Fourier Transform Infrared Spectroscopy Data Research Articles

Brassinosteroid improves lipid productivity and stress tolerance of Chlorella cells induced by high temperature

The application of exogenous brassinosteroids (BRs) against high-temperature stress in algae is poorly studied. The present work aims to assess the function of 2,4-epibrassinolide (EBL) on lipid production during the stress phase of Chlorella vulgaris cultivation induced by high temperature. The maximum growth rate was reached by the treatment with EBL at the optimum temperature of 25 °C, while the highest lipid content was obtained by the treatment with EBL at 30 °C, indicating that EBL significantly increases the lipid content of algae subjected to the stress induced by high temperature. Therefore, the maximum lipid productivity was obtained by cells in the media with EBL under optimum temperature (25 °C). The application of Fourier transform infrared spectroscopy (FTIR) in this work demonstrated that this technique can effectively and rapidly determine the changes in lipid and carbohydrate. Principal component analysis (PCA) can provide a full view of multivariate shift of cell compositions (i.e., lipids, carbohydrates, and proteins), which is much faster than individual band comparison. Based on FTIR data and PCA analysis, we successfully demonstrated that overall composition changes in algal cell, including lipid, protein, and carbohydrate, in response to the assimilation of high temperature and plant hormones.

Comparative adsorption of amylase, protease and lipase on ZnFe2O4: kinetics, isothermal and thermodynamics studies.

The role of enzyme engineering in biotechnology, biological and pharmaceutical process cannot be over emphasized. This study compared the adsorption of digestives enzymes; amylase, protease and lipase on to Zn-ferrite (ZnFe2O4). The metal ferrite was synthesized via a sol-gel technique and characterized with scanning electron microscopy (SEM), X-ray diffraction (XRD), Electron paramagnetic resonance (EPR) and Fourier transform infrared spectroscopy (FTIR). The adsorption was studied in a batch process and the data were subjected to kinetics and isotherm models. Characterization shows that the particle has a nanoporous structure, with pore sizes of about 5.4nm and good magnetic properties. The FTIR data showed the presence of M-O bond, which is a characteristic of metal ferrites. The adsorption of the amylase, lipase and protease on ZnFe2O4 follow first-order kinetic model with rate constants increasing with concentration. The maximum adsorption capacities as revealed by the generalized adsorption isotherms are 7.20, 42.90 and 22.24mgg-1 for amylase, lipase and protease, respectively, with cooperative binding. The Dubinin-Radushkevich model gave the maximum adsorption energies, E of 3.74kJmol-1 for amylase, 2.01kJmol-1 for lipase and 1.51kJmol-1 for the protease adsorption, showing that the process is physisorption dominated. The isotherms fit the adsorption data in the order of Freundlinch>Generalized>Guggenheim-Anderson-de Boer>Tempkin isotherm>Dubinin-Radushkevich. Thermodynamic study revealed a spontaneous adsorption process with increased entropy. ZnFe2O4, therefore, is a very good adsorbent for the purification of enzymes and can be used as a supporter for enzymatic process that required immobilization of the enzymes.

Carbon Dot Assisted Synthesis of Nanostructured Polyaniline for Dye Sensitized Solar Cells

Herein, we have reported a facile method to synthesize surface passivated carbon dots (CDs) with high quantum yield. The structure and optical properties of the CDs are successfully investigated using high-resolution transmission electron microscopy; dynamic light scattering; and UV–vis, fluorescence, and Fourier transform infrared spectroscopy (FTIR). The synthesized CDs with excellent water solubility have been utilized to prepare nanostructured polyaniline (PANI) where CDs act both as a dopant as well as nucleating agent. The synthesis of PANI is achieved through a simple and one pot chemical oxidative polymerization. The UV–vis and FTIR data clearly indicates the formation of highly doped PANI (emeraldine salt form), which will really be helpful for fabricating photovoltaic device. We have examined the current–voltage characteristics of CD-PANI samples both in dark and illuminated state, which evidently designates the enhancement of current in the illuminated state. Hence, we have employed the CD-PANI samples for photovoltaic study, and the DSSCs are studied under illumination of 100 mW/cm2. Among the CD-PANI samples, CDPA10 shows a maximum power conversion efficiency of 3.65%.

Rice Husk Ash Modified with Vanadium Pentoxide

Rice husk collected in Barreiras City, Bahia, Brazil was converted to rice husk ash (RHA) by acidic or basic leaching, followed by calcination. The resulting RHA was modified with vanadium pentoxide (2, 5, or 10 mass% of V 2 O 5 ). The modified RHA samples were characterized by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). RHA exhibited FTIR bands associated with silica. After modification of acid-leached RHA with vanadium, the XRD data indicated the formation of V 2 O 5 phases. Base-leached RHA modified with vanadium pentoxide showed the presence of the V 2 O 5 phase only in the sample containing 10 mass% V 2 O 5 . The FTIR data indicated the formation of cristobalite, where bands associated with Si-O-V interactions were observed only for the sample with 10 mass% V 2 O 5 prepared with acid-leached RHA. DOI: http://dx.doi.org/10.17807/orbital.v9i2.916

Neem extract as a green inhibitor for microbiologically influenced corrosion of carbon steel API 5LX in a hypersaline environments

In this study, the efficiency of neem extract to inhibit the corrosion of carbon steel API 5LX in the presence of different bacterial strains (Bacillus subtilis A1, Streptomyces parvus B7, Pseudomonas stutzeri NA3 and Acinetobacter baumannii MN3) were evaluated. 150ppm of Azadirachta indica leave extract (AILE) was identified as minimal inhibitory concentration for the bacterial strains B. subtilis A1, S. parvus B7, P. stutzeri NA3 and A. baumannii MN3. Weight loss, electrochemical studies including potential measurements, potentiodynamic polarization and impedance and surface analysis includes Fourier transform infrared spectroscopy (FT-IR) were used to examine the corrosion inhibition efficiency (IE) of AILE on carbon steel API 5LX. The individual bacterial strains and mixed consortium had showed severe corrosion of carbon steel API 5LX in hypersaline environment. In contrast with AILE, the IE of abiotic control and mixed consortia were about 81% and 72% respectively. The corrosion rate was observed as increased trends in presence of all bacterial strains (0.179mm/y) when compared to abiotic system with AILE system (0.012mm/y). X-ray diffraction spectroscopy (XRD) confirms that all bacterial strains has accelerates the corrosion by the production of higher intensity peaks of corrosion products when compared to AILE systems. FT-IR data reveals that AILE extracts consists of azadirachtin and other phytochemical compound which was play a key role in control of bacterial biofilm on metal surface and thus leads to inhibit corrosion process. This is the first report on the application of AILE as a natural, eco-friendly corrosion inhibitor with antibacterial activities to control microbiologically influenced corrosion in hypersaline environment of oil reservoir.

Spectroscopic Investigation of the Formation and Disruption of Hydrogen Bonds in Pharmaceutical Semicrystalline Dispersions

We recently found that indomethacin (IMC) can effectively act as a powerful crystallization inhibitor for polyethylene glycol 6000 (PEG) despite the fact that the absence of interactions between the drug and the carrier in the solid state was reported in the literature. However, in the present study, we investigate the possibility of drug-carrier interactions in the liquid state to explain the polymer crystallization inhibition effect of IMC. We also aim to discover other potential PEG crystallization inhibitors. Drug-carrier interactions in both liquid and solid state are characterized by variable temperature Fourier transform infrared spectroscopy (FTIR) and cross-polarization magic angle spinning 13C nuclear magnetic resonance spectroscopy (CP/MAS NMR). In the liquid state, FTIR data show evidence of the breaking of hydrogen bonding between IMC molecules to form interactions of the IMC monomer with PEG. The drug-carrier interactions are disrupted upon storage and polymer crystallization, resulting in segregation of IMC from PEG crystals that can be observed under polarized light microscopy. This process is further confirmed by 13C NMR since in the liquid state, when the IMC/PEG monomer units ratio is below 2:1, IMC signals are undetectable because of the loss of cross-polarization efficiency in the mobile IMC molecules upon attachment to PEG chains via hydrogen bonding. This suggests that each ether oxygen of the PEG unit can form hydrogen bonds with two IMC molecules. The NMR spectrum of IMC shows no change in solid dispersions with PEG upon storage, indicating the absence of interactions in the solid state, hence confirming previous studies. The drug-carrier interactions in the liquid state elucidate the crystallization inhibition effect of IMC on PEG as well as other semicrystalline polymers such as poloxamer and Gelucire. However, hydrogen bonding is a necessary but apparently not a sufficient condition for the polymer crystallization inhibition. Screening of crystallization inhibitors of semicrystalline polymers discovers numerous candidates that exhibit the same behavior as IMC, demonstrating a general pattern of polymer crystallization inhibition rather than a particular case. Furthermore, the crystallization inhibition effect of drugs on PEG is independent of the carrier molecular weight. These mechanistic findings on the formation and disruption of hydrogen bonds in semicrystalline dispersions can be extended to amorphous dispersions and are of significant importance for preparation of solid dispersions with consistent and reproducible physicochemical properties.

Microarc oxidation discharge types and bio properties of the coating synthesized on zirconium

This study is an attempt for gaining a better understanding on relationship between microarc oxidation (MAO) coating discharge types and bioactivity of an oxide-based coating synthesized on a Zr substrate. The discharge types and the coating growth mechanism were identified by the examination of the real cross-section image of the coating microstructure. The coating was conducted by using MAO in an electrolyte containing Na2SiO3, Ca(CH3COO)2 and C3H7Na2O6P, for different durations of 2.5, 5, 15, and 30mins. The effect of the process duration on the different discharge model types (Type-A, B, and C) and bioactivity of the coatings were investigated by using X-ray Diffractometry (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy-Energy-Dispersive X-ray spectroscopy measurements (SEM-EDS) and Optical Surface Profilometry (OSP). It was found that the increasing MAO duration resulted in thicker and rougher coatings. The XRD data revealed that all the samples prepared at different process durations contained the t-ZrO2 (tetragonal zirconia) phase. During the MAO process, non-crystalline hydroxyapatite (HA) formed, which was confirmed from the FTIR data. The surface morphology, the amount and distribution of the features of the coating surface were modified by increasing voltage. The simulated body fluid (SBF) tests showed that the more bioactive surface with more HA crystals formed owing to chemical composition and high surface roughness of the coating. The pore, crack and discharge structures played a key role in apatite nucleation and growth, and provided ingrowth of apatite into discharge channels on the coating surface.

Activity and Stability of Trypsin Immobilized onto Chitosan Magnetic Nanoparticles

The aim of this study was to develop a thermally and operationally stable trypsin through covalent immobilization onto chitosan magnetic nanoparticles (Fe3O4 @CTS). The successful preparation of the Fe3O4 @CTS nanoparticles was verified by Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and transmission electron microscopy (TEM), which indicated that the prepared Fe3O4 @CTS nanoparticles have superparamagnetic properties, with an average size of approximately 17 nm. Then, trypsin was covalently immobilized onto the Fe3O4 @CTS nanoparticles at a high loading capacity (149.25 mg/g). The FTIR data demonstrated that the trypsin had undergone a conformational change compared with free trypsin, and the Michaelis constant (Km) and the maximum hydrolysis reaction rate (Vmax) showed that the trypsin immobilized on the Fe3O4 @CTS had a lower affinity for BAEE and lower activity compared with free trypsin. However, the immobilized trypsin showed higher activity than free trypsin at pH 6.0 and in alkaline conditions and retained more than 84% of its initial activity at 60°C after 8 h incubation. Its excellent performance across a broader pH range and high thermal stability, as well as its effective hydrolysis of bovine serum albumin (BSA) and its reusability, make it more attractive than free trypsin for application in protein digestion.

Potassium Oleate as a Dissolution and Corrosion Inhibitor during Chemical Mechanical Planarization of Chemical Vapor Deposited Co Films for Interconnect Applications

1,2-4 Triazole (TAZ), N-lauroylsarcosine sodium salt (NLS) and potassium oleate (PO) were tested as passivating additives to previously developed H2O2 and citric acid-based silica dispersions for the polishing of chemical vapor deposited Co films for interconnect applications. In comparison to TAZ and NLS, Co corrosion currents are ∼1 to 2 order of magnitude lower (∼1–3 μA cm−2) at pH 7 with PO and post-polish surface quality was much better. The galvanic corrosion currents between Co-Ti and Ti-TiN couples with PO were also very low (∼0.1 μA cm−2), making the previously developed silica and citric acid-based dispersion, now containing PO, suitable for both bulk removal of Co (step I) and for planarizing Co/Ti/TiN structures (step II) with excellent selectivity while stopping on low-k dielectric. Langmuir adsorption isotherm model analysis showed that the standard free energies of adsorption values were ∼−40 kJ/mol for PO suggesting chemisorption. Fourier transform infra-red (FTIR) and attenuated FTIR spectroscopy data show bridging coordination between the carboxylate ligand of PO and the Co surface.

Dipentaerythritol penta-acrylate phosphate - an alternative phosphate ester monomer for bonding of methacrylates to zirconia.

The present work examined the effects of dipentaerythritol penta-acrylate phosphate (PENTA) as an alternative phosphate ester monomer for bonding of methacrylate-based resins to yttria-stabilized tetragonal zirconia polycrystals (Y-TZP) and further investigated the potential bonding mechanism involved. Shear bond strength testing was performed to evaluate the efficacy of experimental PENTA-containing primers (5, 10, 15, 20 or 30 wt% PENTA in acetone) in improving resin-Y-TZP bond strength. Bonding without the use of a PENTA-containing served as the negative control, and a Methacryloyloxidecyl dihydrogenphosphate(MDP)-containing primer was used as the positive control. Inductively coupled plasma-mass spectrometry (ICP-MS), X-ray photoelectron spectroscopy (XPS) and Fourier-transform infrared spectroscopy (FTIR) were used to investigate the potential existence of chemical affinity between PENTA and Y-TZP. Shear bond strengths were significant higher in the 15 and 20 wt% PENTA groups. The ICP-MS, XPS and FTIR data indicated that the P content on the Y-TZP surface increased as the concentration of PENTA increased in the experimental primers, via the formation of Zr–O–P bond. Taken together, the results attest that PENTA improves resin bonding of Y-TZP through chemical reaction with Y-TZP. Increasing the concentration of PENTA augments its binding affinity but not its bonding efficacy with zirconia.

Evaluation of folic acid release from spray dried powder particles of pectin-whey protein nano-capsules

Our main goal was to evaluate release kinetics of nano-encapsulated folic acid within a double W1/O/W2 emulsion. First, W1/O nano-emulsions loaded with folic acid were prepared and re-emulsified into an aqueous phase (W2) containing single whey protein concentrate (WPC) layer or double layer complex of WPC-pectin to form W1/O/W2 emulsions. Final double emulsions were spray dried and their microstructure was analyzed in terms of scanning electron microscopy (SEM), and Fourier Transform Infrared spectroscopy (FTIR). Also the release trends of folic acid were determined and fitted with experimental models of zero and first order, Higuchi, and Hixson-Crowell. It was revealed that folic acid nano-capsules made with Span as the surfactant had the lowest release rate in acidic conditions (pH=4) and highest release in the alkaline conditions (pH=11). The best model fitting for folic acid release data was observed for single layer WPC encapsulated powders with the highest R2. Our FTIR data showed there was no chemical interaction between WPC and pectin in double layered capsules and based on SEM results, single WPC layered capsules resulted in smooth and uniform particles which by incorporating pectin, some wrinkles and shrinkage were found in the surface of spray dried powder particles.

Unravelling the Binding Mechanism of a Poly(cationic) Anthracenyl Fluorescent Probe with High Affinity toward Double-Stranded DNA.

We report the synthesis, spectroscopy, and the DNA binding properties of a biocompatible, water-soluble, polycationic two-photon absorbing anthracenyl derivative (Ant-PIm) specifically designed for biorelated applications. Detailed insights into the Ant-PIm-DNA binding interaction are provided by using several spectroscopic approaches, including UV-vis absorption, circular dichroism (CD), Fourier-transform infrared spectroscopy (FTIR), steady-state, and time-resolved fluorescence techniques. Absorption and fluorescence quantitative data analysis show a strong Ant-PIm-duplex interaction with binding constants of Kf = 4.7 ± 0.2 × 105 M-1, 7.1 ± 0.3 × 105 M-1, and 1.0 ± 0.1 × 106 M-1 at 298, 304, and 310 K, respectively. Spectral changes observed upon DNA binding provide evidence for a complex formation with off-on fluorescence pattern, which can be related to two consecutive binding equilibria. Results of DNA binders displacement and iodide quenching experimental assays unambiguously point to the groove binding mode of Ant-PIm to the DNA-helicate. Thermodynamic and chemical denaturation studies suggest that long-range interactions of hydrophobic nature regulate the association of Ant-PIm with the biopolymer. The ionic strength dependence of the binding constant shows that electrostatic component has an important contribution to the overall Gibbs free energy. FTIR and CD data provide evidence of partial modification of the B-DNA secondary structure, while the increase in the melting temperature clearly indicates the enhancement of the thermal stability of the duplex. Furthermore, the two-photon absorption cross section spectrum determined using the two-photon excited fluorescence (TPEF) technique shows a strong 2PA maximum at 820 nm with a σ2 > 800 GM, which emphasizes the advantageous combination of biological and optical properties possessed by this positively charged bioprobe.

PREPARATION, SOLID STATE CHARACTERISATION OF PACLITAXEL AND NARINGEN COCRYSTALS WITH IMPROVED SOLUBILITY

Objective : The objective of the present study is to prepare a better form of paclitaxel cocrystal with improved solubility. Paclitaxel (PTX) is a class-4 drug; this drug has low aqueous solubility and high affinity for P-gp. Available formulation are IV based and using our research work with advantages of co-crystal technology towards the enhancement of paclitaxel solubility and thereby its bioavailability (1) and also to improve the patient compliance. Methods: Naringen was selected based on their chemical nature and its ability to inhibit P-gp, solvent assisted grinding method used to prepare the cocrystals, and prepared cocrystals were subjected to solid state characterization to determine the crystal structure of the cocrystals, as this can provide significant new insights into how the drug and coformer interact, and thereby provide an excellent crystal engineering guide to new cocrystals, potentially with improved properties. Instruments like Fourier transform infrared spectroscopy(FTIR), differential scanning calorimetry, X-ray powder diffraction will be used to determine their stability and any phase transformations (including decomposition) which they might undergo as a function of temperature. Results : Principle involved in the formation of cocrystal is hydrogen bonding between C=O and N-H group of drug and COOH groups of coformers, which is confirmed by FTIR data and DSC experiments were carried out to study the melting point and heat of enthalpy of the cocrystals. Results clearly shows that the melting point of the cocrystals was increased which confirms the formation of cocrystals. The drug and formation of cocrystals are explained by the X-ray powder diffraction patterns. The PXRD patterns of the pure drug showed sharp, well-defined peaks(spectrum attached) and cocrystals PXRD patterns shows that there is a significant difference in the entire diffraction pattern, changes in peak locations with respect to pure drug indicates a change in the arrangement of molecules, hence confirms the development of new crystalline phase. Conclusion: The results obtained from the above experiments clearly shows the formation of cocrystals with improved solubility.

Structural and magnetic properties of Mg doped cobalt ferrite nano particles prepared by sol-gel method

Effect of Mg doping on structural and magnetic properties of nano cobalt ferrites prepared via sol-gel auto-combustion method is reported. The sintered samples (Co1-xMgxFe2O4, where x=0.0, 0.2, 0.4, 0.6, 0.8 and 1.0) were characterized using X-ray diffraction, Raman spectroscopy, Fourier transform infrared (FTIR) spectroscopy and vibrating sample magnetometer. Rietveld refinement of X-ray diffraction spectra shows the single phase cubic structure (space group Fd3m) for the prepared samples. Raman spectroscopy reveals a doublet-like peak behavior in A1g and Eg modes arising due to different ionic radii of Co/Mg and Fe ions. Two prominent vibration frequencies in FTIR spectroscopy data also confirm the cubic spinel structure in the prepared samples. The magnetic parameters such as saturation magnetization, coercivity and remanence are studied with increasing the Mg-concentration in cobalt ferrite. Systematic changes in magnetic properties while going from x=0 to 1 are discussed.

In-situ lubricating oil condition sensoring method based on two-channel and differential dielectric spectroscopy combined with supervised hierarchical clustering analysis

In this article, the two-channel and differential dielectric spectroscopy (TD-DES) has been proposed and employed to obtain the dielectric submicroscopic phase (DSP) and heterogeneous characteristics of the lubricating oil system compared with the Fourier transform infrared spectroscopy (FT-IR) data. The hierarchical clustering analysis (HCA) results based on TD-DES data were well consistent with those based on the FT-IR data. The two phases including the DSP and heterogeneous characteristics of the lubricating oil system featured by TD-DES were the special with regard to the function-group characteristics expressed by FT-IR data, which proved that the TD-DES method was more effective and sensitive than FT-IR to monitor the lubricant systems condition during the early oxidation degradation. A new and qualitative oil condition monitoring technique based on TD-DES and supervised hierarchical clustering analysis (S-HCA) has been proposed, by means of which the in-service lubricating oil samples can be classified well-separately into six clusters: (1) the fresh stage (cluster F), (2) the initial oxidation stage (cluster A), (3) the moderate oxidation stage (cluster B), (4) the accelerated oxidation stage (cluster C), (5) the strong oxidation stage (cluster D), (6) the heterogeneous system stage (cluster E). The signal for an oil change need should be sent in the stage (5) and the lubricating oils in stage (6) could damage the engine. By the leave-one-out cross-validation (LOO CV), the 33 in-service lubricant samples were all clustered correctly, which proved that the TD-DES analysis method combined with S-HCA can provide significant oil change advice.

Calcium pyrophosphate powder derived from avian eggshell waste

Abstract Calcium pyrophosphate (CPP) was prepared by a simple precipitation method using avian eggshell waste as a low-cost alternative calcium precursor source. The synthesized CPP powder was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM/EDS), thermogravimetric analysis (TGA), and Fourier transform infrared spectroscopy (FTIR). The results indicate that pure β-CPP nanocrystallites (Ca/P = 1.067) were successfully synthesized from avian eggshell waste. The correlation among XRD, SEM/EDS, TGA, and FTIR data is well established. The β-CPP particle exhibited spherical morphology with average crystallite size of 62.3 nm, and can be an important bioceramic for medical applications.

Green synthesis of biocompatible silver nanoparticles mediated by Osmanthus fragrans extract in aqueous solution

A practical, convenient and green method for the synthesis of highly stable and small sized silver nanoparticles with narrow distribution from 2nm to 30nm is reported. Silver nitrate was used as silver precursor, and Osmanthus fragrans extract was acted as capping agent as well as reducing agent. The formation of silver nanoparticles was observed by the change of color from colorless to yellow. The as-prepared silver nanoparticles were characterized by scanning electron microscope (SEM), transmission electron microscopy (TEM), high resolution transmission electron microscopic (HRTEM), UV–vis spectroscopy (UV-vis), X-ray diffraction (XRD) and Fourier transform infra-red spectroscopic (FT-IR). The formation of silver nanoparticles was confirmed by its characteristic surface plasmon absorption peak at 400–450nm in UV–vis spectra. The TEM and SEM images showed that the as-synthesized silver fine spherical particles are distributed uniformly with a narrow distribution from 2nm to 30nm. The HRTEM and XRD results demonstrated that the obtained metallic nanoparticles were single crystalline silver nanoparticles. FT-IR data revealed that the silver nanoparticles are coated with Osmanthus fragrans extract. The effects of the silver nitrate and Osmanthus fragrans extract concentrations on the particle size were investigated. The green synthesis method is simple and may be extended to preparation of other noble metal nanoparticles.

ANTIOXIDANT ACTIVITY AND FT-IR ANALYSIS OF DATURA INNOXIA AND DATURA METEL LEAF AND SEED METHANOLIC EXTRACTS

Background:Datura (family- Solanaceae), has a long history of being used as herbal medicine. These medicinal effects have been attributed to the phytochemicals present in the plant leaves and seeds, in particular alkaloids, flavonoids and phenolic compounds. The objective of this study was to investigate the methanolic leaf and seed extracts of Datura innoxia (DLP-I & DSP-I) and Datura metel (DLP-M & DSP-M) for their total phenolic, flavonoids and in-vitro antioxidant properties.Materials and Methods:Determination of total phenolic content and total flavonoid content and antioxidant activity in terms of total antioxidant assay, ABTS assay, DPPH assay and in-vitro lipid peroxidation inhibiting activity were determined along with the FT-IR (Fourier transform infrared spectroscopy) analysis of the extracts.Results:The highest total phenolic and total flavonoid content were registered by the D. innoxia leaf extract (70.26 ±1.12 mg GAE/g and 34.24 ± 1.28 mg RE/g respectively). Maximum DPPH radical scavenging activity was exerted by the leaf extract of D. innoxia (IC50 = 146.69 ± 8.46 μg/mL) among the four different methanolic extracts. The highest activity of the ABTS assay was found in Datura innoxia leaf extract (IC50 value = 149.42 ± 13.43 μg/mL) and the highest total antioxidant capacity was found to be present in D. innoxia leaf extract (221.25 ± 1.06 mg AAE/g) whereas D. metel seed extract registered the maximum lipid peroxidation inhibition activity (IC50 = 112 ± 1.30 μg/mL). The FT-IR data also supported the maximum activity in D. innoxia (leaf and seed) extracts.Conclusion:The results thus obtained suggested that the plant Datura innoxia possess considerable antioxidant activity over Datura metel and therefore can be established as a potential source of natural antioxidant.

HCOOH distributions from IASI for 2008–2014: comparison with ground-based FTIR measurements and a global chemistry-transport model

Abstract. Formic acid (HCOOH) is one of the most abundant volatile organic compounds in the atmosphere. It is a major contributor to rain acidity in remote areas. There are, however, large uncertainties on the sources and sinks of HCOOH and therefore HCOOH is misrepresented by global chemistry-transport models. This work presents global distributions from 2008 to 2014 as derived from the measurements of the Infrared Atmospheric Sounding Interferometer (IASI), based on conversion factors between brightness temperature differences and representative retrieved total columns over seven regions: Northern Africa, southern Africa, Amazonia, Atlantic, Australia, Pacific, and Russia. The dependence of the measured HCOOH signal on the thermal contrast is taken into account in the conversion method. This conversion presents errors lower than 20 % for total columns ranging between 0.5 and 1 × 1016 molec cm−2 but reaches higher values, up to 78 %, for columns that are lower than 0.3 × 1016 molec cm−2. Signatures from biomass burning events are highlighted, such as in the Southern Hemisphere and in Russia, as well as biogenic emission sources, e.g., over the eastern USA. A comparison between 2008 and 2014 with ground-based Fourier transform infrared spectroscopy (FTIR) measurements obtained at four locations (Maido and Saint-Denis at La Réunion, Jungfraujoch, and Wollongong) is shown. Although IASI columns are found to correlate well with FTIR data, a large bias (> 100 %) is found over the two sites at La Réunion. A better agreement is found at Wollongong with a negligible bias. The comparison also highlights the difficulty of retrieving total columns from IASI measurements over mountainous regions such as Jungfraujoch. A comparison of the retrieved columns with the global chemistry-transport model IMAGESv2 is also presented, showing good representation of the seasonal and interannual cycles over America, Australia, Asia, and Siberia. A global model underestimation of the distribution and a misrepresentation of the seasonal cycle over India are also found. A small positive trend in the IASI columns is observed over Australia, Amazonia, and India over the 2008–2014 period (from 0.7 to 1.5 % year−1), while a decrease of ∼ 0.8 % year−1 is measured over Siberia.

Biodegradable date stones filler for enhancing mechanical, dynamic, and flame retardant properties of polyamide‐6 biocomposites

The need of using biodegradable fillers as polymer reinforcements instead of the polluting and hazard fillers has recently become a very important issue. Therefore, the aim of this study was the utilization of date stones (DS) as reinforcing and flame retardant biofiller in polyamide‐6 (PA6) with and without maleic anhydride‐grafted polypropylene (PP‐g‐MAH) compatibilizer. The composition of DS powder was revealed by X‐ray fluorescence (XRF) and chemical methods. Scanning electron microscopy images of biocomposites showed better compatibility of filler/polymer interface at 20 wt% DS and 5 wt% of the compatibilizer. Fourier transform infrared spectroscopy (FTIR) results confirmed our suggested reaction mechanism. The dynamic data showed satisfied enhancement in the storage modulus (E′) for maleated PA6 at 20 wt% DS filler. The tensile and impact strengths of the biocomposites enhanced for maleated PA6. The presence of the biofiller had no distinct effect on the thermal stability of the biocomposite. The flame retardant properties significantly improved with increasing DS filler content. The X‐ray diffraction and FTIR data revealed that the char layer acted as an insulating barrier to oxygen and heat transfer between the gas phase and the condensed phase thus reduced the heat release rate during the burning. POLYM. COMPOS., 39:1978–1987, 2018. © 2016 Society of Plastics Engineers