1,341 research outputs found
Boundary Layer Flow of Ferrofluid over a Stretching Sheet in the presence of Heat Source/Sink
The boundary layer flow of ferrofluid over a stretching sheet with heat source is considered. It is assumed that the magnetic field is sufficiently strong enough to saturate the ferrofluid and the variation of magnetization with temperature can be approximated by a linear function of temperature difference. The boundary layer approximation is used and the transformed governing differential equations are solved using the Shooting technique based on Runge - Kutta Fehlberg and Newton Raphson methods. The effects of various parameters on velocity profiles and wall heat transfer are presented graphically. The results have possible industrial applications in liquid based systems involving stretchable materials
Solving the Bin-Packing Problem by Means of Tissue P System with 2-Division
The ability of tissue P systems with 2-division for solving
NP problems in polynomial time is well-known and many solutions can
be found in the literature to several of such problems. Nonetheless, there
are very few papers devoted to the Bin-packing problem. The reason may
be the difficulties for dealing with different number of bins, capacity and
number of objects by using exclusively division rules that produce two
offsprings in each application. In this paper we present the design of a
family of tissue P systems with 2 division which solves the Bin-packing
problem in polynomial time by combining design techniques which can
be useful for further research
Silica nano particles synthesized from boiler spent ash: Value addition to an industrial waste
Large quantities of biomass ash are generated everyday by the spice industries and are currently disposed off as landfill. However, this could transform into an environmental pollutant unless alternative techniques are developed for its disposal or value addition. Here in this study, the waste ash from biomass combustion wassuccessfully converted into silica nanoparticles with potential for application in several fields. The highly alkaline nature of the ash and presence of unburned carbon warrants a pretreatment which includes digestion and acid treatment. The synthesized silica was characterized in terms of morphology, specific surface area, crystallinity, surface functional groups and size. Alkaline extraction of the pretreated ash followed by acid precipitation yielded an amorphous structure with minimum mineral contaminants, high surface area, and a narrow size distribution (8-10 nm range) characteristic of nano silica. Studies thus indicate that the waste ash and the extraction process could be fine tuned for the large scale production of amorphous silica and could be of use to solve the problem of boiler ash pollution. Keywords: biomass ash, boiler ash, nano silica, value addition to waste, amorphous silic
Effect of Silver Plasmonic Layer on Cu2O/In2S3 Solar Cell
Solar cell with the structure Cu/Cu2O/In2S3/Ag@NP/Ag was fabricated where the In2S3-window layer and the plasmonic Ag nano particle thin film layer were deposited using injection chemical spray pyrolysis technique. Quantum efficiency measurement of these solar cells showed improved performance in the blue region of the visible spectrum compared to their counterparts. The films with Ag nano particles exhibited surface plasmon resonance peak at 432 nm which could be assigned to plasmon resonance of Ag nano-particles. The open circuit voltage of the best solar cell is 0.65 V, with short circuit current density of 1.2 mA/cm2, fill factor 22% and efficiency 0.17 %. We conclude that the in-coupling of light by the metallic nanoparticle thin film layer into the underlying semiconductor layer resulted in improvement in electrical performance of these solar cells containing the plasmonic Ag nano particles
Optical Intraday Variability Studies of Ten Low Energy Peaked Blazars
We have carried out optical (R band) intraday variability (IDV) monitoring of
a sample of ten bright low energy peaked blazars (LBLs). Forty photometric
observations, of an average of ~ 4 hours each, were made between 2008 September
and 2009 June using two telescopes in India. Measurements with good signal to
noise ratios were typically obtained within 1-3 minutes, allowing the detection
of weak, fast variations using N-star differential photometry. We employed both
structure function and discrete correlation function analysis methods to
estimate any dominant timescales of variability and found that in most of the
cases any such timescales were longer than the duration of the observation. The
calculated duty cycle of IDV in LBLs during our observing run is ~ 52%, which
is low compared to many earlier studies; however, the relatively short periods
for which each source was observed can probably explain this difference. We
briefly discuss possible emission mechanisms for the observed variability.Comment: 20 Pages, 9 Figures, 4 Tables, accepted for publication in MNRA
Risk Factors for MDR and XDR-TB in a Tertiary Referral Hospital in India
BACKGROUND: India has a high burden of drug resistant TB, although there are few data on XDR-TB. Although XDR-TB has existed previously in India, the definition has not been widely applied, and surveillance using second line drug susceptibility testing has not been performed. Our objective was to analyze clinical and demographic risk factors associated with isolation of MDR and XDR TB as compared to susceptible controls, at a tertiary center. METHODOLOGY/FINDINGS: Retrospective chart review based on positive cultures isolated in a high volume mycobacteriology laboratory between 2002 and 2007. 47 XDR, 30 MDR and 117 susceptible controls were examined. Drug resistant cases were less likely to be extrapulmonary, and had received more previous treatment regimens. Significant risk factors for XDR-TB included residence outside the local state (OR 7.43, 3.07-18.0) and care costs subsidized (OR 0.23, 0.097-0.54) in bivariate analysis and previous use of a fluoroquinolone and injectable agent (other than streptomycin) (OR 7.00, 95% C.I. 1.14-43.03) and an initial treatment regimen which did not follow national guidelines (OR 5.68, 1.24-25.96) in multivariate analysis. Cavitation and HIV did not influence drug resistance. CONCLUSIONS/SIGNIFICANCE: There is significant selection bias in the sample available. Selection pressure from previous treatment and an inadequate initial regimen increases risk of drug resistance. Local patients and those requiring financial subsidies may be at lower risk of XDR-TB
CDK7 Inhibition Suppresses Super-Enhancer-Linked Oncogenic Transcription in MYCN-Driven Cancer
The MYC oncoproteins are thought to stimulate tumor cell growth and proliferation through amplification of gene transcription, a mechanism that has thwarted most efforts to inhibit MYC function as potential cancer therapy. Using a covalent inhibitor of cyclin-dependent kinase 7 (CDK7) to disrupt the transcription of amplified MYCN in neuroblastoma cells, we demonstrate downregulation of the oncoprotein with consequent massive suppression of MYCN-driven global transcriptional amplification. This response translated to significant tumor regression in a mouse model of high-risk neuroblastoma, without the introduction of systemic toxicity. The striking treatment selectivity of MYCN-overexpressing cells correlated with preferential downregulation of super-enhancer-associated genes, including MYCN and other known oncogenic drivers in neuroblastoma. These results indicate that CDK7 inhibition, by selectively targeting the mechanisms that promote global transcriptional amplification in tumor cells, may be useful therapy for cancers that are driven by MYC family oncoproteins.United States. National Institutes of Health (R01CA148688)United States. National Institutes of Health (R01CA148688S1)United States. National Institutes of Health (R01CA179483-01)United States. National Institutes of Health (CA109901)United States. National Institutes of Health (HG002668)United States. National Institutes of Health (R21HG006778)American Cancer Society (RSG-12-247-TBG)United States. Department of Defense (PR120741A)Friends for Life Neuroblastoma Foundatio
Identification of insect-specific target genes for development of RNAi based control of the Eucalyptus gall pest Leptocybe invasa Fisher & La Salle (Hymenoptera: Eulophidae)
Culture Techniques of Marine Copepods
In recent years, marine finfish resources have been stagnating or showing a declining
trend. It is generally accepted that mariculture of suitable marine finfishes is the only
option to meet the increasing demand for fish in the years to come. In this context, the
availability of seed is the major issue and the ICAR-Central Marine Fisheries Research
Institute has been intensifying its research in the recent past on the seed production
of high value finfishes which are suitable for mariculture. Already technologies for
commercial seed production of cobia (Rachycentron canadum) and silver pompano
(Trachinotus blochii) have been standardised. One of the major hurdles for the seed
production of many lucrative high value finfishes is the lack of proper technologies
for mass production of suitable live feeds to initiate the first feeding of the larvae. The
larvae of many species of high value food fishes are very small and the conventional
live feeds employed in the hatchery such as rotifer and Artemia nauplii are not suitable
to initiate the larval feeding during the critical stage mainly because of their larger size
compared to the mouth size of the concerned fish larvae and also their poor nutritional
value especially the fatty acid profile. Copepods are the best live feed due to their
small sized nauplii and better fatty acid composition especially the DHA, EPA and ARA
combination. But the major bottleneck for employing copepods as live feed is the lack of
technologies for their mass culture in hatcheries. Even at a global level, this is a vital issue
and even though some technologies were developed, research efforts are now being
intensified in this area. In India, not much effort was taken to solve this problem till very
recently. In the last few years, the ICAR-Central Marine Fisheries Research Institute has
been focusing on this aspect and has come out with technologies for mass production
of nine species of copepods. These technologies were successfully applied to seed
production of the orange spotted grouper (Epinephelus coioides), the Indian pompano
(Trachinotus mookalee) and the pink ear emperor (Lethrinus lentjan). I congratulate
Dr. B. Santhosh and his team for developing this unique technology for mass production
of nine species of marine copepods for the first time in India. This publication titled
‘Culture techniques of Marine Copepods’ details this technology. I hope that the same
will be a landmark in the near future which will pave the way for successful seed
production of many more species of finfishes in mariculture
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