is found that the neoclassical resonant transport of ions trapped in the nonaxisymmetric anchor mirror cell and transition mirror cells is significantly smaller than those trapped in the central cell

Caffeine inhibits cell proliferation by G0/G1 phase arrest in JB6 cells.

Science.gov (United States)

Hashimoto, Takashi; He, Zhiwei; Ma, Wei-Ya; Schmid, Patricia C; Bode, Ann M; Yang, Chung S; Dong, Zigang

2004-05-01

Caffeine is a major biologically active constituent in coffee and tea. Because caffeine has been reported to inhibit carcinogenesis in UVB-exposed mice, the cancer-preventing effect of caffeine has attracted considerable attention. In the present study, the effect of caffeine in quiescent (G0 phase) cells was investigated. Pretreatment with caffeine suppressed cell proliferation in a dose-dependent manner 36 h after addition of fetal bovine serum as a cell growth stimulator. Analysis by flow cytometry showed that caffeine suppressed cell cycle progression at the G0/G1 phase, i.e., 18 h after addition of fetal bovine serum, the percentages of cells in G0/G1 phase in 1 mM caffeine-treated cells and in caffeine-untreated cells were 61.7 and 29.0, respectively. The percentage of cells in G0/G1 phase at 0 h was 75.5. Caffeine inhibited phosphorylation of retinoblastoma protein at Ser780 and Ser807/Ser811, the sites where retinoblastoma protein has been reported to be phosphorylated by cyclin-dependent kinase 4 (cdk4). Furthermore, caffeine inhibited the activation of the cyclin D1-cdk4 complex in a dose-dependent manner. However this compound did not directly inhibit the activity of this complex. In addition, caffeine did not affect p16INK4 or p27Kip1 protein levels, but inhibited the phosphorylation of protein kinase B (Akt) and glycogen synthase kinase 3beta. Our results showed that caffeine suppressed the progression of quiescent cells into the cell cycle. The inhibitory mechanism may be due to the inhibition of cell growth signal-induced activation of cdk4, which may be involved in the inhibition of carcinogenesis in vivo.

Unusually large unit cell of lipid bicontinuous cubic phase: towards nature's length scales

Science.gov (United States)

Kim, Hojun; Leal, Cecilia

Lipid bicontinuous cubic phases are of great interest for drug delivery, protein crystallization, biosensing, and templates for directing hard material assembly. Structural modulations of lipid mesophases regarding phase identity and unit cell size are often necessary to augment loading and gain pore size control. One important example is the need for unit cells large enough to guide the crystallization of bigger proteins without distortion of the templating phase. In nature, bicontinuous cubic constructs achieve unit cell dimensions as high as 300 nm. However, the largest unit cell of lipid mesophases synthesized in the lab is an order of magnitude lower. In fact, it has been predicted theoretically that lipid bicontinuous cubic phases of unit cell dimensions exceeding 30 nm could not exist, as high membrane fluctuations would damp liquid crystalline order. Here we report non-equilibrium assembly methods of synthesizing metastable bicontinuous cubic phases with unit cell dimensions as high as 70 nm. The phases are stable for very long periods and become increasingly ordered as time goes by without changes to unit cell dimensions. We acknowledge the funding source as a NIH.

Rate-dependent, Li-ion insertion/deinsertion behavior of LiFePO4 cathodes in commercial 18650 LiFePO4 cells.

Science.gov (United States)

Liu, Qi; He, Hao; Li, Zhe-Fei; Liu, Yadong; Ren, Yang; Lu, Wenquan; Lu, Jun; Stach, Eric A; Xie, Jian

2014-03-12

We have performed operando synchrotron high-energy X-ray diffraction (XRD) to obtain nonintrusive, real-time monitoring of the dynamic chemical and structural changes in commercial 18650 LiFePO4/C cells under realistic cycling conditions. The results indicate a nonequilibrium lithium insertion and extraction in the LiFePO4 cathode, with neither the LiFePO4 phase nor the FePO4 phase maintaining a static composition during lithium insertion/extraction. On the basis of our observations, we propose that the LiFePO4 cathode simultaneously experiences both a two-phase reaction mechanism and a dual-phase solid-solution reaction mechanism over the entire range of the flat voltage plateau, with this dual-phase solid-solution behavior being strongly dependent on charge/discharge rates. The proposed dual-phase solid-solution mechanism may explain the remarkable rate capability of LiFePO4 in commercial cells.

Excessive Afforestation and Soil Drying on China's Loess Plateau

Science.gov (United States)

Zhang, Shuilei; Yang, Dawen; Yang, Yuting; Piao, Shilong; Yang, Hanbo; Lei, Huimin; Fu, Bojie

2018-03-01

Afforestation and deforestation as human disturbances to vegetation have profound impacts on ecohydrological processes influencing both water and carbon cycles and ecosystem sustainability. Since 1999, large-scale revegetation activities such as "Grain-to-Green Program" have been implemented across China's Loess Plateau. However, negative ecohydrological consequences, including streamflow decline and soil drying have emerged. Here we estimate the equilibrium vegetation cover over the Loess Plateau based on an ecohydrological model and assess the water balance under the equilibrium and actual vegetation cover over the past decade. Results show that the current vegetation cover (0.48 on average) has already exceeded the climate-defined equilibrium vegetation cover (0.43 on average) in many parts of the Loess Plateau, especially in the middle-to-east regions. This indicates a widespread overplanting, which is found to primarily responsible for soil drying in the area. Additionally, both the equilibrium vegetation cover and soil moisture tend to decrease under future (i.e., 2011-2050) climate scenarios due to declined atmospheric water supply (i.e., precipitation) and increased atmospheric water demand (i.e., potential evapotranspiration). Our findings suggest that further revegetation on the Loess Plateau should be applied with caution. To maintain a sustainable ecohydrological environment in the region, a revegetation threshold is urgently needed to guide future revegetation activities.

Superfluid to normal phase transition and extreme regularity od superdeformed bands

CERN Document Server

Pavlichenkov, I M

2002-01-01

The exact semiclassical expression for the second inertial parameter B for the superfluid and normal phases is derived. Interpolation between these limiting values shows that the function B(I) changes sign at the spin I sub c , which is critical for a rotational spectrum. The quantity B turns out to be a sensitive measure of the change in static pairing correlations. The superfluid-to-normal transition reveals itself in the specific variation of the ratio B/A versus spin I with the plateau characteristic of the normal phase. This dependence is find to be universal for normal deformed and superdeformed nuclei. The long plateau with a small value B/A approx A sup - sup 8 sup / sup 3 explains the extreme regularity of superdeformed bands

Extensional Seismogenic Stress and Tectonic Movement on the Central Region of the Tibetan Plateau

Directory of Open Access Journals (Sweden)

Jiren Xu

2009-01-01

Full Text Available Various earthquake fault types, mechanism solutions and stress fields, as well as GPS and geothermal data are analyzed for the study of the crustal movements on the Tibetan plateau and their tectonic implications. The results show that a lot of the normal faulting type-event concentrated at altitudes greater than 4000 m on the central Tibetan plateau. The altitudes concentrating normal faulting type-events can be zoned two parts: the western part, the Lhasa block, and the eastern part, the Qiangtang-Changdu region. The azimuths of T-axes are in a general E-W direction in the Lhasa block and NW-SE or NNW-SSE in the Qiangtang-Changdu region at the altitudes of the Tibetan plateau. The tensional stresses in E-W direction and NW-SE direction predominate normal faulting earthquake occurrence in the Lhasa block and the Qiangtang-Changdu region, respectively. The slipping displacements of the normal-faulting-type events have great components in near E-W direction and NW-SE direction in the Lhasa block and the Qiangtang-Changdu region, respectively. The extensions are probably an eastward or southeastward extensional motion, being mainly tectonic activity phenomena in the plateau altitudes. The extensional motions due to normal-fault earthquakes are important tectonic activity regimes on the high altitudes of the plateau. The easterly crustal extensions on the plateau are attributable to the gravitational collapse of the high plateau and eastward extrusion of hotter mantle materials beneath the eastern boundary of the plateau. Numbers of thrust-fault and strike-slip-fault earthquakes with strong compressive stress in a general NNE-SSW direction occur on the edges of the plateau.

Aged dissolved organic carbon exported from rivers of the Tibetan Plateau.

Science.gov (United States)

Qu, Bin; Sillanpää, Mika; Li, Chaoliu; Kang, Shichang; Stubbins, Aron; Yan, Fangping; Aho, Kelly Sue; Zhou, Feng; Raymond, Peter A

2017-01-01

The role played by river networks in regional and global carbon cycle is receiving increasing attention. Despite the potential of radiocarbon measurements (14C) to elucidate sources and cycling of different riverine carbon pools, there remain large regions such as the climate-sensitive Tibetan Plateau for which no data are available. Here we provide new 14C data on dissolved organic carbon (DOC) from three large Asian rivers (the Yellow, Yangtze and Yarlung Tsangpo Rivers) running on the Tibetan Plateau and present the carbon transportation pattern in rivers of the plateau versus other river system in the world. Despite higher discharge rates during the high flow season, the DOC yield of Tibetan Plateau rivers (0.41 gC m-2 yr-1) was lower than most other rivers due to lower concentrations. Radiocarbon ages of the DOC were older/more depleted (511±294 years before present, yr BP) in the Tibetan rivers than those in Arctic and tropical rivers. A positive correlation between radiocarbon age and permafrost watershed coverage was observed, indicating that 14C-deplted/old carbon is exported from permafrost regions of the Tibetan Plateau during periods of high flow. This is in sharp contrast to permafrost regions of the Arctic which export 14C-enriched carbon during high discharge periods.

Soil moisture decline due to afforestation across the Loess Plateau, China

Science.gov (United States)

Jia, Xiaoxu; Shao, Ming'an; Zhu, Yuanjun; Luo, Yi

2017-03-01

The Loess Plateau of China is a region with one of the most severe cases of soil erosion in the world. Since the 1950s, there has been afforestation measure to control soil erosion and improve ecosystem services on the plateau. However, the introduction of exotic tree species (e.g., R. pseudoacacia, P. tabulaeformis and C. korshinskii) and high-density planting has had a negative effect on soil moisture content (SMC) in the region. Any decrease in SMC could worsen soil water shortage in both the top and deep soil layers, further endangering the sustainability of the fragile ecosystem. This study analyzed the variations in SMC following the conversion of croplands into forests in the Loess Plateau. SMC data within the 5-m soil profile were collected at 50 sites in the plateau region via field survey, long-term in-situ observations and documented literature. The study showed that for the 50 sites, the depth-averaged SMC was much lower under forest than under cropland. Based on in-situ measurements of SMC in agricultural plots and C. korshinskii plots in 2004-2014, SMC in the 0-4 m soil profile in both plots declined significantly (p resources demands in the Loess Plateau.

ALG-2 knockdown in HeLa cells results in G2/M cell cycle phase accumulation and cell death

DEFF Research Database (Denmark)

Høj, Berit Rahbek; la Cour, Peter Jonas Marstrand; Mollerup, Jens

2009-01-01

downregulation induces accumulation of HeLa cells in the G2/M cell cycle phase and increases the amount of early apoptotic and dead cells. Caspase inhibition by the pan-caspase inhibitor zVAD-fmk attenuated the increase in the amount of dead cells following ALG-2 downregulation. Thus, our results indicate...... that ALG-2 has an anti-apoptotic function in HeLa cells by facilitating the passage through checkpoints in the G2/M cell cycle phase.......ALG-2 (apoptosis-linked gene-2 encoded protein) has been shown to be upregulated in a variety of human tumors questioning its previously assumed pro-apoptotic function. The aim of the present study was to obtain insights into the role of ALG-2 in human cancer cells. We show that ALG-2...

Double subduction of continental lithosphere, a key to form wide plateau

Science.gov (United States)

Replumaz, Anne; Funiciello, Francesca; Reitano, Riccardo; Faccenna, Claudio; Balon, Marie

2016-04-01

The mechanisms involved in the creation of the high and wide topography, like the Tibetan Plateau, are still controversial. In particular, the behaviour of the indian and asian lower continental lithosphere during the collision is a matter of debate, either thickening, densifying and delaminating, or keeping its rigidity and subducting. But since several decades seismicity, seismic profiles and global tomography highlight the lithospheric structure of the Tibetan Plateau, and make the hypotheses sustaining the models more precise. In particular, in the western syntaxis, it is now clear that the indian lithosphere subducts northward beneath the Hindu Kush down to the transition zone, while the asian one subducts southward beneath Pamir (e.g. Negredo et al., 2007; Kufner et al., 2015). Such double subduction of continental lithospheres with opposite vergence has also been inferred in the early collision time. Cenozoic volcanic rocks between 50 and 30 Ma in the Qiangtang block have been interpreted as related to an asian subduction beneath Qiangtang at that time (De Celles et al., 2011; Guillot and Replumaz, 2013). We present here analogue experiments silicone/honey to explore the subduction of continental lithosphere, using a piston as analogue of far field forces. We explore the parameters that control the subductions dynamics of the 2 continental lithospheres and the thickening of the plates at the surface, and compare with the Tibetan Plateau evolution. We show that a continental lithosphere is able to subduct in a collision context, even lighter than the mantle, if the plate is rigid enough. In that case the horizontal force due to the collision context, modelled by the piston push transmitted by the indenter, is the driving force, not the slab pull which is negative. It is not a subduction driving by the weight of the slab, but a subduction induced by the collision, that we could call "collisional subduction".

Early Human Occupation on the Northeast Tibetan Plateau

Science.gov (United States)

Rhode, D.; Madsen, D.; Brantingham, P.; Perrault, C.

2010-12-01

The Tibetan Plateau presents great challenges for human occupation: low oxygen, high ultraviolet radiation, harsh seasonal climate, low overall biological productivity. How and when early humans were able to cope physiologically, genetically, and behaviorally with these extremes is important for understanding the history of human adaptive flexibility. Our investigations of prehistoric human settlement on the northeast Tibetan Plateau focus on (a) establishing well-dated evidence for occupation of altitudes >3000 m, (b) the environmental context of high altitude adaptation, and (c) relations of hunting and pastoralism to lower-altitude agrarian systems. We observe two major prehistoric settlement patterns in the Qinghai Lake area. The earliest, ~15,000-7500 yr old, consists of small isolated firehearths with sparse associated stone tools and wild mammal remains (1). Numerous hearths often occur in the same localities, indicating repeated short-duration occupations by small hunting parties. A second pattern, ~9000-4000 yr old, was established during the Holocene climatic optimum. These sites represent prolonged seasonal residential occupation, containing dark anthropogenic midden, hearth and pit constructions, abundant stone tools, occasional ceramics, and abundant diverse faunal remains (including medium-large mammals but lacking domestic sheep/yak)(2). These Plateau-margin base camps allowed greater intensity of use of the high Plateau. Residential occupation was strongly influenced by nearby lower-altitude farming communities; development of the socioeconomic landscape along the Yellow River likely played at least as great a role in Plateau occupation patterns as did Holocene environmental changes. Holocene vegetation changes in the NE Tibetan Plateau have been attributed to climate (3) or anthropogenic modification (4). Our results document changes in shrub/tree presence from ~12,000-4000 BP, similar to pollen records, that likely reflect climate rather than

G2 phase arrest of cell cycle induced by ionizing radiation

International Nuclear Information System (INIS)

Liu Guangwei; Gong Shouliang

2002-01-01

The exposure of mammalian cells to X rays results in the prolongation of the cell cycle, including the delay or the arrest in G 1 , S and G 2 phase. The major function of G 1 arrest may be to eliminate the cells containing DNA damage and only occurs in the cells with wild type p53 function whereas G 2 arrest following ionizing radiation has been shown to be important in protecting the cells from death and occurs in all cells regardless of p53 status. So the study on G 2 phase arrest of the cell cycle induced by ionizing radiation has currently become a focus at radiobiological fields

Mineralogy and geochemistry of vanadium in the Colorado Plateau

Science.gov (United States)

Weeks, A.D.

1961-01-01

The chief domestic source of vanadium is uraniferous sandstone in the Colorado Plateau. Vanadium is 3-, 4-, or 5-valent in nature and, as oxides or combined with other elements, it forms more than 40 minerals in the Plateau ores. These ores have been studied with regard to the relative amounts of vanadium silicates and oxide-vanadates, uranium-vanadium ratios, the progressive oxidation of black low-valent ores to high-valent carnotite-type ores, and theories of origin. ?? 1961.

Fukushima Nuclear Accident Recorded in Tibetan Plateau Snow Pits

Science.gov (United States)

Wang, Ninglian; Wu, Xiaobo; Kehrwald, Natalie; Li, Zhen; Li, Quanlian; Jiang, Xi; Pu, Jianchen

2015-01-01

The β radioactivity of snow-pit samples collected in the spring of 2011 on four Tibetan Plateau glaciers demonstrate a remarkable peak in each snow pit profile, with peaks about ten to tens of times higher than background levels. The timing of these peaks suggests that the high radioactivity resulted from the Fukushima nuclear accident that occurred on March 11, 2011 in eastern Japan. Fallout monitoring studies demonstrate that this radioactive material was transported by the westerlies across the middle latitudes of the Northern Hemisphere. The depth of the peak β radioactivity in each snow pit compared with observational precipitation records, suggests that the radioactive fallout reached the Tibetan Plateau and was deposited on glacier surfaces in late March 2011, or approximately 20 days after the nuclear accident. The radioactive fallout existed in the atmosphere over the Tibetan Plateau for about one month. PMID:25658094

[Surgical approaches to tibial plateau fractures].

Science.gov (United States)

Krause, Matthias; Müller, Gunnar; Frosch, Karl-Heinz

2018-06-06

Intra-articular tibial plateau fractures can present a surgical challenge due to complex injury patterns and compromised soft tissue. The treatment goal is to spare the soft tissue and an anatomical reconstruction of the tibial articular surface. Depending on the course of the fracture, a fracture-specific access strategy is recommended to provide correct positioning of the plate osteosynthesis. While the anterolateral approach is used in the majority of lateral tibial plateau fractures, only one third of the joint surface is visible; however, posterolateral fragments require an individual approach, e. g. posterolateral or posteromedial. If necessary, osteotomy of the femoral epicondyles can improve joint access for reduction control. Injuries to the posterior columns should be anatomically reconstructed and biomechanically correctly addressed via posterior approaches. Bony posterior cruciate ligament tears can be refixed via a minimally invasive posteromedial approach.

Crystal growth within a phase change memory cell.

Science.gov (United States)

Sebastian, Abu; Le Gallo, Manuel; Krebs, Daniel

2014-07-07

In spite of the prominent role played by phase change materials in information technology, a detailed understanding of the central property of such materials, namely the phase change mechanism, is still lacking mostly because of difficulties associated with experimental measurements. Here, we measure the crystal growth velocity of a phase change material at both the nanometre length and the nanosecond timescale using phase-change memory cells. The material is studied in the technologically relevant melt-quenched phase and directly in the environment in which the phase change material is going to be used in the application. We present a consistent description of the temperature dependence of the crystal growth velocity in the glass and the super-cooled liquid up to the melting temperature.

Progenitors of low-luminosity Type II-Plateau supernovae

Science.gov (United States)

Lisakov, Sergey M.; Dessart, Luc; Hillier, D. John; Waldman, Roni; Livne, Eli

2018-01-01

The progenitors of low-luminosity Type II-Plateau supernovae (SNe II-P) are believed to be red supergiant (RSG) stars, but there is much disparity in the literature concerning their mass at core collapse and therefore on the main sequence. Here, we model the SN radiation arising from the low-energy explosion of RSG stars of 12, 25 and 27 M⊙ on the main sequence and formed through single star evolution. Despite the narrow range in ejecta kinetic energy (2.5-4.2 × 1050 erg) in our model set, the SN observables from our three models are significantly distinct, reflecting the differences in progenitor structure (e.g. surface radius, H-rich envelope mass and He-core mass). Our higher mass RSG stars give rise to Type II SNe that tend to have bluer colours at early times, a shorter photospheric phase, and a faster declining V-band light curve (LC) more typical of Type II-linear SNe, in conflict with the LC plateau observed for low-luminosity SNe II. The complete fallback of the CO core in the low-energy explosions of our high-mass RSG stars prevents the ejection of any 56Ni (nor any core O or Si), in contrast to low-luminosity SNe II-P, which eject at least 0.001 M⊙ of 56Ni. In contrast to observations, Type II SN models from higher mass RSGs tend to show an H α absorption that remains broad at late times (due to a larger velocity at the base of the H-rich envelope). In agreement with the analyses of pre-explosion photometry, we conclude that low-luminosity SNe II-P likely arise from low-mass rather than high-mass RSG stars.

[Carbon balance of household production system in the transition zone from the Loess Plateau to the Qinghai-Tibet Plateau, China].

Science.gov (United States)

Wu, Chao Chao; Gao, Xiao Ye; Hou, Fu Jiang

2017-10-01

The transition zone from the Loess Plateau to the Qinghai-Tibet Plateau is one of the regions with most dramatic changes in agricultural production mode and most sensitive response to the carbon balance effect. This paper analyzed the carbon balance of the agriculture system along the altitude gradient in Tongwei, Weiyuan and Xiahe counties. The results showed that with the increase of altitude, the carbon emission, carbon fixation and carbon sink capacity of crops per unit area decreased accordingly, while the average carbon emission, carbon fixation and carbon source capacity of each household in livestock system increased. The integrated crop-livestock production system changed from carbon sink to carbon source. The average carbon emission of each household rose with altitude, but the carbon fixation was the opposite. The change of percentage ofhousehold in the transition zone from the Loess Plateau to the Qinghai-Tibet Plateau with carbon balance could be fitted with Logistic equation. In the crop system of Tongwei, Weiyuan and Xiahe with the altitude increase, carbon emission at the inflection point where the household percentage accounted for 50.0% was 1491, 857 and 376 kg CE·household -1 , and carbon fixation was 6187, 3872 and 778 kg CE·household -1 , respectively. For the livestock system, carbon emission was 2218, 3725 and 49511 kg CE·household -1 , and carbon fixation was 138, 230 and 2706 kg CE·household -1 , respectively. For the integrated crop-livestock system, carbon emission was 3615, 4583 and 49918 kg CE·household -1 , and carbon fixation was 6289, 4113 and 3819 kg CE·household -1 , respectively, which could be the key point for the regulation of regional carbon balance.

Geologic studies of the Columbia Plateau: a status report

International Nuclear Information System (INIS)

Myers, C.W.; Price, S.M.

1979-10-01

The results of recent geologic studies of the Columbia Plateau, with emphasis on work completed under the Basalt Waste Isolation Project, Rockwell Hanford Operations, are summarized in this report. Geologic studies were performed mostly during the period from 1977 to 1979. The major objective of these studies was to examine the feasibility of using deep underground tunnels mined into Columbia River basalt beneath the Hanford Site for final storage of nuclear waste. The results are presented in four chapters: Introduction; Regional Geology; Pasco Basin Geology; and Seismicity and Tectonics. Results from surface mapping and remote sensing studies in the Washington State portion of the Columbia Plateau are presented in the Regional Geology chapter. Results from surface mapping, borehole studies, and geophysical surveys in the Pasco Basin are presented in the Pasco Basin Geology chapter. Results that relate to the tectonic stability of the Pasco Basin and Columbia Plateau and discussion of findings from earthquake monitoring in the region for the past ten years are summarized in the Seismicity and Tectonics chapter. A volume of Appendices is included. This volume contains a description of study tasks, a description of the methodology used in geophysical surveys the geophysical survey results, a summary of earthquake records in eastern Washington, a description of tectonic provinces, and a preliminary description of the regional tectonic setting of the Columbia Plateau

Enhancing the early differential diagnosis of plateau iris and pupillary block using a-scan ultrasonography.

Directory of Open Access Journals (Sweden)

Yu-Yen Chen

Full Text Available To distinguish the frequently misdiagnosed plateau iris eyes from pupillary block group and normal group, we compared the ocular biometrical parameters of them by A-scan ultrasongraphy.In total, we retrospectively reviewed general characteristics and ocular findings including ocular biometric measurements of 71 normal, 39 plateau iris, and 83 pupillary block eyes.The normal controls, plateau iris group and pupillary block group were significantly different in age, but not in gender. The anterior chamber depth tended to decrease and the lens thickness tended to increase from normal to plateau iris to pupillary block eyes. Compared to those of plateau iris group, the pupillary block group had significantly shallower anterior chamber depth (2.90mm vs. 2.33mm; p<0.001, thicker lens (4.77mm vs. 5.11mm; p<0.001, shorter axial length (23.16mm vs. 22.63mm; p<0.001, smaller relative lens position (2.28 vs. 2.16; p<0.001 and larger lens/axial length factor (2.06 vs. 2.26; p<0.001. However, when comparing plateau iris and normal eyes, only axial length and lens/axial length factor were significantly different (23.16 vs. 23.54; p<0.05 and 2.06 vs. 1.96; p<0.05.Measured by A-scan ultrasonography, the ocular biometrics of plateau iris were significantly different from those of pupillary block eyes. However, our A-scan ultrasongraphy generally found no significant biometric differences between plateau iris and normal eyes. These findings suggest that while A-scan ultrasonography might be used as a practical tool for differentiating plateau iris and papillary block eyes, a more meticulous gonioscopy and other assessments may be necessary to distinguish plateau iris from normal eyes.

Determination of cell cycle phases in live B16 melanoma cells using IRMS.

Science.gov (United States)

Bedolla, Diana E; Kenig, Saša; Mitri, Elisa; Ferraris, Paolo; Marcello, Alessandro; Grenci, Gianluca; Vaccari, Lisa

2013-07-21

The knowledge of cell cycle phase distribution is of paramount importance for understanding cellular behaviour under normal and stressed growth conditions. This task is usually assessed using Flow Cytometry (FC) or immunohistochemistry. Here we report on the use of FTIR microspectroscopy in Microfluidic Devices (MD-IRMS) as an alternative technique for studying cell cycle distribution in live cells. Asynchronous, S- and G0-synchronized B16 mouse melanoma cells were studied by running parallel experiments based on MD-IRMS and FC using Propidium Iodide (PI) staining. MD-IRMS experiments have been done using silicon-modified BaF2 devices, where the thin silicon layer prevents BaF2 dissolution without affecting the transparency of the material and therefore enabling a better assessment of the Phosphate I (PhI) and II (PhII) bands. Hierarchical Cluster Analysis (HCA) of cellular microspectra in the 1300-1000 cm(-1) region pointed out a distribution of cells among clusters, which is in good agreement with FC results among G0/G1, S and G2/M phases. The differentiation is mostly driven by the intensity of PhI and PhII bands. In particular, PhI almost doubles from the G0/G1 to G2/M phase, in agreement with the trend followed by nucleic acids during cellular progression. MD-IRMS is then proposed as a powerful method for the in situ determination of the cell cycle stage of an individual cell, without any labelling or staining, which gives the advantage of possibly monitoring specific cellular responses to several types of stimuli by clearly separating the spectral signatures related to the cellular response from those of cells that are normally progressing.

Non-lethal effects of low- and high-LET radiation on cultured mammalian cells

International Nuclear Information System (INIS)

Walker, J.T.

1982-01-01

In analyzing post-irradiation growth kinetics of cultured mammalian cells, specifically T1-E human cells, this investigation shows that the shift in post-irradiation clone-size distributions toward small colonies is due to both radiation-induced division delay and increased generation times of the irradiated population. Evidence also indicates that the final shape of the final clone-size distribution is influenced by the age density distribution of the parent cells at the time of plating. From computer-generated delay time distributions it was determined that a large percentage of the parent population was found to be in the plateau phase at early growth times and evidence indicates that these cells may contribute heavily to the total population response to radiation

Gravity-Based Precise Cell Manipulation System Enhanced by In-Phase Mechanism

Directory of Open Access Journals (Sweden)

Koji Mizoue

2016-07-01

Full Text Available This paper proposes a gravity-based system capable of generating high-resolution pressure for precise cell manipulation or evaluation in a microfluidic channel. While the pressure resolution of conventional pumps for microfluidic applications is usually about hundreds of pascals as the resolution of their feedback sensors, precise cell manipulation at the pascal level cannot be done. The proposed system successfully achieves a resolution of 100 millipascals using water head pressure with an in-phase noise cancelation mechanism. The in-phase mechanism aims to suppress the noises from ambient vibrations to the system. The proposed pressure system is tested with a microfluidic platform for pressure validation. The experimental results show that the in-phase mechanism effectively reduces the pressure turbulence, and the pressure-driven cell movement matches the theoretical simulations. Preliminary experiments on deformability evaluation with red blood cells under incremental pressures of one pascal are successfully performed. Different deformation patterns are observed from cell to cell under precise pressure control.

(Bos grunniens) in Qinghai-Tibetan Plateau

African Journals Online (AJOL)

DR. NJ TONUKARI

2012-10-30

Oct 30, 2012 ... Qinghai-Tibetan Plateau, as it represents a unique bovine species adapted to ..... al., 1993; Udina et al., 2003), mastitis caused by. Staphylococcus sp. ... for prevention and treatment in many cases (Gerald et al., 2003). But in ...

Topographic heterogeneity and temperature amplitude explain species richness patterns of birds in the Qinghai-Tibetan Plateau.

Science.gov (United States)

Zhang, Chunlan; Quan, Qing; Wu, Yongjie; Chen, Youhua; He, Peng; Qu, Yanhua; Lei, Fumin

2017-04-01

Large-scale patterns of species richness have gained much attention in recent years; however, the factors that drive high species richness are still controversial in local regions, especially in highly diversified montane regions. The Qinghai-Tibetan Plateau (QTP) and the surrounding mountains are biodiversity hot spots due to a high number of endemic montane species. Here, we explored the factors underlying this high level of diversity by studying the relationship between species richness and environmental variables. The richness patterns of 758 resident bird species were summarized at the scale of 1°×1° grid cell at different taxonomic levels (order, family, genus, and species) and in different taxonomic groups (Passeriformes, Galliformes, Falconiformes, and Columbiformes). These richness patterns were subsequently analyzed against habitat heterogeneity (topographical heterogeneity and land cover), temperature amplitude (annual temperature, annual precipitation, precipitation seasonality, and temperature seasonality) and a vegetation index (net primary productivity). Our results showed that the highest richness was found in the southeastern part of the QTP, the eastern Himalayas. The lowest richness was observed in the central plateau of the QTP. Topographical heterogeneity and temperature amplitude are the primary factors that explain overall patterns of species richness in the QTP, although the specific effect of each environmental variable varies between the different taxonomic groups depending on their own evolutionary histories and ecological requirements. High species richness in the southeastern QTP is mostly due to highly diversified habitat types and temperature zones along elevation gradients, whereas the low species richness in the central plateau of the QTP may be due to environmental and energetic constraints, as the central plateau is harsh environment.

Vegetation greenness trend (2000 to 2009) and the climate controls in the Qinghai-Tibetan Plateau

Science.gov (United States)

Zhang, Li; Guo, Huadong; Ji, Lei; Lei, Liping; Wang, Cuizhen; Yan, Dongmei; Li, Bin; Li, Jing

2013-01-01

The Qinghai-Tibetan Plateau has been experiencing a distinct warming trend, and climate warming has a direct and quick impact on the alpine grassland ecosystem. We detected the greenness trend of the grasslands in the plateau using Moderate Resolution Imaging Spectroradiometer data from 2000 to 2009. Weather station data were used to explore the climatic drivers for vegetation greenness variations. The results demonstrated that the region-wide averaged normalized difference vegetation index (NDVI) increased at a rate of 0.036  yr−1. Approximately 20% of the vegetation areas, which were primarily located in the northeastern plateau, exhibited significant NDVI increase trend (p-value plateau. A strong positive relationship between NDVI and precipitation, especially in the northeastern plateau, suggested that precipitation was a favorable factor for the grassland NDVI. Negative correlations between NDVI and temperature, especially in the southern plateau, indicated that higher temperature adversely affected the grassland growth. Although a warming climate was expected to be beneficial to the vegetation growth in cold regions, the grasslands in the central and southwestern plateau showed a decrease in trends influenced by increased temperature coupled with decreased precipitation.

Default cycle phases determined after modifying discrete DNA sequences in plant cells

International Nuclear Information System (INIS)

Sans, J.; Leyton, C.

1997-01-01

After bromosubstituting DNA sequences replicated in the first, second, or third part of the S phase, in Allium cepa L. meristematic cells, radiation at 313 nm wavelength under anoxia allowed ascription of different sequences to both the positive and negative regulation of some cycle phase transitions. The present report shows that the radiation forced cells in late G 1 phase to advance into S, while those in G 2 remained in G 2 and cells in prophase returned to G 2 when both sets of sequences involved in the positive and negative controls were bromosubstituted and later irradiated. In this way, not only G 2 but also the S phase behaved as cycle phases where cells accumulated by default when signals of different sign functionally cancelled out. The treatment did not halt the rates of replication or transcription of plant bromosubstituted DNA. The irradiation under hypoxia apparently prevents the binding of regulatory proteins to Br-DNA. (author)

THE LONG-LIVED UV ''PLATEAU'' OF SN 2012aw

Energy Technology Data Exchange (ETDEWEB)

Bayless, Amanda J.; Roming, Peter W. A. [Southwest Research Institute, Department of Space Science, 6220 Culebra Road, San Antonio, TX 78238 (United States); Pritchard, Tyler A. [Department of Astronomy and Astrophysics, Penn State University, 525 Davey Lab, University Park, PA 16802 (United States); Kuin, Paul [Mullard Space Science Laboratory, Holmbury St. Mary, Dorking, Surrey RH5 6NT (United Kingdom); Brown, Peter J. [Texas A and M University, Department of Physics and Astronomy, College Station, TX 77843-4242 (United States); Botticella, Maria Teresa; Dall' Ora, Massimo [INAF-Osservatorio Astronomico di Capodimonte, via Moiariello 16, I-80131 Napoli (Italy); Frey, Lucille H.; Even, Wesley; Fryer, Chris L. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Maund, Justyn R.; Fraser, Morgan [Astrophysics Research Center, School of Mathematics and Physics, Queen' s University Belfast, Belfast BT7 1NN (United Kingdom)

2013-02-10

Observations with the Swift UV Optical Telescope have unambiguously uncovered for the first time a long-lived, UV ''plateau'' in a Type II-P supernova (SN). Although this flattening in slope is hinted at in a few other SNe, due to its proximity and minimal line-of-sight extinction, SN 2012aw has afforded the first opportunity to clearly observe this UV plateau. The observations of SN 2012aw revealed all Swift UV and u-band light curves initially declined rapidly, but 27 days after the explosion the light curves flattened. Some possible sources of the UV plateau are the same thermal process that causes the optical plateau, heating from radioactive decay, or a combination of both processes.

Thermal radiosensitization in heat- and radiation-sensitive mutants of CHO cells

International Nuclear Information System (INIS)

Kampinga, H.H.; Kanon, B.; Konings, A.W.T.; Stackhouse, M.A.; Bedford, J.S.

1993-01-01

In the current study, the extent of hyperthermic radiosensitization in a new γ-radiation-sensitive cell line, irs-20, recently isolated by Stackhouse and Bedford (1991) and a heat-sensitive mutant hs-36 (Harvey and Bedford 1988) was compared with the radiosensitization of their mutual parent CHO 10B12 cell line. The irs-20 and CHO 10B12 cells have comparable heat (43.5 o C) sensitivities, whereas hs-36 and CHO 10B12 show a similar sensitivity to γ- and X-rays. Radiosensitization due to pre-exposure to 43.5 o C heating of plateau phase cultures was found for all three cell lines, even after relatively mild heat treatment killing <20% of cells. Experiments using CHEF electrophoresis confirmed the dsb repair deficiency of the irs-20 cells (Stackhouse and Bedford 1992) and showed that heat inhibited dsb repair in all three cell lines. (Author)

A Comparative Study of the Electrical Structure of Circum Tibetan Plateau Orogenic Belts and its Tectonic Implications

Science.gov (United States)

Jin, Sheng; Zhang, Letian; Wei, Wenbo; Ye, Gaofeng; Jing, Jianen; Dong, Hao; Xie, Chengliang; Yin, Yaotian

2017-04-01

The Tibetan Plateau, as known as "roof of the world", was created through the on-going continent-continent collision between the Indian and Eurasian plates since 55 Ma. As the process continues, the plateau is growing both vertically and horizontally. The horizontal expansion of the plateau is blocked by the Yangtze block in the east, the Tarim block in the north, and the Ordos block in the northeast, and consequently lead to the formation of the circum Tibetan plateau orogenic belts. To better understand the mechanism behind this process, we conducted a comparative study by collecting 7 magnetotelluric (MT) profiles over the margins of the Tibetan plateau, namely, the INDEPTH 100, 700 and 800 lines in the southern Tibet, the INDEPTH 4000 and 5000 lines across the Altyn Tagh fault on the northern margin of the plateau, as well as other two profiles across the Haiyuan fault and the Longmenshan fault on the northeastern and eastern margins of the plateau deployed under the framework of project SinoProbe. The electrical features of the stable blocks surrounding the Tibetan plateau are generally resistive, while crustal conductive layers are found to be wide spread within the plateau. The southern margin of the Tibetan plateau is characterized by large scale underthrust of the Indian lithosphere beneath the plateau. This intense converging process created the thrust fault system distributed along the southern margin of the Tibetan plateau over 1000 km. Crustal conductive layers discovered in southern Tibet are generally associated with the southward crustal flow that originated from the lower crust within the plateau and exhumed along the thrust belts in the Himalayas. On the eastern margin of the Tibetan plateau, the electrical structures suggest that the Yangtze block wedged into the Tibetan lithosphere and caused decoupling between the crust and upper mantel. Large scale conductors discovered beneath the Songpan-Ganze block reflect that the eastward crustal flow was

Mapping the plateau of novices in virtual reality simulation training of mastoidectomy

DEFF Research Database (Denmark)

A.W. Andersen, Steven; Konge, Lars; Mikkelsen, Peter Trier

2016-01-01

To explore why novices' performance plateau in directed, self-regulated virtual reality (VR) simulation training and how performance can be improved.......To explore why novices' performance plateau in directed, self-regulated virtual reality (VR) simulation training and how performance can be improved....

Plateau Waves of Intracranial Pressure and Partial Pressure of Cerebral Oxygen.

Science.gov (United States)

Lang, Erhard W; Kasprowicz, Magdalena; Smielewski, Peter; Pickard, John; Czosnyka, Marek

2016-01-01

This study investigates 55 intracranial pressure (ICP) plateau waves recorded in 20 patients after severe traumatic brain injury (TBI) with a focus on a moving correlation coefficient between mean arterial pressure (ABP) and ICP, called PRx, which serves as a marker of cerebrovascular reactivity, and a moving correlation coefficient between ABP and cerebral partial pressure of oxygen (pbtO2), called ORx, which serves as a marker for cerebral oxygen reactivity. ICP and ICPamplitude increased significantly during the plateau waves, whereas CPP and pbtO2 decreased significantly. ABP, ABP amplitude, and heart rate remained unchanged. In 73 % of plateau waves PRx increased during the wave. ORx showed an increase during and a decrease after the plateau waves, which was not statistically significant. Our data show profound cerebral vasoparalysis on top of the wave and, to a lesser extent, impairment of cerebral oxygen reactivity. The different behavior of the indices may be due to the different latencies of the cerebral blood flow and oxygen level control mechanisms. While cerebrovascular reactivity is a rapidly reacting mechanism, cerebral oxygen reactivity is slower.

Genetic evidence of paleolithic colonization and neolithic expansion of modern humans on the tibetan plateau.

Science.gov (United States)

Qi, Xuebin; Cui, Chaoying; Peng, Yi; Zhang, Xiaoming; Yang, Zhaohui; Zhong, Hua; Zhang, Hui; Xiang, Kun; Cao, Xiangyu; Wang, Yi; Ouzhuluobu; Basang; Ciwangsangbu; Bianba; Gonggalanzi; Wu, Tianyi; Chen, Hua; Shi, Hong; Su, Bing

2013-08-01

Tibetans live on the highest plateau in the world, their current population size is approximately 5 million, and most of them live at an altitude exceeding 3,500 m. Therefore, the Tibetan Plateau is a remarkable area for cultural and biological studies of human population history. However, the chronological profile of the Tibetan Plateau's colonization remains an unsolved question of human prehistory. To reconstruct the prehistoric colonization and demographic history of modern humans on the Tibetan Plateau, we systematically sampled 6,109 Tibetan individuals from 41 geographic populations across the entire region of the Tibetan Plateau and analyzed the phylogeographic patterns of both paternal (n = 2,354) and maternal (n = 6,109) lineages as well as genome-wide single nucleotide polymorphism markers (n = 50) in Tibetan populations. We found that there have been two distinct, major prehistoric migrations of modern humans into the Tibetan Plateau. The first migration was marked by ancient Tibetan genetic signatures dated to approximately 30,000 years ago, indicating that the initial peopling of the Tibetan Plateau by modern humans occurred during the Upper Paleolithic rather than Neolithic. We also found evidences for relatively young (only 7-10 thousand years old) shared Y chromosome and mitochondrial DNA haplotypes between Tibetans and Han Chinese, suggesting a second wave of migration during the early Neolithic. Collectively, the genetic data indicate that Tibetans have been adapted to a high altitude environment since initial colonization of the Tibetan Plateau in the early Upper Paleolithic, before the last glacial maximum, followed by a rapid population expansion that coincided with the establishment of farming and yak pastoralism on the Plateau in the early Neolithic.

Changes in Cerebral Partial Oxygen Pressure and Cerebrovascular Reactivity During Intracranial Pressure Plateau Waves.

Science.gov (United States)

Lang, Erhard W; Kasprowicz, Magdalena; Smielewski, Peter; Pickard, John; Czosnyka, Marek

2015-08-01

Plateau waves in intracranial pressure (ICP) are frequently recorded in neuro intensive care and are not yet fully understood. To further investigate this phenomenon, we analyzed partial pressure of cerebral oxygen (pbtO2) and a moving correlation coefficient between ICP and mean arterial blood pressure (ABP), called PRx, along with the cerebral oxygen reactivity index (ORx), which is a moving correlation coefficient between cerebral perfusion pressure (CPP) and pbtO2 in an observational study. We analyzed 55 plateau waves in 20 patients after severe traumatic brain injury. We calculated ABP, ABP pulse amplitude (ampABP), ICP, CPP, pbtO2, heart rate (HR), ICP pulse amplitude (ampICP), PRx, and ORx, before, during, and after each plateau wave. The analysis of variance with Bonferroni post hoc test was used to compare the differences in the variables before, during, and after the plateau wave. We considered all plateau waves, even in the same patient, independent because they are separated by long intervals. We found increases for ICP and ampICP according to our operational definitions for plateau waves. PRx increased significantly (p = 0.00026), CPP (p pressure remains stable in ICP plateau waves, while cerebral autoregulatory indices show distinct changes, which indicate cerebrovascular reactivity impairment at the top of the wave. PbtO2 decreases during the waves and may show a slight overshoot after normalization. We assume that this might be due to different latencies of the cerebral blood flow and oxygen level control mechanisms. Other factors may include baseline conditions, such as pre-plateau wave cerebrovascular reactivity or pbtO2 levels, which differ between studies.

Proliferation-dependent changes in amino acid transport and glucose metabolism in glioma cell lines

International Nuclear Information System (INIS)

Sasajima, Toshio; Miyagawa, Tadashi; Oku, Takamitsu; Gelovani, Juri G.; Finn, Ronald; Blasberg, Ronald

2004-01-01

Amino acid imaging is increasingly being used for assessment of brain tumor malignancy, extent of disease, and prognosis. This study explores the relationship between proliferative activity, amino acid transport, and glucose metabolism in three glioma cell lines (U87, Hs683, C6) at different phases of growth in culture. Growth phase was characterized by direct cell counting, proliferation index determined by flow cytometry, and [ 3 H]thymidine (TdR) accumulation, and was compared with the uptake of two non-metabolized amino acids ([ 14 C]aminocyclopentane carboxylic acid (ACPC) and [ 14 C]aminoisobutyric acid (AIB)), and [ 18 F]fluorodeoxyglucose (FDG). Highly significant relationships between cell number (density), proliferation index, and TdR accumulation rate were observed in all cell lines (r>0.99). Influx (K 1 ) of both ACPC and AIB was directly related to cell density, and inversely related to the proliferation index and TdR accumulation in all cell lines. The volume of distribution (V d ) for ACPC and AIB was lowest during rapid growth and highest during the near-plateau growth phase in all cell lines. FDG accumulation in Hs683 and C6 cells was unaffected by proliferation rate, growth phase, and cell density, whereas FDG accumulation was correlated with TdR accumulation, growth phase, and cell density in U87 cells. This study demonstrates that proliferation rate and glucose metabolism are not necessarily co-related in all glioma cell lines. The values of K 1 and V d for ACPC and AIB under different growth conditions suggest that these tumor cell lines can up-regulate amino acid transporters in their cell membranes when their growth conditions become adverse and less than optimal. (orig.)

Cenozoic mountain building on the northeastern Tibetan Plateau

Science.gov (United States)

Lease, Richard O.

2014-01-01

Northeastern Tibetan Plateau growth illuminates the kinematics, geodynamics, and climatic consequences of large-scale orogenesis, yet only recently have data become available to outline the spatiotemporal pattern and rates of this growth. I review the tectonic history of range growth across the plateau margin north of the Kunlun fault (35°–40°N) and east of the Qaidam basin (98°–107°E), synthesizing records from fault-bounded mountain ranges and adjacent sedimentary basins. Deformation began in Eocene time shortly after India-Asia collision, but the northeastern orogen boundary has largely remained stationary since this time. Widespread middle Miocene–Holocene range growth is portrayed by accelerated deformation, uplift, erosion, and deposition across northeastern Tibet. The extent of deformation, however, only expanded ~150 km outward to the north and east and ~150 km laterally to the west. A middle Miocene reorganization of deformation characterized by shortening at various orientations heralds the onset of the modern kinematic regime where shortening is coupled to strike slip. This regime is responsible for the majority of Cenozoic crustal shortening and thickening and the development of the northeastern Tibetan Plateau.

The medicinal plants of Frangensko Plateau (Northeastern Bulgaria)

Science.gov (United States)

Zahariev, Dimcho; Kacheva, Cvetelina

2015-12-01

The Frangensko Plateau is located in the northeastern part of Bulgaria and covers an area of 360 km2. On the territory of the plateau there are two protected areas, as well as two areas of the European ecological network NATURA 2000. The study of the medicinal plants on the territory of the Frangensko Plateau is made for the first time. As a result of our research we found 362 species of vascular plants from 242 genera and 80 families. The most of the families and the genera are represented by a small number of inferior taxa. The analysis of their life form indicates that the hemicryptophytes dominate with 39.50%, followed by the phanerophytes (22.10%). The biological types are represented mainly by perennial herbaceous plants (52.21%), annual herbaceous plants (14.09%) and trees (10.50%). There are 8 types of floristic elements divided in 32 groups. The largest percentage of species is of European type (51.93%). Among the medicinal plants, there are two Balkan endemic species, one Bulgarian endemic species and 30 relic species. Thirty four species with protection statute are described. The anthropophytes among the medicinal plants are 242 species (66.85%).

Enlightening intracellular complexity of living cells with quantitative phase microscopy

Science.gov (United States)

Martinez Torres, C.; Laperrousaz, B.; Berguiga, L.; Boyer Provera, E.; Elezgaray, J.; Nicolini, F. E.; Maguer-Satta, V.; Arneodo, A.; Argoul, F.

2016-03-01

The internal distribution of refractive indices (RIs) of a living cell is much more complex than usually admitted in multi-shell models. The reconstruction of RI maps from single phase images has rarely been achieved for several reasons: (i) we still have very little knowledge of the impact of internal macromolecular complexes on the local RI and (ii) phase changes produced by light propagation through the sample are mixed with diffraction effects by internal cell bodies. We propose the implementation a 2D wavelet-based contour chain detection method to distinguish internal boundaries thanks to their greatest optical path difference gradients. These contour chains correspond to the highest image phase contrast and follow the local RI inhomogeneities linked to the intracellular structural intricacy. Their statistics and spatial distribution are morphological indicators for distinguishing cells of different origins and to follow their transformation in pathologic situations. We use this method to compare non adherent blood cells from primary and laboratory culture origins, in healthy and pathological situations (chronic myelogenous leukaemia). In a second part of this presentation, we concentrate on the temporal dynamics of the phase contour chains and we discuss the spectral decomposition of their dynamics in both health and disease.

TNX GeoSiphon Cell (TGSC-1) Phase II Single Cell Deployment/Demonstration Final Report

Energy Technology Data Exchange (ETDEWEB)

Phifer, M.A.

1999-04-15

This Phase II final report documents the Phase II testing conducted from June 18, 1998 through November 13, 1998, and it focuses on the application of the siphon technology as a sub-component of the overall GeoSiphon Cell technology. [Q-TPL-T-00004

Intraoperative study on anthropometry and gender differences of the proximal tibial plateau at the arthroplasty resection surface.

Science.gov (United States)

Yang, Bo; Yu, Jiakuo; Gong, Xi; Chen, Lianxu; Wang, Yongjian; Wang, Jian; Wang, Haijun; Zhang, Jiying

2014-01-01

The tibial plateau is asymmetric with a larger medial plateau. We observed from clinical practice that the shape of the tibial plateau does not always present a larger medial plateau. Tibial plateau also showed other shapes. The purpose of this study was to analyze the anthropometric data of the proximal tibia in a large group of Chinese patients undergoing total knee arthroplasty and to investigate the morphology of the resected proximal tibial surface and its gender differences. A total of 822 knees (164 males, 658 females) from the Chinese population were measured intraoperatively for medial anteroposterior (MAP) and lateral anteroposterior (LAP) dimensions of the resected proximal tibial surface. The difference of MAP and LAP (DML) was also calculated as MAP minus LAP. We then classified the data into three groups based on the DML (2 mm) to analyze the morphology of the proximal tibia and its distribution between male and female. The shape of proximal tibial plateau was of three types: larger medial plateau type, symmetric type, and larger lateral plateau type. There were significant differences between males and females in relation to the shape distribution of the proximal tibial plateau (P 2 mm and 120 of 822 (14.6%) tibia having a DMLDMLs to better match the different anthropometry of the resected tibial surface.

[The pathogenic ecology research on plague in Qinghai plateau].

Science.gov (United States)

Dai, Rui-xia; Wei, Bai-qing; Li, Cun-xiang; Xiong, Hao-ming; Yang, Xiao-yan; Fan, Wei; Qi, Mei-ying; Jin, Juan; Wei, Rong-jie; Feng, Jian-ping; Jin, Xing; Wang, Zu-yun

2013-12-01

To study the pathogenic ecology characteristics of plague in Qinghai plateau. Applied molecular biology techniques, conventional technologies and geographic information system (GIS) to study phenotypic traits, plasmid spectrum, genotype, infected host and media spectrum etc.of 952 Yersinia pestis strains in Qinghai plateau plague foci, which were separated from different host and media in different regions during 1954 to 2012. The ecotypes of these strains were Qingzang plateau (91.49%, 871/952),Qilian mountain (6.41%, 61/952) and Microtus fuscus (1.26%, 12/952).83.6% (796/952) of these strains contained all the 4 virulence factors (Fr1, Pesticin1,Virulence antigen, and Pigmentation), 93.26% (367/392) were velogenic strains confirmed by virulence test.725 Yersinia pestis strains were separated from Qinghai plateau plague foci carried 9 kinds of plasmid, among which 713 strains from Marmot himalayan plague foci carried 9 kinds of plasmid, the Mr were 6×10(6), 7×10(6), 23×10(6), 27×10(6), 30×10(6), 45×10(6), 52×10(6), 65×10(6) and 92×10(6) respectively. 12 Yersinia pestis strains were separated from Microtus fuscus plague foci carried only 3 kinds of plasmid, the Mr were 6×10(6), 45×10(6), 65×10(6). Meanwhile, the strains carrying large plasmid (52×10(6), 65×10(6) and 92×10(6)) were only distributed in particular geographical location, which had the category property. The research also confirmed that 841 Yersinia pestis strains from two kinds of plague foci in Qinghai plateau had 11 genomovars. The strains of Marmot himalayan plague foci were given priority to genomovar 5 and 8, amounted to 611 strains, genomovar 8 accounted for 56.00% (471/841), genomovar 5 accounted for 23.07% (194/841). Besides, 3 new genomovars, including new 1(62 strains), new 2(52 strains), new 3(48 strains) were newly founded, and 12 strains of Microtus fuscus plague foci were genomovar 14. The main host and media of Qinghai plateau plague foci directly affected the spatial

[Coupling coordinated development of ecological-economic system in Loess Plateau].

Science.gov (United States)

Zhang, Qing-Feng; Wu, Fa-Qi; Wang, Li; Wang, Jian

2011-06-01

Based on system theory, a coupling coordinated development model of ecological-economic system in Loess Plateau was established, and the evaluation criteria and basic types of the coordinated development of the ecological-economic system were proposed. The county-level coupling coordinated development of the ecological-economic system was also discussed, based on the local characteristics. The interactions between the ecological and economic systems in Loess Plateau could be divided into four stages, i.e., seriously disordered development stage, mild-disordered development stage, low-level coordinated development stage, and high level well-coordinated development stage. At each stage, there existed a cyclic process of profit and loss-antagonist-running-dominant-synchronous development. The coupling development degree of the ecological-economic system in Loess Plateau was overall at a lower level, being about 62.7% of the counties at serious disorder, 30.1% of the counties at mild disorder, and 7.1% of the counties at low but coordinated level. The coupling development degree based on the model established in this study could better reflect the current social-economic and ecological environment situations, especially the status of coordination. To fully understand the coupling of ecological-economic system and to adopt appropriate development mode would be of significance to promote the county-level coordinated development in Loess Plateau.

Mapping risk of plague in Qinghai-Tibetan Plateau, China.

Science.gov (United States)

Qian, Quan; Zhao, Jian; Fang, Liqun; Zhou, Hang; Zhang, Wenyi; Wei, Lan; Yang, Hong; Yin, Wenwu; Cao, Wuchun; Li, Qun

2014-07-10

Qinghai-Tibetan Plateau of China is known to be the plague endemic region where marmot (Marmota himalayana) is the primary host. Human plague cases are relatively low incidence but high mortality, which presents unique surveillance and public health challenges, because early detection through surveillance may not always be feasible and infrequent clinical cases may be misdiagnosed. Based on plague surveillance data and environmental variables, Maxent was applied to model the presence probability of plague host. 75% occurrence points were randomly selected for training model, and the rest 25% points were used for model test and validation. Maxent model performance was measured as test gain and test AUC. The optimal probability cut-off value was chosen by maximizing training sensitivity and specificity simultaneously. We used field surveillance data in an ecological niche modeling (ENM) framework to depict spatial distribution of natural foci of plague in Qinghai-Tibetan Plateau. Most human-inhabited areas at risk of exposure to enzootic plague are distributed in the east and south of the Plateau. Elevation, temperature of land surface and normalized difference vegetation index play a large part in determining the distribution of the enzootic plague. This study provided a more detailed view of spatial pattern of enzootic plague and human-inhabited areas at risk of plague. The maps could help public health authorities decide where to perform plague surveillance and take preventive measures in Qinghai-Tibetan Plateau.

Electroporation of micro-droplet encapsulated HeLa cells in oil phase

KAUST Repository

Xiao, Kang; Zhang, Mengying; Chen, Shuyu; Wang, Limu; Chang, Donald Choy; Wen, Weijia

2010-01-01

Electroporation (EP) is a method widely used to introduce foreign genes, drugs or dyes into cells by permeabilizing the plasma membrane with an external electric field. A variety of microfluidic EP devices have been reported so far. However, further integration of prior and posterior EP processes turns out to be very complicated, mainly due to the difficulty of developing an efficient method for precise manipulation of cells in microfluidics. In this study, by means of a T-junction structure within a delicate microfluidic device, we encapsulated HeLa cells in micro-droplet of poration medium in oil phase before EP, which has two advantages: (i) precise control of cell-encapsulating droplets in oil phase is much easier than the control of cell populations or individuals in aqueous buffers; (ii) this can minimize the electrochemical reactions on the electrodes. Finally, we successfully introduced fluorescent dyes into the micro-droplet encapsulated HeLa cells in oil phase. Our results reflected a novel way to realize the integrated biomicrofluidic system for EP. © 2010 Wiley-VCH Verlag GmbH & Co. KGaA.

Electroporation of micro-droplet encapsulated HeLa cells in oil phase

KAUST Repository

Xiao, Kang

2010-08-27

Electroporation (EP) is a method widely used to introduce foreign genes, drugs or dyes into cells by permeabilizing the plasma membrane with an external electric field. A variety of microfluidic EP devices have been reported so far. However, further integration of prior and posterior EP processes turns out to be very complicated, mainly due to the difficulty of developing an efficient method for precise manipulation of cells in microfluidics. In this study, by means of a T-junction structure within a delicate microfluidic device, we encapsulated HeLa cells in micro-droplet of poration medium in oil phase before EP, which has two advantages: (i) precise control of cell-encapsulating droplets in oil phase is much easier than the control of cell populations or individuals in aqueous buffers; (ii) this can minimize the electrochemical reactions on the electrodes. Finally, we successfully introduced fluorescent dyes into the micro-droplet encapsulated HeLa cells in oil phase. Our results reflected a novel way to realize the integrated biomicrofluidic system for EP. © 2010 Wiley-VCH Verlag GmbH & Co. KGaA.

Crystalline phase-dependent eco-toxicity of titania nanoparticles to freshwater biofilms

International Nuclear Information System (INIS)

Li, Kun; Qian, Jin; Wang, Peifang; Wang, Chao; Liu, Jingjing; Tian, Xin; Lu, Bianhe; Shen, Mengmeng

2017-01-01

The potential toxic impacts of different crystal phases of titania nanoparticles (TNPs) on freshwater biofilms, especially under ultraviolet C irradiation (UVC), are unknown. Here, adverse impacts of three phases (anatase, rutile, and P25, 50 mg L −1 respectively) with UVC irradiation (An-UV, Ru-UV, and P25-UV) on freshwater biofilms were conducted. Characterization experiments revealed that rutile TNPs had a higher water environment stability than anatase and P25 TNPs, possessing a stronger photocatalytic activity under UVC irradiation. Phase-dependent inhibition of cell viability and significant decreases of four- and five-fold in algal biomass at 12 h of exposure were observed compared with unexposed biofilms. Moreover, phase-dependent oxidative stress resulted in remarkably significant reductions (P < 0.01) of the photosynthetic yields of the biofilms, to 40.32% (P25-UV), 48.39% (An-UV), and 46.77% (Ru-UV) of the plateau value obtained in the unexposed biofilms. A shift in community composition that manifested as a strong reduction in diatoms, indicating cyanobacteria and green algae were more tolerant than diatoms when exposed to TNPs. In terms of the toxic mechanisms, rutile TNPs resulted in apoptosis by inducing excessive intracellular reactive oxygen species (ROS) production, whereas P25 and anatase TNPs tended to catalyze enormous acellular ROS lead to cell necrosis under UVC irradiation. - Highlights: • Phase-dependent response of freshwater biofilms to three TNPs was studied with UVC. • Rutile is more stable yet P25 and anatase own better photooxidation level in water. • Decrease in Chl-a and φM and a shift in algae bio-cenosis were phase-dependent. • Phase-dependent stress induced cellular or acellular ROS to reduce cells viability. • Rutile tend to induced apoptosis yet P25 and anatase prefer to cause cell necrosis. - Crystalline-dependent eco-toxicity of TNPs to freshwater biofilms show allotrope of nanoparticles must be considered

Estimation of the radiation-induced DNA double-strand breaks number by considering cell cycle and absorbed dose per cell nucleus.

Science.gov (United States)

Mori, Ryosuke; Matsuya, Yusuke; Yoshii, Yuji; Date, Hiroyuki

2018-05-01

DNA double-strand breaks (DSBs) are thought to be the main cause of cell death after irradiation. In this study, we estimated the probability distribution of the number of DSBs per cell nucleus by considering the DNA amount in a cell nucleus (which depends on the cell cycle) and the statistical variation in the energy imparted to the cell nucleus by X-ray irradiation. The probability estimation of DSB induction was made following these procedures: (i) making use of the Chinese Hamster Ovary (CHO)-K1 cell line as the target example, the amounts of DNA per nucleus in the logarithmic and the plateau phases of the growth curve were measured by flow cytometry with propidium iodide (PI) dyeing; (ii) the probability distribution of the DSB number per cell nucleus for each phase after irradiation with 1.0 Gy of 200 kVp X-rays was measured by means of γ-H2AX immunofluorescent staining; (iii) the distribution of the cell-specific energy deposition via secondary electrons produced by the incident X-rays was calculated by WLTrack (in-house Monte Carlo code); (iv) according to a mathematical model for estimating the DSB number per nucleus, we deduced the induction probability density of DSBs based on the measured DNA amount (depending on the cell cycle) and the calculated dose per nucleus. The model exhibited DSB induction probabilities in good agreement with the experimental results for the two phases, suggesting that the DNA amount (depending on the cell cycle) and the statistical variation in the local energy deposition are essential for estimating the DSB induction probability after X-ray exposure.

A pliocene cliff-line around the Giza Pyramids Plateau, Egypt

OpenAIRE

Aigner, Thomas

1982-01-01

Aigner, T., 1983. A Pliocene cliff-line around the Giza Pyramids Plateau, Egypt. Palaeogeogr., Palaeoclimatol., Palaeoecol., 4 2 : 313—322. Escarpments bordering the Giza Pyramids Plateau represent the cliff-line of a Pliocene transgression up the pre-Nile ("Eonile") Valley. Geomorphologically, a limestone cliff can be distinguished from a slip-block shore associated with a distinct fining-up sequence. Differences in bedrock lithology and in structure (Joint pattern, faults) are morphogen...

Crop characteristics and their temporal change on the Loess Plateau of China

NARCIS (Netherlands)

Wu Yongqiu,; Xie Kunqing,; Zhang Qingchun,; Zhnag Yan,; Xie Yun,; Zhang Guanghui,; Zhang Wenbo,; Ritsema, C.J.

2003-01-01

Crop characteristics with obvious seasonal changes strongly influence soil loss. The purpose of this study is to measure and analyze the plant characteristics and their seasonal change in the Loess Plateau. A small watershed, Danangou in the Loess Plateau of north China, was selected for this study.

[Study of blood oxygen saturation, heart rate changes and plateau reaction of the Antarctic Kunlun station investigation team in different plateau environments].

Science.gov (United States)

Zhao, Shun-yun; Wu, Xin-min; Guo, Ya-min; Zhang, Shu-shun; An, Yan-ming; Li, Bing; Wang, Hao

2013-06-11

To explore the blood oxygen saturation and heart rate changes of the Antarctic explorers. During August 2010 to April 2011, the changes in blood oxygen saturation, heart rate and plateau reaction of 16 Antarctic expedition team in different plateau environments (Tibetan plateau versus Antarctic plateau) were monitored with the noninvasive pulse oximeter MD300-C. The extent of acute mountain sickness was determined according to the Lake Louise Consensus acute mountain reaction symptom scores and judgment method. The changes of blood oxygen saturation, heart rate at different altitudes of 110, 3650, 4300 m (96.8% ± 1.2%,89.1% ± 1.2%, 86.1% ± 2.0%, (75.0 ± 5.4) times/min, (104.0 ± 4.3) times/min, (113.0 ± 5.2) times/min,F = 214.155, 240.088,both P rate at different altitudes of 2000, 2500, 3000, 3500 and 4087 m(91.9% ± 1.3%,90.5% ± 1.3%,87.6% ± 1.4%,85.0% ± 1.8%,81.5% ± 2.2%, (85.9 ± 3.2) times/min, (90.6 ± 2.8) times/min, (97.8 ± 4.1) times/min, (102.0 ± 3.4) times/min, (106.3 ± 3.9) times/min, F = 105.418, 90.174, both P rate were both correlated with the risk of altitude sickness (r = -0.446 and 0.565, both P rate of the Antarctic explorers. And with the increases of altitude, the risk of altitude sickness gradually increases.

Study on the relevance of some of the description methods for plateau-honed surfaces

International Nuclear Information System (INIS)

Yousfi, M; Mezghani, S; Demirci, I; El Mansori, M

2014-01-01

Much work has been undertaken in recent years into the determination of a complete parametric description of plateau-honed surfaces with the intention of making a link between the process conditions, the surface topography and the required functional performances. Different advanced techniques (plateau/valleys decomposition using the normalized Abbott–Firestone curve or morphological operators, multiscale decomposition using continuous wavelets transform, etc) were proposed and applied in different studies. This paper re-examines the current state of developments and addresses a discussion on the relevance of the different proposed parameters and characterization methods for plateau-honed surfaces by considering the control loop manufacturing-characterization-function. The relevance of appropriate characterization is demonstrated through two experimental studies. They consider the effect of the most plateau honing process variables (the abrasive grit size and abrasive indentation velocity in finish-honing and the plateau-honing stage duration and pressure) on cylinder liner surface textures and hydrodynamic friction of the ring-pack system. (paper)

Prospects and challenges of quantitative phase imaging in tumor cell biology

Science.gov (United States)

Kemper, Björn; Götte, Martin; Greve, Burkhard; Ketelhut, Steffi

2016-03-01

Quantitative phase imaging (QPI) techniques provide high resolution label-free quantitative live cell imaging. Here, prospects and challenges of QPI in tumor cell biology are presented, using the example of digital holographic microscopy (DHM). It is shown that the evaluation of quantitative DHM phase images allows the retrieval of different parameter sets for quantification of cellular motion changes in migration and motility assays that are caused by genetic modifications. Furthermore, we demonstrate simultaneously label-free imaging of cell growth and morphology properties.

Modulation of the atmospheric quasi-biweekly oscillation on the diurnal variation of the occurrence frequency of the Tibetan Plateau vortices

Science.gov (United States)

Li, Lun; Zhang, Renhe; Wen, Min

2018-06-01

In this study, modulation of the atmospheric quasi-biweekly oscillation (QBWO) on diurnal variation of the occurrence frequency of Tibetan Plateau vortices (TPVs) during May-August of 2000-2009 was investigated. The diurnal variations of the occurrence frequency of the TPVs (OFTPVs) and the related dynamic and thermodynamic features in the positive and negative phases of QBWO were compared. In both the positive and negative phases, the OFTPVs reaches the maximum from evening to midnight (18-00 LT, LT indicates the local time), and minimum from early morning to noon (06-12 LT). At 18 LT, there is strongest convergence at 500 hPa and ascending motion, as well as the most abundant net water vapor budget over the Tibetan Plateau, which is in favor of the precipitation and the related condensation latent heat release, corresponding to the maximum of OFTPVs in 18-00 LT. On the contrary, in the early morning at 06 LT, the conditions are most unfavorable for genesis of TPVs in 06-12 LT. QBWO leads to stronger convergence at 500 hPa, ascending motion as well as more massive water vapor in the positive phases than those in the negative phases, resulting in larger numbers of TPVs occur in all of the four periods of a day (00-06 LT, 06-12 LT, 12-18 LT, and 18-00 LT) in the former. The TPVs generating from the early morning to noon (06-12 LT) are weaker and more sensitive and fragile to the disadvantageous background, while the TPVs occurring from evening to midnight (18-00 LT) are stronger and seem to be well tolerated, leading to more remarkable contrast between the OFTPVs in the negative and positive phases in 06-12 LT than in 18-00 LT.

Complex Medial Meniscus Tears Are Associated With a Biconcave Medial Tibial Plateau.

Science.gov (United States)

Barber, F Alan; Getelman, Mark H; Berry, Kathy L

2017-04-01

To determine whether an association exists between a biconcave medial tibial plateau and complex medial meniscus tears. A consecutive series of stable knees undergoing arthroscopy were evaluated retrospectively with the use of preoperative magnetic resonance imaging (MRI), radiographs, and arthroscopy documented by intraoperative videos. Investigators independently performed blinded reviews of the MRI or videos. Based on the arthroscopy findings, medial tibial plateaus were classified as either biconcave or not biconcave. A transverse coronal plane ridge, separating the front of the tibial plateau from the back near the inner margin of the posterior body of the medial meniscus, was defined as biconcave. The medial plateau slope was calculated with MRI sagittal views. General demographic information, body mass index, and arthroscopically confirmed knee pathology were recorded. A total of 179 consecutive knees were studied from July 2014 through August 2015; 49 (27.2%) biconcave medial tibial plateaus and 130 (72.8%) controls were identified at arthroscopy. Complex medial meniscus tears were found in 103. Patients with a biconcave medial tibial plateau were found to have more complex medial meniscus tears (69.4%) than those without a biconcavity (53.1%) (P = .049) despite having lower body mass index (P = .020). No difference in medial tibial plateau slope was observed for biconcavities involving both cartilage and bone, bone only, or an indeterminate group (P = .47). Biconcave medial tibial plateaus were present in 27.4% of a consecutive series of patients undergoing knee arthroscopy. A biconcave medial tibial plateau was more frequently associated with a complex medial meniscus tear. Level III, case-control study. Copyright © 2016 Arthroscopy Association of North America. All rights reserved.

Exploring the undulating plateau: the future of global oil supply.

Science.gov (United States)

Jackson, Peter M; Smith, Leta K

2014-01-13

In this paper, we analyse the factors that will influence long-term oil supply and describe the future form of the global oil supply profile as an 'undulating plateau' rather than an irreversible, short-term peak or an ever upward trend of increasing production. The ultimate transition from a world of relatively plentiful and cheap oil to one of tight supply and high cost will be slow and challenging. An understanding of the signposts for the future path of supply and the drivers of that profile will be critical to managing the transition. The ultimate form of the global supply curve may well be dictated by demand evolution rather than a limited resource endowment in the longer term. Several factors will probably control future global oil supply. We believe that the scale of global oil resource will not constitute a physical supply limit for at least the next two or three decades. However, all categories of oil resources are already more expensive to develop than in the past, requiring high oil prices to stimulate supply growth. Lower rates of oil demand growth relative to economic growth, combined with more challenging supply growth, will probably lead to an undulating plateau sometime after 2040, with demand from non-Organization for Economic Cooperation and Development states continuing to dominate. Upstream investment requirements and oil price volatility will increase towards and beyond the undulating production plateau. In this new world, high oil prices will induce demand destruction, fuel substitution and ever increasing energy efficiency. As we discuss below, the fundamental differences between the IHS Cambridge Energy Research Associates' (IHS CERA) view of the future of oil supply and many peak oil supply models are the timing of the onset of a dramatic slowdown in the rate of growth of supply and the existence or otherwise of a production plateau. We do not dispute that supply will plateau and eventually fall; the question is when, how and at what price

Modeling the voltage loss mechanisms in lithium-sulfur cells: the importance of electrolyte resistance and precipitation kinetics.

Science.gov (United States)

Zhang, Teng; Marinescu, Monica; O'Neill, Laura; Wild, Mark; Offer, Gregory

2015-09-21

Understanding of the complex electrochemical, transport, and phase-change phenomena in Li-S cells requires experimental characterization in tandem with mechanistic modeling. However, existing Li-S models currently contradict some key features of experimental findings, particularly the evolution of cell resistance during discharge. We demonstrate that, by introducing a concentration-dependent electrolyte conductivity, the correct trends in voltage drop due to electrolyte resistance and activation overpotentials are retrieved. In addition, we reveal the existence of an often overlooked potential drop mechanism in the low voltage-plateau which originates from the limited rate of Li2S precipitation.

Classification Of The Groundwaters Of The Antalya Travertine Plateau By Isotope Techniques

International Nuclear Information System (INIS)

Atilla, O.A.

2002-01-01

The relation between the springs and wells located in Antalya Travertine Plateau is evaluated and classified by using the isotopic composition ({ 3 H(T), ( 18 O), 2 H(D)})of these water resources. The δ 18 O-δD, δ 18 O-TU, δ 18 O-EC, δ 18 O-Cl relations between the water resources in the area are explained and three groups are determined: (1) groundwater with longer residence time discharging in upper plateau and Varsak-Duedenbasi system, (2) groundwater with shorter residence time discharging in the lower plateau, (3) surface waters. The same results obtained by using cluster and principal factor analysis of the hydrogeochemical and isotopic data

Integrated geophysical study of the northeastern margin of Tibetan Plateau

Science.gov (United States)

Shi, L.; Meng, X.; Guo, L.

2011-12-01

Tibetan Plateau, the so-called "Roof of the World", is a direct consequence of collision of the Indian plate with the Eurasian plate starting in the early Cenozoic time. The continent-continent collision is still going on. The northeastern margin of Tibetan Plateau is the front part of the Tibetan Plateau extends to mainland and favorable area for studying uplift and deformation of the Tibetan Plateau. In the past decades, a variety of geophysical methods were conducted to study geodynamics and geological tectonics of this region. We assembled satellite-derived free-air gravity anomalies with a resolution of one arc-minute from the Scripps Institution of Oceanography, and reduced them to obtain Complete Bouguer Gravity Anomalies. Then we gridded Complete Bouguer Gravity Anomalies on a regular grid, and subsequently processed them with the preferential continuation method to attenuate high-frequency noise and analyzed regional and residual anomalies. We also calculated tilt-angle derivative of Complete Bouguer Gravity Anomalies to derive clearer geological structures with more details. Then we calculated the depth distribution of the Moho discontinuity surface in this area by 3D density interface inversion. From the results of preliminary processing, we analyzed the main deep faults and geological tectonics in this region. We extracted seven important profiles' data of Complete Bouguer Gravity Anomalies in this area, and then did forward modeling and inversion on each profile with constraints of geological information and other geophysical data. In the future, we will perform 3D constrained inversion of Complete Bouguer Gravity Anomalies in this region for better understanding deep structure and tectonics of the northeastern margin of Tibetan Plateau. Acknowledgment: We acknowledge the financial support of the SinoProbe project (201011039), the Fundamental Research Funds for the Central Universities (2010ZY26 2011PY0184), and the National Natural Science Foundation

Heterogeneity in cytokinetic, clonogenic, and radiation response induced by nutrient deprivation

International Nuclear Information System (INIS)

Grdina, D.J.; Williamson, K.D.; Johnson, T.S.; Sigdestad, C.P.

1986-01-01

A murine fibrosarcoma cell line (FSA 1233), with a capability to grow in vitro, was used to study biophysical heterogeneity induced by nutrient deprivation. Cell sub-populations were isolated by centrifuging cells through linear Renografin-density gradients. The effects of cell growth to late plateau phase on the cytokinetic, clonogenic, and radiation-survival characteristics were studied. It was observed that with increasing age of the cell culture, an increase in the proportion of relatively dense cells was associated with a decrease in plating efficiency. Cells collected at p=1.08 g/cm 3 have a plating efficiency of 0.2% compared with 0.01% for those isolated at p=1.16 g/cm 3 . Discrepancies were also seen between the tritiated thymidine labeling index (LI) and flow cytometry (FCM, % S phase) for cells collected throughout the gradient. The radiation sensitivities of selected cell populations isolated by density gradient centrifugation were determined and compared with data from a control plateau phase population. 15 refs., 4 figs., 1 tab

Control of Eospalax baileyi (Plateau Zokor) with arrow traps in western China

NARCIS (Netherlands)

Kong, Yang; Xidong, Li; Gaowei, Xu; Wei, Liu; Meerburg, B.G.

2016-01-01

In order to manage Eospalax (Myospalax) baileyi (Plateau zokors) pests with physical method, the efficacy of four different arrow traps was tested to control the plateau zokor in Sichuan Northwest Prairie, China. Population densities of 39.7-42.1 ha-1 were found in the test plots. Such densities

Secretory activity and cell cycle alteration of alveolar type II cells in the early and late phase after irradiation

International Nuclear Information System (INIS)

Willner, Jochen; Vordermark, Dirk; Schmidt, Michael; Gassel, Andreamaria; Flentje, Michael; Wirtz, Hubert

2003-01-01

Purpose: Type II cells and the surfactant system have been proposed to play a central role in pathogenesis of radiation pneumonitis. We analyzed the secretory function and proliferation parameters of alveolar type II cells in the early (until 24 h) and late phase (1-5 weeks) after irradiation (RT) in vitro and in vivo. Methods and Materials: Type II cells were isolated from rats according to the method of Dobbs. Stimulation of secretion was induced with terbutaline, adenosine triphosphate (ATP), and 12-O-tetradecanoylphorbol-13-acetate (TPA) for a 2-h period. Determination of secretion was performed using 3 H-labeled phosphatidylcholine. For the early-phase analysis, freshly isolated and adherent type II cells were irradiated in vitro with 9-21 Gy (stepwise increase of 3 Gy). Secretion stimulation was initiated 1, 6, 24, and 48 h after RT. For late-phase analysis, type II cells were isolated 1-5 weeks after 18 Gy whole lung or sham RT. Each experiment was repeated at least fivefold. Flow cytometry was used to determine cell cycle distribution and proliferating cell nuclear antigen index. Results: During the early-phase (in vitro) analysis, we found a normal stimulation of surfactant secretion in irradiated, as well as unirradiated, cells. No change in basal secretion and no dose effect were seen. During the late phase, 1-5 weeks after whole lung RT, we observed enhanced secretory activity for all secretagogues and a small increase in basal secretion in Weeks 3 and 4 (pneumonitis phase) compared with controls. The total number of isolated type II cells, as well as the rate of viable cells, decreased after the second post-RT week. Cell cycle alterations suggesting an irreversible G 2 /M block occurred in the second post-RT week and did not resolve during the observation period. The proliferating cell nuclear antigen index of type II cells from irradiated rats did not differ from that of controls. Conclusion: In contrast to literature data, we observed no direct

A signature-based method for indexing cell cycle phase distribution from microarray profiles

Directory of Open Access Journals (Sweden)

Mizuno Hideaki

2009-03-01

Full Text Available Abstract Background The cell cycle machinery interprets oncogenic signals and reflects the biology of cancers. To date, various methods for cell cycle phase estimation such as mitotic index, S phase fraction, and immunohistochemistry have provided valuable information on cancers (e.g. proliferation rate. However, those methods rely on one or few measurements and the scope of the information is limited. There is a need for more systematic cell cycle analysis methods. Results We developed a signature-based method for indexing cell cycle phase distribution from microarray profiles under consideration of cycling and non-cycling cells. A cell cycle signature masterset, composed of genes which express preferentially in cycling cells and in a cell cycle-regulated manner, was created to index the proportion of cycling cells in the sample. Cell cycle signature subsets, composed of genes whose expressions peak at specific stages of the cell cycle, were also created to index the proportion of cells in the corresponding stages. The method was validated using cell cycle datasets and quiescence-induced cell datasets. Analyses of a mouse tumor model dataset and human breast cancer datasets revealed variations in the proportion of cycling cells. When the influence of non-cycling cells was taken into account, "buried" cell cycle phase distributions were depicted that were oncogenic-event specific in the mouse tumor model dataset and were associated with patients' prognosis in the human breast cancer datasets. Conclusion The signature-based cell cycle analysis method presented in this report, would potentially be of value for cancer characterization and diagnostics.

Fuel cell power systems for remote applications. Phase 1 final report and business plan

Energy Technology Data Exchange (ETDEWEB)

NONE

1998-02-01

The goal of the Fuel Cell Power Systems for Remote Applications project is to commercialize a 0.1--5 kW integrated fuel cell power system (FCPS). The project targets high value niche markets, including natural gas and oil pipelines, off-grid homes, yachts, telecommunication stations and recreational vehicles. Phase 1 includes the market research, technical and financial analysis of the fuel cell power system, technical and financial requirements to establish manufacturing capability, the business plan, and teaming arrangements. Phase 1 also includes project planning, scope of work, and budgets for Phases 2--4. The project is a cooperative effort of Teledyne Brown Engineering--Energy Systems, Schatz Energy Research Center, Hydrogen Burner Technology, and the City of Palm Desert. Phases 2 through 4 are designed to utilize the results of Phase 1, to further the commercial potential of the fuel cell power system. Phase 2 focuses on research and development of the reformer and fuel cell and is divided into three related, but potentially separate tasks. Budgets and timelines for Phase 2 can be found in section 4 of this report. Phase 2 includes: Task A--Develop a reformate tolerant fuel cell stack and 5 kW reformer; Task B--Assemble and deliver a fuel cell that operates on pure hydrogen to the University of Alaska or another site in Alaska; Task C--Provide support and training to the University of Alaska in the setting up and operating a fuel cell test lab. The Phase 1 research examined the market for power systems for off-grid homes, yachts, telecommunication stations and recreational vehicles. Also included in this report are summaries of the previously conducted market reports that examined power needs for remote locations along natural gas and oil pipelines. A list of highlights from the research can be found in the executive summary of the business plan.

Somatic cell banking - An alternative technology for the conservation of endangered sheep breeds

International Nuclear Information System (INIS)

Gupta, N.; Gupta, S.C.; Ahlawat, S.P.S.; Sharma, R.; Taneja, R.; Gupta, K.

2005-01-01

Skin samples from ear pinna of 10 male and 10 female sheep were collected and cultured in DMEM+Ham's F12 nutrient medium. Cell viability was 95 to 100% in different cultures. Mean cell proliferation rates were 0.94-0.67 and 1.15-0.56 for males and females in different passages, respectively. Cell proliferation rates were highest in first passage and then showed an age-related decline. Average cell doubling time was 30 h in males and 29.6 h in females. Skin fibroblast cell growth curves were in lag phase for the first 2 days, entered log phase (3rd to 7th days) and plateaued on day 8. Diploid chromosomal counts in proliferating cells up to the 5th passage were normal (2N=54), with no gross chromosomal aberrations recorded. Cells frozen from cycling cells at 80-90% confluency showed superior post-thaw growth compared with cells from overconfluent cultures. DMSO at 10% (v/v) in freezing media was optimal. Controlled-rate freezing at -1 deg. C/min showed better post-thaw cell viability and growth potential. Direct plating of thawed cells without removing DMSO and other contents of the freezing medium gave better post-thaw survival and proliferation rates. (author)

Radiosensitizing potential of gemcitabine (2',2'-difluoro-2'-deoxycytidine) within the cell cycle in vitro

International Nuclear Information System (INIS)

Latz, Detlev; Fleckenstein, Katharina; Eble, Michael; Blatter, Johannes; Wannenmacher, Michael; Weber, Klaus J.

1998-01-01

Purpose: Gemcitabine (2',2'-difluorodeoxycytidine; dFdCyd) is a new deoxycitidine analog which exhibits substantial activity against solid tumors and radiosensitizing properties in vitro. To examine cell cycle-specific effects of a combined treatment with gemcitabine and radiation, the in vitro clonogenic survival of two different cell lines was measured for cells from log-phase culture, G1 and S-phase cells. Methods and Materials: Chinese hamster (V79) and human colon carcinoma (Widr) cells were exposed to different radiation doses and for different points of time relative to gemcitabine treatment (2 h). Experiments were also carried out with different cell-cycle populations obtained after mitotic selection (V79) or after serum stimulation of plateau-phase cells (Widr). The resulting survival curves were analyzed according to the LQ model, and mean inactivation doses (MID) and the cell cycle-specific enhancement ratios (ER) were calculated from the survival curve parameters. Results: Effectiveness of combined treatment of log-phase cells was greatest when cells were irradiated at the end of the gemcitabine exposure [ER: 1.28 (V79), 1.24 (Widr)]. For later times after the removal of the drug, radiosensitization declined, approaching independent toxicity. From the time course of interactive-type damage decay half-life values of 75 min (V79) and 92 min (Widr) were derived. Gemcitabine did not radiosensitize G1 Widr cells or V79 cells from the G1/S border, but substantial radiosensitization was observed for the S-phase cell preparations [ER: 1.45 (V79-lateS), 1.57 (Widr)]. Conclusions: Treatment of cells with gemcitabine immediately before irradiation eliminates, or at least greatly reduces, the variation in radiosensitivity during the cell cycle that is manifested by radioresistance during S phase. This reversal of S-phase radioresistance could imply that gemcitabine interferes with the potentially lethal damage repair/fixation pathway. Other approaches have been

Enzymatic Kinetic Properties of the Lactate Dehydrogenase Isoenzyme C4 of the Plateau Pika (Ochotona curzoniae

Directory of Open Access Journals (Sweden)

Yang Wang

2016-01-01

Full Text Available Testis-specific lactate dehydrogenase (LDH-C4 is one of the lactate dehydrogenase (LDH isozymes that catalyze the terminal reaction of pyruvate to lactate in the glycolytic pathway. LDH-C4 in mammals was previously thought to be expressed only in spermatozoa and testis and not in other tissues. Plateau pika (Ochotona curzoniae belongs to the genus Ochotona of the Ochotonidea family. It is a hypoxia-tolerant species living in remote mountain areas at altitudes of 3000–5000 m above sea level on the Qinghai-Tibet Plateau. Surprisingly, Ldh-c is expressed not only in its testis and sperm, but also in somatic tissues of plateau pika. To shed light on the function of LDH-C4 in somatic cells, Ldh-a, Ldh-b, and Ldh-c of plateau pika were subcloned into bacterial expression vectors. The pure enzymes of Lactate Dehydrogenase A4 (LDH-A4, Lactate Dehydrogenase B4 (LDH-B4, and LDH-C4 were prepared by a series of expression and purification processes, and the three enzymes were identified by the method of sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE and native polyacrylamide gel electrophoresis (PAGE. The enzymatic kinetics properties of these enzymes were studied by Lineweaver-Burk double-reciprocal plots. The results showed the Michaelis constant (Km of LDH-C4 for pyruvate and lactate was 0.052 and 4.934 mmol/L, respectively, with an approximate 90 times higher affinity of LDH-C4 for pyruvate than for lactate. At relatively high concentrations of lactate, the inhibition constant (Ki of the LDH isoenzymes varied: LDH-A4 (Ki = 26.900 mmol/L, LDH-B4 (Ki = 23.800 mmol/L, and LDH-C4 (Ki = 65.500 mmol/L. These data suggest that inhibition of lactate by LDH-A4 and LDH-B4 were stronger than LDH-C4. In light of the enzymatic kinetics properties, we suggest that the plateau pika can reduce reliance on oxygen supply and enhance its adaptation to the hypoxic environments due to increased anaerobic glycolysis by LDH-C4.

Timing and mechanism of the rise of the Shillong Plateau in the Himalayan foreland.

OpenAIRE

Govin, Gwladys; Najman, Yanina Manya Rachel; Copley, Alex; Millar, Ian; Van der Beek, Peter; Huyghe, Pascale; Grujic, Djordje; Davenport, Jesse

2018-01-01

The Shillong Plateau (northeastern India) constitutes the only significant topography in the Himalayan foreland. Knowledge of its surface uplift history is key to understanding topographic development and unraveling tectonic–climate–topographic coupling in the eastern Himalaya. We use the sedimentary record of the Himalayan foreland basin north of the Shillong Plateau to show that the paleo-Brahmaputra river was redirected north and west by the rising plateau at 5.2–4.9 Ma. We suggest that on...

Staphylococcus aureus Lpl Lipoproteins Delay G2/M Phase Transition in HeLa Cells.

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Nguyen, Minh-Thu; Deplanche, Martine; Nega, Mulugeta; Le Loir, Yves; Peisl, Loulou; Götz, Friedrich; Berkova, Nadia

2016-01-01

The cell cycle is an ordered set of events, leading to cell growth and division into two daughter cells. The eukaryotic cell cycle consists of interphase (G 1 , S, and G 2 phases), followed by the mitotic phase and G 0 phase. Many bacterial pathogens secrete cyclomodulins that interfere with the host cell cycle. In Staphylococcus aureus four cyclomodulins have been described so far that all represent toxins and are secreted into the culture supernatant. Here we show that the membrane-anchored lipoprotein-like proteins (Lpl), encoded on a genomic island called νSaα, interact with the cell cycle of HeLa cells. By comparing wild type and lpl deletion mutant it turned out that the lpl cluster is causative for the G2/M phase transition delay and also contributes to increased invasion frequency. The lipoprotein Lpl1, a representative of the lpl cluster, also caused G2/M phase transition delay. Interestingly, the lipid modification, which is essential for TLR2 signaling and activation of the immune system, is not necessary for cyclomodulin activity. Unlike the other staphylococcal cyclomodulins Lpl1 shows no cytotoxicity even at high concentrations. As all Lpl proteins are highly conserved there might be a common function that is accentuated by their multiplicity in a tandem gene cluster. The cell surface localized Lpls' suggests a correlation between G2/M phase transition delay and host cell invasion.

Late-Glacial radiocarbon- and palynostratigraphy in the Swiss Plateau

International Nuclear Information System (INIS)

Ammann, B.; Lotter, A.F.

1989-01-01

A detailed Late-Glacial radiocarbon stratigraphy for the Swiss Plateau has been established on the basis of over 90 accelerator 14 C dates on terrestrial plant macrofossils. A comparison of the radiocarbon ages derived from terrestrial, telmatic and limnic material at different sites on the Swiss Plateau yields a proposal for modifying the zonation system of Welten for the Late-Glacial. By retaining the limits of chronozones and by refining the palynostratigraphic criteria for the limits of biozones, a separation between chrono- and biozonation at the beginning of the Boelling and the Younger Dryas becomes obvious. 54 refs

Model Package Report: Central Plateau Vadose Zone Geoframework Version 1.0

Energy Technology Data Exchange (ETDEWEB)

Springer, Sarah D.

2018-03-27

The purpose of the Central Plateau Vadose Zone (CPVZ) Geoframework model (GFM) is to provide a reasonable, consistent, and defensible three-dimensional (3D) representation of the vadose zone beneath the Central Plateau at the Hanford Site to support the Composite Analysis (CA) vadose zone contaminant fate and transport models. The GFM is a 3D representation of the subsurface geologic structure. From this 3D geologic model, exported results in the form of point, surface, and/or volumes are used as inputs to populate and assemble the various numerical model architectures, providing a 3D-layered grid that is consistent with the GFM. The objective of this report is to define the process used to produce a hydrostratigraphic model for the vadose zone beneath the Hanford Site Central Plateau and the corresponding CA domain.

Optical Phase Measurements of Disorder Strength Link Microstructure to Cell Stiffness.

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Eldridge, Will J; Steelman, Zachary A; Loomis, Brianna; Wax, Adam

2017-02-28

There have been sustained efforts on the part of cell biologists to understand the mechanisms by which cells respond to mechanical stimuli. To this end, many rheological tools have been developed to characterize cellular stiffness. However, measurement of cellular viscoelastic properties has been limited in scope by the nature of most microrheological methods, which require direct mechanical contact, applied at the single-cell level. In this article, we describe, to our knowledge, a new analysis approach for quantitative phase imaging that relates refractive index variance to disorder strength, a parameter that is linked to cell stiffness. Significantly, both disorder strength and cell stiffness are measured with the same phase imaging system, presenting a unique alternative for label-free, noncontact, single-shot imaging of cellular rheologic properties. To demonstrate the potential applicability of the technique, we measure phase disorder strength and shear stiffness across five cellular populations with varying mechanical properties and demonstrate an inverse relationship between these two parameters. The existence of this relationship suggests that predictions of cell mechanical properties can be obtained from examining the disorder strength of cell structure using this, to our knowledge, novel, noncontact technique. Copyright © 2017 Biophysical Society. Published by Elsevier Inc. All rights reserved.

Cell Cycle Phase Abnormalities Do Not Account for Disordered Proliferation in Barrett's Carcinogenesis

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Pierre Lao-Sirieix

2004-11-01

Full Text Available Barrett's esophagus (BE epithelium is the precursor lesion for esophageal adenocarcinoma. Cell cycle proteins have been advocated as biomarkers to predict the malignant potential in BE. However, whether disruption of the cell cycle plays a causal role in Barrett's carcinogenesis is not clear. Specimens from the Barrett's dysplasia—carcinoma sequence were immunostained for cell cycle phase markers (cyclin D1 for G1; cyclin A for S, G2, and M; cytoplasmic cyclin B1 for G2; and phosphorylated histone 3 for M phase and expressed as a proportion of proliferating cells. Flow cytometric analysis of the cell cycle phase of prospective biopsies was also performed. The proliferation status of nondysplastic BE was similar to gastric antrum and D2, but the proliferative compartment extended to the luminal surface. In dysplastic samples, the number of proliferating cells correlated with the degree of dysplasia (P < .001. The overall levels of cyclins A and B1 correlated with the degree of dysplasia (P < .001. However, the cell cycle phase distribution measured with both immunostaining and flow cytometry was conserved during all stages of BE, dysplasia, and cancer. Hence, the increased proliferation seen in Barrett's carcinogenesis is due to abnormal cell cycle entry or exit, rather than a primary abnormality within the cell cycle.

Livelihood Vulnerability Assessment Of Farmers and Nomads in Eastern Ecotone of Tibetan Plateau

Science.gov (United States)

Yan, J.; Zhang, Y.

2011-12-01

Livelihood vulnerability assessment provides a scientific basis for anti-poverty of people and regional sustainable development in vulnerable area. Although there are massive discussions on concept of vulnerability, it is still difficult to make it quantitative and to carry out comprehensive appraise. Vulnerability assessments based on sustainable livelihood frame are widely accepted in case studies for attentions to vulnerable groups. However, these case studies are always on regional scale and never reflect how climate change affects people's livelihood and adaptive capability of people. It is necessary to seek vulnerable assessment index system and means based on livelihood process of local people. This paper develops a livelihood vulnerability assessment index system on the basis of sustainable livelihood framework and appraises livelihood vulnerability values of 11 townships, using data of 879 sample households. Livelihood vulnerability assessment index system reflects main risks, livelihood assets and adaptation strategies of local people and government. The results show that livelihood vulnerability level of plateau region is higher than that of mountain to plateau region and mountain gorge region. Manzhang Township in plateau region is the most vulnerable township and nomads there cannot cope with risks of climate change, meadow degeneration and herbs degradation. Upper part of mountain to plateau region and the whole plateau region have high livelihood vulnerability values and local nomads would not cope with risks if no measures are taken by government. The driving forces of livelihood vulnerability include strikes of risks and deficiency of livelihood assets and adaptive capability. Farmers and nomads in high mountain gorge region and lower part of mountain to plateau region can cope with these risks, meanwhile, there are more employment opportunities in second and tertiary industries are needed to help them realize livelihood diversification. Therefore

Changes in distribution of cell cycle phases and DNA content in HeLa S3 cell after irradiation

International Nuclear Information System (INIS)

Wang Shunbao

1992-01-01

The effects of irradiation and hyperthermia on the distribution in various phases and DNA content of HeLa S 3 cells were analyzed by flow cytometry and an image analysis instrument. A marked increase in DNA content from 6.718 to 9.614(AU) in HeLa S 3 cells after 6 Gy irradiation was seen to correspond with the changes in the distribution of various phases in G 2 + M, from 22% to 52%. Meanwhile, the surviving fraction of HeLa S 3 cells after 6 Gy irradiation was less than 1%. However, after heating at 44 deg C for 10 min, the amount of cells in G 2 + M increased from 22.5% to 52.5% and the surviving fraction after hyperthermia was less than 2.65%. The changes in distribution of various phases after Ir-192 irradiation were similar to those seen after X-ray irradiation. The delay of G 2 + M phase after treatment with 8 Gy plus heating at 44 deg C for 7 min in HeLa S 3 cells was similar to that seen in the case of treatment with 8 Gy alone. As the surviving fraction accompanying the G 2 + M delay after irradiation plus heat treatment was very low, we suggest that the changes of distribution in various phases of HeLa S 3 cells after treatment might be used as a rapid indicator of serious injury

The first report of Cryptosporidium spp. in Microtus fuscus (Qinghai vole) and Ochotona curzoniae (wild plateau pika) in the Qinghai-Tibetan Plateau area, China.

Science.gov (United States)

Zhang, Xueyong; Jian, Yingna; Li, Xiuping; Ma, Liqing; Karanis, Gabriele; Karanis, Panagiotis

2018-05-01

Cryptosporidium is one of the most important genera of intestinal zoonotic pathogens, which can infect various hosts and cause diarrhoea. There is little available information about the molecular characterisation and epidemiological prevalence of Cryptosporidium spp. in Microtus fuscus (Qinghai vole) and Ochotona curzoniae (wild plateau pika) in the Qinghai-Tibetan Plateau area of Qinghai Province, Northwest China. Therefore, the aim of this study was to determine Cryptosporidium species/genotypes and epidemiological prevalence in these mammals by detecting the SSU rRNA gene by PCR amplification. The Cryptosporidium spp. infection rate was 8.9% (8/90) in Qinghai voles and 6.25% (4/64) in wild plateau pikas. Positive samples were successfully sequenced, and the following Cryptosporidium species were found: C. parvum, C. ubiquitum, C. canis and a novel genotype in Qinghai voles and C. parvum and a novel genotype in wild plateau pikas. This is the first report of Cryptosporidium infections in M. fuscus and wild O. curzoniae in Northwest China. The results suggest the possibility of Cryptosporidium species transmission among these two hosts, the environment, other animals and humans and provide useful molecular epidemiological data for the prevention and control of Cryptosporidium infections in wild animals and the surrounding environments. The results of the present study indicate the existence of Cryptosporidium species infections that have potential public health significance. This is the first report of Cryptosporidium multi-species infections in these animal hosts.

Some practical notes on the land surface modeling in the Tibetan Plateau

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K. Yang

2009-05-01

Full Text Available The Tibetan Plateau is a key region of land-atmosphere interactions, as it provides an elevated heat source to the middle-troposphere. The Plateau surfaces are typically characterized by alpine meadows and grasslands in the central and eastern part while by alpine deserts in the western part. This study evaluates performance of three state-of-the-art land surface models (LSMs for the Plateau typical land surfaces. The LSMs of interest are SiB2 (the Simple Biosphere, CoLM (Common Land Model, and Noah. They are run at typical alpine meadow sites in the central Plateau and typical alpine desert sites in the western Plateau.

The identified key processes and modeling issues are as follows. First, soil stratification is a typical phenomenon beneath the alpine meadows, with dense roots and soil organic matters within the topsoil, and it controls the profile of soil moisture in the central and eastern Plateau; all models, when using default parameters, significantly under-estimate the soil moisture within the topsoil. Second, a soil surface resistance controls the surface evaporation from the alpine deserts but it has not been reasonably modeled in LSMs; an advanced scheme for soil water flow is implemented in a LSM, based on which the soil resistance is determined from soil water content and meteorological conditions. Third, an excess resistance controls sensible heat fluxes from dry bare-soil or sparsely vegetated surfaces, and all LSMs significantly under-predict the ground-air temperature gradient, which would result in higher net radiation, lower soil heat fluxes and thus higher sensible heat fluxes in the models. A parameterization scheme for this resistance has been shown to be effective to remove these biases.

Monitoring stem cells in phase contrast imaging

Science.gov (United States)

Lam, K. P.; Dempsey, K. P.; Collins, D. J.; Richardson, J. B.

2016-04-01

Understanding the mechanisms behind the proliferation of Mesenchymal Stem cells (MSCs) can offer a greater insight into the behaviour of these cells throughout their life cycles. Traditional methods of determining the rate of MSC differentiation rely on population based studies over an extended time period. However, such methods can be inadequate as they are unable to track cells as they interact; for example, in autologous cell therapies for osteoarthritis, the development of biological assays that could predict in vivo functional activity and biological action are particularly challenging. Here further research is required to determine non-histochemical biomarkers which provide correlations between cell survival and predictive functional outcome. This paper proposes using a (previously developed) advanced texture-based analysis algorithm to facilitate in vitro cells tracking using time-lapsed microscopy. The technique was adopted to monitor stem cells in the context of unlabelled, phase contrast imaging, with the goal of examining the cell to cell interactions in both monoculture and co-culture systems. The results obtained are analysed using established exploratory procedures developed for time series data and compared with the typical fluorescent-based approach of cell labelling. A review of the progress and the lessons learned are also presented.

Results of the speleological exploration on Pešter plateau

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Nešić Dragan

2015-01-01

Full Text Available During the period 2006-2008, basic speleological research was done on Pešter Plateau in Southwestern Serbia. On that occasion, 40 caves were surveyed, 11 of which were measured in detail. Registered caves were grouped on the basis of landscape characteristics and morphogenetic relations. Based on the location and general characteristics of the Pešter karst, it is considered that the objects near Boljare and in the ponor (sinking area of Boroštica are connected to the drainage system of the Pećina nad Vražjim firovima (Vražiji firovi Cave. In morphological terms, the cave Bezdan Kaćunova ravan (Kaćunova Cave near Boljare with its imposing hall is the most important object on Pešter Plateau for the time being. Realized research on Pešter Plateau has the character of basic or initial speleological research, which should be continued in order to solve different problems of karst in this area.

Path of Social Construction in Northwest Sichuan Plateau Pastoral Area

Institute of Scientific and Technical Information of China (English)

2012-01-01

On the basis of main contents of social construction and key points of construction,this paper analyzes features of conditions of northwest Sichuan plateau pastoral area.The social construction at current stage mainly includes social cause in narrow sense,and social management at meso-level.The northwest Sichuan plateau pastoral area is faced with the best policy and development opportunity.However,there are still many weak aspects.Firstly,social structure is not coordinated with economic structure.Secondly,social construction ability of grass-roots government is weak.Thirdly,the ability to respond to public demands is low.Fourthly,there is a big gap in availability of basic public service.Finally,it presents path selection for social construction of northwest Sichuan plateau pastoral area:strengthen social construction ability of grass-roots government;promote social construction with livelihood projects as key projects;boost social construction taking advantage of ecological construction;develop basic public service with the aid of external forces;intensify evaluation system for supervision of social construction works.

Remote sensing of severe convective storms over Qinghai-Xizang Plateau

Science.gov (United States)

Hung, R. J.; Liu, J. M.; Tsao, D. Y.; Smith, R. E.

1984-01-01

The American satellite, GOES-1 was moved to the Indian Ocean at 58 deg E during the First GARP Global Experiment (FGGE). The Qinghai-Xizang Plateau significantly affects the initiation and development of heavy rainfall and severe storms in China, just as the Rocky Mountains influence the local storms in the United States. Satelite remote sensing of short-lived, meso-scale convective storms is particularly important for covering a huge area of a high elevation with a low population density, such as the Qinghai-Xizang Plateau. Results of this study show that a high growth rate of the convective clouds, followed by a rapid collapse of the cloud top, is associated with heavy rainfall in the area. The tops of the convective clouds developed over the Plateau lie between the altitudes of the two tropopauses, while the tops of convective clouds associated with severe storms in the United States usually extend much above the tropopause.

Hypersensitivity of mouse NEIL1-knockdown cells to hydrogen peroxide during S phase

International Nuclear Information System (INIS)

Yamamoto, Ryohei; Ohshiro, Yukari; Shimotani, Tatsuhiko; Yamamoto, Mizuki; Matsuyama, Satoshi; Ide, Hiroshi; Kubo, Kihei

2014-01-01

Oxidative base damage occurs spontaneously due to reactive oxygen species generated as byproducts of respiration and other pathological processes in mammalian cells. Many oxidized bases are mutagenic and/or toxic, and most are repaired through the base excision repair pathway. Human endonuclease VIII-like protein 1 (hNEIL1) is thought to play an important role during the S phase of the cell cycle by removing oxidized bases in DNA replication fork-like (bubble) structures, and the protein level of hNEIL1 is increased in S phase. Compared with hNEIL1, there is relatively little information on the properties of the mouse ortholog mNEIL1. Since mouse cell nuclei lack endonuclease III-like protein (NTH) activity, in contrast to human cell nuclei, mNEIL1 is a major DNA glycosylase for repair of oxidized pyrimidines in mouse nuclei. In this study, we made mNEIL1-knockdown cells using an shRNA expression vector and examined the cell cycle-related variation in hydrogen peroxide (H 2 O 2 ) sensitivity. Hypersensitivity to H 2 O 2 caused by mNEIL1 knockdown was more significant in S phase than in G1 phase, suggesting that mNEIL1 has an important role during S phase, similarly to hNEIL1

Preferential localization of Lactococcus lactis cells entrapped in a caseinate/alginate phase separated system.

Science.gov (United States)

Léonard, Lucie; Gharsallaoui, Adem; Ouaali, Fahima; Degraeve, Pascal; Waché, Yves; Saurel, Rémi; Oulahal, Nadia

2013-09-01

This study aimed to entrap bioprotective lactic acid bacteria in a sodium caseinate/sodium alginate aqueous two-phase system. Phase diagram at pH=7 showed that sodium alginate and sodium caseinate were not miscible when their concentrations exceeded 1% (w/w) and 6% (w/w), respectively. The stability of the caseinate/alginate two-phase system was also checked at pH values of 6.0 and 5.5. Lactococcus lactis subsp. lactis LAB3 cells were added in a 4% (w/w) caseinate/1.5% (w/w) alginate two-phase system at pH=7. Fluorescence microscopy allowed to observe that the caseinate-rich phase formed droplets dispersed in a continuous alginate-rich phase. The distribution of bacteria in such a system was observed by epifluorescence microscopy: Lc. lactis LAB3 cells stained with Live/Dead(®) Baclight kit™ were located exclusively in the protein phase. Since zeta-potential measurements indicated that alginate, caseinate and bacterial cells all had an overall negative charge at pH 7, the preferential adhesion of LAB cells was assumed to be driven by hydrophobic effect or by depletion phenomena in such biopolymeric systems. Moreover, LAB cells viability was significantly higher in the ternary mixture obtained in the presence of both caseinate and alginate than in single alginate solution. Caseinate/alginate phase separated systems appeared thus well suited for Lc. lactis LAB3 cells entrapment. Copyright © 2013 Elsevier B.V. All rights reserved.

Phase-changes in cell cycle of wound tissue irradiated with 5.21 Gy soft X-rays

International Nuclear Information System (INIS)

Liu Jianzhong; Zhou Yuanguo; Cheng Tianmin; Zhou Ping; Liu Xia; Li Ping

2002-01-01

Objective: To study the phase-changes in cell cycle of wound tissue which was locally irradiated with 5.21 Gy soft X-rays. Methods: Flow cytometry and PI staining were used to analyze cell cycle. Cell proliferation was determined with BrdU labeling. Results: During 3-9 days after irradiation, the percentage of the G 0 /G 1 phase cells in wound of the control side decreased while the percentage of S phase cells increased and reached the highest value on day 9. The percentage of G 2 /M phase cells also increased, and reached its peak on day 15. The percentage of G 0 /G 1 phase cell increased in wound of the irradiation side and was higher than that of the control wound, meanwhile the percentages of S and G 2 /M cells were significantly lower than those of the control wound. In the period of 12-22 days after wounding, the percentage of S phase cells increased and reached its peak value on the 22 th day. When most of cells were in S phase and arrested dramatically. Through the whole healing process, the percentage of G 2 /M in wound of the irradiation side was lower than that of the non-irradiated wound. The BrdU-positive cells were fibroblasts, endothelial cells and smooth muscle cells. Conclusion: These results suggest that G 1 block, S phase arrest, and switch of G 2 /M with suppression of mitotic activity of these cells are induced by local 5.21 Gy soft X-ray irradiation. Therefore, wound healing delay is induced partly by cell cycle arrest

Study on phase formation mechanism and electrochemical properties of La{sub 0.75−x}Nd{sub x}Mg{sub 0.25}Ni{sub 3.3} (x = 0, 0.15) alloys prepared by powder sintering

Energy Technology Data Exchange (ETDEWEB)

Wang, Jinding [Hebei Key Laboratory of Applied Chemistry, Yanshan University, Qinhuangdao 066004 (China); Han, Shumin, E-mail: hanshm@ysu.edu.cn [State Key Laboratory of Metastable Materials, Science and Technology, Yanshan University, Qinhuangdao 066004 (China); Hebei Key Laboratory of Applied Chemistry, Yanshan University, Qinhuangdao 066004 (China); Li, Yuan; Liu, Jingjing [Hebei Key Laboratory of Applied Chemistry, Yanshan University, Qinhuangdao 066004 (China); Che, Linda [Desert Vista High School, Phoenix, AZ 85048 (United States); Zhang, Lu; Zhang, Junling [Hebei Key Laboratory of Applied Chemistry, Yanshan University, Qinhuangdao 066004 (China)

2014-01-05

Highlights: • Gd{sub 2}Co{sub 7} phase abundance increases with Nd substitution dramatically. • Nd substitution results in the depletion of the minor CaCu{sub 5}-type phase. • The equilibrium plateau is elevated and broadened with Nd substitution. -- Abstract: An investigation of the phase formation mechanism and electrochemical properties of the La{sub 0.75−x}Nd{sub x}Mg{sub 0.25}Ni{sub 3.3} (x = 0, 0.15) alloys has been conducted in this paper. As explored by Rietveld analysis of the XRD data, the La{sub 0.75}Mg{sub 0.25}Ni{sub 3.3} alloy is composed of Ce{sub 2}Ni{sub 7}-type and Gd{sub 2}Co{sub 7}-type phases accompanied by minor CaCu{sub 5}-type phase. The partial substitution Nd for La benefits the formation of Gd{sub 2}Co{sub 7}-type phase, indicating that the atoms with smaller radius favor the formation of the Gd{sub 2}Co{sub 7}-type phase. However, CaCu{sub 5}-type phase disappears with Nd substitution. Because part of the replaced La atoms transform into [A{sub 2}B{sub 4}] subunits with the Ni atoms, and the formed [A{sub 2}B{sub 4}] subunits crystallize with [AB{sub 5}] subunits to produce A{sub 2}B{sub 7}-type phase, resulting in the depletion of the minor CaCu{sub 5}-type phase. The electrochemical P–C isotherms present that the La{sub 0.60}Nd{sub 0.15}Mg{sub 0.25}Ni{sub 3.3} alloy only containing A{sub 2}B{sub 7}-type phase has one single plateau while the La{sub 0.75}Mg{sub 0.25}Ni{sub 3.3} alloy which contains minor LaNi{sub 5} phase has two plateaus. It is beneficial for the elevation of equilibrium plateau pressure ascribing to the contraction in cell volumes by Nd substitution. Electrochemical measurements show that the substitution of La by Nd improves the discharge capacity and the high rate dischargeability owing to the increase of A{sub 2}B{sub 7}-type phase abundance.

Linkages between orogenic plateau build-up, fold-thrust shortening, and foreland basin evolution in the Zagros (NW Iran)

Science.gov (United States)

Barber, D. E.; Stockli, D. F.

2017-12-01

The Iranian Plateau (IP) is a thickened, low-relief morphotectonic province of diffuse deformation that formed due to Arabia-Eurasia collision and may serve as a younger analogue for the Tibetan Plateau. Despite detailed geophysical characterization of the IP, its deformation history and relationship to the Zagros fold-thrust belt and its foreland basin evolution remains unresolved. Low-temperature thermochronometry and provenance data from a transect across the internal and external Zagros track growth of the IP and delineate multiphase interaction between upper- and lower-plate processes during closure of the Neotethys and Arabia-Eurasia suturing. Inversion of zircon (U-Th)/He and fission-track data from plutonic and metamorphic basement rocks in the Sanandaj-Sirjan Zone (SSZ) of the IP reveals an initial stage of low-rate exhumation from 36-25 Ma, simultaneous with the onset of tectonic subsidence and marine incursion in the Zagros foreland basin. Overlapping apatite fission-track and (U-Th)/He ages indicate sharp acceleration in SSZ exhumation rates between 20-15 Ma, coincident with rejuvenation of foreland basin subsidence and an influx of Eurasian-derived sediments into the Zagros foreland deposited above an Oligocene unconformity. The mid-Miocene marks a transition in focused exhumation from the SSZ to Arabian lower-plate. Apatite (U-Th)/He ages suggest in-sequence fold-thrust propagation from the High Zagros to simply folded belt from 10 Ma to recent, which is reflected in the foreland by a shift in provenance to dominantly recycled Arabian-derived detritus and clastic facies progradation. Integrated thermochronometric and provenance data document a two-phase outward expansion of the Iranian Plateau and Zagros fold-thrust belt, tightly coupled to distinct phases of basin evolution and provenance shifts in the Zagros foreland. We associate multiple deformation and basin episodes with protracted collisional processes, from subduction of attenuated Arabian

Re-evaluating the 1940s CO2 plateau

Science.gov (United States)

Bastos, Ana; Ciais, Philippe; Barichivich, Jonathan; Bopp, Laurent; Brovkin, Victor; Gasser, Thomas; Peng, Shushi; Pongratz, Julia; Viovy, Nicolas; Trudinger, Cathy M.

2016-09-01

The high-resolution CO2 record from Law Dome ice core reveals that atmospheric CO2 concentration stalled during the 1940s (so-called CO2 plateau). Since the fossil-fuel emissions did not decrease during the period, this stalling implies the persistence of a strong sink, perhaps sustained for as long as a decade or more. Double-deconvolution analyses have attributed this sink to the ocean, conceivably as a response to the very strong El Niño event in 1940-1942. However, this explanation is questionable, as recent ocean CO2 data indicate that the range of variability in the ocean sink has been rather modest in recent decades, and El Niño events have generally led to higher growth rates of atmospheric CO2 due to the offsetting terrestrial response. Here, we use the most up-to-date information on the different terms of the carbon budget: fossil-fuel emissions, four estimates of land-use change (LUC) emissions, ocean uptake from two different reconstructions, and the terrestrial sink modelled by the TRENDY project to identify the most likely causes of the 1940s plateau. We find that they greatly overestimate atmospheric CO2 growth rate during the plateau period, as well as in the 1960s, in spite of giving a plausible explanation for most of the 20th century carbon budget, especially from 1970 onwards. The mismatch between reconstructions and observations during the CO2 plateau epoch of 1940-1950 ranges between 0.9 and 2.0 Pg C yr-1, depending on the LUC dataset considered. This mismatch may be explained by (i) decadal variability in the ocean carbon sink not accounted for in the reconstructions we used, (ii) a further terrestrial sink currently missing in the estimates by land-surface models, or (iii) LUC processes not included in the current datasets. Ocean carbon models from CMIP5 indicate that natural variability in the ocean carbon sink could explain an additional 0.5 Pg C yr-1 uptake, but it is unlikely to be higher. The impact of the 1940-1942 El Niño on the

A comparison of the radiosensitivity of stationary, exponential and G1 phase wild type and repair deficient yeast cultures: supporting evidence for stationary phase yeast cells being in G0

International Nuclear Information System (INIS)

Tippins, R.S.; Parry, J.M.

1982-01-01

The main points to emerge from this comparison of the radiosensitivity of stationary, exponential and G 1 phase yeast cultures were: (1) In wild type yeast cultures, G 1 cells were the most sensitive to the lethal effects of X-rays, exponential phase cells were the most resistant and stationary phase cells were intermediate in sensitivity. (2) With the excision-repair-defective strain D61-3 (rad 3) stationary phase cells were more resistant than exponential cells with G 1 cells again being most sensitive. (3) The rad 50 gene present in JD50 had a marked effect on the X-ray inactivation response of this strain. In the presence of the defective rad 50 allele, exponential phase cells were as sensitive as G 1 phase cells, with stationary phase cells being more resistant than either. (4) There were marked differences in sensitivity between stationary phase and G 1 phase cells. These differences, along with other physiological differences reported by other workers, lead the authors to suggest that stationary phase cells can be better described as being in G 0 phase, i.e. a stage which is outside the normal mitotic cell cycle of an exponential culture. (author)

Transition zone cells reach G2 phase before initiating elongation in maize root apex

Directory of Open Access Journals (Sweden)

M. Victoria Alarcón

2017-06-01

Full Text Available Root elongation requires cell divisions in the meristematic zone and cell elongation in the elongation zone. The boundary between dividing and elongating cells is called the transition zone. In the meristem zone, initial cells are continuously dividing, but on the basal side of the meristem cells exit the meristem through the transition zone and enter in the elongation zone, where they stop division and rapidly elongate. Throughout this journey cells are accompanied by changes in cell cycle progression. Flow cytometry analysis showed that meristematic cells are in cycle, but exit when they enter the elongation zone. In addition, the percentage of cells in G2 phase (4C strongly increased from the meristem to the elongation zone. However, we did not observe remarkable changes in the percentage of cells in cell cycle phases along the entire elongation zone. These results suggest that meristematic cells in maize root apex stop the cell cycle in G2 phase after leaving the meristem.

1/3 magnetization plateau in a one-dimensional anisotropic ferrimagnet

Energy Technology Data Exchange (ETDEWEB)

Tonegawa, T [Department of Mechanical Engineering, Fukui University of Technology, Fukui 910-8505 (Japan); Sakai, T [Japan Atomic Energy Agency (JAEA), Spring-8, Hyogo 679-5148, and Crest JST, Japan (Japan); Okamoto, K [Department of Physics, Tokyo Institute of Technology, Tokyo 152-8551 (Japan); Kaburagi, M [Faculty of Cross-Cultural Studies, Kobe University, Kobe 657-8501 (Japan)

2006-11-15

Using mainly numerical methods, we investigate the ground-state magnetization curve of a mixed spin chain with uniaxial single-ion anisotropies, where S = 1 and S = 2 spins are alternating and coupled antiferromagnetically. Special attention is paid to the magnetization plateau, the 1/3-plateau, which appears at one third of the saturation magnetization in the magnetization curve. It is found that there appear three kinds of 1/3-plateaux, one of which has a quantum nature, while the remaining two have a classical (Ising) nature.

Plateau hypoxia attenuates the metabolic activity of intestinal flora to enhance the bioavailability of nifedipine.

Science.gov (United States)

Zhang, Juanhong; Chen, Yuyan; Sun, Yuemei; Wang, Rong; Zhang, Junmin; Jia, Zhengping

2018-11-01

Nifedipine is completely absorbed by the gastrointestinal tract and its pharmacokinetics and metabolism may be influenced by microorganisms. If gut microbes are involved in the metabolism of nifedipine, plateau hypoxia may regulate the bioavailability and the therapeutic effect of nifedipine by altering the metabolic activity of the gut microbiota. We herein demonstrated for the first time that gut flora is involved in the metabolism of nifedipine by in vitro experiments. In addition, based on the results of 16S rRNA analysis of feces in rats after acute plateau, we first confirmed that the plateau environment could cause changes in the number and composition of intestinal microbes. More importantly, these changes in flora could lead to a slower metabolic activity of nifedipine in the body after an acute plateau, resulting in increased bioavailability and therapeutic efficacy of nifedipine. Our research will provide basis and new ideas for changes in the fecal flora of human acutely entering the plateau, and contribute to rational drug use of nifedipine.

Strain transformation between tectonic extrusion and crustal thickening in the growth of the Tibetan Plateau

Science.gov (United States)

Liu, M.; Li, Y.; Sun, Y.; Shen, X.

2017-12-01

The Indo-Eurasian continental collision since 50 Ma has thickened the crust to raise the Himalayan-Tibetan Plateau and driven lateral extrusion of Asian lithospheric blocks to affect Cenozoic tectonics in central and east Asia. The relative roles of crustal thickening and tectonic extrusion, and the strain partitioning between them over time and space, remain controversial. We have analyzed the strain rates using GPS velocities, and correlated the results with vertical motion derived from precise leveling. We found that tectonic extrusion largely transforms to crustal thickening near the margins of the Tibetan Plateau. Near the NW margin of the Tibetan Plateau, the shear stain transforms to compressive strain, consistent with neotectonic studies that indicate crustal shortening and uplift. Around the SE margin, shear stain largely terminates in the southern Yunnan province of China. The present-day crustal motion in SE Tibetan Plateau can be well explained by gravitational spreading without invoking plate-edge push as envisioned in the tectonic extrusion model. Using data collected from local seismic arrays, we derived receiver functions to image the lithospheric structures across the Tibetan Plateau and the Alashan block to its north and the Ordos block to its east. Our results indicate that the mantle lithosphere of these bounding Asian blocks has not been reworked by Tibetan tectonics; instead they have acted as restrictive walls to the growing Tibetan Plateau. Our finite element modeling shows that crustal deformation along the margins of the Tibetan Plateau are consistent with the notion that the east- and southeastward extrusion of the Tibetan lithosphere is largely confined to the Tibetan Plateau because of the restrictive bounding blocks of the Asian lithosphere. Thus the tectonic impact of the Indo-Eurasian collision on the Cenozoic Asian tectonics may not be as extensive as previously thought.

Label-free cell-cycle analysis by high-throughput quantitative phase time-stretch imaging flow cytometry

Science.gov (United States)

Mok, Aaron T. Y.; Lee, Kelvin C. M.; Wong, Kenneth K. Y.; Tsia, Kevin K.

2018-02-01

Biophysical properties of cells could complement and correlate biochemical markers to characterize a multitude of cellular states. Changes in cell size, dry mass and subcellular morphology, for instance, are relevant to cell-cycle progression which is prevalently evaluated by DNA-targeted fluorescence measurements. Quantitative-phase microscopy (QPM) is among the effective biophysical phenotyping tools that can quantify cell sizes and sub-cellular dry mass density distribution of single cells at high spatial resolution. However, limited camera frame rate and thus imaging throughput makes QPM incompatible with high-throughput flow cytometry - a gold standard in multiparametric cell-based assay. Here we present a high-throughput approach for label-free analysis of cell cycle based on quantitative-phase time-stretch imaging flow cytometry at a throughput of > 10,000 cells/s. Our time-stretch QPM system enables sub-cellular resolution even at high speed, allowing us to extract a multitude (at least 24) of single-cell biophysical phenotypes (from both amplitude and phase images). Those phenotypes can be combined to track cell-cycle progression based on a t-distributed stochastic neighbor embedding (t-SNE) algorithm. Using multivariate analysis of variance (MANOVA) discriminant analysis, cell-cycle phases can also be predicted label-free with high accuracy at >90% in G1 and G2 phase, and >80% in S phase. We anticipate that high throughput label-free cell cycle characterization could open new approaches for large-scale single-cell analysis, bringing new mechanistic insights into complex biological processes including diseases pathogenesis.

Interactions between ecosystems and hydrology in the Loess Plateau

Science.gov (United States)

Fu, B.; Wang, S.

2017-12-01

The Loess Plateau is located in the arid and semi-arid temperate continental monsoon climatic zone. Large-scale "Grain-for-Green" project has been implemented in the since 1999, which has made remarkable contribution to the soil and water control, but also has led to some negative ecological effects. Understanding the interactions between ecosystems and hydrology is significant for the vegetation carrying capacity assessment and guiding the vegetation restoration. We observed the soil moisture at multiple scales including slope, catchment and transect across Loess Plateau to analyze the effects of land use change and its trend along the precipitation gradient. Remote sensing data also used to capture the spatiotemporal variance of soil moisture in the Loess Plateau, as well as the in-situ measured soil moisture decrease following the massive re-vegetation. We found soil moisture decrease in response to the massive re-vegetation occurred in a transition zone of grass-forest ecosystems with annual precipitation between 450-550 mm. The average runoff in the Loess Plateau also decreased continuously during the period 1961-2009 (average rate of -0.9 mm yr-1, P < 0.001). Human intervention played a dominant role in creating the transition points, Water yield (i.e., the ratio of runoff to precipitation) decreased following each anthropogenic transition, causing a 56% reduction in available freshwater resources during the period 1961-2009. From currently revegetated areas and human water demand, we estimate a threshold of NPP of 400±5 g C m-2 yr-1 above which the population will suffer water shortages. NPP in this region is found to be already close to this limit.

S-phase cell distribution in the small intestine irradiated at different times of the day. 2. Recovery phase

Energy Technology Data Exchange (ETDEWEB)

Becciolini, A; Balzi, M; Cremonini, D; Fabbrica, D [Florence Univ. (Italy). Ist. di Radiologia

1983-01-01

Modifications occurring during recovery in the small intestine of animals exposed to the same radiation dose given at different times of the day were evaluated. S-phase cell distribution along the crypts and invertase activity were evaluated to ascertain the functional capacity of epithelial cells. In animals killed between 5 and 6 days after exposure, S-phase cell distribution and functional conditions tended towards normality although recovery was not complete. Labelled cells occurred also at villus junctions, demonstrating limitation in size of the differentiating compartment. This was confirmed by reduced activity of the brush border enzymes. Animals irradiated at the end of the dark period recovered more quickly and efficiently. In this group, labelled cell distribution was almost the same as in the controls starting from 120 h, and invertase activity was also closer to the controls than in any other group.

Seismic studies in the southern Puna plateau and the Peruvian Andes

Science.gov (United States)

Calixto Mory, Frank Jimmy

I present three studies in two regions, both within the Central Andes. In both regions it is clear that there are significant variations in the subduction geometry. I have used surface wave tomography to investigate the shear wave velocity structure beneath the southern Puna plateau and found evidence of widespread melting of the crust beneath the high elevations which correlates with a gap in intermediate depth seismicity and the recent eruptions of ignimbrite complexes. All of these observations can be explained by the delamination of the lithospheric mantle beneath it. I measured Rayleigh wave phase velocities as a function of frequency and inverted then to obtain shear wave velocities as a function of depth. The results show a high velocity body sitting above the subducting Nazca plate beneath the northern edge of the Cerro Galan ignimbrite. This high velocity body is interpreted to be the delaminated piece of lithosphere that detached and sank leading to a localized upwelling of asthenosphere that, in turn, caused widespread crustal melting leading to the eruption of the most recent ignimbrite complexes. Furthermore it is possible that this upwelling also thermally eroded the slab in this region. It is apparent that there is a significant slab gap or hole where there are very few intermediate depth earthquakes. In addition, I have used shear wave splitting analysis and shear wave splitting tomography in the southern Puna plateau to investigate the patterns of seismic anisotropy and mantle flow. The results show very complex shear wave splitting and seismic anisotropy patterns throughout the southern Puna plateau. The observations suggest that different mechanisms are driving the mantle flow from region to region. The subslab mantle outside the region where delamination took place is mostly driven by slab roll back and small degree of coupling between the subducting slab and the mantle below it. In the region apparently dominated by delamination, the subslab

Sensitivity of LUCC on the Surface Temperature of Tibetan Plateau

Science.gov (United States)

Qi, W.; Deng, X.; Wu, F.

2016-12-01

The Tibetan Plateau has an important effect on the ecological security in China, even in Asia, which makes the region become the hot spot in recently research. Under the joint influence of global change and human activities, ecosystem destabilizing and the increasing pressure on resources and environment emerge on the Tibetan Plateau, but the potential spatial sensitivity of land use and land cover changes(LUCC) on surface temperature has not been quantitatively analyzed. This study analyzed the mainly types of LUCC, urbanization, grassland degradation, deforestation on Tibetan Plateau along with Representative Concentration Pathways (RCPs) of the Intergovernmental Panel on Climate Change (IPCC). The LUCC in recent decades was first quantitatively analyzed in this study to give the basic fact with a significant increase in temperatures, reduced precipitation and increased evaporation. This study focused on the future spatio-temporal heterogeneity of the temperature and precipitation. Finally, the influencing factors with LUCC on Tibetan Plateau were simulated with the Weather Research and Forecasting (WRF) model, and the sensitivity of different land use types was spatially analyzed with Singular Value Decomposition (SVD). The results indicate that the large-area alpine grassland plays a more important role in alleviating global warming than other vegetation types do. The changes of the landscape structure resulting from the urban expansion play a significant role in intensifying regional temperature increase. In addition, the effects of LUCC on monthly average temperature change would vary from month to month with obviously spatial heterogeneity.

Plateau onset for correlation dimension: When does it occur?

International Nuclear Information System (INIS)

Ding, M.; Grebogi, C.; Ott, E.; Sauer, T.; Yorke, J.A.

1993-01-01

Chaotic experimental systems are often investigated using delay coordinates. Estimated values of the correlation dimension in delay coordinate space typically increase with the number of delays and eventually reach a plateau (on which the dimension estimate is relatively constant) whose value is commonly taken as an estimate of the correlation dimension D 2 of the underlying chaotic attractor. We report a rigorous result which implies that, for long enough data sets, the plateau begins when the number of delay coordinates first exceeds D 2 . Numerical experiments are presented. We also discuss how lack of sufficient data can produce results that seem to be inconsistent with the theoretical prediction

Is precipitation a trigger for the onset of xylogenesis in Juniperus przewalskii on the north-eastern Tibetan Plateau?

Science.gov (United States)

Ren, Ping; Rossi, Sergio; Gricar, Jozica; Liang, Eryuan; Cufar, Katarina

2015-01-01

Background and Aims A series of studies have shown that temperature triggers the onset of xylogenesis of trees after winter dormancy. However, little is known about whether and how moisture availability influences xylogenesis in spring in drought-prone areas. Methods Xylogenesis was monitored in five mature Qilian junipers (Juniperus przewalskii) by microcore sampling from 2009 to 2011 in a semi-arid area of the north-eastern Tibetan Plateau. A simple physical model of xylem cell production was developed and its sensitivity was analysed. The relationship between climate and growth was then evaluated, using weekly wood production data and climatic data from the study site. Key Results Delayed onset of xylogenesis in 2010 corresponded to a negative standardized precipitation evapotranspiration index (SPEI) value and a continuous period without rainfall in early May. The main period of wood formation was in June and July, and drier conditions from May to July led to a smaller number of xylem cells. Dry conditions in July could cause early cessation of xylem differentiation. The final number of xylem cells was mainly determined by the average production rate rather than the duration of new cell production. Xylem growth showed a positive and significant response to precipitation, but not to temperature. Conclusions Precipitation in late spring and summer can play a critical role in the onset of xylogenesis and xylem cell production. The delay in the initiation of xylogenesis under extremely dry conditions seems to be a stress-avoidance strategy against hydraulic failure. These findings could thus demonstrate an evolutionary adaptation of Qilian juniper to the extremely dry conditions of the north-eastern Tibetan Plateau. PMID:25725006

Three-dimensional Crustal Structure beneath the Tibetan Plateau Revealed by Multi-scale Gravity Analysis

Science.gov (United States)

Xu, C.; Luo, Z.; Sun, R.; Li, Q.

2017-12-01

The Tibetan Plateau, the largest and highest plateau on Earth, was uplifted, shorten and thicken by the collision and continuous convergence of the Indian and Eurasian plates since 50 million years ago, the Eocene epoch. Fine three-dimensional crustal structure of the Tibetan Plateau is helpful in understanding the tectonic development. At present, the ordinary method used for revealing crustal structure is seismic method, which is inhibited by poor seismic station coverage, especially in the central and western plateau primarily due to the rugged terrain. Fortunately, with the implementation of satellite gravity missions, gravity field models have demonstrated unprecedented global-scale accuracy and spatial resolution, which can subsequently be employed to study the crustal structure of the entire Tibetan Plateau. This study inverts three-dimensional crustal density and Moho topography of the Tibetan Plateau from gravity data using multi-scale gravity analysis. The inverted results are in agreement with those provided by the previous works. Besides, they can reveal rich tectonic development of the Tibetan Plateau: (1) The low-density channel flow can be observed from the inverted crustal density; (2) The Moho depth in the west is deeper than that in the east, and the deepest Moho, which is approximately 77 km, is located beneath the western Qiangtang Block; (3) The Moho fold, the directions of which are in agreement with the results of surface movement velocities estimated from Global Positioning System, exists clearly on the Moho topography.This study is supported by the National Natural Science Foundation of China (Grant No. 41504015), the China Postdoctoral Science Foundation (Grant No. 2015M572146), and the Surveying and Mapping Basic Research Programme of the National Administration of Surveying, Mapping and Geoinformation (Grant No. 15-01-08).

Does the climate warming hiatus exist over the Tibetan Plateau?

OpenAIRE

Anmin Duan; Zhixiang Xiao

2015-01-01

The surface air temperature change over the Tibetan Plateau is determined based on historical observations from 1980 to 2013. In contrast to the cooling trend in the rest of China, and the global warming hiatus post-1990s, an accelerated warming trend has appeared over the Tibetan Plateau during 1998–2013 (0.25 °C decade−1), compared with that during 1980–1997 (0.21 °C decade−1). Further results indicate that, to some degree, such an accelerated warming trend might be attributable to cloud–ra...

Therapeutical Management of the Tibial Plateau Fractures

Directory of Open Access Journals (Sweden)

Obada B.

2016-11-01

Full Text Available The study was aimed to identify the role of surgical treatment of tibial plateau fractures, its functional outcome and complications. Demographic data for the patients and details of current clinical and radiological follow-up findings were obtained to assess range of motion, clinical stability, alignment of the knee, and posttraumatic arthrosis (Kellgren/Lawrence score. 64 cases of tibial plateau fractures treated by different surgical methods and variuos implants type were studied from 2013 to 2015 and followed-up for minimum period of 6 months. The systematisation of the casuitry was made using Schatzker and AO classifications. The treatment methods consist of: percutaneous cannulated cancellous screws, ORIF with buttress plate with or without bone grafting, locking or nonlocking plates, external fixator. As complications we found: redepression 4 case, malunion 2 cases, knee stiffness 9, wound dehiscence in 1 cases and non-union or infection in none of our cases. The average flexion of the injured knee was significantly lower in comparison with the contralateral side (124.9°/135.2°. Knee stability did not differ statistically significantly. There were no signs of posttraumatic arthrosis in 45% of cases, mild signs in 30%, clear signs in 18%, and severe signs in 7%. As conclusion we found that surgical management of tibial plateau fractures will give excellent anatomical reduction and rigid fixation to restore articular congruity, facilitate early motion and reduce arthrosis risk and hence to achieve optimal knee function. The choice of optimal surgical methods, proper approach and implant is made in relation to fracture type according Schatzker and AO classification.

The effect of caffeine on x-ray repair of radioresistant HeLa cells

International Nuclear Information System (INIS)

Kubo, Kihei; Koiwai, Soichiro; Morita, Kazuo

1985-01-01

The contribution of caffeine-modifiable repair process to the radiosensitivity of a radioresistant HeLa strain (RC-355) has been investigated in comparison with control HeLa strain (CC-24). Both the final slope and the shoulder of X-ray survival curve for log-phase cells were affected by caffeine posttreatment. When the treatment with 10 mM caffeine delayed, an increase in survival was observed with increasing interval between irradiation and the treatment. During first several hours of the repair interval, the steepness of the final slope of survival curve decreased rapidly, and rate of the decrease was found to be higher in RC-355 than in CC-24 cells. Longer time (24 hours or more) before the initiation of caffeine treatment was required for the complete recovery of the shoulder. When the cells were incubated in plateau-phase after irradiation, an appreciable increase in survival was observed in comparison with when plated immediately following X-ray. The increase was found to be greater for RC-355 than for CC-24. The results suggest that the radioresistant RC-355 cells repaired more X-ray-induced PLD than CC-24 cells did. (author)

Past and future spatiotemporal changes in evapotranspiration and effective moisture on the Tibetan Plateau

Science.gov (United States)

Yin, Yunhe; Wu, Shaohong; Zhao, Dongsheng

2013-10-01

evaporative demand has decreased worldwide during the past several decades. This trend is also noted on the Tibetan Plateau, a region that is particularly sensitive to climate change. However, patterns and trends of evapotranspiration and their relationship to drought stress on the Tibetan Plateau are complex and poorly understood. Here, we analyze spatiotemporal changes in evapotranspiration and effective moisture (defined as the ratio of actual evapotranspiration (ETa) to reference crop evapotranspiration (ETo)) based on the modified Lund-Potsdam-Jena Dynamic Global Vegetation Model (LPJ). Climate data from 80 meteorological stations on the Tibetan Plateau were compiled for the period 1981-2010 and future climate projections were generated by a regional climate model through the 21st century. The results show regional trends towards decreasing ETo and statistically significant increases in ETa (p stress, because of generally increased effective moisture. Future regional differences are most pronounced in terms of effective moisture, which shows notable increases in the northwestern plateau and decreases in the southeastern plateau. Moreover, the reduced magnitude of effective moisture is likely to intensify in the long term, due mainly to increased evaporative demand.

Full-angle tomographic phase microscopy of flowing quasi-spherical cells.

Science.gov (United States)

Villone, Massimiliano M; Memmolo, Pasquale; Merola, Francesco; Mugnano, Martina; Miccio, Lisa; Maffettone, Pier Luca; Ferraro, Pietro

2017-12-19

We report a reliable full-angle tomographic phase microscopy (FA-TPM) method for flowing quasi-spherical cells along microfluidic channels. This method lies in a completely passive optical system, i.e. mechanical scanning or multi-direction probing of the sample is avoided. It exploits the engineered rolling of cells while they are flowing along a microfluidic channel. Here we demonstrate significant progress with respect to the state of the art of in-flow TPM by showing a general extension to cells having almost spherical shapes while they are flowing in suspension. In fact, the adopted strategy allows the accurate retrieval of rotation angles through a theoretical model of the cells' rotation in a dynamic microfluidic flow by matching it with phase-contrast images resulting from holographic reconstructions. So far, the proposed method is the first and the only one that permits to get in-flow TPM by probing the cells with full-angle, achieving accurate 3D refractive index mapping and the simplest optical setup, simultaneously. Proof of concept experiments were performed successfully on human breast adenocarcinoma MCF-7 cells, opening the way for the full characterization of circulating tumor cells (CTCs) in the new paradigm of liquid biopsy.

Industrialization of polymer solar cells - phase 1

Energy Technology Data Exchange (ETDEWEB)

Lauritzen, H.; Krebs, F.C. [Technical Univ. of Denmark. DTU Energy Conversion, DTU Risoe Campus, Roskilde (Denmark); Andersen, Rasmus B. [Mekoprint A/S, Stoevrimg (Denmark); Bork, J.; Bentzen, B.

2012-03-15

A three-phased project with the objective to industrialize DTU's basic polymer solar cell technology was started in the summer of 2009. The technology comprises a specific design of the polymer solar cell and a corresponding roll-to-roll manufacturing process. This basic technology is referred to as ProcessOne in the open literature. The present report relates to the project's phase 1.The key tasks in phase 1 are to stream-line DTU's tech-nology for the industrial utilization, to demonstrate production according to this stream-lined technology at Mekoprint A/S and finally to fertilize the market for polymer solar cells by demonstrating their use in appli-cations that harmonize with their present maturity level. The main focus in the stream-lining of DTU's technology has been to demonstrate a convincing rate of reduction for the production cost, and thereby make a competitive price plausible. This has been materialized as a learning curve showing that the polymer technology presently develops considerably faster than the silicon technology. The polymer solar cells will, under the assumption that both technologies follow a projection of the learning curve, gain a cost-leading position within a reasonable time. A production cost of 5 Euro/Wp has already been demonstrated in DTU's pilot plant, and a road map for the further decrease to 1 Euro/Wp is drawn. This target is expected to be reached in 2013 in the ongoing phase 2 of the project. Another activity essential for the industrialization has been the launch of specialized materials, equipment and services required for the processing of DTU's polymer solar cells. Relevant products and services are made available for sale on DTU's homepage, www.energyconversion.dtu.dk. A production line for polymer solar cells has been established at Mekoprint. For this a retrofit solution was chosen where the core of an existing screen-printing line was dismantled and fitted to a slot-die printing head manufactured in DTU's workshop

Parasitisme du safoutier par les Tapinanthus au plateau de Logbessou (Douala, Cameroun

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Mony, R.

2014-01-01

Full Text Available Safou Parasitism by Tapinanthus on Logbessou's plateau (Douala, Cameroon. In Cameroon, parasitism by Loranthaceae is a limiting factor of the safou tree cultivation as well as the perishable nature of the fruit which reduces the shelf life. Inventories were carried out in the home gardens of Logbessou's plateau in Douala. All the safou trees likely to produce and located within a perimeter of 200 m x 25 m from the center to the periphery of the plateau were observed and characterized by the circumference of the trunk, the number of tufts of Loranthaceae present on the tree and the taxon of the parasite. Safou trees are primarily parasitized by two species of Tapinanthus. Parasitism rate (34% varied significantly between center and periphery of the plateau. The average number of tufts of Tapinanthus by tree was also significantly different according to the location of the trees and between the two species of Tapinanthus. It is important to investigate the age at which pests significantly affect Safou yields in order to be able to propose adequate control methods when the farmers want to limit the parasitism of this species.

Response of human osteosarcoma in vitro to irradiation

International Nuclear Information System (INIS)

Weichselbaum, R.; Little, J.B.; Nove, J.

1977-01-01

Osteogenic sarcomas are very difficult to cure by conventional local radiotherapy. An investigation has been carried out into the effects of X-radiation on density-inhibited, slowly-proliferating, plateau-phase cultures of human osteosarcoma cells. Plates were irradiated at room temperature at a dose-rate of 80 rad/min, then returned to the incubator for intervals of up to 24 hours before the cells were trypsinized and replated at low density. Under these growth conditions, osteosarcoma cells have been found to be far more efficient in the repair of potentially-lethal radiation damage than either a human fibroblast strain or other established human cell lines, and the survival fraction of the osteosarcoma cells increased throughout the 24 hour period at all the doses tested. Complete X-ray survival curves for plateau phase osteosarcoma cells showed a marked difference in slope between the survival curve for cells subcultured immediately and that for cells which has been allowed 4 hours repair time. Studies of cellular proliferation kinetics showed that the increased capacity of the osteosarcoma cells for potentially-lethal-damage repair cannot be explained on the bases of a lower turnover rate in plateau-phase cultures. Consideration is given to the relevance of these results to the radiotherapy of osteosarcomas. In addition, osteosarcoma cells have unexpectedly been shown to be considerably more sensitive to killing by UV light than most normal cells. (U.K.)

A new classification of large-scale climate regimes around the Tibetan Plateau based on seasonal circulation patterns

Directory of Open Access Journals (Sweden)

Xin-Gang Dai

2017-03-01

Full Text Available This study aims to develop a large-scale climate classification for investigating the characteristics of the climate regimes around the Tibetan Plateau based on seasonal precipitation, moisture transport and moisture divergence using in situ observations and ERA40 reanalysis data. The results indicate that the climate can be attributed to four regimes around the Plateau. They situate in East Asia, South Asia, Central Asia and the semi-arid zone in northern Central Asia throughout the dryland of northwestern China, in addition to the Köppen climate classification. There are different collocations of seasonal temperature and precipitation: 1 in phase for the East and South Asia monsoon regimes, 2 anti-phase for the Central Asia regime, 3 out-of-phase for the westerly regime. The seasonal precipitation concentrations are coupled with moisture divergence, i.e., moisture convergence coincides with the Asian monsoon zone and divergence appears over the Mediterranean-like arid climate region and westerly controlled area in the warm season, while it reverses course in the cold season. In addition, moisture divergence is associated with meridional moisture transport. The northward/southward moisture transport corresponds to moisture convergence/divergence, indicating that the wet and dry seasons are, to a great extent, dominated by meridional moisture transport in these regions. The climate mean southward transport results in the dry-cold season of the Asian monsoon zone and the dry-warm season, leading to desertification or land degradation in Central Asia and the westerly regime zone. The mean-wind moisture transport (MMT is the major contributor to total moisture transport, while persistent northward transient eddy moisture transport (TEMT plays a key role in dry season precipitation, especially in the Asian monsoon zone. The persistent TEMT divergence is an additional mechanism of the out-of-phase collocation in the westerly regime zone. In addition

Aeolian processes during the Holocene in Gannan Region, Eastern Tibetan Plateau

Science.gov (United States)

Yang, S.; Cheng, T.; Li, S.; Liang, M.

2016-12-01

Aeolian desertification occurring in the Tibetan Plateau has received attention recently for it has become a severe environmental problem by accelerating the grassland degradation and eco-environment damage. The Gannan Region is located in the northeastern Tibetan Plateau with a mean altitude of 3500m. It is highly sensitive to global environmental change and human disturbance. Serious soil erosion and desertification and extensive land degradation have caused heavy eco-environmental impacts. To investigate the evolution of the desertification in Holocene in the Plateau is of great importance for understanding the desertification trend under the global changes in the Tibetan Plateau. Loess and aeolian sands is a key geological archive related to desertification processes and the past environment changes. In this study a typical 8.5m-thick loess-sands profile named MQQ, was selected at the Maqu city. It is situated on the first terrace (T1) of the Yellow River. Detailed accelerator mass spectrometry (AMS) 14C dating of bulk organic matter content has shown the Aeolian sediments of the MQQ section occurring since the early Holocene. the mass-specific frequency-dependent magnetic susceptibility (χfd) and grainsize records show a clear upward increase in the contents of superparamagnetic grains and fine fractions in grain size, which indicates a gradual wetting trend during the Holocene.The sediment rates change from very high in the early Holocene to low values after 8.2 ka. The wetting process can be divided into three steps: 10.0-8.2 ka, 8.2-3.0 ka and 3.0-present. It indicates that the climate in the eastern Tibetan Plateau was dry during the early Holocene. After that the climate was getting wet gradually. The variations of the westerlies and the Asian monsoon may cause the environmental change in this region.

Radioautographic analysis of changes in different phases of cell kinetics in murine oral mucosa

International Nuclear Information System (INIS)

Park, Chang Suck; You, Dong Soo

1983-01-01

The age related changes in the life cycle of the progenitor cell population of murine oral epithelia was studied. Using radioautographic methods which have been adopted in previous cell cycle studies, the age-related changes of different phases in renewing cells of the palatal, buccal and lingual mucosae were determined. The results confirm published findings on cell cycle changes of epithelia with aging and illustrated further that mitotic phases which has hither to been considered stationary, also changes with aging. The major parts revealed by this study are as follows: 1. The basal progenitor cells in different regions of oral mucosa have different generation times. 2. The basal cell cycle time increases as a function of aging and the region most affected by aging appears to be the epithelium of the cheek. 3. The phases of the cell cycle affected by the process of aging are in increasing order of magnitude: M-, S- and G1-phase. 4. The age related change in the number of DNA synthesizing basal progenitor cells occurs at two age periods. Between 1 and 12 months of life it decreases, while from 12 to 20 months it increases.

Industrialisation of polymer solar cells. Phase 2: Consolidation

DEFF Research Database (Denmark)

Lauritzen, Hanne; Gevorgyan, Suren; Frausig, Jesper

of the OPV devices – targets that are import both for niche applications and bulk power production. Besides the work dedicated to solving these three key targets, two more activities have been included in the project; a pre-study on OPV solar parks and an evaluation of the business opportunities arising......The present report refers to the project “Industrialization of polymer solar cells – phase 2”. Both the project and this report build directly upon the prior phase 1 where the basic OPV technology, ProcessOne, was transferred to Mekoprint. This second phase focuses on an anchoring......-scale power production. The project represents thus a crossroad, where Mekoprint and DTU gradually differentiate themselves with respect to applications and therefore also their R&D priorities. The key targets of phase 2 relate to production cost, stabilization of the production and operational lifetime...

Plateau's problem an invitation to varifold geometry

CERN Document Server

Frederick J Almgren, Jr

2001-01-01

There have been many wonderful developments in the theory of minimal surfaces and geometric measure theory in the past 25 to 30 years. Many of the researchers who have produced these excellent results were inspired by this little book--or by Fred Almgren himself. The book is indeed a delightful invitation to the world of variational geometry. A central topic is Plateau's Problem, which is concerned with surfaces that model the behavior of soap films. When trying to resolve the problem, however, one soon finds that smooth surfaces are insufficient: Varifolds are needed. With varifolds, one can obtain geometrically meaningful solutions without having to know in advance all their possible singularities. This new tool makes possible much exciting new analysis and many new results. Plateau's problem and varifolds live in the world of geometric measure theory, where differential geometry and measure theory combine to solve problems which have variational aspects. The author's hope in writing this book was to encour...

[Operative treatment for complex tibial plateau fractures].

Science.gov (United States)

Song, Qi-Zhi; Li, Tao

2012-03-01

To explore the surgical methods and clinical evaluation of complex tibial plateau fractures resulted from high-energy injuries. From March 2006 to May 2009,48 cases with complex tibial plateau fractures were treated with open reduction and plate fixation, including 37 males and 11 females, with an average age of 37 years (ranged from 18 to 63 years). According to Schatzker classification, 16 cases were type IV, 20 cases type V and 12 cases type VI. All patients were examined by X-ray flim and CT scan. The function of knee joint were evaluated according to postoperative follow-up X-ray and Knee Merchant Rating. Forty-eight patients were followed up with a mean time of 14 months. According to Knee Merchant Rating, 24 cases got excellent results, 16 cases good, 6 cases fair and 2 cases poor. Appropriate operation time, anatomical reduction, suitable bone graft and reasonable rehabilitation exercises can maximally recovery the function of knee joint.

Biogeography of cryoconite bacterial communities on glaciers of the Tibetan Plateau.

Science.gov (United States)

Liu, Yongqin; Vick-Majors, Trista J; Priscu, John C; Yao, Tandong; Kang, Shichang; Liu, Keshao; Cong, Ziyuang; Xiong, Jingbo; Li, Yang

2017-06-01

Cryoconite holes, water-filled pockets containing biological and mineralogical deposits that form on glacier surfaces, play important roles in glacier mass balance, glacial geochemistry and carbon cycling. The presence of cryoconite material decreases surface albedo and accelerates glacier mass loss, a problem of particular importance in the rapidly melting Tibetan Plateau. No studies have addressed the microbial community composition of cryoconite holes and their associated ecosystem processes on Tibetan glaciers. To further enhance our understanding of these glacial ecosystems on the Tibetan Plateau and to examine their role in carbon cycling as the glaciers respond to climate change, we explored the bacterial communities within cryoconite holes associated with three climatically distinct Tibetan Plateau glaciers using Illumina sequencing of the V4 region of the 16S rRNA gene. Cryoconite bacterial communities were dominated by Cyanobacteria, Chloroflexi, Betaproteobacteria, Bacteroidetes and Actinobacteria. Cryoconite bacterial community composition varied according to their geographical locations, exhibiting significant differences among glaciers studied. Regional beta diversity was driven by the interaction between geographic distance and environmental variables; the latter contributed more than geographic distance to the variation in cryoconite microbial communities. Our study is the first to describe the regional-scale spatial variability and to identify the factors that drive regional variability of cryoconite bacterial communities on the Tibetan Plateau. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Deep mantle forces and the uplift of the Colorado Plateau

Energy Technology Data Exchange (ETDEWEB)

Moucha, R; Forte, A M; Rowley, D B; Mitrovica, J X; Simmons, N A; Grand, S P

2009-06-23

Since the advent of plate tectonics, it has been speculated that the northern extension of the East Pacific Rise, specifically its mantle source, has been over-ridden by the North American Plate in the last 30 Myrs. Consequently, it has also been postulated that the opening of the Gulf of California, the extension in the Basin and Range province, and the uplift of the Colorado Plateau are the resulting continental expressions of the over-ridden mantle source of the East Pacific Rise. However, only qualitative models based solely on surface observations and heuristic, simplified conceptions of mantle convection have been used in support or against this hypothesis. We introduce a quantitative model of mantle convection that reconstructs the detailed motion of a warm mantle upwelling over the last 30 Myrs and its relative advance towards the interior of the southwestern USA. The onset and evolution of the crustal uplift in the central Basin and Range province and the Colorado Plateau is determined by tracking the topographic swell due to this mantle upwelling through time. We show that (1) the extension and magmatism in the central Basin and Range province between 25 and 10 Ma coincides with the reconstructed past position of this focused upwelling, and (2) the southwestern portion of the Colorado Plateau experienced significant uplift between 10 Ma and 5 Ma that progressed towards the northeastern portion of the plateau. These uplift estimates are consistent with a young, ca. 6 Ma, Grand Canyon model and the recent commencement of mafic magmatism.

A Complex System of Glacial Sub-Refugia Drives Endemic Freshwater Biodiversity on the Tibetan Plateau.

Science.gov (United States)

Clewing, Catharina; Albrecht, Christian; Wilke, Thomas

2016-01-01

Although only relatively few freshwater invertebrate families are reported from the Tibetan Plateau, the degree of endemism may be high. Many endemic lineages occur within permafrost areas, raising questions about the existence of isolated intra-plateau glacial refugia. Moreover, if such refugia existed, it might be instructive to learn whether they were associated with lakes or with more dynamic ecosystems such as ponds, wetlands, or springs. To study these hypotheses, we used pulmonate snails of the plateau-wide distributed genus Radix as model group and the Lake Donggi Cona drainage system, located in the north-eastern part of the plateau, as model site. First, we performed plateau-wide phylogenetic analyses using mtDNA data to assess the overall relationships of Radix populations inhabiting the Lake Donggi Cona system for revealing refugial lineages. We then conducted regional phylogeographical analyses applying a combination of mtDNA and nuclear AFLP markers to infer the local structure and demographic history of the most abundant endemic Radix clade for identifying location and type of (sub-)refugia within the drainage system. Our phylogenetic analysis showed a high diversity of Radix lineages in the Lake Donggi Cona system. Subsequent phylogeographical analyses of the most abundant endemic clade indicated a habitat-related clustering of genotypes and several Late Pleistocene spatial/demographic expansion events. The most parsimonious explanation for these patterns would be a scenario of an intra-plateau glacial refugium in the Lake Donggi Cona drainage system, which might have consisted of isolated sub-refugia. Though the underlying processes remain unknown, an initial separation of lake and watershed populations could have been triggered by lake-level fluctuations before and during the Last Glacial Maximum. This study inferred the first intra-plateau refugium for freshwater animals on the Tibetan Plateau. It thus sheds new light on the evolutionary history

Changes in effective moisture on the Tibetan Plateau during the period 1981-2010

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Yin, Y.; Wu, S.; Zhao, D.

2013-12-01

Observed evaporative demand has decreased worldwide during the past several decades. This trend is also noted on the Tibetan Plateau, a region that is particularly sensitive to climate change. However, actual evapotranspiration trends and their relationship to drought stress on the Tibetan Plateau are poorly understood. We analyzed the spatiotemporal changes in potential evapotranspiration(PET), actual evapotranspiration(AET) and effective moisture (defined as AET/PET) during 1981-2010. Climate data from 80 meteorological stations on the Tibetan Plateau were compiled for the period 1981-2010. New plant functional types were defined for the Tibetan Plateau and evapotranspiration is simulated by the modified Lund-Potsdam-Jena Dynamic Global Vegetation Model (LPJ). The results show regional trends towards decreasing PET and statistically significant increases in AET (p < 0.05) and effective moisture (p < 0.001) during the period 1981-2010. A transition from significant negative to positive PET occurred in 1997. Additionally, a pronounced increase in effective moisture occurred during the period 1981-1997 because of significant decreased PET before 1997.

Characterisation of phase evolution under load by means of phase contrast imaging using synchrotron radiation

International Nuclear Information System (INIS)

Besseghini, S.; Stortiero, F.; Carcano, G.; Villa, E.; Mancini, L.; Tromba, G.; Zanini, F.; Montanari, F.; Airoldi, G.

2003-01-01

Phase contrast radiography (PCR) is a quite novel technique that is collecting increasing attention due to the possibility to obtain image information in presence of very small differences in the densities of the materials under analysis. Phase contrast imaging (PCI) has some specific advantage when compared with common microscopic techniques: (a) no special preparation of the sample is needed (b) the simultaneously investigated area is very large and (c) it allows the setting up of complex experimental apparatus. The results here presented are a good evidence of these three advantages. In this paper, we report on the application of phase contrast imaging in the study of the phase evolution during pseudoelastic transformation in the NiTiCu shape memory alloys (SMAs). The investigation was undertaken with the aim to identify some modification of the structure taking place at the end of the transformation plateau in the pseudoelastic behaviour of the alloy

Parametric decay of current-driven Langmuir waves in plateau plasmas: Relevance to solar wind and foreshock events

Science.gov (United States)

Sauer, Konrad; Malaspina, David M.; Pulupa, Marc; Salem, Chadi S.

2017-07-01

Langmuir amplitude modulation in association with type III radio bursts is a well-known phenomenon since the beginning of space observations. It is commonly attributed to the superposition of beam-excited Langmuir waves and their backscattered counterparts as a result of parametric decay. The dilemma, however, is the discrepancy between fast beam relaxation and long-lasting Langmuir wave activity. Instead of starting with an unstable electron beam, our focus in this paper is on the nonlinear response of Langmuir oscillations that are driven after beam stabilization by the still persisting current of the (stable) two-electron plasma. The velocity distribution function of the second population forms a plateau (index h) with a point at which ∂fh/∂v ˜0 associated with weak damping over a more or less extended wave number range k. As shown by particle-in-cell simulations, this so-called plateau plasma drives primarily Langmuir oscillations at the plasma frequency (ωe) with k = 0 over long times without remarkable change of the distribution function. These Langmuir oscillations act as a pump wave for parametric decay by which an electron-acoustic wave slightly below ωe and a counterstreaming ion-acoustic wave are generated. Both high-frequency waves have nearly the same amplitude, which is given by the product of plateau density and velocity. Beating of these two wave types leads to pronounced Langmuir amplitude modulation, in reasonable agreement with solar wind and terrestrial foreshock observations made by the Wind spacecraft.

Phase microscopy using light-field reconstruction method for cell observation.

Science.gov (United States)

Xiu, Peng; Zhou, Xin; Kuang, Cuifang; Xu, Yingke; Liu, Xu

2015-08-01

The refractive index (RI) distribution can serve as a natural label for undyed cell imaging. However, the majority of images obtained through quantitative phase microscopy is integrated along the illumination angle and cannot reflect additional information about the refractive map on a certain plane. Herein, a light-field reconstruction method to image the RI map within a depth of 0.2 μm is proposed. It records quantitative phase-delay images using a four-step phase shifting method in different directions and then reconstructs a similar scattered light field for the refractive sample on the focus plane. It can image the RI of samples, transparent cell samples in particular, in a manner similar to the observation of scattering characteristics. The light-field reconstruction method is therefore a powerful tool for use in cytobiology studies. Copyright © 2015 Elsevier Ltd. All rights reserved.

Application of two-phase flow for cooling of hybrid microchannel PV cells: A comparative study

International Nuclear Information System (INIS)

Valeh-e-Sheyda, Peyvand; Rahimi, Masoud; Karimi, Ebrahim; Asadi, Masomeh

2013-01-01

Highlights: ► Showing cooling potential of gas–liquid two-phase flow in microchannels for PV cell. ► Introducing the concept of using slug flow in microchannels for cooling of PV cells. ► In single-phase flow, increasing the liquid flow rate enhances the PV power. ► Showing that in two-phase flow the output power related the fluid flow regime. ► By coupling PV and microchannel an increase up to 38% in output power was observed. - Abstract: This paper reports the experimental data from performance of two-phase flows in a small hybrid microchannel solar cell. Using air and water as two-phase fluid, the experiments were conducted at indoor condition in an array of rectangular microchannels with a hydraulic diameter of 0.667 mm. The gas superficial velocity ranges were between 0 and 3.27 m s −1 while liquid flow rate was 0.04 m s −1 . The performance analysis of the PV cell at slug and transitional slug/annular flow regimes are the focus of this study. The influence of two-phase working fluid on PV cell cooling was compared with single-phase. In addition, the great potential of slug flow for heat removal enhancement in PV/T panel was investigated. The obtained data showed the proposed hybrid system could substantially increases the output power of PV solar cells

Characterisation of precipitates in a Mg–7Gd–5Y–1Nd–0.5Zr alloy aged to peak-ageing plateau

International Nuclear Information System (INIS)

Li, Ting; Du, Zhiwei; Zhang, Kui; Li, Xinggang; Yuan, Jiawei; Li, Yongjun; Ma, Minglong; Shi, Guoliang; Fu, Xin; Han, Xiaolei

2013-01-01

Highlights: •A Mg 7 RE-type structure model was suggested for the β′ phase using HAADF-STEM. •A new type of phase was found in peak-aged samples. •The new type of plate-shape phase was precipitated on the (0 0 0 1) α plane. •The new type of phase is completely coherent with matrix. -- Abstract: The precipitates in a Mg–7Gd–5Y–1Nd–0.5Zr alloy aged to peak-ageing plateau (aged at 210 °C from 18 h to 180 h) were studied using transmission electron microscopy (TEM), high-resolution TEM (HRTEM) and high-angle annular detector dark-field scanning transmission electron microscopy (HAADF-STEM). Precipitation at the peak-ageing plateau involves the formation of the β ′ phase and a new type of plate-shaped phase precipitated along the (0001) α habit plane. The ellipsoid morphology of β ′ was illustrated according to [0001] α and [101 ¯ 0] α zone axes observations. The orientation relationship between the β ′ precipitates and matrix satisfies [001] β ′ //[0001] α and (100) β ′ //(112 ¯ 0) α , respectively. The TEM and HRTEM results indicate that the β ′ precipitates have a base-centred orthorhombic structure with lattice parameters a = 0.64 nm, b = 2.22 nm and c = 0.52 nm. Further, atomic-scaled HAADF-STEM observations suggest a Mg 7 RE-type and not a Mg 15 RE-type structure for the β ′ phase. The positive thermal stability of the alloy at 210 °C ageing is attributed to the coherent relationship with the matrix and the formation of an interlaced network of the β ′ precipitates. Aside from the β ′ phase, a large amount of precipitate particles were observed to form on the (0001) α habit plane in the peak-aged samples. The new type of precipitates have a plate shape, of approximately 5 nm wide along the [101 ¯ 0] α direction of the matrix and approximately 5 nm long along the [2 ¯ 110] α direction. A completely coherent relationship with the matrix can also be observed

Teachable, high-content analytics for live-cell, phase contrast movies.

Science.gov (United States)

Alworth, Samuel V; Watanabe, Hirotada; Lee, James S J

2010-09-01

CL-Quant is a new solution platform for broad, high-content, live-cell image analysis. Powered by novel machine learning technologies and teach-by-example interfaces, CL-Quant provides a platform for the rapid development and application of scalable, high-performance, and fully automated analytics for a broad range of live-cell microscopy imaging applications, including label-free phase contrast imaging. The authors used CL-Quant to teach off-the-shelf universal analytics, called standard recipes, for cell proliferation, wound healing, cell counting, and cell motility assays using phase contrast movies collected on the BioStation CT and BioStation IM platforms. Similar to application modules, standard recipes are intended to work robustly across a wide range of imaging conditions without requiring customization by the end user. The authors validated the performance of the standard recipes by comparing their performance with truth created manually, or by custom analytics optimized for each individual movie (and therefore yielding the best possible result for the image), and validated by independent review. The validation data show that the standard recipes' performance is comparable with the validated truth with low variation. The data validate that the CL-Quant standard recipes can provide robust results without customization for live-cell assays in broad cell types and laboratory settings.

Coseismic Strain Steps of the 2008 Wenchuan Earthquake Indicate EW Extension of Tibetan Plateau and Increased Hazard South to Epicenter

Science.gov (United States)

Fu, G.; Shen, X.; Tang, J.; Fukuda, Y.

2008-12-01

The 2008 Wenchuan earthquake (Ms8.0) occurred at the east edge of Tibetan Plateau. It is the biggest seismic disaster in China since the 1976 Tangshan earthquake. To determine the effects of the earthquake on the deformation field of Tibetan Plateau, we collect and analyze continuing strain data of three stations before and after the earthquake in Tibetan Plateau observed by capacitance-type bore-hole strainmeters (Chi, 1985). We collect strain data in NS, EW, NE-SW and NW-NS directions at each borehole. Then we deduce the co-seismic strain steps at time point 14:28 of May 12, 2008 (at this time point the earthquake occurred) with the data before and after the earthquake using the least squares method. Our observation shows that in Tibetan Plateau significant co-seismic strain steps are accompanied with the 2008 Wenchuan earthquake. Extension in EW direction is observed at interior and north Tibetan Plateau which indicates a rapid EW extension of the whole Plateau. Field investigation shows that the 2008 Wenchuan earthquake is a manifestation of eastward growth of the Tibetan Plateau (Dong et al., 2008). Eastwards growth of the Tibetan Plateau results naturally in the extension of the Plateau in EW direction. Our co-seismic strain observation agrees well with the conclusion from surface rupture investigation. The magnitude of co-seismic strain step equals to five times of average year extensional strain rate throughout the plateau interior. Shortening in SE- NW direction is observed at the east edge of the Plateau. As hints that the eastward extension of Tibetan Plateau is resisted by Sichuan rigid basin which increases the potential earthquake hazard around the observation station, manifests the declaration from co-seismic stress changes calculation (Persons et al., 2008). Our observed co-seismic strain steps are in total lager than theoretical calculations of dislocation theories which indicate that magnitude of the great earthquake should be bigger than 7.9. Due

Inhibition of G1-phase arrest induced by ionizing radiation in hematopoietic cells by overexpression of genes involved in the G1/S-phase transition

International Nuclear Information System (INIS)

Epperly, M.; Berry, L.; Halloran, A.; Greenberger, J.S.

1995-01-01

D-type cyclins and cyclin-dependent kinase (cdk-4) are likely involved in regulating passage of cells through the G 1 phase of the cell cycle. A decrease in the proportion of cells in G 1 , a relatively radiation-sensitive phase of the cell cycle, should result in increased resistance to ionizing radiation; however, the effect of such overexpression on X-ray-induced G 1 -phase arrest is not known. Radiation survival curves were obtained at a dose rate of either 8 cGy/min or 1 Gy/min for subclones of the IL-3-dependent hematopoietic progenitor cell line 32D cl 3 expressing transgenes for either cyclin-D1, D2 or D3 or cdk-4. We compared the results to those with overexpression of the transgene for Bcl-2, whose expression enhances radiation survival and delays apoptosis. Cells overexpressing transgenes for each D-type cyclin or Bcl-2 had an increased number of cells in S phase compared to parent line 32D cl 3; however, overexpression of cdk-4 had no effect on cell cycle distribution. Cell death resulting from withdrawal of IL-3 was not affected by overexpression of D2, cdk-4 or Bcl-2. Flow cytometry 24 h after 5 Gy irradiation demonstrated that overexpression of each G 1 -phase regulatory transgene decreased the proportion of cells at the G 1 /S-phase border. Western analysis revealed induction of cyclin-D protein levels by irradiation, but no change in the D O , but a significant increase in the rvec n for cyclin-D or cdk-4 transgene-overexpressing clones at 1 Gy/min (P 1 /S-phase arrest. 31 refs., 4 figs., 4 tabs

Mixing on the Heard Island Plateau during HEOBI

Science.gov (United States)

Robertson, R.

2016-12-01

On the plateau near Heard and McDonald Islands, the water column was nearly always well mixed. Typically, temperature differences between the surface and the bottom, 100-200 m, were less than 0.2oC and often less that 0.1oC. Surface stratification developed through insolation and deep primarily through a combination of upwelling from canyons and over the edge of the plateau and tidal advection. This stratification was primarily removed by a combination of wind and tidal mixing. Persistent winds of 30 knots mixed the upper 20-50 m. Strong wind events, 40-60 knots, mixed the water column to 100-200 m depth, which over the plateau, was often the entire water column. Benthic tidal friction mixed the bottom 30-50 m. Although the water column was unstratified at the two plume sites intensively investigated, tidal velocities were baroclinic, probably due to topographic controls. Tidal advection changed the bottom temperatures by 0.5oC within 8 hours, more than doubling the prior stratification. Wind mixing quickly homogenized the water column, resulting in the surface often showing the deeper upwelling and advective events. Although acoustic plumes with bubbles were observed in the water column, there was no evidence of geothermal vents or geothermal influence on temperatures. Mixing by bubbles rising in the water column was indistinguishable from the wind and tidal mixing, although the strongest upward vertical velocities were observed at the sites of these acoustic/bubble plumes.

The Colorado Plateau III: integrating research and resources management for effective conservation

Science.gov (United States)

Sogge, Mark K.; van Riper, Charles

2008-01-01

Roughly centered on the Four Corners region of the southwestern United States, the Colorado Plateau covers an area of 130,000 square miles. The relatively high semi-arid province boasts nine national parks, sixteen national monuments, many state parks, and dozens of wilderness areas. With the highest concentration of parklands in North America and unique geological and ecological features, the area is of particular interest to researchers. Derived from the Eighth Biennial Conference of Research on the Colorado Plateau, this third volume in a series of research on the Colorado Plateau expands upon the previous two books. This volume focuses on the integration of science into resource management issues, summarizes what criteria make a successful collaborative effort, outlines land management concerns about drought, provides summaries of current biological, sociological, and archaeological research, and highlights current environmental issues in the Four Corner States of Arizona, New Mexico, Colorado, and Utah. With broad coverage that touches on topics as diverse as historical aspects of pronghorn antelope movement patterns through calculating watershed prescriptions to the role of wind-blown sand in preserving archaeological sites on the Colorado River, this volume stands as a compendium of cuttingedge management-oriented research on the Colorado Plateau. The book also introduces, for the first time, tools that can be used to assist with collaboration efforts among landowners and managers who wish to work together toward preserving resources on the Colorado Plateau and offers a wealth of insights into land management questions for many readers, especially people interested in the natural history, biology, anthropology, wildlife, and cultural management issues of the region.

Spatial and temporal variation of tectonic uplift in the southeastern Ethiopian Plateau from morphotectonic analysis

Science.gov (United States)

Xue, Liang; Alemu, Tadesse; Gani, Nahid D.; Abdelsalam, Mohamed G.

2018-05-01

We use morphotectonic analysis to study the tectonic uplift history of the southeastern Ethiopian Plateau (SEEP). Based on studies conducted on the Northwestern Ethiopian Plateau, steady-state and pulsed tectonic uplift models were proposed to explain the growth of the plateau since 30 Ma. We test these two models for the largely unknown SEEP. We present the first quantitative morphotectonic study of the SEEP. First, in order to infer the spatial distribution of the tectonic uplift rates, we extract geomorphic proxies including normalized steepness index ksn, hypsometric integral HI, and chi integral χ from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) digital elevation model (DEM). Second, we compare these rates with the thickness of flood basalt that we estimated from geological maps. Third, to constrain the timing of regional tectonic uplift, we develop a knickpoint celerity model. Fourth, we compare our results to those from the Northwestern Ethiopian Plateau to suggest a possible mechanism to explain regional tectonic uplift of the entire Ethiopian Plateau. We find an increase in tectonic uplift rates from the southeastern escarpments of the Afar Depression in the northeast to that of the Main Ethiopian Rift to the southwest. We identify three regional tectonic uplift events at 11.7, 6.5, and 4.5 Ma recorded by the development of regionally distributed knickpoints. This is in good agreement with ages of tectonic uplift events reported from the Northwestern Ethiopian Plateau.

Quantitative tracking of tumor cells in phase-contrast microscopy exploiting halo artifact pattern

Science.gov (United States)

Kang, Mi-Sun; Song, Soo-Min; Lee, Hana; Kim, Myoung-Hee

2012-03-01

Tumor cell morphology is closely related to its invasiveness characteristics and migratory behaviors. An invasive tumor cell has a highly irregular shape, whereas a spherical cell is non-metastatic. Thus, quantitative analysis of cell features is crucial to determine tumor malignancy or to test the efficacy of anticancer treatment. We use phase-contrast microscopy to analyze single cell morphology and to monitor its change because it enables observation of long-term activity of living cells without photobleaching and phototoxicity, which is common in other fluorescence-labeled microscopy. Despite this advantage, there are image-level drawbacks to phase-contrast microscopy, such as local light effect and contrast interference ring, among others. Thus, we first applied a local filter to compensate for non-uniform illumination. Then, we used intensity distribution information to detect the cell boundary. In phase-contrast microscopy images, the cell normally appears as a dark region surrounded by a bright halo. As the halo artifact around the cell body is minimal and has an asymmetric diffusion pattern, we calculated the cross-sectional plane that intersected the center of each cell and was orthogonal to the first principal axis. Then, we extracted the dark cell region by level set. However, a dense population of cultured cells still rendered single-cell analysis difficult. Finally, we measured roundness and size to classify tumor cells into malignant and benign groups. We validated segmentation accuracy by comparing our findings with manually obtained results.

Widespread Dependence of Backup NHEJ on Growth State: Ramifications for the Use of DNA-PK Inhibitors

International Nuclear Information System (INIS)

Singh, Satyendra K.; Wu Wenqi; Zhang Lihua; Klammer, Holger; Wang Minli; Iliakis, George

2011-01-01

Purpose: The backup pathway of nonhomologous end joining (B-NHEJ) enables cells to process DNA double-strand breaks (DSBs) when the DNA-PK-dependent pathway of NHEJ (D-NHEJ) is compromised. Our previous results show marked reduction in the activity of B-NHEJ when LIG4 -/- mouse embryo fibroblasts (MEFs) cease to grow and enter a plateau phase. The dependence of B-NHEJ on growth state is substantially stronger than that of D-NHEJ and points to regulatory mechanisms or processing determinants that require elucidation. Because the different D-NHEJ mutants show phenotypes distinct in their details, it is necessary to characterize the dependence of their DSB repair capacity on growth state and to explore species-specific responses. Methods and Materials: DSB repair was measured in cells of different genetic background from various species using pulsed-field gel electrophoresis, or the formation of γ-H2AX foci, at different stages of growth. Results: Using pulsed-field gel electrophoresis, we report a marked reduction of B-NHEJ during the plateau phase of growth in KU and XRCC4, mouse or Chinese hamster, mutants. Notably, this reduction is only marginal in DNA-PKcs-deficient cells. However, reduced B-NHEJ is also observed in repair proficient, plateau-phase cells after treatment with DNA-PK inhibitors. The reduction of B-NHEJ activity in the plateau phase of growth does not derive from the reduced expression of participating proteins, is detectable by γ-H2AX foci analysis, and leads to enhanced cell killing. Conclusions: These results further document the marked dependence on growth state of an essential DSB repair pathway and show the general nature of the effect. Molecular characterization of the mechanism underlying this response will help to optimize the administration of DNA repair inhibitors as adjuvants in radiation therapy.

Subduction of a buoyant plateau at the Manila Trench: Tomographic evidence and geodynamic implications

Science.gov (United States)

Fan, Jianke; Zhao, Dapeng; Dong, Dongdong

2016-02-01

We determined P-wave tomographic images by inverting a large number of arrival-time data from 2749 local earthquakes and 1462 teleseismic events, which are used to depict the three-dimensional morphology of the subducted Eurasian Plate along the northern segment of the Manila Trench. Dramatic changes in the dip angle of the subducted Eurasian Plate are revealed from the north to the south, being consistent with the partial subduction of a buoyant plateau beneath the Luzon Arc. Slab tears may exist along the edges of the buoyant plateau within the subducted plate induced by the plateau subduction, and the subducted lithosphere may be absent at depths greater than 250 km at ˜19°N and ˜21°N. The subducted buoyant plateau is possibly oriented toward NW-SE, and the subducted plate at ˜21°N is slightly steeper than that at ˜19°N. These results may explain why the western and eastern volcanic chains in the Luzon Arc are separated by ˜50 km at ˜18°N, whereas they converge into a single volcanic chain northward, which may be related to the oblique subduction along the Manila Trench caused by the northwestern movement of the Philippine Sea Plate. A low-velocity zone is revealed at depths of 20-200 km beneath the Manila Accretionary Prism at ˜22°N, suggesting that the subduction along the Manila Trench may stop there and the collision develops northward. The Taiwan Orogeny may originate directly from the subduction of the buoyant plateau, because the initial time of the Taiwan Orogeny is coincident with that of the buoyant plateau subduction.

Double hump sign in indentation gonioscopy is correlated with presence of plateau iris configuration regardless of patent iridotomy.

Science.gov (United States)

Kiuchi, Yoshiaki; Kanamoto, Takashi; Nakamura, Takao

2009-02-01

A plateau iris is one of the clinical forms of angle closure glaucoma. In patients with a patent iridotomy, the double hump sign detected during indentation gonioscopy has been reported to indicate the existence of a plateau iris configuration. The purpose of this study was to determine whether the double hump sign is correlated with the presence of the plateau iris syndrome regardless of the patency of the iridotomy. Five women and 3 men without a patent iridotomy presented with narrow angles on gonioscopy and a double hump sign on indentation gonioscopy. Ultrasound biomicroscopy (UBM) imaging was performed to determine the etiology of the narrow angle and double hump sign, and to determine the appropriate treatment to prevent the progression of visual field damage. Ten patients with narrow angles and without a double hump sign were also examined by UBM to serve as a control group. All 8 patients who showed double hump sign had a short iris root, which was inserted anterior to the ciliary face, a typical anatomic appearance of a plateau iris. On the other hand, only 1 eye of 10 eyes in control group appeared to have a plateau iris. A double hump sign observed on indentation gonioscopy is strongly correlated with the presence of a plateau iris, and therefore a useful indicator of a plateau iris configuration regardless of the patency of a laser iridotomy. Thus, a plateau iris configuration can be detected without using a UBM in many cases.

Comparison of γ i-irradiation-induced accumulation of ataxia telangiesctasia and control cells in G2 phase

International Nuclear Information System (INIS)

Bates, P.R.; Lavin, M.F.

1989-01-01

Recent reports from a number of laboratories have linked radiosensitivity in ataxia telangiectasia (AT) to a large and prolonged block of some cells in G 2 phase. Previous results from this laboratory, largely with one Epstein-Barr virus-transformed A-T lymphoblastoid cell line, presented evidence for a dramatic increase in the number of cells in G 2 phase over controls during a 24 h period post irradiation. We describe here a study of the effect of γ-radiation on G 2 phase delay in several A-T cell lines. Based on previous results with several cell lines 24 h post irradiation was selected as the optimum time to discriminate between G 2 phase delay in control and A-T cells. All A-T homozygotes showed a signigicantly greater number of cells in G 2 phase, 24 h post irradiation, than observed in controls. A more prolonged delay in G 2 phase after irradiation was seen in different A-T cell types that included lymphoblastoid cells, fibroblasts and SV40-transformed fibroblasts. At the radiation dose used it was not possibel to distinguish A-T heterozygotes from controls (Author). 28 refs.; 2 figs.; 1 tab

COASTING EXTERNAL SHOCK IN WIND MEDIUM: AN ORIGIN FOR THE X-RAY PLATEAU DECAY COMPONENT IN SWIFT GAMMA-RAY BURST AFTERGLOWS

Energy Technology Data Exchange (ETDEWEB)

Shen Rongfeng; Matzner, Christopher D., E-mail: rfshen@astro.utoronto.ca, E-mail: matzner@astro.utoronto.ca [Department of Astronomy and Astrophysics, University of Toronto, Ontario M5S 3H4 (Canada)

2012-01-01

The plateaus observed in about one half of the early X-ray afterglows are the most puzzling feature in gamma-ray bursts (GRBs) detected by Swift. By analyzing the temporal and spectral indices of a large X-ray plateau sample, we find that 55% can be explained by external, forward shock synchrotron emission produced by a relativistic ejecta coasting in a {rho}{proportional_to}r{sup -2}, wind-like medium; no energy injection into the shock is needed. After the ejecta collects enough medium and transitions to the adiabatic, decelerating blast wave phase, it produces the post-plateau decay. For those bursts consistent with this model, we find an upper limit for the initial Lorentz factor of the ejecta, {Gamma}{sub 0} {<=} 46({epsilon}{sub e}/0.1){sup -0.24}({epsilon}{sub B}/0.01){sup 0.17}; the isotropic equivalent total ejecta energy is E{sub iso} {approx} 10{sup 53}({epsilon}{sub e}/0.1){sup -1.3}({epsilon}{sub B}/0.01){sup -0.09}(t{sub b} /10{sup 4} s) erg, where {epsilon}{sub e} and {epsilon}{sub B} are the fractions of the total energy at the shock downstream that are carried by electrons and the magnetic field, respectively, and t{sub b} is the end of the plateau. Our finding supports Wolf-Rayet stars as the progenitor stars of some GRBs. It raises intriguing questions about the origin of an intermediate-{Gamma}{sub 0} ejecta, which we speculate is connected to the GRB jet emergence from its host star. For the remaining 45% of the sample, the post-plateau decline is too rapid to be explained in the coasting-in-wind model, and energy injection appears to be required.

Cenozoic Uplift and Climate Change of the Northeast Tibetan Plateau: Evidence from Leaf Wax Stable Isotopic Records

Science.gov (United States)

Hou, M.; Zhuang, G.; Wu, M.

2017-12-01

Topics about the deformation history and uplift mechanism of Tibetan Plateau have been largely debated in the past few decades. Different geodynamic models present different predictions on the mountain building processes and hence the surface uplift history. For example, one tectonic model suggests a rapid uplift (>1.0 to 2.0 km) of the Tibetan Plateau in the period of ca. 10 to 8 Ma as result of isostatic rebound due to the removal of over-thickened mental lithosphere beneath. Whilst the stepwise uplift model infers that the high topography was growing progressively from south to north with the Northeast Tibetan Plateau being built in the Pliocene to present. In this case, the timing of Cenozoic uplift of Northeast Tibetan Plateau would provide information for distinguishing competing geodynamic processes. The stable isotope based paleoaltimetry holds the key to answering when the high topography was built. Additionally, the evolution of Cenozoic Asian climate was argued to be closely related to the high topography built up on the Tibetan Plateau since the India-Asian collision and/or impacted by the global change. To understand when the high topography was built and how the growth of Tibetan Plateau impacted the climate, we reconstructed the long-term histories of paleohydrology from hinterland and foreland basins in the Northeast Tibetan Plateau. We applied the compound-specific isotope hydrogen analysis to leaf wax n-alkanes (δ2Hn-alk) that are preserved in well-dated stratigraphic series (ca. 24 Ma to the present) in the Northeast Tibetan Plateau. The newly reconstructed δ2Hn-alk supports the inference of high topography on the Northeast Tibetan Plateau was built during the middle to late Miocene. Our inference is consistent with sedimentary and basement rock studies that show fundamental changes in facies and provenance and exhumation history. The new δ2Hn-alk record also reveals that the regional climate became drier since the middle Miocene following the

FINAL FRONTIER AT HANFORD TACKLING THE CENTRAL PLATEAU

International Nuclear Information System (INIS)

GERBER MS

2008-01-01

The large land area in the center of the vast Department of Energy (DOE) Hanford Site in southeast Washington State is known as 'the plateau'--aptly named because its surface elevations are 250-300 feet above the groundwater table. By contrast, areas on the 585-square mile Site that border the Columbia River sit just 30-80 feet above the water table. The Central Plateau, which covers an ellipse of approximately 70 square miles, contains Hanford's radiochemical reprocessing areas--the 200 East and 200 West Areas--and includes the most highly radioactive waste and contaminated facilities on the Site. Five 'canyons' where chemical processes were used to separate out plutonium (Pu), 884 identified soil waste sites (including approximately 50 miles of solid waste burial trenches), more than 900 structures, and all of Hanford's liquid waste storage tanks reside in the Central Plateau. (Notes: Canyons is a nickname given by Hanford workers to the chemical reprocessing facilities. The 177, underground waste tanks at Hanford comprise a separate work scope and are not under Fluor's management). Fluor Hanford, a DOE prime cleanup contractor at the Site for the past 12 years, has moved aggressively to investigate Central Plateau waste sites in the last few years, digging more than 500 boreholes, test pits, direct soil 'pushes' or drive points; logging geophysical data sets; and performing electrical-resistivity scans (a non-intrusive technique that maps patterns of sub-surface soil conductivity). The goal is to identify areas of contamination areas in soil and solid waste sites, so that cost-effective and appropriate decisions on remediation can be made. In 2007, Fluor developed a new work plan for DOE that added 238 soil waste-site characterization activities in the Central Plateau during fiscal years (FYs) 2007-2010. This number represents a 50 percent increase over similar work previously done in central Hanford. Work Plans are among the required steps in the Comprehensive

Estimates of grassland biomass and turnover time on the Tibetan Plateau

Science.gov (United States)

Xia, Jiangzhou; Ma, Minna; Liang, Tiangang; Wu, Chaoyang; Yang, Yuanhe; Zhang, Li; Zhang, Yangjian; Yuan, Wenping

2018-01-01

The grassland of the Tibetan Plateau forms a globally significant biome, which represents 6% of the world’s grasslands and 44% of China’s grasslands. However, large uncertainties remain concerning the vegetation carbon storage and turnover time in this biome. In this study, we quantified the pool size of both the aboveground and belowground biomass and turnover time of belowground biomass across the Tibetan Plateau by combining systematic measurements taken from a substantial number of surveys (i.e. 1689 sites for aboveground biomass, 174 sites for belowground biomass) with a machine learning technique (i.e. random forest, RF). Our study demonstrated that the RF model is effective tool for upscaling local biomass observations to the regional scale, and for producing continuous biomass estimates of the Tibetan Plateau. On average, the models estimated 46.57 Tg (1 Tg = 1012g) C of aboveground biomass and 363.71 Tg C of belowground biomass in the Tibetan grasslands covering an area of 1.32 × 106 km2. The turnover time of belowground biomass demonstrated large spatial heterogeneity, with a median turnover time of 4.25 years. Our results also demonstrated large differences in the biomass simulations among the major ecosystem models used for the Tibetan Plateau, largely because of inadequate model parameterization and validation. This study provides a spatially continuous measure of vegetation carbon storage and turnover time, and provides useful information for advancing ecosystem models and improving their performance.

Cell cycle phase dependent emergence of thymidylate synthase studied by monoclonal antibody (M-TS-4).

Science.gov (United States)

Shibui, S; Hoshino, T; Iwasaki, K; Nomura, K; Jastreboff, M M

1989-05-01

A method of identifying thymidylate synthase (TS) at the cellular level was developed using anti-TS monoclonal antibody (M-TS-4), a monoclonal antibody created against purified TS from a HeLa cell line. In HeLa cells and four human glioma cell lines (U-251, U-87, 343-MGA, and SF-188), TS was identified primarily in the cytoplasm. Autoradiographic and flow cytometric studies showed that TS appeared mainly in the G1 phase and subsided early in the S phase; thus, the G1 phase can be divided into TS-positive and -negative fractions. Nuclear TS was not demonstrated unequivocally with M-TS-4, and the relationship between nuclear TS and DNA synthesis could not be determined. Although the percentage of TS-positive cells was larger than the S-phase fraction measured by autoradiography after a pulse of tritiated thymidine or by the immunoperoxidase method using BUdR, the ratios were within a similar range (1.2-1.4) in all cell lines studied. Therefore, the S-phase fraction can be estimated indirectly from the percentage of TS-positive cells measured by M-TS-4. Because the emergence of TS detected by our method is cell cycle dependent, M-TS-4 may be useful for biochemical studies of TS and for cytokinetic analysis.

Reconsideration of Orth I and Orth II Phases in Ln-System Superconductors

Science.gov (United States)

Liu, Yue-Wei; Wang, Lu; Zhang, Han

2006-02-01

A block model is used to calculate the combinative energy in LnBa2Cu3O7-x (Ln=Y, Er, Nd) systems, and the energy has no difference for orth-I and orth-II in the plateau range. Namely, no matter what phase it is, when the oxygen deficiency is in the range of δ~0.35-0.55, the plateau appears in the energy -δ curves, and the combinative energy has close correlation with the Tc value. The result in the present work gives some hints to reconsider the role of the order of oxygen defects or its effect on superconductivity in LnBa2Cu3O7-x. The existence of the orth-II seems not to be the reason for the plateau in the Tc curve. This is an important problem for LnBa2Cu3O7-x and some suggestion is given in the discussion.

The regulation of ras-raf signaling pathway on G1 phase of the irradiated cells

International Nuclear Information System (INIS)

Guo Dehuang; Dong Bo; Liu Nongle; Wen Gengyun; Luo Qingliang; Mao Bingzhi

2000-01-01

Objective: To investigate the way of ras-raf signaling pathway which regulate the G 1 phase in irradiated KG-1 cells. Methods: Blocked the GM-CSF signaling pathway by transfected DN-ras and then momentary transfected cyclin D1 into irradiated KG-1 cells, the effects of cyclin D1 on G 1 phase was examined. Results: The irradiated KG-1 cells transfected DN-ras can't recover form G 1 phase arrest even though the GM-CSF was given,momentary transfected cyclin D1 promote the irradiated KG-1 cells from G 1 arrest. Conclusion: Activation of ras-raf signaling pathway regulate the cell cycle of the irradiated KG-1 cells through promotion the expression of the cyclin D1

Deciphering the internal complexity of living cells with quantitative phase microscopy: a multiscale approach

Science.gov (United States)

Martinez-Torres, Cristina; Laperrousaz, Bastien; Berguiga, Lotfi; Boyer-Provera, Elise; Elezgaray, Juan; Nicolini, Franck E.; Maguer-Satta, Veronique; Arneodo, Alain; Argoul, Françoise

2015-09-01

The distribution of refractive indices (RIs) of a living cell contributes in a nonintuitive manner to its optical phase image and quite rarely can be inverted to recover its internal structure. The interpretation of the quantitative phase images of living cells remains a difficult task because (1) we still have very little knowledge on the impact of its internal macromolecular complexes on the local RI and (2) phase changes produced by light propagation through the sample are mixed with diffraction effects by the internal cell bodies. We propose to implement a two-dimensional wavelet-based contour chain detection method to distinguish internal boundaries based on their greatest optical path difference gradients. These contour chains correspond to the highest image phase contrast and follow the local RI inhomogeneities linked to the intracellular structural intricacy. Their statistics and spatial distribution are the morphological indicators suited for comparing cells of different origins and/or to follow their transformation in pathologic situations. We use this method to compare nonadherent blood cells from primary and laboratory culture origins and to assess the internal transformation of hematopoietic stem cells by the transduction of the BCR-ABL oncogene responsible for the chronic myelogenous leukemia.

Precipitation change and its effects on prehistorical human activities in the Gonghe Basin, Northeastern Qinghai-Tibet Plateau during middle and late Holocene

Science.gov (United States)

Hou, Xiaoqing; Hou, Guangliang; Wang, Fangfang; Wang, Qingbo

2018-02-01

Northeastern Qinghai-tibet Plateau is considered as the ideal region for study of the climate change during the Holocene. Based on the meteorological data, the surface & fossil pollen data, this paper reconstructed the precipitation series of the region since middle Holocene with the GIS and MAT techniques, and discussed its relationship with prehistorical human activities. The results indicate that there are four major climatic phases: (I) Middle Holocene Humid Phase (6300-5000 aBP), with the primitive millet-farming first imported into the region; (II) Late Middle Holocene Sub-humid Phase (5000-3900 aBP), with the millet-farming spread rapidly within the region; (III) Late Holocene Fluctuation Phase (3900-2900 aBP), with the mean annual precipitation dropped down to lower than 240 mm, and a production mode-shift to a combination of cropping and husbandry; (IV) Late Holocene Stationary Phase (2900-0 aBP), with a precipitation alike the modern time, and a steady farming-pastoral economic pattern.

Implications of Zn/Fe ratios for the sources of Colorado Plateau basalts

Science.gov (United States)

Rudzitis, S.; Reid, M. R.

2011-12-01

Early Miocene to recent mafic magmatism migrated across the Arizona Transition Zone towards the center of the stable Colorado Plateau at a rate of ~ 3-6 km/Myr (Roy et al., 2009). Present-day volcanic centers are close to a stepwise change in the thickness of the lithosphere between the Colorado Plateau and Basin and Range. Accordingly, volcanic migration might track progressive thinning of the lithosphere towards the center of the Colorado Plateau. This project aims to determine the conditions of melt generation across the transition zone in order to investigate the temporal/spatial correlation between volcanism and thinning of the Colorado Plateau lithosphere. Pressure and temperature estimates for Colorado Plateau basalts can be obtained from the Mg and Si contents of melts (Lee et al, 2009) but require melting of a peridotitic source. Eclogite and pyroxenite xenoliths reported in Colorado Plateau basalts show that melt sources could be olivine-poor. Zn/Fe ratios in melts can help to distinguish contributions from olivine-poor sources because they are sensitive to differences in bulk chemistry and to mineralogy (Le Roux et al., 2010). Specifically, Zn/Fe is not fractionated between melt, olivine, and orthopyroxene, but is highly fractionated when clinopyroxene and garnet are present. Our work to date has focused on laser ablation-IC-PMS analysis of individual olivine grains from high-Mg basalts (>8.0 wt. %) from the San Francisco and Mormon Mountain volcanic fields. Preliminary values of Zn/Fe ratios that represent the averages of multiple analyses of several grains in individual samples range from 7.9 to 9.3 (x10000). Variations of up to 1.7 (x10000) in the ratios exist between individual grains within samples and could be the result of co-crystallization of clinopyroxene with olivine. The lowest values in each sample should approach the Zn/Fe ratios of parental melts, and are, in turn, similar to MORB values and predicted peridotite melts. The results suggest

Sequential processing of quantitative phase images for the study of cell behaviour in real-time digital holographic microscopy.

Science.gov (United States)

Zikmund, T; Kvasnica, L; Týč, M; Křížová, A; Colláková, J; Chmelík, R

2014-11-01

Transmitted light holographic microscopy is particularly used for quantitative phase imaging of transparent microscopic objects such as living cells. The study of the cell is based on extraction of the dynamic data on cell behaviour from the time-lapse sequence of the phase images. However, the phase images are affected by the phase aberrations that make the analysis particularly difficult. This is because the phase deformation is prone to change during long-term experiments. Here, we present a novel algorithm for sequential processing of living cells phase images in a time-lapse sequence. The algorithm compensates for the deformation of a phase image using weighted least-squares surface fitting. Moreover, it identifies and segments the individual cells in the phase image. All these procedures are performed automatically and applied immediately after obtaining every single phase image. This property of the algorithm is important for real-time cell quantitative phase imaging and instantaneous control of the course of the experiment by playback of the recorded sequence up to actual time. Such operator's intervention is a forerunner of process automation derived from image analysis. The efficiency of the propounded algorithm is demonstrated on images of rat fibrosarcoma cells using an off-axis holographic microscope. © 2014 The Authors Journal of Microscopy © 2014 Royal Microscopical Society.

Effects of nicotine on cellular proliferation, cell cycle phase distribution, and macromolecular synthesis in human promyelocytic HL-60 leukaemia cells

International Nuclear Information System (INIS)

Konno, S.; Wu, J.M.; Chiao, J.W.

1986-01-01

Addition of nicotine causes a dose- and time-dependent inhibition of cell growth in the human promyelocytic HL-60 leukemia cells, with 4 mM nicotine resulting in a 50% inhibition of cellular proliferation after 48-50h. Accompanying the anticellular effect of nicotine is a significant change in the cell cycle distribution of HL-60 cells. For example, treatment with 4 mM nicotine for 20h causes an increase in the proportion of G1-phase cells (from 49% to 57%) and a significant decrease in the proportion of S-phase cells (from 41% to 32%). These results suggest that nicotine causes partial cell arrest in the G-1 phase which may in part account for its effects on cell growth. To determine whether nicotine changes the cellular uptake/transport to macromolecular precursors, HL-60 cells were treated with 216 mM nicotine for 30h, at the end of which time cells were labelled with ( 3 H)thymidine, ( 3 H)uridine, ( 14 C)lysine and( 35 S)methionine, the trichloroacetic acid soluble and insoluble radioactivities from each of the labelling conditions were determined. These studies show that nicotine mainly affects the ''de novo synthesis'' of proteins. (author)

Reconstructing plateau icefields: Evaluating empirical and modelled approaches

Science.gov (United States)

Pearce, Danni; Rea, Brice; Barr, Iestyn

2013-04-01

Glacial landforms are widely utilised to reconstruct former glacier geometries with a common aim to estimate the Equilibrium Line Altitudes (ELAs) and from these, infer palaeoclimatic conditions. Such inferences may be studied on a regional scale and used to correlate climatic gradients across large distances (e.g., Europe). In Britain, the traditional approach uses geomorphological mapping with hand contouring to derive the palaeo-ice surface. Recently, ice surface modelling enables an equilibrium profile reconstruction tuned using the geomorphology. Both methods permit derivation of palaeo-climate but no study has compared the two methods for the same ice-mass. This is important because either approach may result in differences in glacier limits, ELAs and palaeo-climate. This research uses both methods to reconstruct a plateau icefield and quantifies the results from a cartographic and geometrical aspect. Detailed geomorphological mapping of the Tweedsmuir Hills in the Southern Uplands, Scotland (c. 320 km2) was conducted to examine the extent of Younger Dryas (YD; 12.9 -11.7 cal. ka BP) glaciation. Landform evidence indicates a plateau icefield configuration of two separate ice-masses during the YD covering an area c. 45 km2 and 25 km2. The interpreted age is supported by new radiocarbon dating of basal stratigraphies and Terrestrial Cosmogenic Nuclide Analysis (TCNA) of in situ boulders. Both techniques produce similar configurations however; the model results in a coarser resolution requiring further processing if a cartographic map is required. When landforms are absent or fragmentary (e.g., trimlines and lateral moraines), like in many accumulation zones on plateau icefields, the geomorphological approach increasingly relies on extrapolation between lines of evidence and on the individual's perception of how the ice-mass ought to look. In some locations this results in an underestimation of the ice surface compared to the modelled surface most likely due to

Experimental investigation two phase flow in direct methanol fuel cells

International Nuclear Information System (INIS)

Mat, M. D.; Kaplan, Y.; Celik, S.; Oeztural, A.

2007-01-01

Direct methanol fuel cells (DMFC) have received many attentions specifically for portable electronic applications since it utilize methanol which is in liquid form in atmospheric condition and high energy density of the methanol. Thus it eliminates the storage problem of hydrogen. It also eliminates humidification requirement of polymeric membrane which is a problem in PEM fuel cells. Some electronic companies introduced DMFC prototypes for portable electronic applications. Presence of carbon dioxide gases due to electrochemical reactions in anode makes the problem a two phase problem. A two phase flow may occur at cathode specifically at high current densities due to the excess water. Presence of gas phase in anode region and liquid phase in cathode region prevents diffusion of fuel and oxygen to the reaction sites thus reduces the performance of the system. Uncontrolled pressure buildup in anode region increases methanol crossover through membrane and adversely effect the performance. Two phase flow in both anode and cathode region is very effective in the performance of DMYC system and a detailed understanding of two phase flow for high performance DMFC systems. Although there are many theoretical and experimental studies available on the DMFC systems in the literature, only few studies consider problem as a two-phase flow problem. In this study, an experimental set up is developed and species distributions on system are measured with a gas chromatograph. System performance characteristics (V-I curves) is measured depending on the process parameters (temperature, fuel ad oxidant flow rates, methanol concentration etc)

InGaN High Temperature Photovoltaic Cells, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — The objectives of this Phase II project are to develop InGaN photovoltaic cells for high temperature and/or high radiation environments to TRL 4 and to define the...

Phytol isolated from watermelon (Citrullus lanatus) sprouts induces cell death in human T-lymphoid cell line Jurkat cells via S-phase cell cycle arrest.

Science.gov (United States)

Itoh, Tomohiro; Ono, Akito; Kawaguchi, Kaori; Teraoka, Sayaka; Harada, Mayo; Sumi, Keitaro; Ando, Masashi; Tsukamasa, Yasuyuki; Ninomiya, Masayuki; Koketsu, Mamoru; Hashizume, Toshiharu

2018-05-01

The phytol isolated from watermelon (Citrullus lanatus) sprouts inhibited the growth of a human T-cell leukemia line Jurkat cell and suppressed tumor progression in a xenograft model of human lung adenocarcinoma epithelial cell line A549 in nude mice. To elucidate the mechanisms underlying the phytol-induced cell death in the present study, we examined the changes in cell morphology, DNA fragmentation, and intracellular reactive oxygen species (ROS) levels and performed flow cytometric analysis to evaluate cell cycle stage. There were no significant changes in apoptosis, autophagy, and necrosis marker in cells treated with the phytol. But, we found, for the first time, that phytol remarkably induced S-phase cell cycle arrest accompanied with intracellular ROS production. Western blot analyses showed that phytolinduced S-phase cell cycle arrest was mediated through the decreased expression of cyclins A and D and the downregulations of MAPK and PI3K/Akt. The tumor volume levels in mice treated with phytol were lower than those of non-treatment groups, and it showed very similar suppression compared with those of mice treated with cyclophosphamide. Based on the data of in vitro and in vivo studies and previous studies, we suggest phytol as a potential therapeutic compound for cancer. Copyright © 2018 Elsevier Ltd. All rights reserved.

Complex actions of ionomycin in cultured cerebellar astrocytes affecting both calcium-induced calcium release and store-operated calcium entry

DEFF Research Database (Denmark)

Müller, Margit S; Obel, Linea Lykke Frimodt; Waagepetersen, Helle S

2013-01-01

The polyether antibiotic ionomycin is a common research tool employed to raise cytosolic Ca(2+) in almost any cell type. Although initially thought to directly cause physicochemical translocation of extracellular Ca(2+) into the cytosol, a number of studies have demonstrated that the mechanism of......(2+), consisting of an initial peak and a subsequent sustained plateau. The response was dependent on concentration and exposure time. While the plateau phase was abolished in the absence of extracellular Ca(2+), the peak phase persisted. The peak amplitude could be lowered significantly...... by application of dantrolene, demonstrating involvement of Ca(2+)-induced Ca(2+)-release (CICR). The plateau phase was markedly reduced when store-operated Ca(2+)-entry (SOCE) was blocked with 2-aminoethoxydiphenyl borate. Our results show that ionomycin directly affects internal Ca(2+) stores in astrocytes...

Rapid cell cycle analysis by measurement of the radioactivity per cell in a narrow window in S phase (RCSsub(i))

International Nuclear Information System (INIS)

Gray, J.W.; Carver, J.H.; George, Y.S.; Mendelsohn, M.L.

1977-01-01

A new rapid method for the cell cycle analysis of asynchronously growing cells is presented. The new method is an alternative to the more time consuming and subjective fraction of labeled mitoses (FLM) method. Like the FLM method, all cells in the S phase of the cell cycle are marked by pulse labeling with a radioactive DNA precursor. The subsequent progress of the cohort of cells thus labeled is monitored through a narrow window in the cell cycle. The window is defined by a narrow range of DNA contents corresponding to cells in mid-S phase and is designated Ssub(i). The cellular DNA content is measured by flow cytometry and the cells in the window Ssub(i) are selected by electronic cell sorting. The radioactivity per cell in Ssub(i) (RCSsub(i)) is determined by liquid scintillation counting. The duration of S phase and of the total cycle and the dispersions therein are determined from the oscillation of the RCSsub(i) values with time. The complete cell cycle analysis can be accomplished in as little as 1 day following the collection of samples. Exponentially growing Chinese hamster ovary (CHO) cells were analyzed according to the RCSsub(i) method and the FLM method. It is demonstrated that the two techniques give essentially the same results. (author)

Successive phase transitions in perovskites. II. Cell distortion and atomic displacements

Energy Technology Data Exchange (ETDEWEB)

Aleksandrov, K S; Pozdnyakova, L A; Orlova, T A [AN SSSR, Novosibirsk. Inst. Fiziki; Krasnoyarskij Gosudarstvennyj Univ. (USSR))

1977-01-01

A method is suggested for evaluating the structural and thermodynamic parameters from cell distortions at phase transformation. The method was applied for investigation of successive phase transformations in CsPbCl/sub 3/ and CsSrCl/sub 3/ crystals. By studying the temperature dependencies of the lattice parameters, the phase stereo groups for these crystals were established; the respective rotation angles and atom displacements were also evaluated.

Neoclassical resonant-plateau transport calculation in an effectively axisymmetrized tandem mirror with finite end plate resistance

International Nuclear Information System (INIS)

Katanuma, I.; Kiwamoto, Y.; Adachi, S.; Inutake, M.; Ishii, K.; Yatsu, K.; Sawada, K.; Miyoshi, S.

1987-05-01

Calculations are made for neoclassical resonant-plateau transports in the geometry of the effectively axisymmetrized tandem mirror GAMMA 10 magnetic field, which has minimum B inbord anchors inside the axisymmetric plug/barrier mirror cells. Azimuthal drifts at the local non-axisymmetric regions are included. The radial potential profile is determined by solving selfconsistently the charge neutrality equation. A finite resistance connecting end plate to machine ground provides appropriate boundary conditions on the radial electrostatic potential distribution so that it can be determined uniquely. The calculation is consistent with experimental results of GAMMA 10. (author)

Iceberg incursions across Campbell Plateau

International Nuclear Information System (INIS)

Northcote, L.; Neil, H.; Carter, L.

1999-01-01

The last reported sighting of icebergs off eastern New Zealand was on 28th October, 1892, at the Chatham Islands. Prior to that time, the SW Pacific Ocean periodically hosted flotillas of icebergs, as revealed by a palaeoceanographic analysis of 8 cores from the Campbell Plateau. Stable isotope stratigraphy, coupled with down-core measurements of magnetic susceptibility, grain size, calcium carbonate and ice-rafted debris, highlight climate-related fluctuations in iceberg activity back to at least marine isotope stage (MIS) 6 - our longest complete record. (author)

The plateau zokors' learning and memory ability is related to the high expression levels of foxP2 in the brain.

Science.gov (United States)

Ma, Ben-Yuan; Wei, Lian; Sun, Sheng-Zhen; Wang, Duo-Wei; Wei, Deng-Bang

2014-04-25

Plateau zokor (Myospalax baileyi) is a subterranean mammal. Plateau zokor has high learning and memory ability, and can determine the location of blocking obstacles in their tunnels. Forkhead box p2 (FOXP2) is a transcription factor implicated in the neural control of orofacial coordination and sensory-motor integration, particularly with respect to learning, memory and vocalization. To explore the association of foxP2 with the high learning and memory ability of plateau zokor, the cDNA of foxP2 of plateau zokor was sequenced; by using plateau pika as control, the expression levels of foxP2 mRNA and FOXP2 protein in brain of plateau zokor were determined by real-time PCR and Western blot, respectively; and the location of FOXP2 protein in the brain of plateau zokor was determined by immunohistochemistry. The result showed that the cDNA sequence of plateau zokor foxP2 was similar to that of other mammals and the amino acid sequences showed a relatively high degree of conservation, with the exception of two particular amino acid substitutions [a Gln (Q)-to-His (H) change at position 231 and a Ser (S)-to-Ile (I) change at position 235]. Higher expression levels of foxP2 mRNA (3-fold higher) and FOXP2 protein (>2-fold higher) were detected in plateau zokor brain relative to plateau pika brain. In plateau zokor brain, FOXP2 protein was highly expressed in the cerebral cortex, thalamus and the striatum (a basal ganglia brain region). The results suggest that the high learning and memory ability of plateau zokor is related to the high expression levels of foxP2 in the brain.

Comparison of radiosensitization by 41 deg. C hyperthermia during low dose rate irradiation and during pulsed simulated low dose rate irradiation in human glioma cells

International Nuclear Information System (INIS)

Raaphorst, G. Peter; Ng, Cheng E.; Shahine, Bilal

1999-01-01

Purpose: Long duration mild hyperthermia has been shown to be an effective radiosensitizer when given concurrently with low dose rate irradiation. Pulsed simulated low dose rate (PSLDR) is now being used clinically, and we have set out to determine whether concurrent mild hyperthermia can be an effective radiosensitizer for the PSLDR protocol. Materials and Methods: Human glioma cells (U-87MG) were grown to plateau phase and treated in plateau phase in order to minimize cell cycle redistribution during protracted treatments. Low dose rate (LDR) irradiation and 41 deg. C hyperthermia were delivered by having a radium irradiator inside a temperature-controlled incubator. PSLDR was given using a 150 kVp X-ray unit and maintaining the cells at 41 deg. C between irradiations. The duration of irradiation and concurrent heating depended on total dose and extended up to 48 h. Results: When 41 deg. C hyperthermia was given currently with LDR or PSLDR, the thermal enhancement ratios (TER) were about the same if the average dose rate for PSLDR was the same as for LDR. At higher average dose rates for PSLDR the TERs became less. Conclusions: Our data show that concurrent mild hyperthermia can be an effective sensitizer for PSLDR. This sensitization can be as effective as for LDR if the same average dose rate is used and the TER increases with decreasing dose rate. Thus mild hyperthermia combined with PSLDR may be an effective clinical protocol

Live cell plasma membranes do not exhibit a miscibility phase transition over a wide range of temperatures.

Science.gov (United States)

Lee, Il-Hyung; Saha, Suvrajit; Polley, Anirban; Huang, Hector; Mayor, Satyajit; Rao, Madan; Groves, Jay T

2015-03-26

Lipid/cholesterol mixtures derived from cell membranes as well as their synthetic reconstitutions exhibit well-defined miscibility phase transitions and critical phenomena near physiological temperatures. This suggests that lipid/cholesterol-mediated phase separation plays a role in the organization of live cell membranes. However, macroscopic lipid-phase separation is not generally observed in cell membranes, and the degree to which properties of isolated lipid mixtures are preserved in the cell membrane remain unknown. A fundamental property of phase transitions is that the variation of tagged particle diffusion with temperature exhibits an abrupt change as the system passes through the transition, even when the two phases are distributed in a nanometer-scale emulsion. We support this using a variety of Monte Carlo and atomistic simulations on model lipid membrane systems. However, temperature-dependent fluorescence correlation spectroscopy of labeled lipids and membrane-anchored proteins in live cell membranes shows a consistently smooth increase in the diffusion coefficient as a function of temperature. We find no evidence of a discrete miscibility phase transition throughout a wide range of temperatures: 14-37 °C. This contrasts the behavior of giant plasma membrane vesicles (GPMVs) blebbed from the same cells, which do exhibit phase transitions and macroscopic phase separation. Fluorescence lifetime analysis of a DiI probe in both cases reveals a significant environmental difference between the live cell and the GPMV. Taken together, these data suggest the live cell membrane may avoid the miscibility phase transition inherent to its lipid constituents by actively regulating physical parameters, such as tension, in the membrane.

Internal tides and vertical mixing over the Kerguelen Plateau

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Park, Young-Hyang; Fuda, Jean-Luc; Durand, Isabelle; Naveira Garabato, Alberto C.

2008-03-01

Within the context of the natural iron-fertilization study KEOPS, time series measurements of CTD and LADCP profiles at a site (50.6°S, 72°E; 528 m) coinciding with an annual phytoplankton bloom over the Kerguelen Plateau were made during the January-February 2005 KEOPS cruise. An important activity of highly nonlinear semidiurnal internal tides having peak-to-peak isopycnal displacements of up to 80 m is identified. These internal tides appear to be a principal agent for promoting elevated vertical mixing indispensable for upward transfer of iron within the seasonal thermocline. We estimate local vertical eddy diffusivities of the order of 4×10 -4 m 2 s -1 using a Thorpe scale analysis. Although this estimate is higher by an order of magnitude than the canonical value O (0.1×10 -4 m 2 s -1) in the open ocean away from boundaries, it is consistent with nonlinear internal wave/wave interaction theories, as verified by independent diffusivity estimates using the vertical wavenumber spectral methods for shear and strain. It is also suggested that the general ocean circulation may play an important role in preconditioning the bloom in that the relatively sluggish circulation over the shallow plateau (compared to the much more dynamic neighbouring deep ocean) may foster the bloom's observed annual recurrence over the plateau.

Phase locking and multiple oscillating attractors for the coupled mammalian clock and cell cycle.

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Feillet, Céline; Krusche, Peter; Tamanini, Filippo; Janssens, Roel C; Downey, Mike J; Martin, Patrick; Teboul, Michèle; Saito, Shoko; Lévi, Francis A; Bretschneider, Till; van der Horst, Gijsbertus T J; Delaunay, Franck; Rand, David A

2014-07-08

Daily synchronous rhythms of cell division at the tissue or organism level are observed in many species and suggest that the circadian clock and cell cycle oscillators are coupled. For mammals, despite known mechanistic interactions, the effect of such coupling on clock and cell cycle progression, and hence its biological relevance, is not understood. In particular, we do not know how the temporal organization of cell division at the single-cell level produces this daily rhythm at the tissue level. Here we use multispectral imaging of single live cells, computational methods, and mathematical modeling to address this question in proliferating mouse fibroblasts. We show that in unsynchronized cells the cell cycle and circadian clock robustly phase lock each other in a 1:1 fashion so that in an expanding cell population the two oscillators oscillate in a synchronized way with a common frequency. Dexamethasone-induced synchronization reveals additional clock states. As well as the low-period phase-locked state there are distinct coexisting states with a significantly higher period clock. Cells transition to these states after dexamethasone synchronization. The temporal coordination of cell division by phase locking to the clock at a single-cell level has significant implications because disordered circadian function is increasingly being linked to the pathogenesis of many diseases, including cancer.

The relationship between the opening of South China Sea and the formation of the Tibetan Plateau (Invited)

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Mo, X.

2010-12-01

The South China Sea is one of the largest marginal seas in western Pacific and underwent a complex history. Xu et al.(2004) suggested that the evolution of the South China Sea can be divided into two first order phases: Paleogene (—Early Miocene) rifting and Neogene post- rifting. An oceanic crust was formed during 32-17 Ma. Whether or not the opening of South China Sea were related to Indo-Eurasia collision and the formation of the Tibetan Plateau is one of challenging problem in Earth sciences. With an exception of the southwestern China, the Chinese continent has become an united continent in the Triassic by the Indosinian orogeny. However, the Qinghai-Tibet area in SW China was still an oceanic region, that is, the Neo-Tethys. During the period of 145-100 Ma, the Lhasa terrane collided with the Qiangtang terrane and added to the south margin of the Eurasian continent. On the other hand, the Indian plate subducted underneath the Eurasian continent since Jurassic- Cretaceous. Subsequently, collision between the two continents, India and Eurasia, were completed during 65-40 Ma, and went into a post-collisional stage, characterized by intra-continental movements, including intra-continental subduction, overthrust, strike-slip and so on. The Tibetan Plateau, the highest plateau in the world had been formed by multi-stage uplifts. Several huge strike-slip shear zone such as the Red River Fault and the Altyn were formed during that period. The >1000-km-long Oligocene—Miocene left-lateral Red River shear zone (RRSZ) and the Pliocene—active right-lateral Red River fault (RRF), stretching from SE Tibet to the South China Sea, has been cited as a lithospheric scale strike-slip fault. The age of RRSZ was recently determined no earlier than 31.9-24.2Ma and no later than 21.7 Ma (Searle et al., 2010). Many geologists believe that there possibly be close relationship between the opening of the South China Sea and Indo-Eurasia collision and the formation of the Tibetan

Genetic variation and phylogenetic relationships of the ectomycorrhizal Floccularia luteovirens on the Qinghai-Tibet Plateau.

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Xing, Rui; Gao, Qing-Bo; Zhang, Fa-Qi; Fu, Peng-Cheng; Wang, Jiu-Li; Yan, Hui-Ying; Chen, Shi-Long

2017-08-01

Floccularia luteovirens, as an ectomycorrhizal fungus, is widely distributed in the Qinghai-Tibet Plateau. As an edible fungus, it is famous for its unique flavor. Former studies mainly focus on the chemical composition and genetic structure of this species. However, the phylogenetic relationship between genotypes remains unknown. In this study, the genetic variation and phylogenetic relationship between the genotypes of F. luteovirens in Qinghai-Tibet Plateau was estimated through the analysis on two protein-coding genes (rpb1 and ef-1α) from 398 individuals collected from 24 wild populations. The sample covered the entire range of this species during all the growth seasons from 2011 to 2015. 13 genotypes were detected and moderate genetic diversity was revealed. Based on the results of network analysis, the maximum likelihood (ML), maximum parsimony (MP), and Bayesian inference (BI) analyses, the genotypes H-1, H-4, H-6, H-8, H-10, and H-11 were grouped into one clade. Additionally, a relatively higher genotype diversity (average h value is 0.722) and unique genotypes in the northeast edge of Qinghai- Tibet plateau have been found, combined with the results of mismatch analysis and neutrality tests indicated that Southeast Qinghai-Tibet plateau was a refuge for F. luteovirens during the historical geological or climatic events (uplifting of the Qinghai-Tibet Plateau or Last Glacial Maximum). Furthermore, the present distribution of the species on the Qinghai-Tibet plateau has resulted from the recent population expansion. Our findings provide a foundation for the future study of the evolutionary history and the speciation of this species.

Factors involved in depletion of glutathione from A549 human lung carcinoma cells: implications for radiotherapy

International Nuclear Information System (INIS)

Biaglow, J.E.; Varnes, M.E.; Epp, E.R.; Clark, E.P.

1984-01-01

The rate of GSH resynthesis has been measured in plateau phase cultures of A549 human lung carcinoma cells subjected to a fresh medium change. Buthionine sulfoximine (BSO) blocks this resynthesis. Diethyl maleate (DEM) causes a decrease in accumulation of GSH. If DEM is added concurrently with BSO there is a rapid decline in GSH that is maximal in the presence of 0.5 mM DEM. GSH depletion rapidly occurs when BSO is added to log phase cultures which initially are higher in GSH content. Twenty-four hr treatment of A549 cells with BSO results in cells that are more radiosensitive in air and show a slight hypoxic radiation response. A 2 hr treatment with DEM results in some hypoxic sensitization and little increase in the aerobic radiation response. Cells treated simultaneously with BSO + DEM show little increase in the hypoxic radiation response, compared to DEM alone, but are more sensitive under aerobic conditions. Decreased cell survival for aerobically irradiated log phase A549 cells occurs within minutes after addition of a mixture of BSO + DEM. The authors suggest that the enhanced aerobic radiation response is related to an inability of GSH depleted cells to inactivate either peroxy radicals or hydroperoxides that may be produced during irradiation of BSO treated cells. Furthermore, enhancement of the aerobic radiation response may be useful in vivo if normal tissue responses are not also increased

A novel single virus infection system reveals that influenza virus preferentially infects cells in g1 phase.

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Ryuta Ueda

Full Text Available BACKGROUND: Influenza virus attaches to sialic acid residues on the surface of host cells via the hemagglutinin (HA, a glycoprotein expressed on the viral envelope, and enters into the cytoplasm by receptor-mediated endocytosis. The viral genome is released and transported in to the nucleus, where transcription and replication take place. However, cellular factors affecting the influenza virus infection such as the cell cycle remain uncharacterized. METHODS/RESULTS: To resolve the influence of cell cycle on influenza virus infection, we performed a single-virus infection analysis using optical tweezers. Using this newly developed single-virus infection system, the fluorescence-labeled influenza virus was trapped on a microchip using a laser (1064 nm at 0.6 W, transported, and released onto individual H292 human lung epithelial cells. Interestingly, the influenza virus attached selectively to cells in the G1-phase. To clarify the molecular differences between cells in G1- and S/G2/M-phase, we performed several physical and chemical assays. Results indicated that: 1 the membranes of cells in G1-phase contained greater amounts of sialic acids (glycoproteins than the membranes of cells in S/G2/M-phase; 2 the membrane stiffness of cells in S/G2/M-phase is more rigid than those in G1-phase by measurement using optical tweezers; and 3 S/G2/M-phase cells contained higher content of Gb3, Gb4 and GlcCer than G1-phase cells by an assay for lipid composition. CONCLUSIONS: A novel single-virus infection system was developed to characterize the difference in influenza virus susceptibility between G1- and S/G2/M-phase cells. Differences in virus binding specificity were associated with alterations in the lipid composition, sialic acid content, and membrane stiffness. This single-virus infection system will be useful for studying the infection mechanisms of other viruses.

Factors limiting SOS expression in log-phase cells of Escherichia coli.

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Massoni, Shawn C; Leeson, Michael C; Long, Jarukit Edward; Gemme, Kristin; Mui, Alice; Sandler, Steven J

2012-10-01

In Escherichia coli, RecA-single-stranded DNA (RecA-ssDNA) filaments catalyze DNA repair, recombination, and induction of the SOS response. It has been shown that, while many (15 to 25%) log-phase cells have RecA filaments, few (about 1%) are induced for SOS. It is hypothesized that RecA's ability to induce SOS expression in log-phase cells is repressed because of the potentially detrimental effects of SOS mutagenesis. To test this, mutations were sought to produce a population where the number of cells with SOS expression more closely equaled the number of RecA filaments. Here, it is shown that deleting radA (important for resolution of recombination structures) and increasing recA transcription 2- to 3-fold with a recAo1403 operator mutation act independently to minimally satisfy this condition. This allows 24% of mutant cells to have elevated levels of SOS expression, a percentage similar to that of cells with RecA-green fluorescent protein (RecA-GFP) foci. In an xthA (exonuclease III gene) mutant where there are 3-fold more RecA loading events, recX (a destabilizer of RecA filaments) must be additionally deleted to achieve a population of cells where the percentage having elevated SOS expression (91%) nearly equals the percentage with at least one RecA-GFP focus (83%). It is proposed that, in the xthA mutant, there are three independent mechanisms that repress SOS expression in log-phase cells. These are the rapid processing of RecA filaments by RadA, maintaining the concentration of RecA below a critical level, and the destabilizing of RecA filaments by RecX. Only the first two mechanisms operate independently in a wild-type cell.

Deformation styles and exhumation patterns in the Northern Iranian Plateau: New results from integrated balanced cross sections and low-temperature thermochronology (AHe and ZHe)

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Balling, Philipp; Ballato, Paolo; Dunkl, István; Zeillinger, Gerold; Heidarzadeh, Ghasem; Ghasemi, Mohammad; Strecker, Manfred R.

2014-05-01

predated by at least one contractional episode, which was most likely associated with the deposition of red continental conglomerates (Fajan Fm.). Consequently, some of the major faults affecting Tertiary units in the region may be inherited structures, reactivated during collisional deformation. Our structural results indicate that the different mountain ranges constituting the northern plateau are characterized by thick-skinned deformation (tectonics) with major deep-seated faults exposing basement rocks. Locally, thin-skinned tectonics occurred, with multiple detachment horizons within evaporites of the Lower and Upper Red formations (Oligo-Miocene), and shales of the Shemshak (Jurassic), and the Barut (Cambrian) formations. The first obtained AHe cooling ages for this area suggest that the more internal sectors of the Iranian Plateau (SW of the Mah Neshan profile) record an early cooling phase at 25-20 Ma. This was followed by outward propagation of deformation fronts to the north and northeast from approximately 12 to 8 Ma. This resulted in the development of a contractional basin and range morphology of the Iranian Plateau.

Discussion on the Regional Paleotemperature Evolution since the Late Pleistocene in the Loess Plateau with GDGT as an Index

Science.gov (United States)

Yingchun, S.

2017-12-01

It is an effective way to understand the modern climate and predict the future climate trend by using the geological substitute indicators to reconstruct the past climate. In recent years, scientists have begun to apply Glycerol dialkyl glycerol tetraethers (GDGTs) to reconstruct paleoclimate and many proxies about ancient air temperature based on GDGTs have been proposed, even the empirical formulas used for China have also been established. In this paper, five loess-paleosol sequences spanning the Late Pleistocene from the Loess Plateau have been used to examine the effectiveness of the formulas as well as to discuss the regional evolution of the ancient temperature of the plateau. The results are as follows: (1) The relative content of iGDGT is higher than that of bGDGT in all Loess sections, and that of each compound follows relatively fixed regularity. Seen from the geographical distribution, the relative content of GDGT in southernmost sections is the highest, which in the northernmost is the smallest. (2) In the last interglacial period, from the northern part to the southern part of the Loess Plateau, the mean annual air temperature (MAAT) of northern Jingbian was 14°, central Luochuan was up to 15°, and southern Weinan was nearly 18°. And at the end of the last glacial period the temperature, where LC and WN located, dropped to 13.5°. Along the east-west direction of the Plateau, in the last interglacial period, the MAAT of western Qin'an secion was 13°, and that of central Baoji and eastern Weinan was about 18°. To the end of the last glacial period, the MAAT decreased to the lowest, Weinan 13.5°, Baoji 14.5°, while Qin'an 10.8°. (3)In contrast to the magnetic susceptibility index, the curves of GDGT MAAT have great similarity with the magnetic susceptibility curve, but it is obvious that there are phase differences between them. That may be indicating that the temperature rise was before the onset of the East-Asian summer monsoon in the Plateau

Plateau diffusion coefficient for arbitrary flux surface geometry

International Nuclear Information System (INIS)

Meier, H.K.; Hirshman, S.P.; Sigmar, D.J.; Lao, L.L.

1981-03-01

A relatively simple but accurate representation has been developed for magnetic flux surfaces; it is valid for finite β and it describes configurations with both ellipticity and D-shape. This representation has been applied to the computation of the diffusion coefficient in the plateau regime

Neoclassical kinetic theory near an X point: Plateau regime

International Nuclear Information System (INIS)

Solano, E.R.; Hazeltine, R.D.

1994-01-01

Traditionally, neoclassical transport calculations ignore poloidal variation of the poloidal magnetic field. Near an X point of the confining field of a diverted plasma, the poloidal field is small, causing guiding centers to linger at that poloidal position. A study of how neoclassical transport is affected by this differential shaping is presented. The problem is solved in general in the plateau regime, and a model poloidal flux function with an X point is utilized as an analytic example to show that the plateau diffusion coefficient can change considerably (factor of 2 reduction). Ion poloidal rotation is proportional to the local value of B pol but otherwise it is not strongly affected by shaping. The usual favorable scaling of neoclassical confinement time with plasma current is unaffected by the X point

[Dynamic changes of Ruoergai Plateau wetland ecosystem service value].

Science.gov (United States)

Zhang, Xiao-Yun; Lü, Xian-Guo; Shen, Song-Ping

2009-05-01

Based on the satellite remote sensing data acquired in 1975 and 2006, and by using the assessment method of ecosystem service value, the dynamic changes of physical production value, gas regulation value, and water storage value of Ruoergai Plateau wetland ecosystem in 1975-2006 were studied. During study period, the total value of the three services decreased from 19.59 billion RMB Yuan to 12.38 billion Yuan RMB, among which, physical production value increased by 0.302 billion RMB Yuan, while the gas regulation and water storage value decreased by 7.507 billion RMB Yuan. The benefit from the increase of physical production was much less than the loss of ecosystem degradation. Overgrazing induced the biomass reduction and soil deterioration, resulting in the decline of Ruoergai Plateau wetland ecosystem service value and service capacity.

Single cell low dose studies of bystander cell killing with targeted ultrasoft x-rays

International Nuclear Information System (INIS)

Schettino, G.; Prise, K.M.; Folkard, M.; Vojnovic, B.; Michael, B.D.; Wu, L.; Held, K.D.

2003-01-01

Full text: Bystander responses have attracted considerable interest in the recent years and several investigations have reported a binary behavior with the effect triggered by very small doses and immediately reaching a plateau. The Ultrasoft X-ray Microprobe in operation at the GCI is a facility designed to precisely assess the biological response of individual cells in vitro irradiated with a sub-micron size X-ray beam . Although recent improvements have upgrade the facility with AlK and TiK X-rays, most of the bystander studies have been performed using CK X-rays of 278 eV. The high sensitivity and the accurate irradiation and revisiting of the individual samples allowed us to investigate specific characteristics of the bystander phenomenon. In particular, evidences of a dose dependency of cell killing by bystander effect have been found at doses below 0.2 Gy where no differences is observed between all cell and single cell irradiation. Recent improvements have also allowed us to individually identify the phase of the cell cycle of all samples exposed. Although the G2-S phase have been found the most sensitive in responding to the bystander signal (a factor of 1.3), cells in the G1 phase also respond significantly while the phase of the irradiated cell doesn't seem to play a critical role. The time scale of the bystander effect has also been investigated by irradiating the same sample(s) twice with a few hours gap between exposures. Results indicate that the bystander signal is transmitted within a few minutes from the irradiation as replacing the medium immediately after irradiation does not influence the response, and it doesn't depend on the number of cells irradiated (up to 5). However, after a resting time of a few hours (3 h), the system seems to reset itself and a second irradiation has been shown to trigger a further bystander effect. Finally, by considering the total amount of energy deposited in to the sample population as critical parameter (instead

Diurnal variations of summer precipitation over the regions east to Tibetan Plateau

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Wu, Yang; Huang, Anning; Huang, Danqing; Chen, Fei; Yang, Ben; Zhou, Yang; Fang, Dexian; Zhang, Lujun; Wen, Lijuan

2017-12-01

Based on the hourly gauge-satellite merged precipitation product with the horizontal resolution of 0.1° latitude/longitude during 2008-2014, diurnal variations of the summer precipitation amount (PA), frequency (PF), and intensity (PI) with different duration time over the regions east to Tibetan Plateau have been systematically revealed in this study. Results indicate that the eight typical precipitation diurnal patterns identified by the cluster analysis display pronounced regional features among the plateaus, basins, plains, hilly and coastal areas. The precipitation diurnal cycles are significantly affected by the sub-grid terrain fluctuations. The PA, PF and PI of the total rainfall show much more pronounced double diurnal peaks with the sub-grid topography standard deviation (SD) decreased. Meanwhile, the diurnal peaks of PA and PF (PI) strengthen (weaken) with the sub-grid topography SD enhanced. Over the elevated mountain ranges, southeastern hilly and coastal regions, the PA and PF diurnal patterns of the total rainfall generally show predominant late-afternoon peaks, which are closely associated with the short-duration (≤slant 3 h) rainfall. Along the Tibetan Plateau to its downstream, the diurnal peaks of PA, PF and PI for the total rainfall all exhibit obvious eastward phase time delay mainly due to the diurnal evolutions of long-duration (> 6 h) rainfall. However, the 4-6 h rainfall leads to the eastward phase time delay of the total rainfall along the Taihang Mountains to its downstream. Further mechanism analysis suggests that the midnight to morning diurnal evolution of the long-duration rainfall is closely associated with the diurnal variations of the upward branches of thermally driven mountain-plain solenoids and the water vapor transport associated with the accelerated nocturnal southwesterly winds. The late-afternoon peak of the short-duration PA over the southeastern hilly and coastal regions is ascribed to the strong local thermal

Geomorphological investigations and GIS approach of the Tamiš loess plateau, Banat region (northern Serbia

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Popov Dragan

2012-01-01

Full Text Available The focus of this study was the loess plateau located in the Tamiš River valley in the central part of Banat region (northern Serbia. This morphologic unit has been formed by the loess accumulation process during the last two glacial periods. Digital elevation model (DEM is based on the 1:25.000 scale topographic maps. Detailed geomorphologic and hypsometric maps are provided with selected cross sections. The borders of the plateau and spatial distribution of the micromorphology are precisely defined on DEM. The plateau rises gradually from the Upper Pleistocene terrace on the north and northwest, while to the east and south slopes and vertical bluffs were controlled by the lateral erosion process of surrounding channels and by the weathering process on the loess. The plateau has an atypical morphology characterized by reduced geomorphologic diversity. Loess topography is significantly flattened by human impact. Its micromorphology is characterised by shallow depressions and gullies.

Element concentrations in surface soils of the Coconino Plateau, Grand Canyon region, Coconino County, Arizona

Science.gov (United States)

Van Gosen, Bradley S.

2016-09-15

This report provides the geochemical analyses of a large set of background soils collected from the surface of the Coconino Plateau in northern Arizona. More than 700 soil samples were collected at 46 widespread areas, sampled from sites that appear unaffected by mineralization and (or) anthropogenic contamination. The soils were analyzed for 47 elements, thereby providing data on metal concentrations in soils representative of the plateau. These background concentrations can be used, for instance, for comparison to metal concentrations found in soils potentially affected by natural and anthropogenic influences on the Coconino Plateau in the Grand Canyon region of Arizona.The soil sampling survey revealed low concentrations for the metals most commonly of environmental concern, such as arsenic, cobalt, chromium, copper, mercury, manganese, molybdenum, lead, uranium, vanadium, and zinc. For example, the median concentrations of the metals in soils of the Coconino Plateau were found to be comparable to the mean values previously reported for soils of the western United States.

Cell-free soluble-phase radioimmunoassay for Thy-1 antigen

Energy Technology Data Exchange (ETDEWEB)

Shalev, A.; Zuckerman, F. (Ben-Gurion Univ. of the Negev, Beersheba (Israel))

1983-12-01

A cell-free, soluble-phase, radioimmunoassay has been developed for Thy-1 antigen. The method is based on immunoprecipitation of radiolabelled Thy-1 molecules with specific antibodies, antiimmunoglobulin serum and polyethyleneglycol (PEG). The method can be used with convenience to screen for the presence of Thy-1 in various fluids as well as on cell surfaces for qualitative or quantitative purposes. Presence of antibodies or autoantibodies against Thy-1 can also be detected specifically. Evidence that the dog, carp, hamster and goldfish carry Thy-1-like molecules on neuronal (brain) cells is demonstrated by this method.

Peripheral laser iridoplasty opens angle in plateau iris by thinning the cross-sectional tissues

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Liu J

2013-09-01

Full Text Available Ji Liu,1,2 Tania Lamba,1 David A Belyea1 1Department of Ophthalmology, The George Washington University, Washington DC, USA; 2Yale Eye Center, Yale University, New Haven, CT, USA Abstract: Plateau iris syndrome has been described as persistent angle narrowing or occlusion with intraocular pressure elevation after peripheral iridotomy due to the abnormal plateau iris configuration. Argon laser peripheral iridoplasty (ALPI is an effective adjunct procedure to treat plateau iris syndrome. Classic theory suggests that the laser causes the contraction of the far peripheral iris stroma, "pulls" the iris away from the angle, and relieves the iris-angle apposition. We report a case of plateau iris syndrome that was successfully treated with ALPI. Spectral domain optical coherence tomography confirmed the angle was open at areas with laser treatment but remained appositionally closed at untreated areas. Further analysis suggested significant cross-sectional thinning of the iris at laser-treated areas in comparison with untreated areas. The findings indicate that APLI opens the angle, not only by contracting the iris stroma, but also by thinning the iris tissue at the crowded angle. This is consistent with the ALPI technique to aim at the iris as far peripheral as possible. This case also suggests that spectral domain optical coherence tomography is a useful adjunct imaging tool to gonioscopy in assessing the angle condition. Keywords: plateau iris, optic coherence tomography, argon laser peripheral iridoplasty, angle-closure glaucoma

Enrichment of G2/M cell cycle phase in human pluripotent stem cells enhances HDR-mediated gene repair with customizable endonucleases.

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Yang, Diane; Scavuzzo, Marissa A; Chmielowiec, Jolanta; Sharp, Robert; Bajic, Aleksandar; Borowiak, Malgorzata

2016-02-18

Efficient gene editing is essential to fully utilize human pluripotent stem cells (hPSCs) in regenerative medicine. Custom endonuclease-based gene targeting involves two mechanisms of DNA repair: homology directed repair (HDR) and non-homologous end joining (NHEJ). HDR is the preferred mechanism for common applications such knock-in, knock-out or precise mutagenesis, but remains inefficient in hPSCs. Here, we demonstrate that synchronizing synchronizing hPSCs in G2/M with ABT phase increases on-target gene editing, defined as correct targeting cassette integration, 3 to 6 fold. We observed improved efficiency using ZFNs, TALENs, two CRISPR/Cas9, and CRISPR/Cas9 nickase to target five genes in three hPSC lines: three human embryonic stem cell lines, neural progenitors and diabetic iPSCs. neural progenitors and diabetic iPSCs. Reversible synchronization has no effect on pluripotency or differentiation. The increase in on-target gene editing is locus-independent and specific to the cell cycle phase as G2/M phase enriched cells show a 6-fold increase in targeting efficiency compared to cells in G1 phase. Concurrently inhibiting NHEJ with SCR7 does not increase HDR or improve gene targeting efficiency further, indicating that HR is the major DNA repair mechanism after G2/M phase arrest. The approach outlined here makes gene editing in hPSCs a more viable tool for disease modeling, regenerative medicine and cell-based therapies.

In vitro development of cloned bovine embryos produced by handmade cloning using somatic cells from distinct levels of cell culture confluence.

Science.gov (United States)

Gerger, R P C; Ribeiro, E S; Forell, F; Bertolini, L R; Rodrigues, J L; Ambrósio, C E; Miglino, M A; Mezzalira, A; Bertolini, M

2010-02-18

The relationship between the level of cell confluence near the plateau phase of growth and blastocyst yield following somatic cell cloning is not well understood. We examined the effect of distinct cell culture confluence levels on in vitro development of cloned bovine embryos. In vitro-matured bovine oocytes were manually bisected and selected by DNA staining. One or two enucleated hemi-cytoplasts were paired and fused with an adult skin somatic cell. Cultured skin cells from an adult Nellore cow harvested at three distinct culture confluence levels (70-80, 80-90, and >95%) were used for construction of embryos and hemi-embryos. After activation, structures were cultured in vitro as one embryo (1 x 100%) or as aggregates of two hemi-embryos (2 x 50%) per microwell. Fusion, cleavage and blastocyst rates were compared using the chi(2) test. The fusion rate for hemi-embryos (51.4%) was lower than for embryos (67.6%), with no influence of degree of cell confluence. However, blastocyst rates improved linearly (7.0, 17.5, and 29.4%) with increases in cell confluence. We conclude that degree of cell culture confluence significantly influences subsequent embryo development; use of a cell population in high confluence (>90%) for nuclear transfer significantly improved blastocyst yield after cloning.

Pseudoarthrosis of medial tibial plateau fracture-role of alignment procedure

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Devgan Ashish

2013-04-01

Full Text Available 【Abstract】 Nonunion in tibial plateau fractures is very rare. Limited literature is available on Pubmed search on intraarticular tibial nonunion. Most of the cases reported have been following failed surgical treatment and none was neglected fractures. Three patients of isolated and neglected medial tibial plateau nonunion with almost similar demo-graphic profile are reported in this paper. All the three pa-tients were managed by minimally invasive compression fixation using lag screws supplemented with limb realign-ment procedure of high tibial osteotomy. We discussed the injury mechanism, management and rehabilitation in such cases and reviewed the available literature regarding such a presentation. Key words: Fracture healing; Tibial fractures; Frac-ture fixation; Osteotomy

[Simulation of Stipa purpurea distribution pattern on Tibetan Plateau based on MaxEnt model and GIS].

Science.gov (United States)

Hu, Zhong-jun; Zhang, Yi-li; Yu, Hai-bin

2015-02-01

The impact of climate change on species distribution is a hot issue in biogeography research. This study utilized the constructive species Stipa purpurea as the research object, which was widely distributed in alpine meadow of the Tibetan Plateau, investigated its distribution in the Tibetan Plateau through the field survey and herbarium search, and used MaxEnt model to simulate its historical, current and future distribution trends to analyze its distribution pattern in each historical period and explore the cause of species distribution changes. Research results showed that diversity of Stipa species in alpine grassland of the Tibetan Plateau was high, its main distribution area was the hinterland of the Tibetan Plateau and areas along the Himalaya, and its distribution was strongly affected by precipitation of warmest quarter, precipitation of wettest quarter and annual precipitation. According to the distribution pattern of S. purpurea in the Last Glacial Maximum, and geographical and geological features of the Tibetan Plateau, this paper proposed that: North Tibet core area of South Qiangtang and Ali region of west Himalaya mountainous area were the core area of the potential distribution for S. purpurea, since these regions could provide more suitable habitats for S. purpurea than other regions and be the refugia where the current S. purpurea was migrated and differentiated from. The presence of refugia may contribute to the understanding of related issues of the alpine plants' origin and differentiation in the Tibetan Plateau.

Glacier mass changes on the Tibetan Plateau 2003–2009 derived from ICESat laser altimetry measurements

International Nuclear Information System (INIS)

Neckel, N; Kropáček, J; Hochschild, V; Bolch, T

2014-01-01

Glacier mass changes are a valuable indicator of climate variability and monsoon oscillation on the underexplored Tibetan Plateau. In this study data from the Ice Cloud and Elevation Satellite (ICESat) is employed to estimate elevation and mass changes of glaciers on the Tibetan Plateau between 2003 and 2009. In order to get a representative sample size of ICESat measurements, glaciers on the Tibetan Plateau were grouped into eight climatically homogeneous sub-regions. Most negative mass budgets of − 0.77 ± 0.35 m w.e. a −1 were found for the Qilian Mountains and eastern Kunlun Mountains while a mass gain of + 0.37 ± 0.25 m w.e. a −1 was found in the westerly-dominated north-central part of the Tibetan Plateau. A total annual mass budget of − 15.6 ± 10.1 Gt a −1 was estimated for the eight sub-regions sufficiently covered by ICESat data which represents ∼80% of the glacier area on the Tibetan Plateau. 13.9 ± 8.9 Gt a −1 (or 0.04 ± 0.02 mm a −1 sea-level equivalent) of the total mass budget contributed ‘directly’ to the global sea-level rise while 1.7 ± 1.9 Gt a −1 drained into endorheic basins on the plateau. (paper)

Distributional patterns of anemophilous tree pollen indicating the pathways of Indian monsoon through Qinghai–Tibetan Plateau

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Zhi-Yong Zhang

2017-10-01

Full Text Available The distribution pattern of vegetation on Qinghai–Tibetan Plateau is fundamentally influenced by the plateau climate, which is mainly controlled by Indian monsoon during summer. The long distance transportation of pollen (mostly anemophilous taxa produced by trees on the plateau has been recorded by modern pollen samples in previous studies, and hypothesized to be a good indicator of monsoon dynamics. Here we use 270 surface pollen samples from Qinghai–Tibetan Plateau to test the distribution patterns of the anemophilous tree pollen. Meanwhile factors related to Indian monsoon affecting pollen transportation are simulated and analyzed. Results show that depositional patterns of anemophilous tree pollen, especially Abies, Pinus, Quercus and Betula are completely controlled by the pathways of Indian monsoon. This is reflected by climatic indicators of the atmospheric pressure pattern over June–July–August, by the precipitation pattern over June–July–August and by the topographic feature of the plateau. The spatial interpolation of thin plate spline results also display two depositional centers (ca. 30°N, 95°E and 30°N, 105°E of the anemophilous tree pollen. In contrast to previous conclusion that pollen distributional pattern is determined by mean annual precipitation, we argue that Indian monsoon is the essential controller because of the synchronization between timing of monsoon wind and timing of plants flowering. Our finding strongly suggests that distributional pattern of anemophilous tree pollen on the plateau is a good proxy of Indian monsoon.

Minimal surfaces, stratified multivarifolds, and the plateau problem

CERN Document Server

Thi, Dao Trong; Primrose, E J F; Silver, Ben

1991-01-01

Plateau's problem is a scientific trend in modern mathematics that unites several different problems connected with the study of minimal surfaces. In its simplest version, Plateau's problem is concerned with finding a surface of least area that spans a given fixed one-dimensional contour in three-dimensional space--perhaps the best-known example of such surfaces is provided by soap films. From the mathematical point of view, such films are described as solutions of a second-order partial differential equation, so their behavior is quite complicated and has still not been thoroughly studied. Soap films, or, more generally, interfaces between physical media in equilibrium, arise in many applied problems in chemistry, physics, and also in nature. In applications, one finds not only two-dimensional but also multidimensional minimal surfaces that span fixed closed "contours" in some multidimensional Riemannian space. An exact mathematical statement of the problem of finding a surface of least area or volume requir...

Mapping of lithologic and structural units using multispectral imagery. [Afar-Triangle/Ethiopia and adjacent areas (Ethiopian Plateau, Somali Plateau, and parts of Yemen and Saudi Arabia)

Science.gov (United States)

Kronberg, P. (Principal Investigator)

1974-01-01

The author has identified the following significant results. ERTS-1 MSS imagery covering the Afar-Triangle/Ethiopia and adjacent regions (Ethiopian Plateau, Somali Plateau, and parts of Yemen and Saudi Arabi) was applied to the mapping of lithologic and structural units of the test area at a scale 1:1,000,000. Results of the geological evaluation of the ERTS-1 imagery of the Afar have proven the usefullness of this type of satellite data for regional geological mapping. Evaluation of the ERTS images also resulted in new aspects of the structural setting and tectonic development of the Afar-Triangle, where three large rift systems, the oceanic rifts of the Red Sea and Gulf of Aden and the continental East African rift system, seem to meet each other. Surface structures mapped by ERTS do not indicate that the oceanic rift of the Gulf of Aden (Sheba Ridge) continues into the area of continental crust west of the Gulf of Tadjura. ERTS data show that the Wonji fault belt of the African rift system does not enter or cut through the central Afar. The Aysha-Horst is not a Horst but an autochthonous spur of the Somali Plateau.

A possible cause of the Miocene uplift and volcanism in the central Anatolian plateau

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Bartol, J.; Govers, R. M.; Wortel, M. J.

2010-12-01

During the middle and late Miocene (13-5Ma) several seemingly unrelated events occurred in central Anatolia, Turkey; (1) a new epoch of widespread volcanic activity with a mantle signature, (2) sudden uplift and disruption of a Oligocene-lower Miocene palaeo drainage system in the Western Taurus (southwest Turkey) and (3) a regional regression across southern Turkey (Antalya, Adana, Mut) coeval with volcanic activity. These observations suggest an uplift (>1000 meters) of the central Anatolian plateau by a mechanism which also triggered widespread volcanic activity. In eastern Anatolia, similar events are attributed to delamination of the lithospheric mantle [e.g. Keskin et al., 2003]. Results from tomography [W.Spakman, pers. com]) suggest that the (deeper) Bitlis slab was laterally continuous below the eastern and central Anatolian plateau. We therefore propose that the scenario developed for eastern Anatolian plateau also applies to the central Anatolian plateau. In this scenario, delamination started along the Izmir-Ankara-Erzincan suture zone and was possibly induced by remnants of a northern Neotethys slab or continental collision between Arabia and Eurasia. As the lithospheric mantle separated from the crust it sank into the asthenosphere and was replaced by hot mantle material. If true, delamination is expected to have had a thermal and isostatic imprint. Using a three-dimensional thermal-flexural model and taking changes of the effective elastic thickness due to thermal perturbation into account, we aim to quantify the possible imprints in the geological record of the central and eastern Anatolian plateau. Our model results show that delamination of the lithospheric mantle can explain the present day elevation (1500 m) of the central Anatolian plateau. For the eastern Anatolian plateau, however, delamination of the lithospheric mantle alone can only explain half (1000 m) of the present day elevation. Thickening of the eastern Anatolia crust by 1-5 km (β=1

Long-term, deep-mantle support of the Ethiopia-Yemen Plateau

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Sembroni, Andrea; Faccenna, Claudio; Becker, Thorsten W.; Molin, Paola; Abebe, Bekele

2016-04-01

Ethiopia is a key site to investigate the interactions between mantle dynamics and surface processes because of the presence of the Main Ethiopian Rift (MER), Cenozoic continental flood basalt volcanism, and plateau uplift. The role of mantle plumes in causing Ethiopia's flood basalts and tectonics has been commonly accepted. However, the location and number of plumes and their impact on surface uplift are still uncertain. Here, we present new constraints on the geological and topographic evolution of the Ethiopian Plateau (NW Ethiopia) prior to and after the emplacement of the large flood basalts (40-20 Ma). Using geological information and topographic reconstructions, we show that the large topographic dome that we see today is a long-term feature, already present prior the emplacement of the flood basalts. We also infer that large-scale doming operated even after the emplacement of the flood basalts. Using a comparison with the present-day topographic setting we show that an important component of the topography has been and is presently represented by a residual, non-isostatic, dynamic contribution. We conclude that the growth of the Ethiopian Plateau is a long-term, probably still active, dynamically supported process. Our arguments provide constraints on the processes leading to the formation of one of the largest igneous plateaus on Earth.

Diversity and Ecology of Dendrobiums (Orchidaceae in Chotanagpur Plateau, India

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Pankaj Kumar

2011-03-01

Full Text Available As part of All India Coordinated Research Project on Taxonomy of orchids (AICOPTAX Chotanagpur Plateau was surveyed extensively for documentation of orchid species and distribution during 2002 -2006. Sixty three species were collected from the study area with Dendrobium as one of the largest group of epiphytic orchids comprising of 11 species, namely, Dendrobium aphyllum, D. bicameratum, D. cucullatum, D. crepidatum, D. formosum, D. fimbriatum, D. herbaceum, D. moschatum, D. peguanum, D. regium and D. transparens. Most of the species were found in the Sal (Shorea robusta dominated forests. Stratified Random Sampling was used for ecological studies in the forested regions on the plateau. Results show that D. aphyllum was the most common amongst 11 species and it was distributed through out the altitudinal gradient, whereas, rest of the orchid species were found to be localised at comparatively higher altitudes. D. herbaceum was always found on the upper areas of the plateaus between 900-1000 m asl. D. crepidatum was seen in both epiphytic as well as lithophytic conditions, whereas D. moschatum were found growing as lithophytes along the streams. Rest of the species were epithytic. The paper also deals some microhabitat features governing the distribution of these orchids on the plateau along with their key for identification.

Tectonic setting of Cretaceous basins on the NE Tibetan Plateau: Insights from the Jungong basin

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Craddock, W.H.; Kirby, E.; Dewen, Z.; Jianhui, L.

2012-01-01

Quantifying the Cenozoic growth of high topography in the Indo-Asian collision zone remains challenging, due in part to significant shortening that occurred within Eurasia before collision. A growing body of evidence suggests that regions far removed from the suture zone experienced deformation before and during the early phases of Himalayan orogenesis. In the present-day north-eastern Tibetan Plateau, widespread deposits of Cretaceous sediment attest to significant basin formation; however, the tectonic setting of these basins remains enigmatic. We present a study of a regionally extensive network of sedimentary basins that are spatially associated with a system of SE-vergent thrust faults and are now exposed in the high ranges of the north-eastern corner of the Tibetan Plateau. We focus on a particularly well-exposed basin, located ~20km north of the Kunlun fault in the Anyemaqen Shan. The basin is filled by ~900m of alluvial sediments that become finer-grained away from the basin-bounding fault. Additionally, beds in the proximal footwall of the basin-bounding fault exhibit progressive, up-section shallowing and several intraformational unconformities which can be traced into correlative conformities in the distal part of the basin. The observations show sediment accumulated in the basin during fault motion. Regional constraints on the timing of sediment deposition are provided by both fossil assemblages from the Early Cretaceous, and by K-Ar dating of volcanic rocks that floor and cross-cut sedimentary fill. We argue that during the Cretaceous, the interior NE Tibetan Plateau experienced NW-SE contractional deformation similar to that documented throughout the Qinling-Dabie orogen to the east. The Songpan-Ganzi terrane apparently marked the southern limit of this deformation, such that it may have been a relatively rigid block in the Tibetan lithosphere, separating regions experiencing deformation north of the convergent Tethyan margin from regions deforming

Response of the RIF-1 tumor in vitro and in C3H/Km mice to x-radiation (cell survival, regrowth delay, and tumor control), chemotherapeutic agents, and activated macrophages

International Nuclear Information System (INIS)

Brown, J.M.; Twentyman, P.R.; Zamvil, S.S.

1980-01-01

The radiation response of logarithmic growth phase and fed plateau phase RIF-1 cells in vitro was found to be characterized by D 0 values of 110 and 133 rads and extrapolation numbs of 36 and 28, respectively. The response of the tumor in vivo to X-irradiation in nonanesthetized mice showed a dependence on the tumor implantation site. In the leg muscle, the response indicated that most cells were at an intermediate level of oxygenation, whereas in the subcutaneous tissue of the flank, the response of the tumor indicated that it had a small fraction of hypoxic cells of maximum radioresistance. Misonidazole radiosensitized the leg-implanted tumor as measured both by cell survival and regrowth delay. The tumor was relatively insensitive to a single dose of 1,3-bis(2-chloroethyl)-1-nitrosourea, sensitive to a single dose of cis-platinum, and highly sensitive to a single dose of cyclophosphamide

Phase transitions during compression and decompression of clots from platelet-poor plasma, platelet-rich plasma and whole blood.

Science.gov (United States)

Liang, Xiaojun; Chernysh, Irina; Purohit, Prashant K; Weisel, John W

2017-09-15

Blood clots are required to stem bleeding and are subject to a variety of stresses, but they can also block blood vessels and cause heart attacks and ischemic strokes. We measured the compressive response of human platelet-poor plasma (PPP) clots, platelet-rich plasma (PRP) clots and whole blood clots and correlated these measurements with confocal and scanning electron microscopy to track changes in clot structure. Stress-strain curves revealed four characteristic regions, for compression-decompression: (1) linear elastic region; (2) upper plateau or softening region; (3) non-linear elastic region or re-stretching of the network; (4) lower plateau in which dissociation of some newly made connections occurs. Our experiments revealed that compression proceeds by the passage of a phase boundary through the clot separating rarefied and densified phases. This observation motivates a model of fibrin mechanics based on the continuum theory of phase transitions, which accounts for the pre-stress caused by platelets, the adhesion of fibrin fibers in the densified phase, the compression of red blood cells (RBCs), and the pumping of liquids through the clot during compression/decompression. Our experiments and theory provide insights into the mechanical behavior of blood clots that could have implications clinically and in the design of fibrin-based biomaterials. The objective of this paper is to measure and mathematically model the compression behavior of various human blood clots. We show by a combination of confocal and scanning electron microscopy that compression proceeds by the passage of a front through the sample that separates a densified region of the clot from a rarefied region, and that the compression/decompression response is reversible with hysteresis. These observations form the basis of a model for the compression response of clots based on the continuum theory of phase transitions. Our studies may reveal how clot rheology under large compression in vivo due

Three-dimensional two-phase mass transport model for direct methanol fuel cells

International Nuclear Information System (INIS)

Yang, W.W.; Zhao, T.S.; Xu, C.

2007-01-01

A three-dimensional (3D) steady-state model for liquid feed direct methanol fuel cells (DMFC) is presented in this paper. This 3D mass transport model is formed by integrating five sub-models, including a modified drift-flux model for the anode flow field, a two-phase mass transport model for the porous anode, a single-phase model for the polymer electrolyte membrane, a two-phase mass transport model for the porous cathode, and a homogeneous mist-flow model for the cathode flow field. The two-phase mass transport models take account the effect of non-equilibrium evaporation/ condensation at the gas-liquid interface. A 3D computer code is then developed based on the integrated model. After being validated against the experimental data reported in the literature, the code was used to investigate numerically transport behaviors at the DMFC anode and their effects on cell performance

The effect of the immunophilin ligands rapamycin and FK506 on proliferation of mast cells and other hematopoietic cell lines.

Science.gov (United States)

Hultsch, T; Martin, R; Hohman, R J

1992-01-01

The immunosuppressive drugs FK506 and cyclosporin A have an identical spectrum of activities with respect to IgE receptor (Fc epsilon RI)-mediated exocytosis from mast cells and T cell receptor-mediated transcription of IL-2. These findings suggest a common step in receptor-mediated signal transduction leading to exocytosis and transcription and imply that immunosuppressive drugs target specific signal transduction pathways, rather than specific cell types. This hypothesis is supported by studies on the effect of rapamycin on IL-3 dependent proliferation of the rodent mast cell line PT18. Rapamycin inhibits proliferation of PT18 cells, achieving a plateau of 80% inhibition at 1 nM. This inhibition is prevented in a competitive manner by FK506, a structural analogue of rapamycin. Proliferation of rat basophilic leukemia cells and WEHI-3 cells was also inhibited, at doses comparable to those shown previously to inhibit IL-2-dependent proliferation of cytotoxic T lymphocyte line (CTLL) cells. In contrast, proliferation of A-431 cells, a epidermoid cell line, was not affected by rapamycin. DNA histograms indicate that complexes formed between the rapamycin-FK506-binding protein (FKBP) and rapamycin arrest-proliferating PT18 cells in the G0/G1-phase. It is concluded that FKBP-rapamycin complexes may inhibit proliferative signals emanating from IL-3 receptors, resulting in growth arrest of cytokine-dependent, hematopoietic cells. PMID:1384815

Evolution of cell resistance, threshold voltage and crystallization temperature during cycling of line-cell phase-change random access memory

NARCIS (Netherlands)

Oosthoek, J. L. M.; Attenborough, K.; Hurkx, G. A. M.; Jedema, F. J.; Gravesteijn, D. J.; Kooi, B. J.

2011-01-01

Doped SbTe phase change (PRAM) line cells produced by e-beam lithography were cycled 100 million times. During cell cycling the evolution of many cell properties were monitored, in particular the crystalline and amorphous resistance, amorphous resistance drift exponent, time-dependent threshold

Growing season carries stronger contributions to albedo dynamics on the Tibetan plateau.

Science.gov (United States)

Tian, Li; Chen, Jiquan; Zhang, Yangjian

2017-01-01

The Tibetan Plateau has experienced higher-than-global-average climate warming in recent decades, resulting in many significant changes in ecosystem structure and function. Among them is albedo, which bridges the causes and consequences of land surface processes and climate. The plateau is covered by snow/ice and vegetation in the non-growing season (nGS) and growing season (GS), respectively. Based on the MODIS products, we investigated snow/ice cover and vegetation greenness in relation to the spatiotemporal changes of albedo on the Tibetan Plateau from 2000 through 2013. A synchronous relationship was found between the change in GSNDVI and GSalbedo over time and across the Tibetan landscapes. We found that the annual average albedo had a decreasing trend, but that the albedo had slightly increased during the nGS and decreased during the GS. Across the landscapes, the nGSalbedo fluctuated in a synchronous pattern with snow/ice cover. Temporally, monthly snow/ice coverage also had a high correspondence with albedo, except in April and October. We detected clear dependencies of albedo on elevation. With the rise in altitude, the nGSalbedo decreased below 4000 m, but increased for elevations of 4500-5500 m. Above 5500 m, the nGSalbedo decreased, which was in accordance with the decreased amount of snow/ice coverage and the increased soil moisture on the plateau. More importantly, the decreasing albedo in the most recent decade appeared to be caused primarily by lowered growing season albedo.

Growing season carries stronger contributions to albedo dynamics on the Tibetan plateau.

Directory of Open Access Journals (Sweden)

Li Tian

Full Text Available The Tibetan Plateau has experienced higher-than-global-average climate warming in recent decades, resulting in many significant changes in ecosystem structure and function. Among them is albedo, which bridges the causes and consequences of land surface processes and climate. The plateau is covered by snow/ice and vegetation in the non-growing season (nGS and growing season (GS, respectively. Based on the MODIS products, we investigated snow/ice cover and vegetation greenness in relation to the spatiotemporal changes of albedo on the Tibetan Plateau from 2000 through 2013. A synchronous relationship was found between the change in GSNDVI and GSalbedo over time and across the Tibetan landscapes. We found that the annual average albedo had a decreasing trend, but that the albedo had slightly increased during the nGS and decreased during the GS. Across the landscapes, the nGSalbedo fluctuated in a synchronous pattern with snow/ice cover. Temporally, monthly snow/ice coverage also had a high correspondence with albedo, except in April and October. We detected clear dependencies of albedo on elevation. With the rise in altitude, the nGSalbedo decreased below 4000 m, but increased for elevations of 4500-5500 m. Above 5500 m, the nGSalbedo decreased, which was in accordance with the decreased amount of snow/ice coverage and the increased soil moisture on the plateau. More importantly, the decreasing albedo in the most recent decade appeared to be caused primarily by lowered growing season albedo.

Erosion patterns produced by the paleo Haizishan ice cap, SE Tibetan Plateau

Science.gov (United States)

Fu, P.; Stroeven, A. P.; Harbor, J.; Hättestrand, C.; Heyman, J.; Caffee, M. W.

2017-12-01

Erosion is a primary driver of landscape evolution, topographic relief production, geochemical cycles, and climate change. Combining in situ 10Be and 26Al exposure age dating, geomorphological mapping, and field investigations, we examine glacial erosion patterns of the almost 4,000 km2 paleo Haizishan ice cap on the southeastern Tibetan Plateau. Our results show that ice caps on the low relief Haizishan Plateau produced a zonal pattern of landscape modification. In locations where apparent exposure ages on bedrock are consistent with the last deglaciation, complete resetting of the cosmogenic exposure age clock indicates glacial erosion of at least a few meters. However, older apparent exposure ages on bedrock in areas known to have been covered by the paleo ice cap during the Last Glacial Maximum indicate inheritance and thus limited glacial erosion. Inferred surface exposure ages from cosmogenic depth profiles through two saprolites vary from resetting and thus saprolite profile truncation to nuclide inheritance indicating limited erosion. Finally, significant nuclide inheritance in river sand samples from basins on the scoured plateau surface also indicate limited glacial erosion during the last glaciation. Hence, for the first time, our study shows clear evidence of preservation under non-erosive ice on the Tibetan Plateau. As patterns of glacial erosion intensity are largely driven by the basal thermal regime, our results confirm earlier inferences from geomorphology for a concentric basal thermal pattern for the paleo Haizishan ice cap during the LGM.

A study of cloud microphysics and precipitation over the Tibetan Plateau by radar observations and cloud-resolving model simulations: Cloud Microphysics over Tibetan Plateau

Energy Technology Data Exchange (ETDEWEB)

Gao, Wenhua [State Key Laboratory of Severe Weather, Chinese Academy of Meteorological Sciences, Beijing China; Pacific Northwest National Laboratory, Richland Washington USA; Sui, Chung-Hsiung [Department of Atmospheric Sciences, National Taiwan University, Taipei Taiwan; Fan, Jiwen [Pacific Northwest National Laboratory, Richland Washington USA; Hu, Zhiqun [State Key Laboratory of Severe Weather, Chinese Academy of Meteorological Sciences, Beijing China; Zhong, Lingzhi [State Key Laboratory of Severe Weather, Chinese Academy of Meteorological Sciences, Beijing China

2016-11-27

Cloud microphysical properties and precipitation over the Tibetan Plateau (TP) are unique because of the high terrains, clean atmosphere, and sufficient water vapor. With dual-polarization precipitation radar and cloud radar measurements during the Third Tibetan Plateau Atmospheric Scientific Experiment (TIPEX-III), the simulated microphysics and precipitation by the Weather Research and Forecasting model (WRF) with the Chinese Academy of Meteorological Sciences (CAMS) microphysics and other microphysical schemes are investigated through a typical plateau rainfall event on 22 July 2014. Results show that the WRF-CAMS simulation reasonably reproduces the spatial distribution of 24-h accumulated precipitation, but has limitations in simulating time evolution of precipitation rates. The model-calculated polarimetric radar variables have biases as well, suggesting bias in modeled hydrometeor types. The raindrop sizes in convective region are larger than those in stratiform region indicated by the small intercept of raindrop size distribution in the former. The sensitivity experiments show that precipitation processes are sensitive to the changes of warm rain processes in condensation and nucleated droplet size (but less sensitive to evaporation process). Increasing droplet condensation produces the best area-averaged rain rate during weak convection period compared with the observation, suggesting a considerable bias in thermodynamics in the baseline simulation. Increasing the initial cloud droplet size causes the rain rate reduced by half, an opposite effect to that of increasing droplet condensation.

Phases in lanthanum-nickel-aluminum alloys

International Nuclear Information System (INIS)

Mosley, W.C.

1992-01-01

Lanthanum-nickel-aluminum (LANA) alloys will be used to pump, store and separate hydrogen isotopes in the Replacement Tritium Facility (RTF). The aluminum content (y) of the primary LaNi 5 -phase is controlled to produce the desired pressure-temperature behavior for adsorption and desorption of hydrogen. However, secondary phases cause decreased capacity and some may cause undesirable retention of tritium. Twenty-three alloys purchased from Ergenics, Inc. for development of RTF processes have been characterized by scanning electron microscopy (SEM) and by electron microprobe analysis (EMPA) to determine the distributions and compositions of constituent phases. This memorandum reports the results of these characterization studies. Knowledge of the structural characteristics of these alloys is a useful first step in selecting materials for specific process development tests and in interpreting results of those tests. Once this information is coupled with data on hydrogen plateau pressures, retention and capacity, secondary phase limits for RTF alloys can be specified

Numberical Calculations of Atmospheric Conditions over Tibetan Plateau by Using WRF Model

International Nuclear Information System (INIS)

Qian, Xuan; Yao, Yongqiang; Wang, Hongshuai; Liu, Liyong; Li, Junrong; Yin, Jia

2015-01-01

The wind field, precipitable water vapor are analyzed by using the mesoscale numerical model WRF over Tibetan Plateau, and the aerosol is analyzed by using WRF- CHEM model. The spatial and vertical distributions of the relevant atmospheric factors are summarized, providing truth evidence for selecting and further evaluating an astronomical site. It has been showed that this method could provide good evaluation of atmospheric conditions. This study serves as a further demonstration towards astro-climate regionalization, and provides with essential database for astronomical site survey over Tibetan Plateau. (paper)

Diurnal variations of summertime precipitation over the Tibetan Plateau in relation to orographically-induced regional circulations

International Nuclear Information System (INIS)

Liu Xiaodong; Bai Aijuan; Liu Changhai

2009-01-01

The diurnal patterns of variation of summertime precipitation over the Tibetan Plateau were first investigated using the TRMM multi-satellite precipitation analysis product for five summer seasons (i.e. June to August for 2002-2006). Both hourly precipitation amount and precipitation frequency exhibit pronounced daily variability with an overall late-afternoon-evening maximum and a dominant morning minimum. A notable exception is the prevalent nocturnal maximum around the periphery of the Plateau. In terms of the normalized harmonic amplitude, the diurnal signal shows significant regional contrast with the strongest manifestation over the central Plateau and the weakest near the periphery. This remarkable spatial dependence in daily rainfall cycles is clear evidence of orographic and heterogeneous land-surface impacts on convective development. Using six-hourly NCEP FNL data, we then examined the diurnal variability in the atmospheric circulation and thermodynamics in this region. The results show that the Plateau heats (cools) the overlying atmosphere during the day (night) more than the surrounding areas, and as a consequence a relatively stronger confluent circulation in this region occurs during the day than during the night, consistent with the diurnal rainfall cycles. Moreover, the regions with large low-level convergence and upper-level divergence correspond to the strong diurnal rainfall variations. The reversed daily alterations of convergence-divergence patterns in the vicinity of the Plateau edges are in agreement with the observed nighttime rainfall peak therein. This study further demonstrates the importance of the Tibetan Plateau in regulating regional circulation and precipitation.

Impact of Cryosphere Hydrological Changes on the River Runoff in the Tibetan Plateau

Science.gov (United States)

Wang, Y.; Yang, D.

2015-12-01

The Tibetan Plateau is the headwaters of many major rivers in Asia, the change in streamflow is significant for social and economic development and natural ecology in the middle and lower reaches. Located in the alpine region, streamflow in the plateau is mainly affected by the cryosphere hydrological processes. Due to global warming in recent decades, the Tibetan Plateau is experiencing glaciers shrinking and permafrost degradation. Accelerated glacier melt led to the increasing meltwater, thus affecting the streamflow. Permafrost is an important factor in stabilizing the water cycle and streamflow, the ecological degradation and the significant changes of rivers, lakes, swamps, wetlands and other hydrological environment in recent decades in the Tibetan plateau is closely related to permafrost degradation. Therefore, it is important to explore the impact of cryosphere hydrological changes on the streamflow for the future water management. This study uses a method of base flow separation and a stepwise multiple regression model to investigate the reasons for the runoff changes in different regions of the Tibetan Plateau during 1960-2000. The contribution of glacier melt to annual runoff is particularly estimated to explore the possible influences of soil freezing and thawing on annual runoff changes. The results show an increasing trend of the annual runoff in the upstream of Nujiang River, Lancang River and Qilian Mountains, dominated by the increasing of base flow; and a decreasing trend of the runoff in the upper reach of the Yarlung Zangbo River, Yellow River and Yangtze River, dominated by the reduction of quick flow. Change in the amount of runoff was mainly due to change in precipitation. Rising temperature accelerates the melting of glaciers and increases the summer quick flow. In addition, rising temperature may reduce the quick flow and increase the base flow due to change of the active permafrost layers, which leads to the increase of soil water storage

Comparison of. gamma. i-irradiation-induced accumulation of ataxia telangiesctasia and control cells in G sub 2 phase

Energy Technology Data Exchange (ETDEWEB)

Bates, P.R. (Royal Brisbane Hospital, Herston (Australia)); Lavin, M.F. (Queensland Inst. of Medical Research, Brisbane (Australia))

1989-09-01

Recent reports from a number of laboratories have linked radiosensitivity in ataxia telangiectasia (AT) to a large and prolonged block of some cells in G{sub 2} phase. Previous results from this laboratory, largely with one Epstein-Barr virus-transformed A-T lymphoblastoid cell line, presented evidence for a dramatic increase in the number of cells in G{sub 2} phase over controls during a 24 h period post irradiation. We describe here a study of the effect of {gamma}-radiation on G{sub 2} phase delay in several A-T cell lines. Based on previous results with several cell lines 24 h post irradiation was selected as the optimum time to discriminate between G{sub 2} phase delay in control and A-T cells. All A-T homozygotes showed a signigicantly greater number of cells in G{sub 2} phase, 24 h post irradiation, than observed in controls. A more prolonged delay in G{sub 2} phase after irradiation was seen in different A-T cell types that included lymphoblastoid cells, fibroblasts and SV40-transformed fibroblasts. At the radiation dose used it was not possibel to distinguish A-T heterozygotes from controls (Author). 28 refs.; 2 figs.; 1 tab.

Effect of p53 activation on cell growth, thymidine kinase-1 activity, and 3'-deoxy-3'fluorothymidine uptake

International Nuclear Information System (INIS)

Schwartz, Jeffrey L.; Tamura, Yasuko; Jordan, Robert; Grierson, John R.; Krohn, Kenneth A.

2004-01-01

The use of thymidine (TdR) and thymidine analogs such as 3'-deoxy-3'-fluorothymidine (FLT) as positron emission tomography (PET)-based tracers of tumor proliferation rate is based on the hypothesis that measurement of uptake of these nucleosides, a function primarily of thymidine kinase-1 (TK 1 ) activity, provides an accurate measure of cell proliferation in tumors. Tumor growth is influenced by many factors including the oxygen concentration within tumors and whether tumor cells have been exposed to cytotoxic therapies. The p53 gene plays an important role in regulating growth under both of these conditions. The goal of this study was to investigate the influence of p53 activation on cell growth, TK 1 activity, and FLT uptake. To accomplish this, TK 1 activity, S phase fraction, and the uptake of FLT were determined in plateau-phase and exponentially growing cultures of an isogenic pair of human tumor cell lines in which p53 expression was normal or inactivated by human papilloma virus type 16 E6 expression. Ionizing radiation exposure was used to stimulate p53 activity and to induce alterations in cell cycle progression. We found that exposure of cells to ionizing radiation induced dose-dependent changes in cell cycle progression in both cell lines. The relationship between S phase percentage, TK 1 activity, and FLT uptake were essentially unchanged in the p53-normal cell line. In contrast, TK 1 activity and FLT uptake remained high in the p53-deficient variant even when S phase percentage was low due to a p53-dependent G2 arrest. We conclude that a functional p53 response is required to maintain the normal relationship between TK1 activity and S phase percentage following radiation exposure

Neglected, semimembranosus osteochondral avulsion fracture of the posteromedial tibial plateau

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Rakesh John

2018-06-01

Full Text Available Semimembranosus avulsion fracture is infrequently reported and is easy to miss on plain radiographs; the mechanism of injury is highly controversial. Initial reports linked it to anterior cruciate ligament and medial meniscal tears. We report an osteochondral semimembranosus avulsion fracture of the posteromedial tibial plateau with associated posterior cruciate ligament rupture. Also described is a novel surgical fixation technique for such osteochondral fractures where the surgical exposure is limited due to the obliquity of the fracture line resulting in a greater involvement of the articular cartilage than the small bony component. The fixation technique described may be used for osteochondral fractures where the application of a conventional compression screw may not be feasible. Keywords: Osteochondral fracture, Semimembranosus avulsion fracture, Posteromedial tibial plateau, Neglected, Nonunion

Influence of cell microenvironment on the intrinsic radiosensitivity of mammalian cells

International Nuclear Information System (INIS)

Reddy, N.M.S.; Nori, Dattatreyudu

1995-01-01

Survival of cells cultured in the regular growth medium has been compared with that of cells cultured in media with reduced nutrient concentration. Nutrient concentration in the cell microenvironment cultured in regular physiological growth medium, composed of MEM with 15% serum, has been taken to be 100%. Relative to this, the nutrient concentration in the dilute media has been varied from 20 to 80%. The cell survival increased with the decrease in the nutrient concentration in the microenvironment, and reached a plateau in media with 40% or less of nutrient concentration. The magnitude of increase in the radioresistance of log phase cells in medium with 40% nutrient concentration was by a factor of 2.4. Growth kinetics in regular growth medium and in diluted media with nutrient concentration of 40% were nearly the same. The survival of cells cultured in reduced nutrient concentration was the same under growth and non growth post-irradiation repair conditions. Reduction in the concentration of serum, the source of hormones and growth factors, from 15% to 5% also increased the radioresistance of cell by a factor of 1.64. Conclusions: (1) cells in micro environments with reduced nutrient concentration are more refractory to radiation induced cell killing by a factor of as much as 2.4, (2) post-irradiation cell cycle progression does not appear to reduce the repair of x-ray induced damage, and (3) failure of radiotherapy in the local control of some large solid tumors may be related to the presence of pockets of cells in micro environments with inadequate and/or reduce supply of nutrients. 11 refs., 3 figs., 1 tab

The Impact of Computed Tomography on Decision Making in Tibial Plateau Fractures.

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Castiglia, Marcello Teixeira; Nogueira-Barbosa, Marcello Henrique; Messias, Andre Marcio Vieira; Salim, Rodrigo; Fogagnolo, Fabricio; Schatzker, Joseph; Kfuri, Mauricio

2018-02-14

Schatzker introduced one of the most used classification systems for tibial plateau fractures, based on plain radiographs. Computed tomography brought to attention the importance of coronal plane-oriented fractures. The goal of our study was to determine if the addition of computed tomography would affect the decision making of surgeons who usually use the Schatzker classification to assess tibial plateau fractures. Image studies of 70 patients who sustained tibial plateau fractures were uploaded to a dedicated homepage. Every patient was linked to a folder which contained two radiographic projections (anteroposterior and lateral), three interactive videos of computed tomography (axial, sagittal, and coronal), and eight pictures depicting tridimensional reconstructions of the tibial plateau. Ten attending orthopaedic surgeons, who were blinded to the cases, were granted access to the homepage and assessed each set of images in two different rounds, separated to each other by an interval of 2 weeks. Each case was evaluated in three steps, where surgeons had access, respectively to radiographs, two-dimensional videos of computed tomography, and three-dimensional reconstruction images. After every step, surgeons were asked to present how would they classify the case using the Schatzker system and which surgical approaches would be appropriate. We evaluated the inter- and intraobserver reliability of the Schatzker classification using the Kappa concordance coefficient, as well as the impact of computed tomography in the decision making regarding the surgical approach for each case, by using the chi-square test and likelihood ratio. The interobserver concordance kappa coefficients after each assessment step were, respectively, 0.58, 0.62, and 0.64. For the intraobserver analysis, the coefficients were, respectively, 0.76, 0.75, and 0.78. Computed tomography changed the surgical approach selection for the types II, V, and VI of Schatzker ( p  < 0.01). The addition of

Les jeux de plateau: une géographie ludique

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Frédéric BIZET

1997-12-01

Full Text Available Les jeux de plateau utilisent le plus souvent une carte «papier» comme support. Au-delà de l'aspect cartographique, ces jeux intègrent également des notions de territorialité et d'analyse spatiale.

Human-computer interfaces applied to numerical solution of the Plateau problem

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Elias Fabris, Antonio; Soares Bandeira, Ivana; Ramos Batista, Valério

2015-09-01

In this work we present a code in Matlab to solve the Problem of Plateau numerically, and the code will include human-computer interface. The Problem of Plateau has applications in areas of knowledge like, for instance, Computer Graphics. The solution method will be the same one of the Surface Evolver, but the difference will be a complete graphical interface with the user. This will enable us to implement other kinds of interface like ocular mouse, voice, touch, etc. To date, Evolver does not include any graphical interface, which restricts its use by the scientific community. Specially, its use is practically impossible for most of the Physically Challenged People.

Doped SbTe phase change material in memory cells

NARCIS (Netherlands)

in ‘t Zandt, M.A.A.; Jedema, F.J.; Gravesteijn, Dirk J; Gravesteijn, D.J.; Attenborough, K.; Wolters, Robertus A.M.

2009-01-01

Phase Change Random Access Memory (PCRAM) is investigated as replacement for Flash. The memory concept is based on switching a chalcogenide from the crystalline (low ohmic) to the amorphous (high ohmic) state and vice versa. Basically two memory cell concepts exist: the Ovonic Unified Memory (OUM)

Renal cell carcinoma metastases to the pancreas - Value of arterial phase imaging at MDCT

International Nuclear Information System (INIS)

Corwin, Michael T.; Lamba, Ramit; McGahan, John P.; Wilson, Machelle

2013-01-01

Background: The pancreas is an increasingly recognized site of renal cell carcinoma metastases. It is important to determine the optimal MDCT protocol to best detect RCC metastases to the pancreas. Purpose: To compare the rate of detection of renal cell carcinoma metastases to the pancreas between arterial and portal venous phase MDCT. Material and Methods: A retrospective review of CTs of the abdomen yielded six patients with metastatic RCC to the pancreas. Five of six patients had pathologically proven clear cell RCC. Two blinded reviewers independently reported the number of pancreatic lesions seen in arterial and venous phases. Each lesion was graded as definite or possible. The number of lesions was determined by consensus review of both phases. Attenuation values were obtained for metastatic lesions and adjacent normal pancreas in both phases. Results: There were a total of 24 metastatic lesions to the pancreas. Reviewer 1 identified 20/24 (83.3%) lesions on the arterial phase images and 13/24 (54.2%) lesions on the venous phase. Seventeen of 20 (85.0%) arterial lesions were deemed definite and 9/13 (69.2%) venous lesions were definite. Reviewer 2 identified 19/24 (79.2%) lesions on the arterial phase and 14/24 (58.3%) on the venous phase. Seventeen of 19 (89.5%) arterial lesions were definite and 7/14 (50%) venous lesions were definite. Mean attenuation differential between lesion and pancreas was 114 HU and 39 HU for arterial and venous phases, respectively (P<0.0001). Conclusion: Detection of RCC metastases to the pancreas at MDCT is improved using arterial phase imaging compared to portal venous phase imaging

Tectonic History and Deep Structure of the Demerara Plateau from Combined Wide-Angle and Reflection Seismic Data and Plate Kinematic Reconstructions

Science.gov (United States)

Klingelhoefer, F.; Museur, T.; Roest, W. R.; Graindorge, D.; Chauvet, F.; Loncke, L.; Basile, C.; Poetisi, E.; Deverchere, J.; Lebrun, J. F.; Perrot, J.; Heuret, A.

2017-12-01

Many transform margins have associated intermediate depth marginal plateaus, which are commonly located between two oceanic basins. The Demerara plateau is located offshore Surinam and French Guiana. Plate kinematic reconstructions show that the plateau is located between the central and equatorial Atlantic in a position conjugate to the Guinean Plateau. In the fall of 2016, the MARGATS cruise acquired geophysical data along the 400 km wide Demerara plateau. The main objective of the cruise was to image the deep structure of the Demerara plateau and to study its tectonic history. A set of 4 combined wide-angle and reflection seismic profiles was acquired along the plateau, using 80 ocean-bottom seismometers, a 3 km long seismic streamer and a 8000 cu inch tuned airgun array. Forward modelling of the wide-angle seismic data on a profile, located in the eastern part of the plateau and oriented in a NE-SW direction, images the crustal structure of the plateau, the transition zone and the neighbouring crust of oceanic origin, up to a depth of 40 km. The plateau itself is characterised by a crust of 30 km thickness, subdivided into three distinct layers. However, the velocities and velocity gradients do not fit typical continental crust, with a lower crustal layer showing untypically high velocities and an upper layer having a steep velocity gradient. From this model we propose that the lowermost layer is probably formed from volcanic underplated material and that the upper crustal layer likely consists of the corresponding extrusive volcanic material, forming thick seaward-dipping reflector sequences on the plateau. A basement high is imaged at the foot of the slope and forms the ocean-continent transition zone. Further oceanward, a 5-6 km thick crust is imaged with velocities and velocity gradients corresponding to a thin oceanic crust. A compilation of magnetic data from the MARGATS and 3 previous cruises shows a high amplitude magnetic anomaly along the northern

Satellite precipitation estimation over the Tibetan Plateau

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Porcu, F.; Gjoka, U.

2012-04-01

Precipitation characteristics over the Tibetan Plateau are very little known, given the scarcity of reliable and widely distributed ground observation, thus the satellite approach is a valuable choice for large scale precipitation analysis and hydrological cycle studies. However,the satellite perspective undergoes various shortcomings at the different wavelengths used in atmospheric remote sensing. In the microwave spectrum often the high soil emissivity masks or hides the atmospheric signal upwelling from light-moderate precipitation layers, while low and relatively thin precipitating clouds are not well detected in the visible-infrared, because of their low contrast with cold and bright (if snow covered) background. In this work an IR-based, statistical rainfall estimation technique is trained and applied over the Tibetan Plateau hydrological basin to retrive precipitation intensity at different spatial and temporal scales. The technique is based on a simple artificial neural network scheme trained with two supervised training sets assembled for monsoon season and for the rest of the year. For the monsoon season (estimated from June to September), the ground radar precipitation data for few case studies are used to build the training set: four days in summer 2009 are considered. For the rest of the year, CloudSat-CPR derived snowfall rate has been used as reference precipitation data, following the Kulie and Bennartz (2009) algorithm. METEOSAT-7 infrared channels radiance (at 6.7 and 11 micometers) and derived local variability features (such as local standard deviation and local average) are used as input and the actual rainrate is obtained as output for each satellite slot, every 30 minutes on the satellite grid. The satellite rainrate maps for three years (2008-2010) are computed and compared with available global precipitation products (such as C-MORPH and TMPA products) and with other techniques applied to the Plateau area: similarities and differences are

A Mechanism of Land Degradation in Turf-Mantled Slopes of the Tibetan Plateau

Science.gov (United States)

Okin, Gregory S.; D'Odorico, Paolo; Liu, Jianquan

2018-05-01

Kobresia pygmaea meadows are typical of Tibetan Plateau landscapes in the 3,000 to 5,500 m elevation range and constitute the most extensive alpine ecosystem in the world. Kobresia pygmaea forms turf mats that stabilize the surface and shelter the underlying soils from water erosion. Large tracts of the Plateau, however, exhibit signs of ongoing degradation of the turf and erosion of the underlying soil. Despite the crucial role played by K. pygmaea turf mats in the stabilization of the headwaters of major Asian rivers, the mechanisms responsible for their degradation remain poorly investigated. Here we develop a process-based model of land degradation of Tibetan Plateau slopes, which accounts for (i) turf cracking, (ii) water flow concentration in the cracks, (iii) crack widening by scouring, and (iv) sheet-flow erosion. As expected, soil erosion increases with the slope and drainage area (hence the observation of stronger erosion in relatively steep downhill sites). Model simulations indicate that with a sensible set of parameters representative of soil and hydrologic conditions in the region, Tibetan Plateau landscapes are vulnerable to turf mat degradation and soil erosion. As soon as polygonal cracks develop, water flow widens them until the landscape is completely barren. At this point sheet flow eventually erodes the mineral soil leaving behind a highly degraded landscape.

Effectiveness of 10 polymorphic microsatellite markers for parentage and pedigree analysis in plateau pika (Ochotona curzoniae

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Zhang Yanming

2010-11-01

Full Text Available Abstract Background The plateau pika (Ochotona curzoniae is an underground-dwelling mammal, native to the Tibetan plateau of China. A set of 10 polymorphic microsatellite loci has been developed earlier. Its reliability for parentage assignment has been tested in a plateau pika population. Two family groups with a known pedigree were used to validate the power of this set of markers. Results The error in parentage assignment using a combination of these 10 loci was very low as indicated by their power of discrimination (0.803 - 0.932, power of exclusion (0.351 - 0.887, and an effectiveness of the combined probability of exclusion in parentage assignment of 99.999%. Conclusion All the offspring of a family could be assigned to their biological mother; and their father or relatives could also be identified. This set of markers therefore provides a powerful and efficient tool for parentage assignment and other population analyses in the plateau pika.

The Colorado Plateau V: research, environmental planning, and management for collaborative conservation

Science.gov (United States)

Villarreal, Miguel L.; van Riper, Carena J.; Johnson, Matthew J.; van Riper, Charles

2012-01-01

Roughly centered on the Four Corners region of the southwestern United States, the Colorado Plateau covers some 130,000 square miles of sparsely vegetated plateaus, mesas, canyons, arches, and cliffs in Arizona, Utah, Colorado, and New Mexico. With elevations ranging from 3,000 to 14,000 feet, the natural systems found within the plateau are dramatically varied, from desert to alpine conditions. This volume, the fifth from the University of Arizona Press and the tenth overall, focuses on adaptation of resource management and conservation to climate change and water scarcity, protecting biodiversity through restructured energy policies, ensuring wildlife habitat connectivity across barriers, building effective conservation networks, and exploring new opportunities for education and leadership in conservation science. An informative read for people interested in the conservation and natural history of the region, the book will also serve as a valuable reference for those people engaged in the management of cultural and biological resources of the Colorado Plateau, as well as scientists interested in methods and tools for land and resource management throughout the West.

Transcriptional Characterization of Salmonella TAl00 in Growth and Stationary Phase: Mutagenesis of MX in Both Types of Cells

Science.gov (United States)

The Salmonella (Ames) mutagenicity assay can be performed using cells that are in different growth phases. Thus, the plate-incorporation assay involves plating stationary-phase cells with the mutagen, after which the cells undergo a brief lag phase and, consequently, are exposed ...

Stable isotope variations (δ18O and δD) in modern waters across the Andean Plateau

Science.gov (United States)

Bershaw, John; Saylor, Joel E.; Garzione, Carmala N.; Leier, Andrew; Sundell, Kurt E.

2016-12-01

Environmental parameters that influence the isotopic composition of meteoric water (δ18O and δD) are well characterized up the windward side of mountains, where orographic precipitation results in a predictable relationship between the isotopic composition of precipitation and elevation. The topographic and climatic evolution of the Andean Plateau and surrounding regions has been studied extensively by exploiting this relationship through the use of paleowater proxies. However, interpretation on the plateau itself is challenged by a poor understanding of processes that fractionate isotopes during vapor transport and rainout, and by the relative contribution of unique moisture sources. Here, we present an extensive dataset of modern surface water samples for the northern Andean Plateau and surrounding regions to elucidate patterns and causes of isotope fractionation in this continental environment. These data show a progressive increase in δ18O of stream water west of the Eastern Cordillera (∼1‰/70 km), almost identical to the rate observed across the Tibetan Plateau, attributed to a larger fraction of recycled water in precipitation and/or increased evaporative enrichment downwind. This may lead to underestimates of paleoelevation, particularly for sites deep into the rainshadow of the Eastern Cordilleran crest. That said, elevation is a primary control on the isotopic composition of surface waters across the entire Andean Plateau and its flanks when considering the most negative δ18O values, highlighting the need for sufficiently large datasets to distinguish minimally evaporated samples. There is a general increase in δ18O on the plateau from north to south, concomitant with an increase in aridity and decrease in convective moistening (amount effect). Lastly, stable isotope and seasonal precipitation patterns suggest easterlies provide the vast majority of moisture that falls as precipitation across the Andean Plateau and Western Cordillera, from Peru to

Surface ozone at Nam Co in the inland Tibetan Plateau: variation, synthesis comparison and regional representativeness

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X. Yin

2017-09-01

Full Text Available Ozone is an important pollutant and greenhouse gas, and tropospheric ozone variations are generally associated with both natural and anthropogenic processes. As one of the most pristine and inaccessible regions in the world, the Tibetan Plateau has been considered as an ideal region for studying processes of the background atmosphere. Due to the vast area of the Tibetan Plateau, sites in the southern, northern and central regions exhibit different patterns of variation in surface ozone. Here, we present continuous measurements of surface ozone mixing ratios at Nam Co Station over a period of  ∼ 5 years (January 2011 to October 2015, which is a background site in the inland Tibetan Plateau. An average surface ozone mixing ratio of 47.6 ± 11.6 ppb (mean ± standard deviation was recorded, and a large annual cycle was observed with maximum ozone mixing ratios in the spring and minimum ratios during the winter. The diurnal cycle is characterized by a minimum in the early morning and a maximum in the late afternoon. Nam Co Station represents a background region where surface ozone receives negligible local anthropogenic emissions inputs, and the anthropogenic contribution from South Asia in spring and China in summer may affect Nam Co Station occasionally. Surface ozone at Nam Co Station is mainly dominated by natural processes involving photochemical reactions, vertical mixing and downward transport of stratospheric air mass. Model results indicate that the study site is affected differently by the surrounding areas in different seasons: air masses from the southern Tibetan Plateau contribute to the high ozone levels in the spring, and enhanced ozone levels in the summer are associated with air masses from the northern Tibetan Plateau. By comparing measurements at Nam Co Station with those from other sites on the Tibetan Plateau, we aim to expand the understanding of ozone cycles and transport processes over the Tibetan Plateau

Surface ozone at Nam Co in the inland Tibetan Plateau: variation, synthesis comparison and regional representativeness

Science.gov (United States)

Yin, Xiufeng; Kang, Shichang; de Foy, Benjamin; Cong, Zhiyuan; Luo, Jiali; Zhang, Lang; Ma, Yaoming; Zhang, Guoshuai; Rupakheti, Dipesh; Zhang, Qianggong

2017-09-01

Ozone is an important pollutant and greenhouse gas, and tropospheric ozone variations are generally associated with both natural and anthropogenic processes. As one of the most pristine and inaccessible regions in the world, the Tibetan Plateau has been considered as an ideal region for studying processes of the background atmosphere. Due to the vast area of the Tibetan Plateau, sites in the southern, northern and central regions exhibit different patterns of variation in surface ozone. Here, we present continuous measurements of surface ozone mixing ratios at Nam Co Station over a period of ˜ 5 years (January 2011 to October 2015), which is a background site in the inland Tibetan Plateau. An average surface ozone mixing ratio of 47.6 ± 11.6 ppb (mean ± standard deviation) was recorded, and a large annual cycle was observed with maximum ozone mixing ratios in the spring and minimum ratios during the winter. The diurnal cycle is characterized by a minimum in the early morning and a maximum in the late afternoon. Nam Co Station represents a background region where surface ozone receives negligible local anthropogenic emissions inputs, and the anthropogenic contribution from South Asia in spring and China in summer may affect Nam Co Station occasionally. Surface ozone at Nam Co Station is mainly dominated by natural processes involving photochemical reactions, vertical mixing and downward transport of stratospheric air mass. Model results indicate that the study site is affected differently by the surrounding areas in different seasons: air masses from the southern Tibetan Plateau contribute to the high ozone levels in the spring, and enhanced ozone levels in the summer are associated with air masses from the northern Tibetan Plateau. By comparing measurements at Nam Co Station with those from other sites on the Tibetan Plateau, we aim to expand the understanding of ozone cycles and transport processes over the Tibetan Plateau. This work may provide a

Current deformation in the Tibetan Plateau: a stress gauge in the large-scale India-Asia collision tectonics

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Capitanio, F. A.

2017-12-01

The quantification of the exact tectonic forces budget on Earth has remained thus far elusive. Geodetic velocities provide relevant constraints on the current dynamics of the coupling between collision and continental tectonics, however in the Tibetan plateau these support contrasting, non-unique models. Here, we compare numerical models of coupled India-Asia plate convergence, collision and continent interiors tectonics to the geodetically-constrained motions in the Tibetan Plateau to provide a quantitative assessment of the driving forces of plate tectonics in the area. The models develop a range of long-term evolutions remarkably similar to the Asian tectonics in the Cenozoic, reproducing the current large-scale motions pattern under a range of conditions. Balancing the convergent margin forces, following subduction, and the far-field forcing along the trail of the subducting continent, the geodetic rates in the Tibetan Plateau can be matched. The comparisons support the discussion on the likely processes at work, allowing inferences on the drivers of plateau formation and its role on the plate margin-interiors tectonics. More in general, the outcomes highlight the unique role of the Tibetan Plateau as a pressure gauge for the tectonic forces on Earth.

Chemometric perspectives on plankton community responses to natural iron fertilisation over and downstream of the Kerguelen Plateau in the Southern Ocean

Science.gov (United States)

Trull, T. W.; Davies, D. M.; Dehairs, F.; Cavagna, A.-J.; Lasbleiz, M.; Laurenceau-Cornec, E. C.; d'Ovidio, F.; Planchon, F.; Leblanc, K.; Quéguiner, B.; Blain, S.

2015-02-01

We examined phytoplankton community responses to natural iron fertilisation at 32 sites over and downstream from the Kerguelen Plateau in the Southern Ocean during the austral spring bloom in October-November 2011. The community structure was estimated from chemical and isotopic measurements (particulate organic carbon - POC; 13C-POC; particulate nitrogen - PN; 15N-PN; and biogenic silica - BSi) on size-fractionated samples from surface waters (300, 210, 50, 20, 5, and 1 μm fractions). Higher values of 13C-POC (vs. co-located 13C values for dissolved inorganic carbon - DIC) were taken as indicative of faster growth rates and higher values of 15N-PN (vs. co-located 15N-NO3 source values) as indicative of greater nitrate use (rather than ammonium use, i.e. higher f ratios). Community responses varied in relation to both regional circulation and the advance of the bloom. Iron-fertilised waters over the plateau developed dominance by very large diatoms (50-210 μm) with high BSi / POC ratios, high growth rates, and significant ammonium recycling (lower f ratios) as biomass built up. In contrast, downstream polar frontal waters with a similar or higher iron supply were dominated by smaller diatoms (20-50 μm) and exhibited greater ammonium recycling. Stations in a deep-water bathymetrically trapped recirculation south of the polar front with lower iron levels showed the large-cell dominance observed on the plateau but much less biomass. Comparison of these communities to surface water nitrate (and silicate) depletions as a proxy for export shows that the low-biomass recirculation feature had exported similar amounts of nitrogen to the high-biomass blooms over the plateau and north of the polar front. This suggests that early spring trophodynamic and export responses differed between regions with persistent low levels vs. intermittent high levels of iron fertilisation.

Long-term complications following tibial plateau levelling osteotomy in small dogs with tibial plateau angles > 30°.

Science.gov (United States)

Knight, Rebekah; Danielski, Alan

2018-04-21

Tibial plateau levelling osteotomy (TPLO) is commonly performed for surgical management of cranial cruciate ligament (CCL) disease. It has been suggested that small dogs may have steeper tibial plateau angles (TPAs) than large dogs, which has been associated with increased complication rates after TPLO. A retrospective study was performed to assess the rate and nature of long-term complications following TPLO in small dogs with TPAs>30°. Medical records were reviewed for dogs with TPAs>30° treated for CCL rupture by TPLO with a 2.0 mm plate over a five-year period. Radiographs were assessed to determine TPA, postoperative tibial tuberosity width and to identify any complication. Up-to-date medical records were obtained from the referring veterinary surgeon and any complications in the year after surgery were recorded. The effects of different variables on complication rate were assessed using logistic regression analysis. Minor complications were reported in 22.7 per cent of cases. This is similar to or lower than previously reported complication rates for osteotomy techniques in small dogs and dogs with steep TPAs. A smaller postoperative TPA was the only variable significantly associated with an increased complication rate. No major complications were identified. © British Veterinary Association (unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

The Seasonal and Intraseasonal Variability of Diurnal Cloud Activity over the Tibetan Plateau

OpenAIRE

Hatsuki, Fujinami; Tetsuzo, Yasunari; Institute of Geoscience, University of Tsukuba; Institute of Geoscience, University of Tsukuba

2001-01-01

Seasonal variation of diurnal cloud activity(abbreviated DCA)over the Tibetan Plateau throughout the year is examined using 3-hourly geostationary meteorological satellite(GMS)data for 6-years(1989-1994). The DCA shows two distinct variance maxima in the seasonal cycle. One is in spring(pre-monsoon season), and the other is in the summer monsoon season. The DCA begins in late January, and reaches its maximum from March through April. The active DCA extends over almost the whole of the plateau...

Malaria prevalence, anemia and baseline intervention coverage prior to mass net distributions in Abia and Plateau States, Nigeria.

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