Polarized Lidar Reflectance Measurements of Vegetation at Near-Infrared and Green Wavelengths

There is growing interest in the use of lidar for remote sensing of vegetation owing to the emergence of reliable and rugged lasers and highly sensitive detectors. Lidar remote sensing has a distinct advantage over conventional techniques in vegetation remote sensing due to its capability for three-dimensional characterization of vegetative targets. The Multiwavelength Airborne Polarimetric Lidar (MAPL) system was developed primarily for vegetation remote sensing applications from an airborne platform of up to 1,000 -m altitude. The lidar system has full waveform capture and polarimetric measurement capability at two wavelengths in the near-infrared (1064 nm) and the green (532 nm) spectral regions. This study presents preliminary ground-based lidar reflectance measurements on a variety of deciduous and coniferous trees under fully foliated conditions with a view towards tree species discrimination. Variations in the reflectance characteristics of selected deciduous trees under unfoliated and fully foliated conditions were also investigated. Our study reveals distinct differences in the reflectance characteristics of various trees.     

A novel supramolecular assembly of 3,5-dinitro-4-methylbenzoic acid and trans-1,2-bis(4-pyridyl)ethene

A novel organic assembly, formed between 3,5-dinitro-4-methylbenzoic acid and trans-1,2-bis(4-pyridyl)ethene under hydrothermal conditions in the presence of Pr(III) and a layered structure obtained by direct co-crystallization of the reactants at ambient conditions is reported. The structures of the complexes were established, unambiguously, by single crystal X-ray diffraction methods.     

Thermal degradation behavior of radiation synthesized polydiallyldimethylammonium chloride

Thermogravimetric analysis (TGA) and differential scanning calorimetric (DSC) studies were carried out on gamma radiation synthesized polydiallyldimethylammonium chloride (PDADMAC). The polymer was found to undergo thermal degradation in two stages. The first stage showed a weight loss of 33% and the second stage showed a weight loss of 67%. The DSC thermogram shows two endothermic peaks corresponding to the two stages in the TG thermogram and the experimental enthalpy change associated with the first and second stages were 650 J g⁻¹ and 129.5 J g⁻¹, respectively. The nth-order kinetic parameters (order of the reaction, activation energy and the pre-exponential factor) were determined from a single dynamic DSC or thermogravimetric (TG) thermogram by the method of least square. Theoretical TG/differential thermogravimetric (DTG) and DSC thermograms derived from the calculated kinetic parameters were in good agreement with the experimental ones at the heating rate employed. However, the kinetic parameters determined using TG and DSC were different. This leads to the conclusion that the degradation mechanism could be complicated and may consists of a number of parallel or consecutive reactions. The glass transition temperature (T_g) of the polymer was found to be around 150 °C depending on the test method employed.     

Production and Purification of Pectinase from Bacillus subtilis 15A-B92 and Its Biotechnological Applications

Enzymes that degrade pectin are called pectinases. Pectinases of microbial origin are used in juice clarification as the process is cost-effective. This study screened a pectinase-producing bacterium isolated from soil and identified as Bacillus subtilis 15A B-92 based on the 16S rRNA molecular technique. The purified pectinase from the isolate showed 99.6 U/mg specific activity and 11.6-fold purity. The molecular weight of the purified bacterial pectinase was 14.41 ± 1 kD. Optimum pectinase activity was found at pH 4.5 and 50 °C, and the enzyme was 100% stable for 3.5 h in these conditions. No enzymatic inhibition or activation effect was seen with Fe²⁺, Ca²⁺, or Mg²⁺. However, a slight inhibition was seen with Cu²⁺, Mn²⁺, and Zn²⁺. Tween 20 and 80 slightly inhibited the pectinase, whereas iodoacetic acid (IAA), ethylenediaminetetraacetate (EDTA), urea, and sodium dodecyl sulfate (SDS) showed potent inhibition. The bacterial pectinase degraded citrus pectin (100%); however, it was inactive in the presence of galactose. With citrus pectin as the substrate, the Km and Vmax were calculated as 1.72 mg/mL and 1609 U/g, respectively. The high affinity of pectinase for its substrate makes the process cost-effective when utilized in food industries. The obtained pectinase was able to clarify orange and apple juices, justifying its application in the food industry.     

A validated HPLC‐PDA method for identification and quantification of two bioactive alkaloids,ephedrine and cryptolepine,in different Sida species

A simple, rapid, accurate and reproducible reverse‐phase HPLC method has been developed for the identification and quantification of two alkaloids ephedrine and cryptolepine in different extracts of Sida species using photodiode array detection. Baseline separation of the two alkaloids was achieved on a Waters RP‐18 X‐terra column (250 × 4.6 mm, 5 µm) using a solvent system consisting of a mixture of water containing 0.1% Trifluoroacetic acid (TFA) and acetonitrile in a gradient elution mode with detection at 210 and 280 nm for ephedrine and cryptolepine, respectively. The calibration curves were linear in a concentration range of 10–250 µg/mL for both the alkaloids with correlation coefficient values >0.99. The limits of detection and quantification for ephedrine and cryptolepine were 5 and 10 µg/mL and 2.5 and 5 µg/mL, respectively. Relative standard deviation values for intra‐day and inter‐day precision were 1.22 and 1.04% for ephedrine and 1.71 and 2.06% for cryptolepine, respectively. Analytical recovery ranged from 92.46 to 103.95%. The developed HPLC method was applied to identify and quantify ephedrine and cryptolepine in different extracts of Sida species. Copyright © 2013 John Wiley & Sons, Ltd.     

Micron Particles of AlN/Al: Efficient,Novel, and Reusable Heterogeneous Catalyst for the Synthesis of Bis(indolyl)methanes

The present work introduces for the first time the catalytic utility of micron particulate aluminium nitride (AlN/Al) as a novel and reusable heterogeneous catalyst for the synthesis of bis(indolyl)methanes involving the electrophilic substitution of indoles on aldehydes. The catalyst is recyclable and works without any significant change in its catalytic activity.     

Stopping and time reversing a light pulse using dynamic loss tuning of coupled-resonator delay lines

We introduce a light-stopping process that uses dynamic loss tuning in coupled-resonator delay lines. We demonstrate via numerical simulations that increasing the loss of selected resonators traps light in a zero group velocity mode concentrated in the low-loss portions of the delay line. The large dynamic range achievable for loss modulation should increase the light-stopping bandwidth relative to previous approaches based on refractive index tuning.     

Iodine-DMSO catalyzed chemoselective oxidative aromatization and deallylation,nondeallylation of aryl allyl ether of tetrahydro-β-carboline

We have developed a simple method for the chemoselective aromatization of tetrahydro-β-carboline with selective nondeallylation O-allyl groups in the presence of iodine (100 mol %) in dimethyl sulfoxide/H₂O₂. A convergent approach toward the oxidative aromatization with selective deallylation (deprotection) of O-allyl-tetrahydro-β-carboline using iodine in dimethyl sulfoxide/HCl has been described. The present protocol contains cheap catalyst, easy work up, normal reaction conditions, and high selectivity.     

Effect of precursor pH on structural,magnetic and catalytic properties of CoFe2O4@SiO2 green nanocatalyst

Research on Chemical Intermediates - Cobalt ferrite is a promising material for many therapeutic applications, photo-catalysis, gas detectors, high-density data storage, etc. Optimization of...