Jammu and Kashmir Academy of Art, Culture and Languages
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Antimicrobial and Antioxidant activities of Arnebia benthamii (Wall ex. G. Don Johnston) - A Critically Endangered Medicinal plant of Kashmir
Get PDFPlants used in traditional medicines contain a vast array of substances
that can be used to treat chronic and infectious diseases and the
present study was carried out with the same intentto appraisethe
possible medicinal value of Arnebia benthamii L. (Wall. ex G. Don) Johnston
[Syn Macrotomia benthamii (Wall.) DC.] a threatened medicinal plant of
Kashmir valley by examining its phyto-chemical constituents and evaluating
the antimicrobial and antioxidant activity. Preliminary phytochemical screening
was carried out to detect the presence of phyto-chemicals that add to the
medicinal value of the plant. The antimicrobial assay was carried out by Disc
diffusion and Micro-broth dilution methods. The crude plant extracts (both root
as well as aerial parts) exhibited significant antimicrobial activity on majority
of test organisms tested.
The highest occurrence of secondary metabolites was of alkaloids and phenolic
substances. The tannins and saponins were absent in all plant extracts. The total phenolic content that was quantitatively estimated showed highest presence in methanol extracts of the aerial parts.
The antibacterial results revealed that methanol extracts of aerial parts were
found to exhibit significant antibacterial activities against all tested bacterial
strains except Staphylococcus aureus which was found resistant. The highest inhibition zone diameter (30mm) was recorded for Pseudomonas aeruginosa
and Escherichia coli with respect to control i.e. Gentamycin (16 and21mm)
followed by Salmonella typhimurium (28 mm). Chloroform extract also
showed good inhibitory activity against all the tested bacterial strains likeE.
coli (22mm) followed by Klebsella pnuemonie (20 mm) and P. aeruginosa
(17mm). The aqueous extract didn’t show any inhibitory activity against the tested bacterial strains. The root extracts were separately tested for antibacterial
activity against pathogenic strains and it was apparent from the results that they
were less active than aerial part extracts. Among the strains tested, S. aureus
was found susceptible to chloroform, ethyl acetate and methanol root extracts
with an average inhibition zone diameter (10 mm) with respect to control and
rest of extracts showed no activity against it. The Shigella flexneri was found
susceptible to all the root extracts and the highest inhibition zone diameter was
recorded for methanol (20mm) followed by ethanol (15 mm)against the control
(Erythromicin 30 mm). Among all the strains, E. coli was highly susceptible
towards the methanol root extracts followed by chloroform and ethyl acetate
extract while the rest of the extracts did not exhibit any inhibitory activity.
Most of the root extracts exhibit highest antibacterial activity against S.
typhimurium compared to aerial parts.
The screening served a
s an indicator
f
or
the selection of bacterial strains that displayed antibacterial activity for further
testing to determine the MIC’s of plant extracts. Four bacterial strains
S.
fle
xnerii, K.
pneumonia,
E.
coli
and
P. aeruginosa
were found viable for testing
with the specific plant extracts. S.
flexnerii was found highly susceptible
towards methanol aerial part extract with MIC and MBC value of 200μg/ml
and 750 μg/ml respectively as compared to reference (Erythromycin75 and 100
μg/ml) followed by methanol root extract
{
MIC 300 μg/ml and500 MBC μg/ml}. Methanol aerial part extract exhibited the MIC value 500 μg/ml and
MBC
750 μg/ml against K. pneumonia. However the root extracts showed co
mparatively higher value of MIC against the tested organism ranging f
rom400-500μg/ml with respect to positive control (MIC-150 μg/ml).The MIC value
for
E
. coli ranged between 150 to 500 μg/ml towards aerial part extracts w
ith lowest MIC observed for methanol aerial part extract with respect to
Erythromycin (175 μg/ml), and for root extract MIC value ranged between 225
-425 μg/ml. P. aeruginosa was found to be most susceptible towards all aerial
part extracts with MIC value ranged between 75 μg/ml and 425 μg/ml and MBC value from 100 to750 μg/ml. All
the fungal strains except Candida parapsilosis were more or less inhibited b
y both aerial and root part extracts of the plant. The aqueous extract of both root
as well as aerial parts did not show any antifungal activity. Asperigillus flavus
was found to be highly susceptible to butanol aerial part extract with inhibition
zone diameter (25mm) followed by ethyl acetate extract(22 mm) and chlorof
orm extract (14 mm) compared to the control (Nystatin 35mm) used. The
methanol aerial part extract showed highest inhibitory activity against Asperigill
us versicolor with inhibition zone diameter (22 mm) and Acremonium spp (25 mm). The petroleum ether, ethyl acetate and chloroform extracts
of aerial part did not exhibit any inhibitory activity against Candida spp
. Only methanol extract followed by ethanol and butanol extract exhibited antif
ungal activity against Candida spp. Among the Candida spp, the highest inhibition
zone diameter (14 mm) of methanol extract was seen against C. albicans
whereas C. parapsalosis was found completely resistant against the all aerial part extra
cts. The ethanol and aqueous root extracts didn’t exhibit any inhibitory
activity against any tested fungal strains. Meanwhile the ethyl acetate extract sho
wed highest inhibition zone diameter(33mm) against C. albicans f
ollowed by Acremonium spp (18mm).The methanol root extract showed good
inhibitory activity with an average inhibition zone diameter
(12mm) against A. versicolor, C. albicans and C. kruesie with respect to reference used. The four in-vitro tests i.e. DPPH radical scavenging action, riboflavin photo-
oxidation method, hydroxyl scavenging and the lipid peroxidation assay for
antioxidant activity were used. Together all the methods provide a better assessment of antioxidant properties
and results revealed that inhibitory activity
was concentration dependent. Free radical scavenging potential of aerial and
root part extracts at different concentrations was tested by the DPPH method.
Highest inhibition of 86% and 94% was recorded for both methanol extracts of
aerial as well as root parts with respect to reference (Ascorbic acid 90%) at the
higher concentration (300 μg/ml) followed by ethyl acetate (60%) and chloroform extract (63 %) of aerial parts.
The superoxide radical scavenging activity of aerial parts was observed in the
following order butanol extract (85%) >ethyl acetate (79%)> methanol extract
(70%) however Petroleum ether, ethanol and aqueous extracts didn't exhibit
any scavenging activity. The root extracts were also effective in scavenging the
superoxide radicals and the order of scavenging was as butanol (91%)>
methanol (88%)>aqueous (79%) extracts. As far as the protective effect of
deoxyribose was concerned, the highest inhibition of radicals was observed for
methanol extract of root part and aerial part (~85% inhibition). The ethanol
extracts of both parts were found to be ineffective. The overall inhibition of
FeSO4 induced lipid peroxidation was high in presence of positive control
(ascorbic acid 95.78±1.0%) compared to the plant extracts of A. benthamii.
However, the ethyl acetate extract of aerial parts (95 %) showed almost the
same activity as compared to the reference antioxidant. The ethyl acetate (87%)
of root parts also exhibited significant inhibitory activity followed by ethanol extracts (78%)
Job Satisfaction in University Employees: A Case Study of the University of Kashmir
Get PDFHuman resource has gained significant importance over other resources of an organisation, in recent years. In view of this accessing the level of job satisfaction in employees has become an important task for organisations. Job satisfaction refers to an individual’s positive emotional reactions to a particular job.By ensuring that employees are satisfied with their jobs, helps organisations increase their productivity and limit employee turnover. Hence, organisations today are engaged in motivating and minimizing the threat of losing their vital and most prized resource – the human resource, the basic building block of an organisation
Crystal Growth of Some Rare Earth Molybdates by Gel Diffusion Technique
Get PDFHolmium molybdate and gadolnium molybdate crystal were grown via a very
simple and inexpensive gel diffusion technique. The effect of various factors
such as gel age, growth period, temperature, gel pH, concentration of lower
reactant and concentration of upper reactant on the crystallization process
were investigated.
As-grown samples were characterized by polarizing optical microscope,
scanning electron microscopy (SEM), powder X-ray diffraction (XRD), Energy-
Dispersive Analysis of X-rays (EDAX), Thermal methods (TGA, DTA).
The powder X-ray diffraction (pxrd) results revealed these samples are of
crystalline nature and the EDAX results provided their elemental composition.
The pxrd studies revealed that the structure of both the laboratorygrown
holmium molybdate and gadolnium molybdate crystals is triclinic belonging
to the space group of P1 with a = 7.80 ˚A, b = 9.01 ˚A, c = 13.54 ˚A,
α = 76.390, β = 131.380 and γ = 76.730; a = 7.1560 ˚A, b = 10.1980 ˚A, c
= 10.1740 ˚A, α = 48.1400, β = 58.2200 and γ = 44.8400 as cell parameters
respectively.
The optical images showed them to be of spherulitic form and the SEM
results revealed them to be composed of nano-crystallites. Holmium molybdate
spherulites grown at room temperature are composed of nano-plates and
those grown at a temperature of 45 ◦C are composed of nano-rods. Gadolnium
molybdate spherulites were grown only at 45 ◦C and were also composed
of nano-rods. The thermal analysis curves provided their thermal decomposition
behaviour and revealed that the holmium molybdate and gadolnium
molybdate crystals shows an isomorphic phase transion at 520 ◦C
Exploring the immunomodulatory effects of Ajuga bracteosa and Atropa accuminata towards understanding of the their Anti-Arthritic potential
Get PDFRheumatoid Arthritis poses a major health concern with an ever rising global
burden. Owing to the chronic nature of the disease and limitations and risks of
conventional therapy, the past decade has witnessed use of herbal medicines as potent
therapeutic agents. Atropa acuminata and Ajuga bracteosa have been widely used in
folk medicine for rheumatism and other related inflammatory disorders. Our aim was
to study immunomodulation of autoimmune arthritis by these two herbs and to delineate their possible mode of action using several animal models.
Since Rheumatoid arthritis has a strong T-cell based immune mediated
pathogenesis, our first aim was to investigate the possible immunoregulatory effects
of the herbs if any on systemic T helper immunity in SRBC immunized Balb/C mice.
Circulating antibody titers, DTH responses and spleenocyte proliferation were
monitored as markers of Th1 and Th2 immune responses. Lymphocyte
immunophenotying (CD4/CD8 cell counts) and intracellular Th1/Th2 cytokine
concentrations were determined using flow cytometry. Our results indicated a unique immunomodulatory profile for each herbal extract. A.accuminata demonstrated mixed
biphasic modulation of effector T-helper immunity. At lower doses, significant up
regulation of Th1 immunity was observed. However, contrastingly at higher doses
significant Th2 upregulation was observed. It was therefore considered that
A.accuminata at higher doses induces and stimulates Th2 immune response and
concomitantly inhibits the Th1 pathway at the same dose via inhibition of Th1
cytokines and the T-cell proliferation. Contrastingly, A.bracteosa exhibited dual Th1/Th2 immunopotentiating effects at lower doses with significant down regulation at higher doses.
Also, since both the test extracts were found to downregulate T- cell immune responses in the higher dose range,
this premised evaluation of
extracts for
anti-
inflammatory properties on in vitro and in vivo acute inflammatory models. Our findings summarized novel anti-inflammatory mechanisms
for both A.accuminata and A.bracteosa based on dual in vitro Cycloxygenase 1&2/5-Lipoxygenase inhibitory activities and also significant downregulation of nitric oxide (NO)
and pro-
inflammatory cytokine (TNF-α and Il-1 β) release in LPS-stimulated RAW 246.7
macrophage cell line . In acute inflammatory models in vivo (carrageenan induced edema,
carrageenan induced pleurisy in rats and vascular permeability in mice), the test extracts exhibited an extensive diverse mechanism for anti-inflammatory
properties. This was indicated on the basis of dose dependent suppression of multi
targeted inflammatory mediators., NO,TNF-α and IL-1β, eicosanoids (PGE2) and
leukotriene
s (LTB4) along with significantly decreased leucocyte migration , ex
udation and decreased vascular permeability .These effects were more potent and prolong
ed than traditional NSAIDS, thereby indicating fewer side effects .Both test ex
tracts were found to be safe for long term administration, as confirmed by the result
s of acute toxicity studies and MTT assay. The complex mode of action of the herbs
was attributed possibly due to the high polyphenolic, flavanol and flavonoid content
present in the extracts as observed by means of qualitative and quantitative screening for phytochemicals.
To study
y further the effects of the test extracts on the progression of the
disea
se and to explore the underlying mechanisms of action in view of immunological responses, we evaluated the extracts for their effectiveness against the Mycobacterium tubercull
i - induced model of arthritis in male Wistar rats. The polyarthiritis test reve
aled a significant anti-arthritic activity both in the developing and developed phase
of the disease. This was associated with significant suppression of the array of pro-inflammatory mediators (PGE2
, NO and LTB4 ) and Th1 cytokines (IL
-2, TNF-α, I
FN-γ, IL-6) as measured in arthritic paw tissue homogenate, slpeenocytes and serum of
AA & AB treated animals . Significant upregulation of Th2 cytokines (IL-4 and IL
-10) was observed only for A.accuminata. This finding strongly indicated that the test e
xtract not only inhibited the T cells and Th1 cytokines but also elevated the natural
capacity of the immune system to keep the Th1 cytokines under control by increa
sing IL-4 and IL-10. Both the test extracts were also observed to protect rats against
the primary and secondary arthritic lesions, body weight changes and haematolo
gical perturbations (Hb, ESR, WBC and RBC) induced by CFA. The serum markers
of inflammation and arthritis, such as C-reactive protein and rheumatoid factor,
were also reduced in the AA & AB treated arthritic rats. The overall severity of arthrit
is as determined by radiological analysis and pain scores indicated that the extra
cts quite potently decelerated the progression of arthritis in rats. Histopathological assessment and biochemical parameters (SOD, GSH , GRX) further xconfirmed
the reduced signs of
chronic inflammatory response
and cartilage damage.
The study indicates a possiblility of using Atropa accuminata and Ajuga
bracteosa as promising therapeutic agents in the treatment of Rheumatoid
arthritis.The diverse set of properties might be due to the additive / antagonistic
effects of bioactive constituents present in the extracts. The multipronged attack on
the inflammatory mediators and Th1 /Th2 cytokines and strong potency of these extracts may have relevance for inhibition of the acute and chronic inflammatory
responses in arthritis and other related diseases. It is further suggested that for an insight into the molecular mechanism of such effects, bioassay guided fractionation
and isolation of active constituents and in depth studies on transcripiton factors for
cytokines, iNOS, COX 1/2, 5-LOX and others is required. This could provide us with novel
immunostimulatory /anti-arthritic leads for newer and safer therapeutic options in the management of arthritis and related disorders
Realization of Integrable Low- Voltage Companding Filters for Portable System Applications
Get PDFUndoubtedly, today’s integrated electronic systems owe their remarkable performance
primarily to the rapid advancements of digital technology since 1970s. The various
important advantages of digital circuits are: its abstraction from the physical details of
the actual circuit implementation, its comparative insensitiveness to variations in the
manufacturing process, and the operating conditions besides allowing functional
complexity that would not be possible using analog technology. As a result, digital
circuits usually offer a more robust behaviour than their analog counterparts, though
often with area, power and speed drawbacks. Due to these and other benefits, analog
functionality has increasingly been replaced by digital implementations.
In spite of the advantages discussed above, analog components are far from
obsolete and continue to be key components of modern electronic systems. There is
a definite trend toward persistent and ubiquitous use of analog electronic circuits in
day-to-day life. Portable electronic gadgets, wireless communications and the
widespread application of RF tags are just a few examples of contemporary
developments. While all of these electronic systems are based on digital circuitry,
they heavily rely on analog components as interfaces to the real world. In fact, many
modern designs combine powerful digital systems and complementary analog
components on a single chip for cost and reliability reasons. Unfortunately, the design
of such systems-on-chip (SOC) suffers from the vastly different design styles of
analog and digital components. While mature synthesis tools are readily available for
digital designs, there is hardly any such support for analog designers apart from wellestablished
PSPICE-like circuit simulators. Consequently, though the analog part
usually occupies only a small fraction of the entire die area of an SOC, but its design
often constitutes a major bottleneck within the entire development process.
Integrated continuous-time active filters are the class of continuous-time or
analog circuits which are used in various applications like channel selection in radios,
anti-aliasing before sampling, and hearing aids etc. One of the figures of merit of a
filter is the dynamic range; this is the ratio of the largest to the smallest signal that can
be applied at the input of the filter while maintaining certain specified performance.
The dynamic range required in the filter varies with the application and is decided by
the variation in strength of the desired signal as well as that of unwanted signals that are to be rejected by the filter. It is well known that the power dissipation and the
capacitor area of an integrated active filter increases in proportion to its dynamic
range. This situation is incompatible with the needs of integrated systems, especially
battery operated ones. In addition to this fundamental dependence of power dissipation
on dynamic range, the design of integrated active filters is further complicated by the
reduction of supply voltage of integrated circuits imposed by the scaling down of
technologies to attain twin objective of higher speed and lower power consumption in
digital circuits. The reduction in power consumption with decreasing supply voltage
does not apply to analog circuits. In fact, considerable innovation is required with a
reduced supply voltage even to avoid increasing power consumption for a given signal
to noise ratio (S/N). These aspects pose a great hurdle to the active filter designer.
A technique which has attracted the attention of circuit designers as a possible
route to filters with higher dynamic range per unit power consumption is
“companding”. Companding (compression-expansion) filters are a very promising
subclass of continuous-time analog filters, where the input (linear) signal is initially
compressed before it will be handled by the core (non-linear) system. In order to
preserve the linear operation of the whole system, the non-linear signal produced by
the core system is converted back to a linear output signal by employing an
appropriate output stage. The required compression and expansion operations are
performed by employing bipolar transistors in active region or MOS transistors in
weak inversion; the systems thus derived are known as logarithmic-domain (logdomain)
systems. In case MOS transistors operated in saturation region are employed,
the derived structures are known as Square-root domain systems. Finally, the third
class of companding filters can also be obtained by employing bipolar transistors in
active region or MOS transistors in weak inversion; the derived systems are known as
Sinh-domain systems. During the last several years, a significant research effort has been already
carried out in the area of companding circuits. This is due to the fact that their main
advantages are the capability for operation in low-voltage environment and large
dynamic range originated from their companding nature, electronic tunability of the
frequency characteristics, absence of resistors and the potential for operations in varied
frequency regions.Thus, it is obvious that companding filters can be employed for implementing
high-performance analog signal processing in diverse frequency ranges. For example,
companding filters could be used for realizing subsystems in: xDSL modems, disk
drive read channels, biomedical electronics, Bluetooth/ZigBee applications, phaselocked
loops, FM stereo demodulator, touch-tone telephone tone decoder and
crossover network used in a three-way high-fidelity loudspeaker etc.
A number of design methods for companding filters and their building blocks
have been introduced in the literature. Most of the proposed filter structures operate
either above 1.5V or under symmetrical (1.5V) power supplies. According to data that
provides information about the near future of semiconductor technology, International
Technology Roadmap for Semiconductors (ITRS), in 2013, the supply voltage of digital
circuits in 32 nm technology will be 0.5 V. Therefore, the trend for the implementation of
analog integrated circuits is the usage of low-voltage building blocks that use a single
0.5-1.5V power supply.
Therefore, the present investigation was primarily concerned with the study and
design of low voltage and low power Companding filters. The work includes the
study about: the building blocks required in implementing low voltage and low power
Companding filters; the techniques used to realize low voltage and low power
Companding filters and their various areas of application.
Various novel low voltage and low power Companding filter designs have been
developed and studied for their characteristics to be applied in a particular portable
area of application. The developed designs include the N-th order universal
Companding filter designs, which have been reported first time in the open literature.
Further, an endeavor has been made to design Companding filters with orthogonal
tuning of performance parameters so that the designs can be simultaneously used for
various features. The salient features of each of the developed circuit are described.
Electronic tunability is one of the major features of all of the designs. Use of
grounded capacitors and resistorless designs in all the cases makes the designs suitable
for IC technology. All the designs operate in a low-voltage and low-power
environment essential for portable system applications.
Unless specified otherwise, all the investigations on these designs are based on the
PSPICE simulations using model parameters of the NR100N bipolar transistors and BSIM 0.35μm/TSMC 0.25μm /TSMC 0.18μm CMOS process MOS transistors. The
performance of each circuit has been validated by comparing the characteristics
obtained using simulation with the results present in the open literature.
The proposed designs could not be realized in silicon due to non-availability of
foundry facility at the place of study. An effort has already been started to realize
some of the designs in silicon and check their applicability in practical circuits. At the
basic level, one of the proposed Companding filter designs was implemented using the
commercially available transistor array ICs (LM3046N) and was found to verify the
theoretical predictions obtained from the simulation results
