65 research outputs found
Anti-plasmodia activity of leaf extracts of Calotropis procera Linn
The leaves of Calotropis procera were air dried, grounded and soaked
with ethanol. The extracts obtained (29.79g, CP1) was fractionated
sequentially using aqueous methanol with petroleum ether, chloroform
and ethyl acetate respectively. The residue of ethanol extract (marc)
was extracted with 5M HCl, basified and extracted with chloroform.
These were labeled as CP1-01 to CP1-05 for the plant. Each of these
fractions was phytochemically screened to detect the class of secondary
metabolite present. The fractions obtained from the plant were found to
be selectively active against brine shrimp larvae. These fractions were
also subjected to antimalaria parasites bioassay. Fractions CP1, CP1-04
and CP1-05 were found to be active against tested organisms, withCP1-04
being the most active. CP1-04 was further subjected to activity guided
column chromatography that led to the isolation of two pure compounds
CP1-04-1 and CP1-04-61. Compound CP1-04-61 was found to be active
against the malaria parasite. This was further purified and subjected
to qualitative and quantitative analysis
Phytochemical Screening and Antimicrobial Activities of Terminalia catappa , Leaf Extracts
The powdered leaf of Terminalia catappa was extracted using ethanol
and partitioned into n-hexane, chloroform, ethyl acetate and aqueous
methanol fractions. Test for the presence of secondary metabolites
showed the presence of alkaloids, reducing sugars, saponins, tannins,
resins and steroids in ethanol soluble fraction. The antimicrobial
assay of n-hexane, chloroform and ethyl acetate fractions indicated a
positive activity against the bacterial isolates tested. Chloroform
fraction showed activity against Gram-negative Escherichia coli and
Salmonella typhi at 500\ub5g/disc, while ethanol and aqueous
methanol fractions were active only on Salmonella typhi at
concentrations of 300 - 500\ub5g/disc. The present study revealed
that the plant extracts contain phytochemicals responsible for the
activity against Salmonella typhi
Spectral Signatures of the Diffusional Anomaly in Water
Analysis of power spectrum profiles for various tagged particle quantities in
bulk SPC/E water is used to demonstrate that variations in mobility associated
with the diffusional anomaly are mirrored in the exponent of the \onebyf\
region. Monitoring of \onebyf behaviour is shown to be a simple and direct
method for linking phenomena on three distinctive length and time scales: the
local molecular environment, hydrogen bond network reorganisations and the
diffusivity. The results indicate that experimental studies of supercooled
water to probe the density dependence of spectral features, or
equivalent stretched exponential behaviour in time-correlation functions, will
be of interest.Comment: 5 Pages, 4 Figure
Invigorasi Benih Padi Gogo Lokal untuk Meningkatkan Vigor dan Mengatasi Permasalahan Dormansi Fisiologis Pascapanen
The objective of this research was to evaluate the effect of seed invigoration on improving seed viability and vigor, and to overcome problems of postharvest physiological dormancy of upland rice seed. The research was conducted from February to June 2011 at Agrotechnology Laboratory, Faculty of Agriculture, Halu Oleo University. The experiment used randomized complete design which consisted of 13 treatments, i.e control (G0), Hidration-Dehidration (G1), Matriconditioning using ground brick (G2), Matriconditioning using ground burned-rice husk (G3), Bacillus CKD061 (G4), P. fluorescens PG01 (G5), Serratia CMN175 (G6), Biomatriconditioning using ground brick + Bacillus CKD061 (G7), Biomatriconditioning using ground brick + P. fluorescens PG01 (G8), Biomatriconditioning using ground brick + Serratia CMN175 (G9), Biomatriconditioning using ground burned-rice husk + Bacillus CKD061 (G10), Biomatriconditioning using ground burned-rice husk + P. fluorescens PG01 (G11), Biomatriconditioning using ground burned-rice husk + Serratia CMN175 (G12). Each treatment was replicated three times, therefore, overall there were 36 experimental units. Data obtained were analyzed using analysis of variance and followed with Duncan's Multiple Range Test. The research results showed that bio-invigoration treatments integrated with rhizobacteria were effective to overcome the problems of postharvest physiological dormancy when local upland rice seeds were harvested. In addition, this treatment was also able to increase viability and vigour of the seed. Among treatments tested, the use of Bacillus sp. CKD061 or P. fluorescens PG01, either independently or integrated with matriconditioning using ground brick or ground burned- rice husk was more effective in improving viability and vigour of local upland rice seed compared to other treatments
"Smoking gun" signatures of topological milestones in trivial materials by measurement fine-tuning and data postselection
Exploring the topology of electronic bands is a way to realize new states of
matter with possible implications for information technology. Because bands
cannot always be observed directly, a central question is how to tell that a
topological regime has been achieved. Experiments are often guided by a
prediction of a unique signal or a pattern, called "the smoking gun". Examples
include peaks in conductivity, microwave resonances, and shifts in interference
fringes. However, many condensed matter experiments are performed on relatively
small, micron or nanometer-scale, specimens. These structures are in the
so-called mesoscopic regime, between atomic and macroscopic physics, where
phenomenology is particularly rich. In this paper, we demonstrate that the
trivial effects of quantum confinement, quantum interference and charge
dynamics in nanostructures can reproduce accepted smoking gun signatures of
triplet supercurrents, Majorana modes, topological Josephson junctions and
fractionalized particles. The examples we use correspond to milestones of
topological quantum computing: qubit spectroscopy, fusion and braiding. None of
the samples we use are in the topological regime. The smoking gun patterns are
achieved by fine-tuning during data acquisition and by subsequent data
selection to pick non-representative examples out of a fluid multitude of
similar patterns that do not generally fit the "smoking gun" designation.
Building on this insight, we discuss ways that experimentalists can rigorously
delineate between topological and non-topological effects, and the effects of
fine-tuning by deeper analysis of larger volumes of data.Comment: Data are available through Zenodo at DOI: 10.5281/zenodo.834930
Planar Josephson Junctions Templated by Nanowire Shadowing
More and more materials, with a growing variety of properties, are built into
electronic devices. This is motivated both by increased device performance and
by the studies of materials themselves. An important type of device is a
Josephson junction based on the proximity effect between a quantum material and
a superconductor, useful for fundamental research as well as for quantum and
other technologies. When both junction contacts are placed on the same surface,
such as a two-dimensional material, the junction is called ``planar". One
outstanding challenge is that not all materials are amenable to the standard
planar junction fabrication. The device quality, rather than the intrinsic
characteristics, may be defining the results. Here, we introduce a technique in
which nanowires are placed on the surface and act as a shadow mask for the
superconductor. The advantages are that the smallest dimension is determined by
the nanowire diameter and does not require lithography, and that the junction
is not exposed to chemicals such as etchants. We demonstrate this method with
an InAs quantum well, using two superconductors - Al and Sn, and two
semiconductor nanowires - InAs and InSb. The junctions exhibit critical current
levels consistent with transparent interfaces and uniform width. We show that
the template nanowire can be operated as a self-aligned electrostatic gate.
Beyond single junctions, we create SQUIDs with two gate-tunable junctions. We
suggest that our method can be used for a large variety of quantum materials
including van der Waals layers, topological insulators, Weyl semimetals and
future materials for which proximity effect devices is a promising research
avenue.Comment: Written using The Block Method. Data on Zenodo DOI:
https://doi.org/10.5281/zenodo.641608
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