58 research outputs found
Toxicity evaluation of e-juice and its soluble aerosols generated by electronic cigarettes using recombinant bioluminescent bacteria responsive to specific cellular damages
Electronic-cigarettes (e-cigarette) are widely used as an alternative to traditional cigarettes but their safety is not well established. Herein, we demonstrate and validate an analytical method to discriminate the deleterious effects of e-cigarette refills (e-juice) and soluble e-juice aerosol (SEA) by employing stress-specific bioluminescent recombinant bacterial cells (RBCs) as whole-cell biosensors. These RBCs carry luxCDABE-operon tightly controlled by promoters that specifically induced to DNA damage (recA), superoxide radicals (sodA), heavy metals (copA) and membrane damage (oprF). The responses of the RBCs following exposure to various concentrations of e-juice/SEA was recorded in real-time that showed dose-dependent stress specific-responses against both the e-juice and vaporized e-juice aerosols produced by the e-cigarette. We also established that high doses of e-juice (4-folds diluted) lead to cell death by repressing the cellular machinery responsible for repairing DNA-damage, superoxide toxicity, ion homeostasis and membrane damage. SEA also caused the cellular damages but the cells showed enhanced bioluminescence expression without significant growth inhibition, indicating that the cells activated their global defense system to repair these damages. DNA fragmentation assay also revealed the disintegration of total cellular DNA at sub-toxic doses of e-juice. Despite their state of matter, the e-juice and its aerosols induce cytotoxicity and alter normal cellular functions, respectively that raises concerns on use of e-cigarettes as alternative to traditional cigarette. The ability of RBCs in detecting both harmful effects and toxicity mechanisms provided a fundamental understanding of biological response to e-juice and aerosols.open
Predictive value of subendometrial – endometrial blood flow assessment by transvaginal 3D power doppler on the day of HCG on clinical outcome of IVF cycles
Background: The objective of the study was to evaluate the role of subendometrial-endometrial blood flow assessment by 3D Tran-vaginal Power Doppler in predicting pregnancy outcome in IVF-ET cycles. The study was a prospective, non-randomized clinical study.Methods: A total of 107 infertile women undergoing their first IVF-ET cycle with good response were taken for study (From March 2014 to Nov 2014 at Jaipur Fertility Centre, ART unit of Mahatma Gandhi University of Medical Sciences & Technology). Women with Tubal factor, Male factor and unexplained infertility were included in the study. Those with past h/o Genital Koch’s and hypo menorrhea were excluded. Assessment of subendometrial-endometrial blood flow was done on the day of HCG with endometrial thickness ≥ 6.5mm by Tran-vaginal 3D- Power Doppler.Results: There was no significant difference in mean age, duration of infertility, BMI, cause of infertility, stimulation protocol, serological hormone levels, number of mature oocytes, number of good quality embryos and mean endometrial thickness on the day of HCG. According to Doppler study (3D-Power Doppler), women with blood flow to zones 1, 2 and 3 were categorized in to groups A (n=15), B (n=36) and C (n=56). Overall pregnancy rate was 32.71%. The clinical pregnancy rate was significantly higher in Group C in comparison of Group B and A (42.85% vs. 27.77% and 6.66%). Similarly implantation rate was also higher in group C (23.20% vs. 11.22% and 2.38%).Conclusions: The presence of good subendometrial-endometrial vascularity significantly improves pregnancy outcome in IVF-ET cycles in our study.
The Tracking Tapered Gridded Estimator (TTGE) for the power spectrum from drift scan observations
Intensity mapping with the redshifted 21-cm line is an emerging tool in
cosmology. Drift scan observations, where the antennas are fixed to the ground
and the telescope's pointing center (PC) changes continuously on the sky due to
earth's rotation, provide broad sky coverage and sustained instrumental
stability needed for 21-cm intensity mapping. Here we present the Tracking
Tapered Grided Estimator (TTGE) to quantify the power spectrum of the sky
signal estimated directly from the visibilities measured in drift scan radio
interferometric observations. The TTGE uses the data from the different PC to
estimate the power spectrum of the signal from a small angular region located
around a fixed tracking center (TC). The size of this angular region is decided
by a suitably chosen tapering window function which serves to reduce the
foreground contamination from bright sources located at large angles from the
TC. It is possible to cover the angular footprint of the drift scan
observations using multiple TC, and combine the estimated power spectra to
increase the signal to noise ratio. Here we have validated the TTGE using
simulations of MWA drift scan observations. We show that the
TTGE can recover the input model angular power spectrum within accuracy over the range .Comment: Accepted for publication in MNRA
New Trends in Artificial Intelligence: Applications of Particle Swarm Optimization in Biomedical Problems
Optimization is a process to discover the most effective element or solution from a set of all possible resources or solutions. Currently, there are various biological problems such as extending from biomolecule structure prediction to drug discovery that can be elevated by opting standard protocol for optimization. Particle swarm optimization (PSO) process, purposed by Dr. Eberhart and Dr. Kennedy in 1995, is solely based on population stochastic optimization technique. This method was designed by the researchers after inspired by social behavior of flocking bird or schooling fishes. This method shares numerous resemblances with the evolutionary computation procedures such as genetic algorithms (GA). Since, PSO algorithms is easy process to subject with minor adjustment of a few restrictions, it has gained more attention or advantages over other population based algorithms. Hence, PSO algorithms is widely used in various research fields like ranging from artificial neural network training to other areas where GA can be used in the system
Estimation of Cosmological Parameters from HI Observations of Post-reionization Epoch
The emission from neutral hydrogen (HI) clouds in the post-reionization era
(z < 6), too faint to be individually detected, is present as a diffuse
background in all low frequency radio observations below 1420 MHz. The angular
and frequency fluctuations of this radiation (~ 1 mK) is an important future
probe of the large scale structures in the Universe. We show that such
observations are a very effective probe of the background cosmological model
and the perturbed Universe. In our study we focus on the possibility of
determining the redshift space distortion parameter, coordinate distance and
its derivative with redshift. Using reasonable estimates for the observational
uncertainties and configurations representative of the ongoing and upcoming
radio interferometers, we predict parameter estimation at a precision
comparable with supernova Ia observations and galaxy redshift surveys, across a
wide range in redshift that is only partially accessed by other probes. Future
HI observations of the post-reionization era present a new technique,
complementing several existing one, to probe the expansion history and to
elucidate the nature of the dark energy.Comment: 11 pages, 5 figure
HI Fluctuations at Large Redshifts: I--Visibility correlation
We investigate the possibility of probing the large scale structure in the
universe at large redshifts by studying fluctuations in the redshifted 1420 MHz
emission from the neutral hydrogen (HI) at early epochs. The neutral hydrogen
content of the universe is known from absorption studies for z<4.5. The HI
distribution is expected to be inhomogeneous in the gravitational instability
picture and this inhomogeneity leads to anisotropy in the redshifted HI
emission. The best hope of detecting this anisotropy is by using a large
low-frequency interferometric instrument like the Giant Meter-Wave Radio
Telescope (GMRT). We calculate the visibility correlation function <V_nu(u)
V_nu'(u)> at two frequencies nu and nu' of the redshifted HI emission for an
interferometric observation. In particular we give numerical results for the
two GMRT channels centered around nu =325 and 610 MHz from density
inhomogeneity and peculiar velocity of the HI distribution. The visibility
correlation is ~10^-9 to 10^-10 Jy^2. We calculate the signal-to-noise for
detecting the correlation signal in the presence of system noise and show that
the GMRT might detect the signal for integration times ~ 100 hrs. We argue that
the measurement of visibility correlation allows optimal use of the
uncorrelated nature of the system noise across baselines and frequency
channels.Comment: 17 pages, 2 figures, Submitted to JA
Using Gravitational Lensing to study HI clouds at high redshift
We investigate the possibility of detecting HI emission from gravitationally
lensed HI clouds (akin to damped Lyman- clouds) at high redshift by
carrying out deep radio observations in the fields of known cluster lenses.
Such observations will be possible with present radio telescopes only if the
lens substantially magnifies the flux of the HI emission. While at present this
holds the only possibility of detecting the HI emission from such clouds, it
has the disadvantage of being restricted to clouds that lie very close to the
caustics of the lens. We find that observations at a detection threshold of 50
micro Jy at 320 MHz (possible with the GMRT) have a greater than 20%
probability of detecting an HI cloud in the field of a cluster, provided the
clouds have HI masses in the range 5 X 10^8 M_{\odot} < M_{HI} < 2.5 X 10^{10}
M_{\odot}. The probability of detecting a cloud increases if they have larger
HI masses, except in the cases where the number of HI clouds in the cluster
field becomes very small. The probability of a detection at 610 MHz and 233 MHz
is comparable to that at 320 MHz, though a definitive statement is difficult
owing to uncertainties in the HI content at the redshifts corresponding to
these frequencies. Observations at a detection threshold of 2 micro Jy
(possible in the future with the SKA) are expected to detect a few HI clouds in
the field of every cluster provided the clouds have HI masses in the range 2 X
10^7 M_{\odot} < M_{HI} < 10^9 M_{\odot}. Even if such observations do not
result in the detection of HI clouds, they will be able to put useful
constraints on the HI content of the clouds.Comment: 21 pages, 7 figures, minor changes in figures, accepted for
publication in Ap
Detecting neutral hydrogen in emission at redshift z ~ 1
We use a large N-body simulation to examine the detectability of HI in
emission at redshift z ~ 1, and the constraints imposed by current observations
on the neutral hydrogen mass function of galaxies at this epoch. We consider
three different models for populating dark matter halos with HI, designed to
encompass uncertainties at this redshift. These models are consistent with
recent observations of the detection of HI in emission at z ~ 0.8. Whilst
detection of 21 cm emission from individual halos requires extremely long
integrations with existing radio interferometers, such as the Giant Meter Radio
Telescope (GMRT), we show that the stacked 21 cm signal from a large number of
halos can be easily detected. However, the stacking procedure requires accurate
redshifts of galaxies. We show that radio observations of the field of the
DEEP2 spectroscopic galaxy redshift survey should allow detection of the HI
mass function at the 5-12 sigma level in the mass range 10^(11.4) M_sun/h <
M_halo < 10^(12.5)M_sun/h, with a moderate amount of observation time. Assuming
a larger noise level that corresponds to an upper bound for the expected noise
for the GMRT, the detection significance for the HI mass function is still at
the 1.7-3 sigma level. We find that optically undetected satellite galaxies
enhance the HI emission profile of the parent halo, leading to broader wings as
well as a higher peak signal in the stacked profile of a large number of halos.
We show that it is in principle possible to discern the contribution of
undetected satellites to the total HI signal, even though cosmic variance
limitation make this challenging for some of our models.Comment: 14 pages, 9 figures, Submitted To MNRA
Using HI to probe large scale structures at z ~ 3
The redshifted 1420 MHz emission from the HI in unresolved damped
Lyman-\alpha clouds at high z will appear as a background radiation in low
frequency radio observations. This holds the possibility of a new tool for
studying the universe at high-z, using the mean brightness temperature to probe
the HI content and its fluctuations to probe the power spectrum. Existing
estimates of the HI density at z~3 imply a mean brightness temperature of 1 mK
at 320 Mhz. The cross-correlation between the temperature fluctuations across
different frequencies and sight lines is predicted to vary from 10^{-7} K^2 to
10^{-8} K^2 over intervals corresponding to spatial scales from 10 Mpc to 40
Mpc for some of the currently favoured cosmological models. Comparing this with
the expected sensitivity of the GMRT, we find that this can be detected with
\~10 hrs of integration, provided we can distinguish it from the galactic and
extragalactic foregrounds which will swamp this signal. We discuss a strategy
based on the very distinct spectral properties of the foregrounds as against
the HI emission, possibly allowing the removal of the foregrounds from the
observed maps.Comment: 16 pages, includes 6 figures, accepted in JAA (minor revisions,
references added
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