Showing papers by "Aligarh Muslim University published in 2005"

Recent philosophies of automatic generation control strategies in power systems

Abstract: An attempt is made in This work to present critical literature review and an up-to-date and exhaustive bibliography on the AGC of power systems. Various control aspects concerning the AGC problem have been highlighted. AGC schemes based on parameters, such as linear and nonlinear power system models, classical and optimal control, and centralized, decentralized, and multilevel control, are discussed. AGC strategies based on digital, self-tuning control, adaptive, VSS systems, and intelligent/soft computing control have been included. Finally, the investigations on AGC systems incorporating BES/SMES, wind turbines, FACTS devices, and PV systems have also been discussed.

Eutrophication: An ecological vision

Abstract: The present review deals with the studies conducted on the impact of phosphorus on growth of aquatic plants causing eutrophication in well-known water bodies the world over. The review covers the definition and concept of eutrophication and the adverse effects on quality and ecosystem functioning. The eutrophication of several water bodies leads to significant changes in the structure and function of the aquatic ecosystem. Several activities of human interest, including navigation and power generation, are hampered. A large number of lakes in the United States, Europe, and Asia have recently been found to be highly eutrophic. Water, the precious fluid, is not uniformly distributed throughout the surface of the earth. Most of the water bodies world over are surrounded with densely populated human settlement areas and agricultural fields. The size of smaller water bodies in human settlement areas is on the decrease with rise in population. After treatment, a large quantity of sewage from the househ...

PGPR: Prospective Biocontrol Agents of Plant Pathogens

Abstract: Plant growth promoting rhizobacteria (PGPR) are indigenous to soil and the plant rhizosphere and play a major role in the biocontrol of plant pathogens. PGPR can profoundly improve seed germination, root development and water utilization by plants. These rhizobacteria can stimulate plant growth directly by producing growth hormones and improving nutrient uptake or indirectly by changing microbial balance in the rhizosphere in favour of beneficial microorganisms. They can suppress a broad spectrum of bacterial, fungal and nematode diseases. PGPR can also provide protection against viral diseases. The use of PGPR has become a common practice in many regions of the world. Although significant control of plant pathogens has been demonstrated by PGPR in laboratory and greenhouse studies, results in the field have been inconsistent. Recent progress in our understanding of their diversity, colonizing ability, mechanisms of action, formulation and application should facilitate their development as reliable biocontrol agents against plant pathogens. Some of these rhizobacteria may also be used in integrated pest management programmes. Greater application of PGPR is possible in agriculture for biocontrol of plant pathogens and biofertilization.

Effect of certain bioactive plant extracts on clinical isolates of β-lactamase producing methicillin resistant Staphylococcus aureus

Abstract: Ethanolic extracts and some fractions from 10 Indian medicinal plants, known for antibacterial activity, were investigated for their ability to inhibit clinical isolates of beta-lactamase producing methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-sensitive S. aureus (MSSA). Synergistic interaction of plant extracts with certain antibiotics was also evaluated. The MRSA test strains were found to be multi-drug resistant and also exhibited high level of resistance to common beta-lactam antibiotics. These strains produced beta-lactamases, which hydrolyze one or other beta-lactam antibiotics, tested. The extract of the plants from Camellia sinensis (leaves), Delonix regia (flowers), Holarrhena antidysenterica (bark), Lawsonia inermis (leaves), Punica granatum (rind), Terminalia chebula (fruits) and Terminalia belerica (fruits) showed a broad-spectrum of antibacterial activity with an inhibition zone size of 11 mm to 27 mm, against all the test bacteria. The extracts from the leaves of Ocimum sanctum showed better activity against the three MRSA strains. On the other hand, extracts from Allium sativum (bulb) and Citrus sinensis (rind) exhibited little or no activity, against MRSA strains. The antibacterial potency of crude extracts was determined in terms of minimum inhibitory concentration (MIC) by the tube dilution method. MIC values, of the plant extracts, ranged from 1.3 to 8.2 mg/ml, against the test bacteria. Further, the extracts from Punica granatum and Delonix regia were fractionated in benzene, acetone and methanol. Antibacterial activity was observed in acetone as well as in the methanol fractions. In vitro synergistic interaction of crude extracts from Camellia sinensis, Lawsonia inermis, Punica granatum, Terminalia chebula and Terminalia belerica was detected with tetracycline. Moreover, the extract from Camellia sinensis also showed synergism with ampicillin.TLC of the above extracts revealed the presence of major phytocompounds, like alkaloids, glycosides, flavonoids, phenols and saponins. TLC-bioautography indicated phenols and flavonoids as major active compounds.

Effect of salicylic acid on growth and enzyme activities of wheat seedlings

Abstract: grains of wheat (Triticum aestivumL. cv. Raj-3077) were soaked in 0, 10-5, 10-4or 10-3 M aqueous solutions of salicylic acid (SA) for 3, 6 or 9 h. The seedlings raised from grains pre-treated with 10-5 M SA possessed significantly higher leaf number, fresh and dry mass per plant, and nitrate reductase and carbonic anhydrase activities 30 and 40 days after sowing. However, 10-3 M SA reduced all the above-mentioned parameters.

Plant Growth Promoting Rhizobacteria Formulations and its Scope in Commercialization for the Management of Pests and Diseases

Abstract: The export oriented agricultural and horticultural crops depends on the export of residue free produce and has created a great potential and demand for the incorporation of biopesticides in crop protection. To ensure the sustained availability of biocontrol agent’s mass production technique and formulation development protocols has to be standardized to increase the shelf life of the formulation. It facilitates the industries to involve in commercial production of plant growth promoting rhizobacteria (PGPR). PGPR with wide scope for commercialization includes Pseudomonas fluorescens, P. putida, P. aeruginosa, Bacillus subtilis and other Bacillus spp. The potential PGPR isolates are formulated using different organic and inorganic carriers either through solid or liquid fermentation technologies. They are delivered either through seed treatment, bio-priming, seedling dip, soil application, foliar spray, fruit spray, hive insert, sucker treatment and sett treatment. Application of PGPR formulations with strain mixtures perform better than individual strains for the management of pest and diseases of crop plants, in addition to plant growth promotion. Supplementation of chitin in the formulation increases the efficacy of antagonists. More than 33 products of PGPR have been registered for commercial use in greenhouse and field in North America. Though PGPR has a potential scope in commercialization, the threat of certain PGPR (P. aeruginosa, P. cepacia and B. cereus) to infect human beings as opportunistic pathogens has to be clarified before large scale acceptance, registration and adoption of PGPR for pest and disease management.

Shoot multiplication in Rauvolfia tetraphylla L. using thidiazuron

Abstract: The effect of thidiazuron (TDZ) was investigated on in vitro shoot proliferation from nodal explants of Rauvolfia tetraphylla. Murashige and Skoog (MS) medium containing TDZ (0.5–10μM) was effective in inducing shoot buds and maintaining high rates of shoot multiplication on hormone free medium. The highest shoot regeneration frequency (90%) and mean number (18.50 ± 1.25) of shoots per explant were achieved from nodal segments cultured on MS medium supplemented with 5μM TDZ for 4 weeks prior to transfer to MS medium without TDZ for 8 weeks. The regenerated shoots rooted best on MS medium containing 0.5μM indole-3-butyric acid (IBA). Micropropagated plantlets were hardened to survive ex vitro conditions and were then established into soil.

Effects of Antioxidant Vitamins on Glutathione Depletion and Lipid Peroxidation Induced by Restraint Stress in the Rat Liver

Abstract: Background and aim: Stress as a cofactor has been reported to affect the progression and severity of several diseases. The influence of stress on the liver is of interest from the clinical point of view because stress plays a potential role in aggravating liver diseases in general and hepatic inflammation in particular, probably through generation of reactive oxygen species. The present study was undertaken to investigate the potential of the antioxidant vitamins A (retinol), E (tocopherol) and C (ascorbic acid) individually and in combination (vitamin E + C) to modulate restraint stress-induced oxidative changes. These effects were determined by measuring changes in hepatic levels of free radical scavenging enzymes such as superoxide dismutase (SOD), glutathione-S-transferase (GST) and catalase, as well as levels of total glutathione (GSH), malondialdehyde (MDA), aspartate aminotransferase (AST) and alanine aminotransferase (ALT). Methods: Immobilisation was achieved by placing the animals in wire mesh cages of their size. The rats were orally administered vitamins A, E and C individually and in combination (E + C) prior to and after 6 hours of immobilisation stress exposure. The hepatic levels of SOD, GST, catalase, GSH and MDA were determined by spectrophotometric methods. Liver SOD activity was assayed by monitoring the amount of enzyme required to inhibit autoxidation of pyrogallol by 50%. Hepatic GST was monitored by following the increase in absorbance at 340nm of CDNB-GSH conjugate generated due to GST catalysis between GSH and CDNB. Catalase activity in liver tissues was determined using peroxidase as the substrate. Lipid peroxidation was measured by determining the level of thiobarbituric acid reactive substances. ALT and AST were determined by commercial kits. Results: Six hours of immobilisation stress caused a decrease in liver levels of SOD (p = 0.001), catalase (p = 0.031), GST (p = 0.021) and GSH (0.013), while levels of MDA (p = 0.0015), AST (p = 0.05) and ALT (p = 0.046) were increased compared with non-stressed control rats. Both pre-vitamin stress and post-vitamin stress treatments either alone or in combination were associated with increased normalisation of these parameters towards control values, with post-vitamin treatment being the more effective of the two. Vitamins E and C individually were found to be more effective in restoring the endogenous antioxidant system than vitamin A. The combined vitamin (E + C) post-stress treatment was found to be effective but not additive in combating hepatic oxidative stress. The beneficial effects of these vitamin treatments were also reflected in reversions of altered AST and ALT levels towards their control values. Conclusion: Vitamins E or C alone or in combination can be given as prophylactic/therapeutic supplements for combating scavenging free radicals generated in liver tissue. This approach may reduce oxidative stress caused by diseases such as cirrhosis.

An experimental study of sexual function improving effect of Myristica fragrans Houtt. (nutmeg).

Abstract: Myristica fragrans Houtt. (nutmeg) has been mentioned in Unani medicine to be of value in the management of male sexual disorders. The present study was undertaken to evaluate the aphrodisiac effect of 50% ethanolic extract of nutmeg along with its likely adverse effects and acute toxicity using various animal models. The suspension of the extract was administered (100, 250 and 500 mg/kg, p.o.) to different groups of male rats daily for seven days. The female rats involved in mating were made receptive by hormonal treatment. The general mating behaviour, libido and potency were studied and compared with the standard reference drug sildenafil citrate. Likely adverse effects and acute toxicity of the extract were also evaluated. Oral administration of the extract at the dose of 500 mg/kg, produced significant augmentation of sexual activity in male rats. It significantly increased the Mounting Frequency, Intromission Frequency, Intromission Latency and caused significant reduction in the Mounting Latency and Post Ejaculatory Interval. It also significantly increased Mounting Frequency with penile anaesthetisation as well as Erections, Quick Flips, Long Flips and the aggregate of penile reflexes with penile stimulation. The extract was also observed to be devoid of any adverse effects and acute toxicity. The resultant significant and sustained increase in the sexual activity of normal male rats without any conspicuous adverse effects indicates that the 50% ethanolic extract of nutmeg possesses aphrodisiac activity, increasing both libido and potency, which might be attributed to its nervous stimulating property. The present study thus provides a scientific rationale for the traditional use of nutmeg in the management of male sexual disorders.

Current controlled third order quadrature oscillator

Abstract: A novel current controlled third order translinear-C quadrature oscillator based on a new second order high input impedance voltage-mode low-pass filter is proposed. The circuit with grounded capacitors enjoys electronically tunable, non-interactive frequency and condition control, generates four quadrature current outputs at high impedance nodes and two quadrature voltage outputs. Design verifications are included using CBIC-R process parameters of AT & T transistors with attractive results.

Interactive Effect of Rhizotrophic Microorganisms on Growth, Yield, and Nutrient Uptake of Wheat

Abstract: The interactive effect of rhizotrophic microorganisms on growth, yield, and nutrient uptake of wheat (Triticum aestivum L.) was determined in a pot experiment using sterilized soil deficient in available phosphorus (P). Positive effect on plant vigor, nutrient uptake, and yield in wheat plants was recorded in the treatment receiving mixed inoculum of nitrogen-fixing Azotobacter chroococcum + phosphate solubilizing microorganism (PSM) Pseudomonas striata + arbuscular mycorrhizal (AM) fungus Glomus fasciculatum. The available P status of the soil improved significantly (P ≤ 0.5) following triple inoculation with A. chroococcum, P. striata, and G. fasciculatum. The residual nitrogen (N) content of the soil did not change appreciably among the treatments. Addition of Penicillium variable to single- or double-inoculation treatments negatively affected the measured parameters. The population of A. chroococcum, PSM, percentage root infection, and spore density of the AM fungus in inoculated treatments i...

The use of electronic resources at IIT Delhi Library: a study of search behaviours

Abstract: Purpose – The paper seeks to examine the use of electronic information services (EIS) among the users of the Indian Institute of Technology (IIT) Library in Delhi, India.Design/methodology/approach – Both questionnaire and observational methods were used for data collection where 300 valid samples were collected. The analysis of data collected covers awareness of EIS services, use of e‐journals, advanced search facilities, acquaintance with electronic information sources, the purpose of using e‐information, problems faced by the users while using EIS, infrastructure facility available and satisfaction level of users.Findings – The study found that Boolean logic and truncation are the most often used search facilities by IIT users. Lack of printing facilities, terminals and trained staff are the major reasons that would discourage users from accessing the EIS. The survey also reveals that some 60 per cent of users face difficulties while browsing e‐information.Originality/value – The paper provides suggest...

Determination and separation of Pb2+ from aqueous solutions using a fibrous type organic–inorganic hybrid cation-exchange material: Polypyrrole thorium(IV) phosphate

Abstract: The separation of Pb2+ from aqueous solutions was studied using a fibrous type polypyrrole thorium(IV) phosphate cation-exchanger column. This type of organic–inorganic composite material was prepared by incorporating polypyrrole into inorganic precipitate of Th(IV) phosphate, providing a new class of hybrid cation-exchangers with good ion-exchange capacity, higher stability, reproducibility and selectivity for heavy metals. The physico-chemical properties of this material were determined using some instrumental analyses. Ion-exchange capacity, pH-titrations, elution and distribution behavior etc. were also carried out to understand the ion-exchange behavior of the material. On the basis of distribution studies, the material was found to be highly selective for Pb(II) and its selectivity was examined by achieving some important binary separations like Pb(II)–Zn(II), Pb(II)–Al(III), Pb(II)–Mg(II), Zn(II)–Hg(II) etc. on its column that indicate its utility in environmental pollution control in one-way or other. For the determination of Pb(II) ions in solutions, a new heterogeneous precipitate based selective ion-sensitive membrane electrode was developed by means of this composite cation-exchanger as electroactive material. The membrane electrode is mechanically stable, with a quick response time, and can be operated over a wide pH range. The selectivity coefficients were determined by mixed solution method and revealed that the electrode is selective for Pb(II) in presence of interfering cations. The practical utility of this membrane electrode has been established by employing it as an indicator electrode in the potentiometric titration of Pb(II).

Heavy Metal Pollution Assessment in Surface Water Bodies and its Suitability for Irrigation around the Neyevli Lignite Mines and Associated Industrial Complex, Tamil Nadu, India

Abstract: Opencast lignite mines, pit-head thermal power plants, and other associated industries in the Neyveli mining and industrial complex generate huge quantities of solid and liquid wastes that are contaminated with heavy metals. Some of these are toxic or carcinogenic at sufficient concentrations. Copper, Zn, Mn, Fe, Ni, Cd, Cr, Co, Pb, and Hg concentrations in surface water in the study area are from 2 to 1200 times higher than average concentrations in river water worldwide. Heavy metal contamination in the natural reservoirs (Peria, Kolakudi, Walaza, and Perumal Ponds, and the Paravannar River) is mainly due to the discharge of untreated mine water, fly-ash pond water, and effluents from associated industries. These waters have long been used for bathing, washing, animal watering, etc. Untreated mine and industrial waste water, and natural reservoir water have been used by nearby villagers for irrigation for the last four decades, which may have led to deterioration of soils, surface water, and groundwater. Heavy metal analyses of mine water, fly-ash pond and industrial effluents and the natural reservoirs reveals that Co, Cr, and Hg are above the recommended irrigation water quality standards in 17%, 75%, and 100% of the samples, respectively. Most samples were within the permissible limits for Mn, Ni, and Fe, while Pb, Zn, Cd, and Cu were within the limits in all samples. At elevated concentrations, toxic metals like Cr, Co, and Hg can accumulate in soils and enter the food chain, leading to serious health hazards and threatening the long-term sustainability of the local ecosystem.

PECTIN BASED CERIUM (IV) AND THORIUM (IV) PHOSPHATES AS NOVEL HYBRID FIBROUS ION EXCHANGERS Synthesis, characterization and thermal behaviour

Abstract: Pectin based cerium (IV) and thorium (IV) phosphates have been synthesized as new phases of hybrid fibrous ion exchangers. Both materials were characterized using X-ray diffraction, infrared (IR) spectra, thermogravimetric analysis (TG), differntial thermogravimetry (DTG), differntial thermal analysis (DTA) and scanning electron microscopy (SEM), as well as the determination of their ion exchange capacity, elution and pH titration. The X-ray study reveals the amorphous nature of the materials, while SEM studies confirm the fibrous nature of the materials. The thermal studies of these materials indicate that both of them are highly stable on heating as they retain about 97% of their ion-exchange capacity (i.e.c.) on heating up to 100°C and about 81% on heating up to 200°C.

Heavy Metal Biosorption potential of Aspergillus and Rhizopus sp. isolated from Wastewater treated soil

Abstract: Two isolates belonging to the predominant genera Aspergillus and Rhizopus isolated from agricultural field treated with sewage/ industrial effluents were selected for the biosorption potential evaluation of Cr and Cd. Pretreated, dead biomass of above fungi was used for bioadsorption experiment at pH value 4.5 with the biomass, 1-5 mg in a 100 ml metal solution of different concentration (2, 4, 6 and 8 mM) with a contact time of 18 hrs and agitation, 120 rpm. Bioadsorption of Cr ranged from 6.20-9.5 mg/g of dry mass at one or other initial metal concentrations by Aspergillus and Rhizopus sp. The bioadsorption of Cd was ranged from 2.3-8.21mg/g. On the comparative basis Rhizopus sp. could bioadsorbed higher concentration of both metals as compared to Aspergillus sp. Bioadsorption of Cd and Cr was influenced by initial metal concentration and nature of organism. The findings revealed that fungi of metal polluted sites showed higher metal tolerance and bioadsorption capacity of chromium and cadmium. Journal of Applied Sciences and Environmental Management Vol. 9(1) 2005: 123-126

Comparison of guanidine hydrochloride (GdnHCl) and urea denaturation on inactivation and unfolding of human placental cystatin (HPC).

Abstract: The activity and conformational change of human placental cystatin (HPC), a low molecular weight thiol proteinase inhibitor (12,500) has been investigated in presence of guanidine hydrochloride (GdnHCl) and urea. The denaturation of HPC was followed by activity measurements, fluorescence spectroscopy and Circular Dichroism (CD) studies. Increasing the denaturant concentration significantly enhanced the inactivation and unfolding of HPC. The enzyme was 50% inactivated at 1.5 M GdnHCl or 3 M urea. Up to 1.5 M GdnHCl concentration there was quenching of fluorescence intensity compared to native form however at 2 M concentration intensity increased and emission maxima had 5 nm red shift with complete unfolding in 4–6 M range. The mid point of transition was in the region of 1.5–2 M. In case of urea denaturation, the fluorescence intensity increased gradually with increase in the concentration of denaturant. The protein unfolded completely in 6–8 M concentration of urea with a mid-point of transition at 3 M. CD spectroscopy shows that the ellipticity of HPC has increased compared to that of native up to 1.5 M GdnHCl and then there is gradual decrease in ellipticity from 2 to 5 M concentration. At 6 M GdnHCl the protein had random coil conformation. For urea the ellipticity decreases with increase in concentration showing a sigmoidal shaped transition curve with little change up to 1 M urea. The protein greatly loses its structure at 6 M urea and at 8 M it is a random coil. The urea induced denaturation follows two-state rule in which Native→Denatured state transition occurs in a single step whereas in case of GdnHCl, intermediates or non-native states are observed at lower concentrations of denaturant. These intermediate states are possibly due to stabilizing properties of guanidine cation (Gdn+) at lower concentrations, whereas at higher concentrations it acts as a classical denaturant.

Development of an Analog Maximum Power Point Tracker for Photovoltaic Panel

Abstract: Maximum power point trackers (MPPT) are used to operate a solar photovoltaic (PV) panel at its maximum power point (MPP) A number of tracking algorithms have been used in the past A simple and cheap analog MPPT has been simulated and constructed The MPP tracking algorithm is based on the fact that the MPP voltage is approximately a fixed percentage of the open circuit voltage of the PV panel The PV panel is usually disconnected from the load after regular intervals, to record the open circuit voltage In the present work, an unloaded pilot PV panel, with characteristics similar to those of the main PV panel and installed under similar conditions, is used to measure the open circuit voltage The main PV panel is never disconnected from the load, resulting in increased energy output The simulation and experimental results show that the panel tracks the MPP under changing atmospheric and load conditions