2,274 research outputs found
PHARMACOGNOSTIC, PHYSICOCHEMICAL, AND PHYTOCHEMICAL STUDIES ON STEM BARK OF ZANTHOXYLUM ARMATUM DC.
Objectives: To analyze the microscopic, macroscopic, physicochemical, and phytochemical standards of the Zanthoxylum armatum DC. (stem bark).
Methods: Pharamacognostic studies, namely macroscopic, microscopic, and powder microscopic analysis of stem bark were carried out. Physicochemical standards - ash content including total ash content, water soluble, and acid insoluble ash values, moisture content by loss on drying, solubility and extractive values of Z. armatum DC. were determined. Preliminary phytochemical screening, fluorescence analysis and quantification of alkaloids, flavonoids, phenol, tannins, saponins, and terpenoids were also studied.
Results: The macroscopic studies of stem bark showed the stem and its branches, armed with long, sharp prickles with variable size. The transverse section of bark showed the phellogen, phelloderm, cortex, phloem, and medullary rays that are characteristics to Z. armatum DC. The results of physicochemical standards give the identity and purity of the selected sample. Phytochemical studies revealed the presence of alkaloids, flavonoids, phenols, tannins, saponins, and terpenoids.
Conclusion: The present findings provide the pharmacognostic, physicochemical, and phytochemical information about the stem bark of Z. armatum and this might be useful by providing additional support with regard to its identification and standardization parameters
Invasive properties of south Indian strains of Streptococcus pyogenes in a HEp-2 cell model
The objective of this study was to consider the invasive properties of Streptococcus pyogenes in human pharyngeal epithelial cells, and to correlate these with their clinical significance. Clinical isolates of S. pyogenes obtained from blood cultures over a period of 10 years, and throat and skin isolates from a community-based study, were used in this investigation. The S. pyogenes isolates were inoculated in HEp-2 cells and subsequently treated with antibiotics to kill the extracellular bacteria. The cells were then lyzed, and a colony count was carried out to check for invasion. The throat and skin isolates had 45.7%, 25.7% and 28.5% of low, intermediate and high invasion efficiencies, respectively, while 80%, 8.6% and 11.4% of the blood isolates had low, intermediate and high invasion efficiencies. We concluded that the throat and the skin isolates from superficial infections were more invasive than the blood isolates, which is an interesting and paradoxical feature
The workings of the single member plurality electoral system in India and the need for reform
India uses single member plurality system (SMPS) to elect the members of the lower house of its national parliament and the state assemblies. Under SMPS, elections are conducted for separate geographical areas, known as constituencies or districts, and the electors cast one vote each for a candidate with the winner being the candidate who gets the plurality of votes. SMPS is traditionally defended primarily on the grounds of simplicity and its tendency to produce winning candidates, which promotes a link between constituents and their representatives. It tends to provide a clear-cut choice for voters between two main parties, and is expected to gives rise to single-party rather than coalition governments. It also has the benefit of excluding extremist parties from gaining representation, unless their support is geographically concentrated
Application studies of the halotolerant protease from a newly isolated Virgibacillus dokdonensis VIT P14
Protease extracted from halotolerant bacterium - was tested for possible industrial applications. This enzyme was able to dissolve blood clot and coagulated egg within 30 min. The enzyme exhibited substantial keratinolytic activity. It was compatible with all the tested commercial detergents like Rin, Surfexcel, Henko, Tide, Ariel and Technobright and was found to be effective in the removal of blood strains from cotton fabric in the presence of these detergents. The enzyme was compatible with the organic solvents like xylene, toluene, hexane and ethanol and the maximum activity was observed in the presence of ethanol. The enzyme was tested for antimicrobial activity against gram positive and gram negative bacteria and it was found that it possesses good inhibition capability against Escherichia coli, Streptococcus eqiuns, Staphylococcus aureus and Salmonella enterica. The present report indicates that this halotolerant protease has a wide range of properties and the conditions could be optimized to suit any particular industrial application
Direct Detection of a (Proto)Binary-Disk System in IRAS 20126+4104
We report the direct detection of a binary/disk system towards the high-mass
(proto)stellar object IRAS20126+4104 at infrared wavengths. The presence of a
multiple system had been indicated by the precession of the outflow and the
double jet system detected earlier at cm-wavelengths. Our new K, L' & M' band
infrared images obtained with the UKIRT under exceptional seeing conditions on
Mauna Kea are able to resolve the central source for the first time, and we
identify two objects separated by ~ 0.5'' (850 AU). The K and L' images also
uncover features characteristic of a nearly edge-on disk, similar to many low
mass protostars with disks: two emission regions oriented along an outflow axis
and separated by a dark lane. The peaks of the L' & M' band and mm-wavelength
emission are on the dark lane, presumably locating the primary young star. The
thickness of the disk is measured to be ~ 850 AU for radii < 1000 AU.
Approximate limits on the NIR magnitudes of the two young stars indicate a
high-mass system, although with much uncertainty. These results are a
demonstration of the high-mass nature of the system, and the similarities of
the star-formation process in the low-mass and high-mass regimes viz. the
presence of a disk-accretion stage. The companion is located along the dark
lane, consistent with it being in the equatorial/disk plane, indicating a
disk-accretion setting for massive, multiple, star-formation.Comment: 12 pages, 3 figures (1 pseudo colour), 1 table; colour figure
replaced with jpg file; to be published in ApJL; (back after temoprary
withdrawal due to non-scientific reasons.
Determinants of joint venture performance in the construction industry: cases from the mass rapid transit project of Singapore
International Construction firms have extensively used joint ventures as a vehicle to
enter new construction markets in South East Asia since the early seventies. Despite
its immense popularity, the failure rate of such ventures has been quite alarming.
While extensive research has been carried out in the manufacturing and service
industries in determining the factors that influence the performance of joint ventures,
similar work has not been carried out in the construction industry.
This study seeks to fill this gap. A thorough review of the joint venture literature
shows that eleven factors have influenced the performance of joint ventures in the
manufacturing and services industries. These are partners' objectives in forming the
joint venture, partner selection process, partner size, equity control, management
control, partner need, commitment, trust, cooperation, conflict and cultural differences.
The main aim of this study is to test the relevance of these factors to joint ventures
in the construction industry. In this study, a longitudinal research approach is used in
order to closely examine the influence of these factors on joint venture performance.
Sixteen cases of joint ventures from the Singapore Mass Rapid Transit Project which
was built between 1983 and 1990 were chosen for detailed examination. Data for the
study was collected through personal interviews, questionnaire and search of MRTC
archives. A research model was also developed in order to organise and analyse the
cases in a logical manner.
The results of the study indicate that cultural differences have a significant influence
over the performance of international construction joint ventures. Equally critical are
the influence of partner related variables such as trust, commitment, cooperation and
conflict. Task related variables such as level of equity and resource contributions have
had less impact on the performance
Precise Null Pointer Analysis Through Global Value Numbering
Precise analysis of pointer information plays an important role in many
static analysis techniques and tools today. The precision, however, must be
balanced against the scalability of the analysis. This paper focusses on
improving the precision of standard context and flow insensitive alias analysis
algorithms at a low scalability cost. In particular, we present a
semantics-preserving program transformation that drastically improves the
precision of existing analyses when deciding if a pointer can alias NULL. Our
program transformation is based on Global Value Numbering, a scheme inspired
from compiler optimizations literature. It allows even a flow-insensitive
analysis to make use of branch conditions such as checking if a pointer is NULL
and gain precision. We perform experiments on real-world code to measure the
overhead in performing the transformation and the improvement in the precision
of the analysis. We show that the precision improves from 86.56% to 98.05%,
while the overhead is insignificant.Comment: 17 pages, 1 section in Appendi
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