90 research outputs found
A Short Review on the Development of Salt Tolerant Cultivars in Rice
Rice is staple food for half of the world. With a population of almost 9.6 billion by the year 2050, there is a dire need of developing techniques to improve the crop plants, not only in terms of better yield but also to withstand harsh environmental conditions and stresses like drought, temperature, flood and salinity. Salinity is second to drought stress and hence it is very important to develop crops tolerant to salinity stress. This review discusses the mechanisms of salt tolerance and the recent developments in understanding the complex tolerance phenomena. One way to address the salinity issue is to develop tolerant rice varieties using conventional and modern breeding techniques for which screening the rice germplasm for the varieties with desired traits is critical. Conventional methods to develop tolerant rice varieties are discussed along with modern biotechnology techniques are also discussed. Quantitative Trait Loci (QTL) and Marker Assisted Selection (MAS) are promising techniques. In addition to these modern techniques, some recent developments in the fields of transgenic plants, haploid breeding and Somaclonal variations have also been discussed. The limited knowledge about molecular and genetic mechanisms to tolerate abiotic stresses, however is a barrier to efficiently develop tolerant cultivars. A combination of conventional and modern biotechnology techniques could possibly open up the new ways
Nanotechnology Based Therapeutic Approach in Alzheimer\u27s
Alzheimer\u27s disease is a neurodegenerative disorder that ultimately results from the accumulation of beta-amyloid plaques in the brain. The Alzheimer\u27s disease cannot be prevented or cured at this time, and there is no recognised alternative. The medicinal solutions that are currently available can merely slow down its development. However, nanotechnology has demonstrated its applications in the medical field, and it demonstrates a great deal of promise in the treatment of Alzheimer\u27s disease. In particular, it has shown significant promise in the detection of the condition and the development of an alternative technique to cure it. It is necessary for the medication delivery system to have the capability of penetrating and crossing the blood-brain barrier in order to accomplish this need. On the other hand, greater research is necessary in order to discover and overcome these limitations, which have the potential to improve drug absorption while simultaneously reducing toxicity and adverse effects. Certain nanotechnology-based techniques to treating Alzheimer\u27s disease include regenerative medicine, neuroprotection, and stem cell regeneration. These are just few of the emerging approaches. This article\u27s goal is to take a look at nanotechnology from every angle, including its advantages and disadvantages and how it\u27s helping with neurodegenerative disease research and therapy
Effect of heavy metal on survival of certain groups of indigenous soil microbial population
Heavy metal pollution of soil is known to adversely effect microbial
activities at elevated concentration. However, response of indigenous
soil bacterial population to added heavy metal and metal combinations
is poorly understood. In the present study salts of heavy metals like
Cu, Cd, Cr, Hg, Mn, Ni, Pb and Zn were added in soil under laboratory
conditions with different concentrations (50, 100, 150 and 200
\u3bcg/g of soil) and sufficient moisture. The microcosm were stored
at 28 \ub1 1 \ub0C for 28 days. Viable count of aerobic
heterotrophs, asymbiotic nitrogen fixers and actinomycetes were
determined at different time intervals (0, 7, 14, 21 and 28 days of
incubation) using the plate dilution method. Aerobic- heterotrophic
bacterial population were more sensitive to metal groups like Ni and Cd
followed by Cu, Cd, Hg, Mn, Cr and Zn. Similarly a symbiotic nitrogen
fixers showed higher sensitivity to metal groups like Cd, Pb, Hg
followed by Cu, Cr, Mn, Ni and Zn. Actinomycetes were found most
sensitive. Metal toxicity was higher for Pb, Mn, Ni followed by Cd, Hg,
Cr and least to Cu and Zn. Toxicity of heavy metal was concentration as
well as time dependent. Loss of microbial diversity is evident as we
move towards higher concentration of heavy metal in soil. Further,
experimentation is needed to understand the genetic diversity of the
sensitive and metal tolerant microbial population and metal - microbe
interaction under natural condition in soil. @JASE
An Update on Eosinophilic Esophagitis: Etiological Factors, Coexisting Diseases, and Complications
BACKGROUND: Eosinophilic esophagitis (EoE) is an immune-mediated clinicopathological condition characterized by esophageal infiltration with eosinophils resulting in chronic inflammation and stricture. SUMMARY: The recent increase in the incidence of EoE and the characteristic presentation of symptoms with difficulty swallowing and food bolus impaction has raised key concerns of clinicians as well as researchers. EoE often presents with dysphagia, food impaction, nausea, regurgitation or vomiting, and decreased appetite. It is more common in males, affecting both adults and children. The causative manner of this condition is complex and multifactorial. Throughout recent years, researchers have made a significant contribution to understanding the pathogenesis of EoE, genetic background, natural history, work on allergy, and standardization in the evaluation of disease activity. There is relatively high prevalence of EoE among the population, emphasizing the importance of this disease. Key messages: Esophageal involvement with eosinophils may be manifested as isolated or with coexisting conditions and should be taken into consideration in the differential diagnosis. This study aimed to provide gastroenterologists with novel insights into the evaluation of esophageal involvement with eosinophils and to pay special attention to the etiological factors, coexisting clinical diseases, and complications
Microphysical Approach to Nonequilibrium Dynamics of Quantum Fields
We examine the nonequilibrium dynamics of a self-interacting
scalar field theory. Using a real time formulation of finite temperature field
theory we derive, up to two loops and , the effective equation of
motion describing the approach to equilibrium. We present a detailed analysis
of the approximations used in order to obtain a Langevin-like equation of
motion, in which the noise and dissipation terms associated with quantum
fluctuations obey a fluctuation-dissipation relation. We show that, in general,
the noise is colored (time-dependent) and multiplicative (couples nonlinearly
to the field), even though it is still Gaussian distributed. The noise becomes
white in the infinite temperature limit. We also address the effect of
couplings to other fields, which we assume play the r\^ole of the thermal bath,
in the effective equation of motion for . In particular, we obtain the
fluctuation and noise terms due to a quadratic coupling to another scalar
field.Comment: 30 pages, LaTex (uses RevTex 3.0), DART-HEP-93/0
Perturbative nonequilibrium dynamics of phase transitions in an expanding universe
A complete set of Feynman rules is derived, which permits a perturbative
description of the nonequilibrium dynamics of a symmetry-breaking phase
transition in theory in an expanding universe. In contrast to a
naive expansion in powers of the coupling constant, this approximation scheme
provides for (a) a description of the nonequilibrium state in terms of its own
finite-width quasiparticle excitations, thus correctly incorporating
dissipative effects in low-order calculations, and (b) the emergence from a
symmetric initial state of a final state exhibiting the properties of
spontaneous symmetry breaking, while maintaining the constraint . Earlier work on dissipative perturbation theory and spontaneous symmetry
breaking in Minkowski spacetime is reviewed. The central problem addressed is
the construction of a perturbative approximation scheme which treats the
initial symmetric state in terms of the field , while the state that
emerges at later times is treated in terms of a field , linearly related
to . The connection between early and late times involves an infinite
sequence of composite propagators. Explicit one-loop calculations are given of
the gap equations that determine quasiparticle masses and of the equation of
motion for and the renormalization of these equations is
described. The perturbation series needed to describe the symmetric and
broken-symmetry states are not equivalent, and this leads to ambiguities
intrinsic to any perturbative approach. These ambiguities are discussed in
detail and a systematic procedure for matching the two approximations is
described.Comment: 22 pages, using RevTeX. 6 figures. Submitted to Physical Review
Utilization of sugarcane bagasse ash in concrete as partial replacement of cement
This research addresses the suitability of sugarcane bagasse ash (SCBA) in concrete used as partial cement replacement. Two grades of concrete M15 and M20 were used for the experimental analysis. The cement was partially replaced by SCBA at 0%, 5%, and 10%, by weight in normal strength concrete (NSC). The innovative part of this study is to consider two grades of concrete mixes to evaluate the performance of concrete while cement is replaced by sugarcane bagasse ash. The cylindrical specimens having size 150 mm x 300 mm were used and tested after curing period of 7, 14 and 28 days. It was observed through the experimental work that the compressive strength increases with incorporating SCBA in concrete. Results indicated that the use of SCBA in concrete (M20) at 5% increased the average amount of compressive strength by 12% as compared to the normal strength concrete. The outcome of this work indicates that maximum strength of concrete could be attained at 5% replacement of cement with SCBA. Furthermore, the SCBA also gives compatible slump values which increase the workability of concrete
Quantum Rolling Down out of Equilibrium
In a scalar field theory, when the tree level potential admits broken
symmetry ground states, the quantum corrections to the static effective
potential are complex. (The imaginary part is a consequence of an instability
towards phase separation and the static effective potential is not a relevant
quantity for understanding the dynamics). Instead, we study here the equations
of motion obtained from the one loop effective action for slow rollover out of
equilibrium.
We considering the case in which a scalar field theory undergoes a rapid
phase transition from to . We find that, for slow rollover
initial conditions (the field near the maximum of the tree level potential),
the process of phase separation controlled by unstable long-wavelength
fluctuations introduces dramatic corrections to the dynamical evolution of the
field. We find that these effects slow the rollover even furtherComment: 33 pages, Latex,LPTHE-PAR 92-33 PITT 92-0
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