244 research outputs found
Characterization and Electrical Conductivity of Electron Beam Irradiated Metal Phthalocyanine Complexes
Variation of DC electrical conductivity with temperature from 273-473 K of electron beam irradiated Tetra-nitro zinc, and Cu-Pcs, were carried out. It shows semiconductor behavior and resistivity varies from 0.043×10 5 Ω -cm to 64.61×10 5 Ω -cm for all complexes. Variation of conductivity with temperature shows two straight lines of different slopes the first line (LT), resembles the α– phase, (Ea 1 ) = 0.226 eV while the second line at 362 K resembles the β - phase (Ea 2 ) = 0.460 eV (for Cu- Pcs). The β -phase shows higher activation energy than the α -phase, and the X-ray diffraction studies reveal that the crystals are monoclinic. The conductivity is explained on the basis of Davis and Mott model. The conduction mechanism at lower temperature is explained in terms of hoping through a band of localized states and at higher temperatures in terms of thermal excitation of carriers to the band edge
Characterization and Antibacterial Activity of a Glycoside Antibiotic from Streptomyces variabilis PO-178
In the present study, characterization and antibacterial activity of a glycoside antibiotic from fermentation broth of bioactive Streptomyces variabilis PO-178 recovered previously from Western Ghat soil of Agumbe, Karnataka, India was investigated. Mass cultivation of the strain PO-178 was carried out in Starch casein nitrate broth. The fermentation broth was extracted using butanol solvent in a separation funnel. The concentrated butanol extract was subjected to chromatographic techniques viz., thin layer and silica gel column chromatography for purification of bioactive components. Out of 3 fractions (A, B and C) obtained, only one fraction (C) displayed inhibitory activity against Staphylococcus aureus and Pseudomonas aeruginosa. The bioactive fraction C was subjected to spectral analysis (LC-MS, IR, 1H-NMR and 13C-NMR) in order to determine the structure. On the basis result of spectral analysis, the purified fraction was predicted as a glycoside antibiotic with molecular weight 514 and molecular formula C24H34O12. The antibiotic displayed marked inhibitory activity against S. aureus as revealed by wider zones of inhibition and low minimum inhibitory concentration value
Limited Data Speaker Verification: Fusion of Features
The present work demonstrates experimental evaluation of speaker verification for different speech feature extraction techniques with the constraints of limited data (less than 15 seconds). The state-of-the-art speaker verification techniques provide good performance for sufficient data (greater than 1 minutes). It is a challenging task to develop techniques which perform well for speaker verification under limited data condition. In this work different features like Mel Frequency Cepstral Coefficients (MFCC), Linear Prediction Cepstral Coefficients (LPCC), Delta (4), Delta-Delta (44), Linear Prediction Residual (LPR) and Linear Prediction Residual Phase (LPRP) are considered. The performance of individual features is studied and for better verification performance, combination of these features is attempted. A comparative study is made between Gaussian mixture model (GMM) and GMM-universal background model (GMM-UBM) through experimental evaluation. The experiments are conducted using NIST-2003 database. The experimental results show that, the combination of features provides better performance compared to the individual features. Further GMM-UBM modeling gives reduced equal error rate (EER) as compared to GMM
SPECTROPHOTOMETRIC METHOD FOR THE DETERMINATION OF CEFEPIME, CEFAZOLIN SODIUM AND CEFALOTHIN SODIUM IN PURE AND PHARMACEUTICAL DOSAGE FORMS BY USING NINHYDRIN
Objectives: cefazolin sodium and cefalothin sodium are the broad spectrum of antibiotics, are mainly used to control gram positive and gram negative bacterial infections. Cefepime is used to treat moderate-severe nosocomical pneumonia, infections caused by multi resistant microorganisms.(eg. pseudomonos aeruginosa) and empirical treatment of febrile neutropenia. The objective of our method is to develop an effective, simple and sensitive spectrophotometric method for the assay of the above mentioned drugs in both tablet and in pharmaceutical dosage forms.Methods: The method is based on the reaction of cephalosporin's with ninhydrin reagent in the presence of sodium molybdate by maintaining the pH (5.5) using citrate buffer. The reaction is carried out at a temperature of 100 0C for 10 min for CEPM, 15 min for both CFZS and CFLS. The resulting Ruhemann's purple product having the absorption maximum at 570 nm is measured against the reagent blank.Results: Beer's law is obeyed in the concentration range of (1-10 µg/ml) for cefepime, (2-20 µg/ml) for cefazolin sodium and (6-40 µg/ml) for cefalothin sodium respectively. The correlation coefficient's (r2), molar absorptivity (€), Sandell's sensitivity (s), Limit of detection (LOD) and quantification limits (LOQ) for the studied drugs were calculated. Recovery studies shows that this method is accurate and can be successfully employed for the determination of the studied cephalosporin's.Conclusion: Recovery studies, optical parameters and statistical comparisons justify that the present proposed method can be applied to routine drug formulation in pure and dosage forms and can be recommended for routine analysis and also for quality control of these drugs.Â
En-ROADS: Using the Climate Interactive Tool for Designing and Planning
Designers and planners are facing increasing challenges in creating a liveable environment in the face of global climate change. We are far behind the Paris Agreement’s ambitious goals of limiting global warming to 1.5C, which is in line with pre-industrial levels. Advances towards this require both looking to a future without fossil fuel while also being able to meet global energy demands.
This complex combination of situations requires tools that can assist in understanding the system dynamics of short and long efforts when making designs or planning spaces. The En-ROADS Climate Workshop helps build support for energy strategies by using an openly available cutting-edge simulation tool created by Climate Interactive and MIT Sloan.
In this 90-minute interactive workshop, participants learn why it is important to understand the interdependency of climate change and energy sources. Participants are introduced to the En-ROADS modelling tool, an easy-to-use, science-backed simulation that can inform real-world design strategies.
Through a series of interactions with the facilitator, participants have an opportunity to test various approaches using En-ROADS to see the impact of energy decisions on global temperature and other factors, including equity. The workshop is an opportunity to experience what it is like to create climate futures using engaging conversations that result in an experience that is hopeful, scientifically grounded, action-oriented, and eye-opening
Trust correlation of mobile agent nodes with a regular node in a Adhoc network using decision-making strategy
A mobile agent offers discrete advantage both in facilitating better transmission as well as controlling the traffic load in Mobile Adhoc Network (MANET). Hence, such forms of network offers maximized dependencies on mobile agents in terms of its trust worthiness. At present, there are various work being carried out towards resisting security breach in MANET; however approaches using mobile agent based mechanism is few to found. Therefore, the proposed system introduces a novel mathematical model where an extensive decision making system has been constructed for identifying the malicious intention of mobile agents in case they go rogues. By adopting multi-tier communication policy and fairness concept, the proposed system offers the capability to resist any form of malicious activity of mobile agent without even presence of any apriori information of adversary. The outcome shows proposed system outshines existing security scheme in MANET
Novel framework using dynamic passphrase towards secure and energy-efficient communication in MANET
At Mobile Adhoc Network (MANET) has been long-researched topic in adhoc network owing to the associated advantages in its cost-effective application as well as consistent loophopes owing to its inherent charecteristics. This manuscript draws a relationship between the energy factor and security factor which has not been emphasized in any existing studies much. Review of existing security approaches shows that they are highly attack specific, uses complex encryption, and overlooks the involvement of energy factor in it. Therefore, the proposed system introduces a novel mechanism where security tokens and passphrases are utilized in order to offer better security. The proposed system also introduces the usage of an agent node which communications with mobile nodes using group-based communication system thereby ensuring reduced computational effort of mobile nodes towards establishing secured communication. The outcome shows proposed system offers better outcome in contrast to existing system
POTENTIAL ANTIMICROBIAL, ANTHELMINTIC AND ANTIOXIDANT ACTIVITIES OF MYRISTICA DACTYLOIDES GAETRN BARK
Objective: The present study was undertaken to determine the antimicrobial, anthelmintic and antioxidant activities of bark extracts of Myristica dactyloides Gaetrn.Methods: The antimicrobial activity of the petroleum ether, ethyl acetate and methanol extracts were evaluated by the Agar well diffusion method against different gram-positive, gram-negative bacteria and fungi. Different extracts of the plant were taken for anthelmintic activity against Indian earthworm Pheretima Posthuma. DPPH radical scavenging activity was measured by the DPPH antioxidant assay method using ascorbic acid as standard and the total phenolic content was estimated spectrophotometrically using Folin-Ciocalteu method.Results: Petroleum ether extract exhibited significant antifungal activity, anthelmintic activity and considerable DPPH radical scavenging activity with an IC50 value of 10.97±0.07µg/ml. Whereas methanol extract exhibited significant antibacterial activity against both gram positive and gram negative bacteria and it is the richest source of phenolics with a total phenolic content of 95.11±2.14 mg of Catechol equivalents/100 mg dried extract. Preliminary phytochemical screening revealed the presence of alkaloids, flavonoids, tannins/phenolics, steroids/triterpenoids and saponins which may be the reason for its biological properties.Conclusion: The findings of this study indicate that this plant is medicinal with prominent antioxidant, antimicrobial and anthelmintic property. The plant can be considered as promising plant species with high potential value for drug preparation.Â
REDOX REACTION BASED SPECTROPHOTOMETRIC ASSAY OF SOME DRUGS IN PHARMACEUTICALS
Objectives: Pyridoxine hydrochloride (PRC) is used in the treatment of side roblastic anemia's and is also used in a variety of disorders including the treatment of depression. Dobutamine Hydrochloride (DOB) is used in the case of congestive heart failure to increase cardiac output and is also commonly used in the hospital setting as a pharmacologic stress testing agent to identify coronary artery disease. Linezolid (LZD) is a synthetic antibiotic used for the treatment of serious infections caused by gram-positive bacteria that are resistant to several other antibiotics. The main objective of our method is to develop a simple, accurate and sensitive spectrophotometric method for the assay of the above mentioned drugs in both tablet and pharmaceutical dosage forms.Methods: The method is based on the red ox reaction of drugs with Folin Ciocalteu (FC) reagent in sodium carbonate medium and the resulting blue colored chromogen is measured at 755 nm.Results: Beer's law is obeyed in the concentration range of 2.5–30 µg/ml (PRC), 1–10 µg/ml (DOB) and 2.5–70 µg/ml (LZD) respectively, with the corresponding molar absorptivity values of 7.145 X 103, 3.2080 X 104 and 6.299 X 103 l mol-1 cm-1. The method is validated for accuracy, precision, LOD, LOQ, robustness and ruggedness as per the current ICH guidelines.Conclusion: The validated method is successfully applied to quantify PRC, DOB and LZD in their commercial formulations with satisfactory results; hence the method is suitable for the determination of drugs in bulk and pharmaceuticals.Â
ANALISIS KEMAMPUAN PEMECAHAN MASALAH MATEMATIS DAN SELF EFFICACY SISWA MAN
This study aims to determine students' mathematical problem solving abilities and self efficacy. Data retrieval was carried out in the Public MA in the city of Cimahi with a sample of research, namely the XI MIA 3 class consisting of 34 students. The method used is descriptive analysis by providing instruments and questionnaires. The results of the study obtained results: (1) achievement of mathematical problem solving abilities on the given problem; (2) errors when working on the problem; (2) students' self efficacy from the questionnaire according to their indices. It can be seen that students 'mathematical problem solving abilities in high categories and students' self efficacy are goo
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