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排序方式: 共有718条查询结果,搜索用时 31 毫秒
711.
Praveen Joseph Santhosh Acharya Ganesh Sanjeev N. N. Bhat Y. Narayana 《Journal of Radioanalytical and Nuclear Chemistry》2011,290(1):209-214
In the case of sparsely ionizing radiation such as electron, the dose rate and the pattern of energy deposition of the radiation
are the important physical factors which can affect the amount of damage in living cells. In the present study, the differences
in the cell survival efficiency and dose rate effect in diploid yeast strains Saccharomyces cerevisiae X2180 and Saccharomyces cerevisiae D7 under euoxic and hypoxic condition have been quantified. Irradiation was carried out using 8 MeV pulsed electron beam
from Microtron accelerator. The dose per pulse and pulse width of the beam used was 0.6 Gy and 2.3 μs, respectively, which
correspond to an instantaneous dose rate of 2.6 × 105 Gy s−1. For survival studies doses were delivered at a rate of 50 pulses per second (an average dose rate of 1,800 Gy s−1). Fricke and alanine dosimeters were used to measure the dose delivered to the sample. A significant difference in the dose
response has been observed under euoxic and hypoxic condition. Dose rate effect has been studied by changing the pulse repetition
rate of the Microtron and the dose rate used was from 180 to 1800 Gy min−1. A significant dose rate effect was observed under euoxic condition for Saccharomyces cerevisiae X2180 but the same was absent under hypoxic condition. The dose rate effect was absent for Saccharomyces cerevisiae D7 under both irradiation condition. The survival curves are found to be sigmoidal in shape under both condition but with
a wider shoulder under hypoxic condition. The D0 value and the Oxygen Enhancement Ratio (OER) at that point have been derived. 相似文献
712.
Primal D’Cunha P. Sathyanarayana Bhat Y. Narayana 《Journal of Radioanalytical and Nuclear Chemistry》2011,290(1):171-174
The paper presents systematic studies on the vertical profiles of 210Po, an important decay product of 238U, in soils along coastal Kerala. Soil samples collected from different depth intervals 0–10, 10–20, 20–30 cm were analyzed
for 210Po activity concentration by radiochemical methods. The activity 210Po in soil samples were counted using a ZnS(Ag) alpha scintillation counting system. The mean values of activity concentrations
of 210Po in soil of various depths were found to be 8.66, 5.63 and 4.95 Bq kg−1 for depth intervals of 0–10, 10–20 and 20–30 cm, respectively. The overall activity concentration of 210Po in soil was found to vary from 2.26 ± 0.19 to 14.02 ± 0.12 Bq kg−1 with a mean value of 6.43 Bq kg−1. Maximum activity concentration was found in soil samples of Kollam region with the mean value of 10.08 ± 0.92 Bq kg−1. The activity of 210Po was found to be comparatively high in surface soil. The variation of 210Po activity concentration with organic matter contents was studied. 210Polonium activity concentration was found to increase with increasing organic matter content. 相似文献
713.
In this paper, a method for continuous flow separation of circulating malignant cells from blood in a microfluidic device using dielectrophoresis is discussed. Separation of MDA231 breast cancer cells after mixing with normal blood cells was achieved with a level of accuracy that enabled precise counting of the malignant cells, separation and eventually, sub-culturing. MDA231 cells were separated from the blood to a daughter channel using two pairs of interdigitated activated comb-like electrode structures. All experiments are performed with conductivity adjusted medium samples. The electrode pairs were positioned divergent and convergent with respect to the flow. The AC signals used in the separation are 20 V peak-to-peak with frequencies of 10-50 kHz. The separation is based on balance of magnitude of the dielectrophoretic force and hydrodynamic force. The difference in response between circulating malignant cells and normal cells at a certain band of alternating current frequencies was used for rapid separation of cancer cells from blood. The significance of these experimental results is discussed in this paper, with detailed reporting on the suspension medium, preparation of cells, flow condition and the fabrication process of the microfluidic chip. The present technique could potentially be applied to identify incident cancer at a stage and size that is not yet detectable by standard diagnostic techniques (imaging and biochemical testing). Alternatively, it may also be used to detect cancer recurrences. 相似文献
714.
The Cr-doped rare-earth manganites Nd0.5Ca0.5Mn1−x
Cr
x
O3 (x = 0.03, 0.05, 0.10) are studied by electron magnetic resonance (EMR) and magnetization measurements in the paramagnetic as
well as in the ferromagnetic phase. The magnetization measurements show that the charge-ordered antiferromagnetic phase decreases
at the expense of ferromagnetic metallic phase and for Cr doping of x = 0.1, the charge-ordered phase melts completely. The EMR shows multiple signals for all three compositions in the ferromagnetic
phase indicative of an anisotropic ferromagnetic phase. The difference between the shift of the high-field and low-field signals
decreases with Cr doping, indicating that the magnetic anisotropy decreases with the Cr doping. In the paramagnetic phase
the EMR line width follows Causa's model as observed in other colossal magnetoresistant manganites.
Authors' address: Ajay Sharma, Department of Physics, Indian Institute of Science, Bangalore, India 相似文献
715.
The intense radiation environment at the Large Hadron Collider, CERN at a design energy of $
\sqrt s
$
\sqrt s
= 14 TeV and a luminosity of 1034 cm−2 s−1 poses unprecedented challenges for safe operation and performance quality of the silicon tracker detectors in the CMS and
ATLAS experiments. The silicon trackers are crucial for the physics at the LHC experiments, and the inner layers, being situated
only a few centimeters from the interaction point, are most vulnerable to beam-induced radiation. We have recently carried
out extensive Monte Carlo simulation studies using MARS program to estimate particle fluxes and radiation dose in the CMS
silicon pixel and strip trackers from proton-proton collisions at $
\sqrt s
$
\sqrt s
= 14 TeV and from machine-induced background such as beam-gas interactions and beam halo. We will present results on radiation
dose, particle fluxes and spectra from these studies and discuss implications for radiation damage and performance of the
CMS silicon tracker detectors. 相似文献
716.
Dr. Peiran Wei Dr. Gulzar A. Bhat Prof. Donald J. Darensbourg 《Angewandte Chemie (International ed. in English)》2023,62(48):e202307507
Aliphatic polycarbonates (aPCs) have become increasingly popular as functional materials due to their biocompatibility and capacity for on-demand degradation. Advances in polymerization techniques and the introduction of new functional monomers have expanded the library of aPCs available, offering a diverse range of chemical compositions and structures. To accommodate the emerging requirements of new applications in biomedical and energy-related fields, various manufacturing techniques have been adopted for processing aPC-based materials. However, a summary of these techniques has yet to be conducted. The aim of this paper is to enrich the toolbox available to researchers, enabling them to select the most suitable technique for their materials. In this paper, a concise review of the recent progress in processing techniques, including controlled self-assembly, electrospinning, additive manufacturing, and other techniques, is presented. We also highlight the specific challenges and opportunities for the sustainable growth of this research area and the successful integration of aPCs in industrial applications. 相似文献
717.
Adimule Vinayak Bhat Vinay S. Joshi Rajeev Batakurki Sheetal Hegde Gurumurthy Yallur Basappa C. 《Journal of Solid State Electrochemistry》2023,27(2):511-529
Journal of Solid State Electrochemistry - In the present investigation, we have synthesized samarium (Sm) nanoparticles (NPs) and anchored them onto the surface of CuO:CoO nanostructure (NS) by... 相似文献
718.
Ambre S. K. Patil S. S. Bhat T. S. Patil P. S. 《Journal of Solid State Electrochemistry》2023,27(2):337-343
Journal of Solid State Electrochemistry - Bismuth sulfide (Bi2S3)-sensitized titanium dioxide (TiO2) nanorods have been successfully synthesized by a simple and cost-effective chemical deposition... 相似文献