Synthesis of Novel Symmetric Porphyrin Schiff Base Dimers by Solid–Liquid Reaction Methodology

A new convenient solid–liquid condensation reaction procedure for the synthesis of novel asymmetric and symmetric meso‐tetraarylporphyrin and metalloporphyrin Schiff bases is reported. The condensation reaction between β‐formyl porphyrin or metalloporphyrins and aromatic amines was carried out at solid–liquid interface by using neutral alumina powder as a solid support for β‐formyl porphyrin or metalloporphyrins and absolute ethanol as the carrier solvent for aromatic amines. Six different asymmetric porphyrin/metalloporphyrin Schiff bases were synthesized via solid–liquid interface reaction methodology. The same solid–liquid synthetic methodology was applied for the synthesis of six novel symmetric Schiff base porphyrin/metalloporphyrin dimers. The comparison of UV–visible spectra of porphyrin Schiff base monomers and dimers revealed that some degree of electronic perturbation has occurred upon dimerization as the Soret bands of the monomers underwent peak broadening along with red shifts. Column chromatography and crystallization were used to purify the compounds. Fourier transform infrared, UV–visible, elemental analysis, ¹H NMR, and mass spectrometry were used to characterize the newly synthesized compounds.     

Optical soliton perturbation with full nonlinearity by extended trial function method

The extended trial function scheme is applied to retrieve soliton solutions to the perturbed nonlinear Schrödinger’s equation with ten forms of fiber nonlinearity. Bright, dark and singular soliton solutions are retrieved that appear with their respective existence criteria. Some additional forms of nonlinear waves naturally emerge as a byproduct of the integration scheme.     

Optimizing Image Reconstruction in SENSE Using GPU

Parallel magnetic resonance imaging (MRI) (pMRI) uses multiple receiver coils to reduce the MRI scan time. To accelerate the data acquisition process in MRI, less amount of data is acquired from the scanner which leads to artifacts in the reconstructed images. SENSitivity Encoding (SENSE) is a reconstruction algorithm in pMRI to remove aliasing artifacts from the undersampled multi coil data and recovers fully sampled images. The main limitation of SENSE is computing inverse of the encoding matrix. This work proposes the inversion of encoding matrix using Jacobi singular value decomposition (SVD) algorithm for image reconstruction on GPUs to accelerate the reconstruction process. The performance of Jacobi SVD is compared with Gauss–Jordan algorithm. The simulations are performed on two datasets (brain and cardiac) with acceleration factors 2, 4, 6 and 8. The results show that the graphics processing unit (GPU) provides a speed up to 21.6 times as compared to CPU reconstruction. Jacobi SVD algorithm performs better in terms of acceleration in reconstructions on GPUs as compared to Gauss–Jordan method. The proposed algorithm is suitable for any number of coils and acceleration factors for SENSE reconstruction on real time processing systems.     

Ultrasound-Assisted Extraction of Carotenoids from Carrot Pomace and Their Optimization through Response Surface Methodology

Ultrasound-assisted extraction (UAE) was used to extract carotenoids from the carrot pomace. To investigate the effect of independent variables on the UAE, the response surface methodology (RSM) with central-composite design (CCD) was employed. The study was conducted with three independent variables including extraction time (min), temperature (°C), and ethanol concentration (%). The results showed that the optimal conditions for UAE were achieved with an extraction time of 17 min, temperature of 32 °C, and ethanol concentration of 51% of total carotenoids (31.82 ± 0.55); extraction time of 16 min, temperature of 29 °C, and ethanol concentration of 59% for a combination of β-carotene (14.89 ± 0.40), lutein (5.77 ± 0.19), and lycopene (2.65 ± 0.12). The non-significant (p > 0.05) correlation under optimal extraction conditions between predicted and experimental values suggested that UAE is the more productive process than conventional techniques for the extraction of carotenoids from the carrot pomace.     

A comparative study of interaction of ibuprofen with biocompatible polymers

In this paper we are reporting the interaction of a non-steroidal anti-inflammatory drug ibuprofen (IBF) with various biocompatible polymers. Being amphiphilic, the drug interacts with the polymers similar to the interaction of surfactants and polymers. Therefore, we have considered the polymer-amphiphile interaction approach using conductimetry. The polymers of different charges (cationic, anionic, and nonionic) have been taken for the study. It was found that the critical aggregation concentration (cac) decreases on increasing the polymer concentrations of cationic as well as nonionic polymers whereas it increases for anionic polymers. The results imply that anionic IBF interacts with cationic and nonionic polymers more strongly as compared to the anionic polymers. A possible anionic-anionic repulsion is responsible for the weak interaction of IBF with anionic polymers. On the other side, the critical micelle concentration (cmc) increases for all polymers which is a usual indication of the interaction between amphiphiles and polymers. Free energies of aggregation (ΔG_agg) and micellization (ΔG_mic) were also computed with the help of degrees of micelle ionization obtained from the specific conductivity - [IBF] isotherms.     

A Comparative Study on Hemp (Cannabis sativa)Essential Oil Extraction Using Traditional and Advanced Techniques

A comparative study of Cannabis sativa(Hemp)essential constituents obtained by using Supercritical Fluid Extraction(SCFE),Steam Distillation(SD)and Hydrodistillation(HD)is presented here.The optimized extraction temperatures were 130,110and 50℃for hydrodistillation,steam distillation and supercritical fluid extraction respectively.The essential oil of C.sativa was analyzed by using Gas chromatography mass spectrometry(GC-MS).A total of 33,30and 31components have been identified in HD,SD and SCFE respectively.Yield of essential oil using SCFE(0.039%)was more than HD(0.025%)and SD(0.035%)extraction respectively.The main component of sesquiterpenes obtained by hydrodistillation at 130℃with their percentages included caryophyllene(40.58%),trans-α-bergamotene(5.41%),humulene(10.97%),cis-β-farnesene(8.53%)and monoterpenes includedα-pinene(2.13%),d-limonene(6.46%),p-cymol(0.65%)and cineole(2.58%)respectively.The main component of sesquiterpenes obtained by SD steam distillation at110℃including caryophyllene(38.60%)trans-α-bergamotene(4.22%),humulene(10.26%),cis-β-farnesene(6.67%)and monoterpenes includedα-pinene(3.21%),d-limonene(7.07%),p-cymol(2.59%)and cineole(3.88%)whereas the more percentages of major components were obtained by SCFE at 50℃included caryophyllene(44.31%),trans-α-bergamotene(6.79%),humulene(11.97%)cis-β-farnesene(9.71%)and monoterpenes includedα-pinene(0.45%),d-limonene(2.13%)p-cymol(0.19%)and cineole(1.38%)respectively.We found yield/efficiency,chemical composition,quality of the essential oils by supercritical fluid extraction superior in terms of modern,green,saving energy and a rapid approach as compared to traditional techniques.     

TsOH-SiO2 as an efficient and eco-friendly catalyst for Knoevenagel condensation

Tosic acid on silica gel (TsOH-SiO₂) was synthesized and characterized using microscopic and spectroscopic techniques such as powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and FT-IR spectroscopy. Thermal behaviour of the catalyst was investigated by differential scanning calorimetry (DSC) and thermogravimetric (TG) analysis. TsOH-SiO₂ showed excellent catalytic activity for the Knoevenagel condensation and was recyclable for six cycles.     

Is hairpin formation in single-stranded polynucleotide diffusion-controlled?

An intriguing puzzle in biopolymer science is the observation that single-stranded DNA and RNA oligomers form hairpin structures on time scales of tens of microseconds, considerably slower than the estimated time for loop formation for a semiflexible polymer of similar length. To address the origin of the slow kinetics and to determine whether hairpin dynamics are diffusion-controlled, the effect of solvent viscosity (eta) on hairpin kinetics was investigated using laser temperature-jump techniques. The viscosity was varied by addition of glycerol, which significantly destabilizes hairpins. A previous study on the viscosity dependence of hairpin dynamics, in which all the changes in the measured rates were attributed to a change in solvent viscosity, reported an apparent scaling of relaxation times (tau(r)) on eta as tau(r) approximately eta(0.8). In this study, we demonstrate that if the effect of viscosity on the measured rates is not deconvoluted from the inevitable effect of change in stability, then separation of tau(r) into opening (tau(o)) and closing (tau(c)) times yields erroneous behavior, with different values (and opposite signs) of the apparent scaling exponents, tau(o) approximately eta(-0.4) and tau(c) approximately eta(1.5). Under isostability conditions, obtained by varying the temperature to compensate for the destabilizing effect of glycerol, both tau(o) and tau(c) scale as approximately eta(1.1+/-0.1). Thus, hairpin dynamics are strongly coupled to solvent viscosity, indicating that diffusion of the polynucleotide chain through the solvent is involved in the rate-determining step.     

Purification and characterization of Taxol and 10-Deacetyl baccatin III from the bark,needles, and endophytes of Taxus baccata by preparative high-performance liquid chromatography,ultra-high-performance liquid chromatography-mass spectrometry,and nuclear magnetic resonance

Taxol and 10-Deacetyl baccatin III are major taxanes in the bark, needles, and endophytes of Taxus baccata. The current study aimed to develop a process for their separation from different matrices. Crude taxoid was prepared by extraction of samples with methanol, followed by partitioning with dichloromethane and precipitation with hexane. Analytical high-performance liquid chromatography involved isocratic elution on C18 column (4.6 × 250 mm, 5 μm) with methanol-water (70:30 v/v) at a flow rate of 1 ml/min. Injection volume was 20 μl and detection was carried out at 227 nm. The content of Taxol and 10-Deacetyl baccatin III in bark, needles and endophytic culture broth was 11.19 and 1.75 μg/mg; 11.19 and 1.75 μg/mg; and 2.80 and 0.22 μg/L, respectively. Preparative high-performance liquid chromatography was done on C18 column (10 × 250 mm, 5 μm) at a flow rate of 10 ml/min. About 20 g crude taxoid was processed in < 3 h with a recovery of about 90% for both the analytes. The purity of recovered Taxol and 10-Deacetyl baccatin III determined by ultra-high-performance liquid chromatography-mass spectrometry was found to be 95.78 ± 3.63% and 99.72 ± 0.18%, respectively. The structure of recovered Taxol was confirmed by nuclear magnetic resonance. The method can find use in biotransformation studies.