Site directed mutagenesis of L-pyrrolysine in dimethylamine methyltransferase

Methanosarcina barkeri is an archaeon and is able to use methylamines as growth substrates for methanogenesis. The methylamine methyltransferases that are involved in initiating methanogenesis from the methylamines have an in-frame amber codon (UAG) that does not terminate translation, but in fact encodes for the 22nd amino acid L-pyrrolysine. This thesis attempts to examine the rationale for the presence of pyrrolysine in one of these three methylamine methyltransferases. A system that allowed the recombinant expression of the dimethylamine methyltransferase gene, mtbB, in the native organism Methanosarcina acetivorans, was developed (9). Site directed mutagenesis of mtbB was performed wherein UAG, which encodes for pyrrolysine, was substituted by GCA, which encodes for alanine (Jodie Lee). This allowed for functional studies of MtbB vs. the mutant MtbB, dubbed MtbB(O356A). An activity assay, which measured the ability of MtbB and MtbB(O356A) to methylate hydroxocobalamin, showed that MtbB(O356A) had lost its functionality. This indicated that pyrrolysine is an essential residue in MtbB and that it may play a catalytic role. However, preliminary data from native gel electrophoresis showed that the ability of MtbB(O356A) to bind its cognate corrinoid cofactor protein, MtbC, was greatly reduced; whilst the wild-type MtbB was able to form a complex with MtbC. This indicated that pyrrolysine is required for proper folding of MtbB and/or it is required for binding MtbC.College of Biological Sciences Dean's Undergraduate Research Fund, The Ohio State UniversityNo embarg

RP-HPLC METHOD DEVELOPMENT AND VALIDATION FOR THE ESTIMATION OF DICLOFENAC SODIUM, TRAMADOL HYDROCHLORIDE AND CHLORZOXAZONE FROM THEIR COMBINED TABLET DOSAGE FORM

Objective: The objective of the current study was to develop and validate the RP-HPLC method for the simultaneous estimation of Tramadol Hydrochloride, Chlorzoxazone and Diclofenac sodium from their combined tablet dosage form Methods: The current method describes RP-HPLC method for the estimation of Tramadol Hydrochloride, Chlorzoxazone and Diclofenac sodium from their combined tablet dosage form. The mobile phase used was Acetonitrile: 0.05M Disodium Hydrogen Phosphate buffer pH 3.5 adjusted with 10% v/v Ortho Phosphoric acid(50:50 v/v) and Hypersil ODS C18 (250 mm x4.6 mm, 5.0 μ particle sizes) was used as a stationary phase with detection wavelength of 220 nm. Result: Linearity was obtained in the concentration range of 15-75 μg/ml, 100-500 μg/ml and 20-100 μg/ml for TRM,CHL and DIC respectively. The % recovery was found to be 99.41 -99.84%, 99.30 - 99.74 % and 99.6 - 99.97 % for DIC, TRM andCHL respectively. The LOQ was found to be 3.33, 3.95 and 36.71 μg/ml for DIC, TRM andCHL respectively. The proposed method has been validated as perICH Q2R1 guidelines and successfully applied to the estimation of TRM, DIC andCHL from their combined Tablet dosage form. Conclusion: The method was found to be simple, accurate, precise, and suitable for the estimation of Tramadol Hydrochloride, Chlorzoxazone and Dicofenac sodium from their combined tablet dosage form

Ultrasonic Enhancement of Pulsed Electrochemical Machining

Electrochemical machining (ECM) has gained prominence in the field on precise machining and has been subjected to a lot of study in order to bring its use to commercial levels. One of the key issues of electrochemical machining is the lack of proper flushing ECM by-products. Ultrasonic assisted ECM is often used to minimize the flushing issue. This study attempts a novel variation in ultrasonic assistance of ECM by introducing ultrasonic waves in the flowing electrolyte without vibrating tool or workpiece. This ensures intense agitation in the inter-electrode gap (IEG) with relatively simpler set-up. Aluminum 6061 is used as a workpiece material to drill holes. Stainless steel tubes coated with Teflon is used as tool. The Teflon coating minimizes the effect of stray current. Use of pulsed DC current and ultrasonic vibration improves the quality of the ECM’ed holes. The intense ultrasonic cavitation disturbs the anodic reaction in IEG negatively affecting MRR. On the other hand, the de-agglomeration of ECM by-products and depassivation of anodic workpiece improves surface roughness by approximately 50% and the taper angle of the hole by approximately 75%

Ultrasonic Enhancement of Pulsed Electrochemical Machining

Electrochemical machining (ECM) has gained prominence in the field on precise machining and has been subjected to a lot of study in order to bring its use to commercial levels. One of the key issues of electrochemical machining is the lack of proper flushing ECM by-products. Ultrasonic assisted ECM is often used to minimize the flushing issue. This study attempts a novel variation in ultrasonic assistance of ECM by introducing ultrasonic waves in the flowing electrolyte without vibrating tool or workpiece. This ensures intense agitation in the inter-electrode gap (IEG) with relatively simpler set-up. Aluminum 6061 is used as a workpiece material to drill holes. Stainless steel tubes coated with Teflon is used as tool. The Teflon coating minimizes the effect of stray current. Use of pulsed DC current and ultrasonic vibration improves the quality of the ECM’ed holes. The intense ultrasonic cavitation disturbs the anodic reaction in IEG negatively affecting MRR. On the other hand, the de-agglomeration of ECM by-products and depassivation of anodic workpiece improves surface roughness by approximately 50% and the taper angle of the hole by approximately 75%

Ultrasonic Enhancement of Pulsed Electrochemical Machining

Electrochemical machining (ECM) has gained prominence in the field on precise machining and has been subjected to a lot of study in order to bring its use to commercial levels. One of the key issues of electrochemical machining is the lack of proper flushing ECM by-products. Ultrasonic assisted ECM is often used to minimize the flushing issue. This study attempts a novel variation in ultrasonic assistance of ECM by introducing ultrasonic waves in the flowing electrolyte without vibrating tool or workpiece. This ensures intense agitation in the inter-electrode gap (IEG) with relatively simpler set-up. Aluminum 6061 is used as a workpiece material to drill holes. Stainless steel tubes coated with Teflon is used as tool. The Teflon coating minimizes the effect of stray current. Use of pulsed DC current and ultrasonic vibration improves the quality of the ECM’ed holes. The intense ultrasonic cavitation disturbs the anodic reaction in IEG negatively affecting MRR. On the other hand, the de-agglomeration of ECM by-products and depassivation of anodic workpiece improves surface roughness by approximately 50% and the taper angle of the hole by approximately 75%

PAPR Reduction in the OFDM Signal Using Selective Mapping

Nowadays Orthogonal Frequency Division Multip lexing is becoming more and more popular Because of it is attractive techniques for high data rate transmission. OFDM is widely used in 4G technologies in recent times. Main advantage of OFDM is that it uses orthogonal signals so removes inter - signal inter ference. PAPR ratio in OFDM is very high because it uses Multicarrier modulation, which is its main drawback. High PAPR means more power need at transmission side. PAPR can be decreased using various techniques such as clipping, selective mapping, etc. In this paper, criterion for new scheme selective mapping is introduced for PAPR reduction in OFD

Visual Cryptography in Biometrics Passport

Every human being is unique in their nature such as traits and physical symptoms so computer science is using the biometric f or perfect identification within large database. Visual cryptography scheme is a cryptographic technique, which allows visual information e.g. printed text, handwritten notes, and picture to be encrypted in such a way that the decryption can be performed by the human visual system, without the aid of computers. Biometric passport is a smart card technology product created by use of biometric data and computer chip f or authenticate identification of citizen of particular country. Current passport has certain shortcoming. In the is method it is proposed to convert scan images of retina, fingerprint and face in secret image and meaningful shares by use of visual cryptography. In this method wi th use of Visual Cryptography three biometrics i.e . retina image, fingerprint image and fa ce image encrypted in two meaningful shares when these two share stacking on one another fingerprint image revealed and that can be verified with on the spot live fingerprint image for perfect identification accuracy

SPECTROPHOTOMETRIC METHOD FOR THE ESTIMATION OF TOTAL ALKALOIDS IN THE TINOSPORA CORDIFOLIA M. AND ITS HERBAL FORMULATIONS

Objective: A simple spectrophotometric method was developed for the estimation of total alkaloids in Tinospora cordifolia M. and its formulations.Methods: The method based on the formation of yellow colored complex by reaction between bromocresol green (BCG) and alkaloids in medicinal plants. A yellow colored complex forms is easily extractable by chloroform at pH 4.7.Results: The method was linear in concentration range of 2-10 μg/ml with λmax at 415 nm. The LOD and LOQ were found to be 0.215 and 0.652 respectively. The intra-day and inter-day precision and accuracy were within the acceptable criteria (relative standard deviation<2.0% and accuracy within 100±2%). Conclusion: The developed method is simple, precise and accurate and can be adopted for the routine quality control and standardization of plant materials containing alkaloids and its pharmaceutical products.Â

ENHANCEMENT OF DISSOLUTION RATE OF MODAFINIL USING SOLID DISPERSIONS WITH POLYETHYLENEGLYCOLS

Solid  dispersions  (SDs)  of  modafinil  (MDF)  were  prepared using polyethyleneglycols (PEGs), in 1;1, 1;2 and 1;4 proportions by  fusion,  solvent  evaporation  and  physical  mixing  method. Differential  scanning  calorimetry  (DSC)  and  X-ray  powder diffractometry (XRD)  were  used to examine the physical state  of the  drug.  The  data  from  the  XRD  showed  that  the  drug  was converted  to  amorphous  form  as  the  number  and  intensity  of peaks  were  decreased  in  solid  dispersion  as  compared  to  pure drug and physical mixture of drug and carrier. DSC thermograms also  confirmed  the  change  in  physical  state  of  the  drug  as  the peaks were altered or disappeared. With the  highest  ratio of the carriers (1:4), the drug  solubility was enhanced by 38.68, 34.78 and 9.29 folds in solvent evaporation, fusion and physical mixing methods  respectively.  Solid  dispersion  batch  S6  containing drug:PEG6000  in  1:4,  was  selected  to  be  formulated  as  tablet (batch  TS6)  and  evaluated  for in  vitro drug  dissolution  &  six month  stability.  An  increased  dissolution  rate  of  modafinil  was observed  from  SDs  and  PMs,  as  compared  to  pure  crystalline drug.  The  dissolution  rate  of  modafinil  from  its  PMs  or  SDs increased with an increasing amount of polymer.Key  words:  Fusion,  solvent  evaporation,  physical  mixture,  in  vitro dissolution, characterization.

Formulation, evaluation and optimization of stomach specific in situ gel of clarithromycin and metronidazole benzoate

The present investigation deals with the formulation, optimization and evaluation of sodium alginate based In situ gel of Clarithromycin and Metronidazole Benzoate. Sodium alginate used as a polymer and CaCO3 was used as a cross-linking agent. The In situ formulation exhibited well, viscosity, drug content and sustained drug release; this study reports that oral administration of aqueous solutions containing sodium alginate results in formation of In situ gel, such formulations are homogenous liquid when administered orally and become gel at the contact site. The results of a 32 full factorial design revealed that the concentration of sodium alginate and concentration of CaCO3 significantly affected the dependent variables Q1, Q12 and T80. These In situ gels are, thus, suitable for oral sustained release of Clarithromycin and Metronidazole Benzoate.Keywords: In situ gel; Stomach specific; Gastric residence time