Magnesium matrix composites for biomedical applications:A review

In recent years,a new wave of bioactive,biocompatibility and biodegradable metallic materials were developed for orthopedic applications.Pure Magnesium,Magnesium alloys,Magnesium alloy-based composites are extensive material to the biomedical applications,by virtue of its high biocompatibility and reasonable strength.Pure magnesium,Magnesium alloys can corrode too fast during the physiological conditions and loses their properties before bone heal.The new era for the development of magnesium-based composites can satisfy the orthopedic applications.Magnesium-based composites,as bio-materials,can produce adjustable mechanical properties like Ultimate tensile strength,ductility,elastic modulus,and corrosion resistance in the physiological conditions.In the Mg based composites,the matrix materials are biomedical magnesium alloys base like Mg-Ca,Mg-Al,Mg-Zn,and Mg-REE alloy and The reinforcements are based on hydroxyapatite(HAP),calcium polyphosphate(CPP),andβ-tricalcium phosphate(β-TCP)particles.This comprehensive review is focused on different grades of biodegradable magnesium matrix composites including their mechanical properties and corrosion resistance.

Estimation of boswellic acids in herbal formulations containing Boswellia serrata extract and comprehensive characterization of secondary metabolites using UPLC-Q-Tof-MS^e

Boswellia serrata is a widely used herb in Indian systems of medicine and is well known for its potential medicinal properties.A chromatographic method was developed for the analysis and quanti cation of six boswellic acid marker compounds,i.e.,keto boswellic acid(1),3-O-Acetyl 11-keto-boswellic acid(2),-b Boswellic acid(3),-Boswellic acid(4),3-O-Acetyl--boswellic acid(5)and 3-O-Acetyl--boswellic acid b(6)in commercial herbal products containing B.serrata as an ingredient.Combining UPLCbwith Q-Tof-MS/MS makes the better identi cation of secondary metabolites and adulterants in the herbal formulations containing B.serrata in rapid time using fragmentation approach than the traditional approaches.In this study quanti cation of boswellic acids with UPLC-PDA method was performed as per the pharmacopeia guidelines.Furthermore,minor phytochemical constituenBoswellia serrata is a widely used herb in Indian systems of medicine and is well known for its potential medicinal properties.A chromatographic method was developed for the analysis and quantification of six boswellic acid marker compounds,i.e.,keto boswellic acid(1),3-O-Acetyl 11-keto b-boswellic acid(2),ɑ-Boswellic acid(3),b-Boswellic acid(4),3-O-Acetyl-ɑ-boswellic acid(5)and 3-O-Acetyl-b-boswellic acid(6)in commercial herbal products containing B.serrata as an ingredient.Combining UPLC with Q-Tof-MS/MS makes the better identification of secondary metabolites and adulterants in the herbal formulations containing B.serrata in rapid time using fragmentation approach than the traditional approaches.In this study quantification of boswellic acids with UPLC-PDA method was performed as per the pharmacopeia guidelines.Furthermore,minor phytochemical constituents were identified and characterized with the help of LC-Q-Tof-MS/MS fragmentation data and various isoforms of boswellic acids and tirucallic acids in B.serrata oleo-gum-resin extract were identified.ts were identi ed and characterized with the help of LC-Q-Tof-MS/MS fragmentation data and various isoforms of boswellic acids and tirucallic acids in B.serrata oleo-gum-resin extract were identi ed.

Development and Validation of a Stability-Indicating RP-HPLC Method for Determination of Darifenacin Hydrobromide in Bulk Drugs

An isocratic stability-indicating reversed phase high performance liquid chromatographic method (RP-HPLC) was developed for determination of process related impurities and assay of darifenacin hydrobromide (DRF) in bulk drugs. DRF was subjected to various stress conditions such as hydrolysis (acid, base, and neutral), oxidation, photolysis and thermal degradation as per International Conference on Harmonization (ICH Q1A(R2) and Q1B) prescribed conditions to investigate the stability-indicating ability of the method. Significant degradation was observed during acidic hydrolysis and oxidative stress conditions. The chromatographic separation was accomplished on a Prodigy C8 column (250 × 4.6 mm, 5 μm) with mobile phase consisting of 0.05 M ammonium acetate (pH adjusted to 7.2 by using ammonia solution) and methanol (36% acetonitrile) in 35:65 v/v ratio in an isocratic elution mode at a flow rate of 1.0 mL/min at 25°C. Detection of analytes was carried out using photo diode array detector at a wavelength of 215 nm. The developed LC method was validated with respect to accuracy, linearity, precision, limits of detection and quantitation and robustness as per ICH guidelines.

Electro-magneto-hydrodynamic flow of couple stress nanofluids in micro-peristaltic channel with slip and convective conditions

This study explores the effects of electro-magneto-hydrodynamics,Hall currents,and convective and slip boundary conditions on the peristaltic propulsion of nanofluids(considered as couple stress nanofluids)through porous symmetric microchannels.The phenomena of energy and mass transfer are considered under thermal radiation and heat source/sink.The governing equations are modeled and non-dimensionalized under appropriate dimensionless quantities.The resulting system is solved numerically with MATHEMATICA(with an in-built function,namely the Runge-Kutta scheme).Graphical results are presented for various fluid flow quantities,such as the velocity,the nanoparticle temperature,the nanoparticle concentration,the skin friction,the nanoparticle heat transfer coefficient,the nanoparticle concentration coefficient,and the trapping phenomena.The results indicate that the nanoparticle heat transfer coefficient is enhanced for the larger values of thermophoresis parameters.Furthermore,an intriguing phenomenon is observed in trapping:the trapped bolus is expanded with an increase in the Hartmann number.However,the bolus size decreases with the increasing values of both the Darcy number and the electroosmotic parameter.

Antioxidant, anti-quorum sensing and anti-biofilm potential of ethanolic leaf extract of Phrynium capitatum and Dryptes indica

Objective: To investigate the antioxidant and anti-infective potential of Phrynium capitatum and Dryptes indica extract. Methods: The antioxidant potentials were determined by DPPH radical scavenging, reducing power, hydroxyl radical scavenging and total antioxidant assays. We further examined anti-quorum sensing activity and inhibition of synthesis of pathogenic factor of Chromobacterium violaceum and Pseudomonas aeruginosa PAO1. Bioactive compounds were determined using gas chromatography–mass spectrometry analysis. In silico analysis was conducted to determine the binding affinity of bioactive compounds of plant extracts for the quorum sensing regulatory receptor LasR. Results: DPPH assay showed that the ethanolic extract of Phrynium capitatum and Dryptes indica at 500 μg/mL showed (86.96 ± 4.07)% and (74.83 ± 3.47)% inhibition, respectively. Hydroxyl radical scavenging assay showed (73.17 ± 3.03)% and (62.63 ± 4.59)% activity, respectively. The ethanolic extract of Phrynium capitatum and Dryptes indica showed high level of attenuation of quorum sensing regulated pyocyanin production. Confocal laser scanning microscopic analysis revealed that the extracts had the potential to effectively inhibit biofilm formation of Pseudomonas aeruginosa. Molecular docking analysis showed a better binding affinity of bioactive compounds from the extracts for the structure of LasR protein of Pseudomonas aeruginosa. Conclusions: The ethanolic extracts of Phrynium capitatum and Dryptes indica possess antioxidant activity and the potential to inhibit the quorum sensing system and its regulatory virulence traits in Pseudomonas aeruginosa PAO1.

Molybdenum disulfide and magnesium oxide nanoparticle performance on micropolar Cattaneo-Christov heat flux model

This article intends to illustrate the Darcy flow and melting heat transmission in micropolar liquid.The major advantage of micropolar fluid is the liquid particle rotation through an independent kinematic vector named the microrotation vector.The novel aspects of the Cattaneo-Christov(C-C)heat flux and Joule heating are incorporated in the energy transport expression.Two different nanoparticles,namely,MoS2 and MgO,are suspended into the base-fluid.The governing partial differential equations(PDEs)of the prevailing problem are slackening into ordinary differential expressions(ODEs)via similarity transformations.The resulting mathematical phenomenon is illustrated by the implication of fourth-fifth order Runge-Kutta-Fehlberg(RKF)scheme.The fluid velocity and temperature distributions are deliberated by using graphical phenomena for multiple values of physical constraints.The results are displayed for both molybdenum disulphide and magnesium oxide nanoparticles.A comparative benchmark in the limiting approach is reported for the validation of the present technique.It is revealed that the incrementing material constraint results in a higher fluid velocity for both molybdenum disulphide and magnesium oxide nanoparticle situations.

Electron Paramagnetic Resonance and Optical Absorption Studies on Copper Ions in Mixed Alkali Cadmium Phosphate Glasses

Electron paramagnetic resonance （EPR） and optical absorption studies were carried out at room temperature on copper doped mixed alkali cadmium phosphate （LiNaCdP） glasses to understand the nature and symmetry of dopant. Three samples with varying concentrations of alkali ions have been prepared. The spin Harniltonian parameters obtained from room temperature EPR spectra are： gli=2.437, 9⊥=2.096, A‖=117×10-4 cm-1, A⊥=26×10-4 cm-1 for LiNaCdP1, g‖=2.441, g⊥=2.088, A‖=121×10-4 cm-1, A⊥=25×10-4 cm-1 for LiNaCdP2and g‖=2.433,g⊥=2.096, A‖=125×10 4cm-1, A⊥=32×10-4cm-1 for LiNaCdP3. TheseEPR results indicate that the dopant Cu2＋ ion enters the glass matrix into a tetragonally elongated octahedral site. The bonding parameters evaluated by correlating optical and EPR data suggest that bonding between the central metal ion and ligands is partially covalent. The mixed alkali effect in cadmium phosphate glasses was reported.

Copper interactions with DNA of chromatin and its role in neurodegenerative disorders

In this study, we have demonstrated the conformational changes to DNA induced by abnormal interactions of copper using circular dichroism, in combination with UV-absorbance and fluorescence spectroscopy. Results confirm that binding of copper to bases of DNA in chromatin is concentration dependent. Binding efficiency of Cu2~ ions to DNA is increased in proportion to the degree of unwinding of the double helix induced by denaturation. Altered B-DNA conformation will alter the integrity of DNA which may affect the normal process of DNA replication and transcription. Copper induced DNA damage in the brain may cause neurotoxicity and the neuronal cell death and is implicated in Alzheimer＇s disease and other neurological disorders.

Evaluation of antiparasitic,anticancer,antimicrobial and hypoglycemic properties of organic extracts from Panamanian mangrove plants

Objective: To investigate 33 organic extracts of mangrove plants for: antiparasitic, anticancer, and antibacterial activities, as well as their ability to inhibit the activity of the α-glucosidase enzyme. Methods: Leaves from all different plant mangrove species located in five mangrove zones of the Pacific coast of Panama were collected according to standard procedures. Qualitative phytochemical analysis of the organic extracts was performed by thin layer chromatography. The antiparasitic activity against Plasmodium falciparum, Trypanosoma cruzi and Leishmania donovani, toxicity against Artemia salina, anticancer activity in MCF-7 cell line, and antibacterial activity against Staphylococcus aureus, Bacillus subtilis, Escherichia coli and Pseudomonas aeruginosa of all organic extract were investigated according protocols stablished in our institution. Finally, the ability to inhibit the enzymatic activity of α-glucosidase was evaluated by monitoring the hydrolysis of p-nitrophenyl α-Dglucopyranoside. Results: Thirty-three different samples belonging to nine different species of vascular plants with seeds of true mangroves were collected. Triterpenoids, phenolics, and tannins were the main groups of compounds found in the sampled mangroves. Saponins, quinones, and coumarins were found in less than 50%of the samples. Laguncularia racemosa showed moderate activity against Plasmodium falciparum. None of the extracts presented anticancer activity. Rhizophora mangle exhibited potent activity against Staphylococcus aureus and Bacillus subtilis [(90.41 ±7.33)% and(96.02±6.14)% of inhibition]; Avicennia germinans and Conocarpus erectus had activity against Escherichia coli[(71.17±6.15)% and(60.60±5. 13)% of inhibition,respectively]. About 60% of the mangroves showed α-glucosidase inhibitory activity. In particular, extracts from Laguncularia racemosa, Pelliciera rhizophorae, Conocarpus erectus, Mora oleifera, and Tabebuia palustris species showed α-glucosidase inhibitory potential, with IC_(50) values of(29.45±0.29),(20.60±0.70),(730.06±3.74),(25.59±0.37), and(853.39±5.30) μg/mL, respectively. Conclusions: Panamanian mangroves are mainly a promising potential source of hypoglycemic compounds, specifically α-glucosidase inhibitors.These results highlight the therapeutic virtues of extracts from American mangrove plants.

A New Method of Construction of Robust Second Order Slope Rotatable Designs Using Pairwise Balanced Designs

The following article has been retracted due to the investigation of complaints received against it. Title: A New Method of Construction of Robust Second Order Slope Rotatable Designs Using Pairwise Balanced Designs. Authors: Bejjam Re. Victorbabu, Kottapalli Rajyalakshmi.The paper is a copy of Dr. Rabindra Nath Das’s former article, entitled “Slope rotatability with correlated errors (Vol. 54, pp. 57-70, 2003)” and “Robust second order rotatable designs (Part I)”. The scientific community takes a very strong view on this matter and we treat all unethical behavior such as plagiarism seriously. This paper published in OJSVol.2 No.3, 319-327, 2012, has been removed from this site.

Spectrophotometric Determination of Etravirine in Bulk and Pharmaceutical Formulations

Two simple, rapid, sensitive, accurate, precise and economical Visible Spectrophotometric methods have been developed for the determination of Etravirine in pure and pharmaceutical formulations. These methods (A and B) were based on nucleophilic substitution and oxidative coupling reactions of Etravirine by 1,2-naphtha quinone-4-sulphonate (NQS) in alkaline medium and 3-methyl-2-benzothiazolinone hydrazone (MBTH) in acidic medium with the maximum absorbance at 414 nm and 635 nm respectively. Linearity was obtained in the concentration range of 5 -30 μg/ml and 2 -10 μg/ml which was corroborated by the correlation coefficient (r) values of 0.9995 and 0.9996 respectively. The methods developed were validated with respect to linearity, accuracy (recovery), precision, Sandell’s sensitivity, molar extinction coefficient and specificity. The proposed methods are successfully applied for the determination of Etravirine in bulk and pharmaceutical formulations and results were validated statistically by recovery studies.

Nano-γ-Fe₂O₃: Efficient, Reusable and Green Catalyst for <i>N</i>-<i>tert</i>-Butoxycarbonylation of Amines in Water

An efficient and versatile practical protocol for the chemoselective N-tert-butoxycarbonylation of amines using Nano-γ-Fe2O3 and (BOC)2O. Nano-γ-Fe2O3 was applied as an efficient, green, heterogeneous and reusable catalyst at ambient temperature;the method is general for the preparation of N-Boc derivatives of aliphatic, heterocyclic, aromatic as well as amino acid derivatives.

Development and Validation of Stability Indicating RP-LC Method for Estimation of Ranolazine in Bulk and Its Pharmaceutical Formulations

An isocratic reverse phase liquid chromatography (RP-LC) method has been developed and subsequently validated for the determination of Ranolazine in Bulk and its pharmaceutical formulation. Separation was achieved with a X-terra RP-18 ((Make: Waters Corporation;150 mm × 4.6 mm I.D.;particle size 5 μm)) Column and Sodium di-hydrogen phosphate monohydrate buffer with Tri ethyl amine (pH adjusted to 5.0 with diluted orthophosphoric acid): Acetonitrile (600:400) v/v as eluent at a flow rate of 1.0 mL/min. UV detection was performed at 225 nm. The method is simple, rapid, and selective. The described method of Ranolazine is linear over a range of 11.98 μg/mL to 37.92 μg/mL. The method precision for the determination of assay was below 1.0%RSD. The percentage recoveries of active pharmaceutical ingredient (API) from dosage forms ranged from 99.1% to 100.9%. The results showed that the proposed method is suitable for the precise, accurate and rapid determination of Ranolazine in bulk, its capsule dosage forms.

Facile and Efficient Method for Synthesis of Benzimidazole Derivatives Catalyzed by Zinc Triflate

We report the synthesis of benzimidazole derivatives using zinc triflate as an efficient catalyst. One-pot synthesis of 2-substituted benzimidazole derivatives from o-phynelyenediamine and substituted aldehydes were developed under zinc triflate in ethanol solvent at reflux temperature.

Stability Indicating RP-UPLC Method for Assay of Emtricitabine and Tenofovir Disoproxil Fumarate in Bulk and Dosage Forms

A simple, sensitive and rapid stability indicating reverse phase ultra performance liquid chromatography (RP-UPLC) method was developed and validated for the determination of Emtricitabine (EMT) and Tenofovir disoproxil fumarate (TDF) in pure and tablet dosage forms. The chromatographic separation was achieved by using Waters (Alliance) UPLC system equipped with auto-sampler and photo diode array detector. A volume of 5 μL of standard or test was injected into the column and the components were separated by using the mixture of 0.68% potassium dihydrogen orthophosphate buffer of pH = 6 and methanol in the ratio 45:55 v/v as mobile phase at a flow rate of 1.2 mL/min through BEH C18 (100 mm × 2.1, 1.8 μm) at ambient temperature and were detected at a wavelength of 261 nm. System suitable parameters such as plate count and tailing factor for EMT and TDF were found to be 2427 & 3685, 1.16 & 1.23 respectively, and resolution between EMT and TDF peaks was found to be 3.12. The chromatographic parameters like retention time, peak area and peak height of EMT and TDF were found to be 0.684 & 0.930, 694,200 & 8,778,000 and 272,881 & 3685 respectively. Percent of assay of EMT and TDF in bulk and dosage forms was determined and found to be 101.48 and 103.22 respectively. Study of degradation was examined and found that the drugs were stable under degradation conditions. The present method was developed keeping the principles of green chemistry by using eco-friendly solvent methanol in mobile phase. The developed method was found to be simple, rapid and applied for the analysis of Truvada;therefore the proposed method is recommended for the analysis of EMT and TDF in pure and tablet dosage forms in any quality control laboratories.

Determination of Phase Transitions of <i>p</i>,<i>n</i>-Alkyloxy Benzoic Acid Mesogens Using Legendre Moments and Image Analysis

Phase transition temperatures of p,n-alkyloxy benzoic acids (nOBA, n = 3 to 10 and 12) are investigated basing on the textural image analysis of liquid crystal. The analysis is carried out by the computation of Legendre moments. Textures of the homeotropically aligned compounds are recorded as a function of temperature using POM in arthroscopic mode attached to the hot stage and high resolution camera. A recurrence formula is used to compute the liquid crystal textures based on Legendre polynomial. The discontinuities and fluctuations in the values of Legendre moments as a function of temperature are related to the phase transition temperatures of the sample. This method is successful in conforming or detecting the phase transition temperatures and the present findings are comparable with literature.

Magnetic and Electrical Properties of Gd Doped Ni-Cu-Zn-Fe₂O₄

Ni0.5Cu0.25Zn0.25GdxFe2-xO4 (x = 0.0, 0.025, 0.05, 0.075, 0.1) ferrites were synthesized using an oxalic-based precursor method. The TC for all the Ni0.5Cu0.25Zn0.25GdxFe2-xO4 (x = 0.0, 0.025, 0.05, 0.075, 0.1) samples was measured by using one of the double coil susceptibility setup. In all the samples it is observed that, at a certain temperature, susceptibility falls to zero indicating the Curie temperature (TC) and ferrimagnetic samples are converted into paramagnetic sample at that temperature. The electrical properties were investigated for these samples. Dielectric properties and ρdc properties were observed to decrease with the increase in the frequency for all the Gd doped ferrite samples.