Determination of origin and sugars of citrus fruits using genetic algorithm, correspondence analysis and partial least square combined with fiber optic NIR spectroscopy

The capacity to confirm the variety or origin and the estimation of sucrose, glucose, fructose of the citrus fruits are major interests of citrus juice industry. A rapid classification and quantification technique was developed and validated for simultaneous and nondestructive quantifying the sugar constituent's concentrations and the origin of citrus fruits using Fourier Transform Near-Infrared (FT-NIR) spectroscopy in conjunction with Artificial Neural Network (ANN) using genetic algorithm, Chemometrics and Correspondences Analysis (CA). To acquire good classification accuracy and to present a wide range of concentration of sucrose, glucose and fructose, we have collected 22 different varieties of citrus fruits from the market during the entire season of citruses. FT-NIR spectra were recorded in the NIR region from 1,100 to 2,500 nm using the fiber optic probe and three types of data analysis were performed. Chemometrics analysis using Partial Least Squares (PLS) was performed in order to determine the concentration of individual sugars. Artificial Neural Network analysis was performed for classification, origin or variety identification of citrus fruits using genetic algorithm. Correspondence analysis was performed in order to visualize the relationship between the citrus fruits. To compute a PLS model based upon the reference values and to validate the developed method, high performance liquid chromatography (HPLC) was performed. Spectral range and the number of PLS factors were optimized for the lowest standard error of calibration (SEC), prediction (SEP) and correlation coefficient (R(2)). The calibration model developed was able to assess the sucrose, glucose and fructose contents in unknown citrus fruit up to an R(2) value of 0.996-0.998. Numbers of factors from F1 to F10 were optimized for correspondence analysis for relationship visualization of citrus fruits based on the output values of genetic algorithm. ANN and CA analysis showed excellent classification of citrus according to the variety to which they belong and well-classified citrus according to their origin. The technique has potential in rapid determination of sugars content and to identify different varieties and origins of citrus in citrus juice industry.     

Convex lattice polygons with all lattice points visible

Two lattice points are visible to one another if there exist no other lattice points on the line segment connecting them. In this paper we study convex lattice polygons that contain a lattice point such that all other lattice points in the polygon are visible from it. We completely classify such polygons, show that there are finitely many of lattice width greater than 2, and computationally enumerate them. As an application of this classification, we prove new obstructions to graphs arising as skeleta of tropical plane curves.     

Chemical composition of the essential oil from the flowering aerial parts of Bupleurum hamiltonii Balak from Uttarakhand, India

The essential oil from the flowering aerial parts of Bupleurum hamiltonii Balak syn. Bupleurum tenue family Apiaceae (Umbellifereae) was obtained by steam distillation and analysed by a combination of GC (RI) and GC-MS. The chemical composition of the isolated oil is reported here for the first time. Twenty-seven compounds were identified, which represent 92.7% of the total oil. The chemical composition of the isolated oil was characterised by a high proportion of sesquiterpene hydrocarbons (61.9%), among which germacrene-D (17.8%), trans-β-farnesene (14.7%) and β-caryophyllene (13.1%) were the predominant compounds. The monoterpene hydrocarbons (16.6%) represented the second major fraction of the same oil followed by the oxygenated sesquiterpenes (7.9%).     

Chemical markers in Origanum vulgare L. from Kumaon Himalayas: a chemosystematic study

The essential oils of four wild growing Origanum vulgare L. (family Lamiaceae) collected from different locations in Kumaon region (Uttarakhand, India) were analysed by capillary GC and GC/MS. The comparative results of O. vulgare L. collected from four different regions showed differences in the chemical constituents of the essential oils. The oil of O. vulgare L. collected from Dhoulchina and Champawat (chemotype I) shows p-cymene (6.7-9.8%), γ-terpinene (12.4-14.0%), thymol (29.7-35.1%) and carvacrol (12.4-20.9%) as major constituents while the oil from Kilbury and Rushi village (chemotype II) shows linalool (6.7-9.7%), bornyl acetate (12.6-16.8%), β-caryophyllene (10.5-13.8%) and germacrene D (6.3-11.3%) as the major constituents. These features highlight the chemosystematics of this genus.     

DFT study on the structure and detonation properties of amino,methyl, nitro,and nitroso substituted 3,4,5-trinitropyrazole-2-oxides: New high energy materials

The structure, band gap, thermodynamic properties and detonation properties of methyl, amino, nitro, and nitroso substituted 3,4,5-trinitropyrazole-2-oxides are explored using density functional theory at the B3LYP/aug-cc-pVDZ level. It is found that the NH₂ or CH₃ group substitution for the acidic proton at the N4 position of trinitropyrazole-2-oxide (P20) decreases the heat of detonation and crystal density. The density (2.20–2.50 g/cm³), detonation velocity (10.20–10.92 km/s), and detonation pressure (52.30–59.84 GPa) of the title compounds are higher compared with 1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX), 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (CL-20), and octanitrocubane (ONC).     

A DFT study on the structure‐property relationship of aminonitropyrazole‐2‐oxides

Density functional theory (DFT) calculations at the B3LYP/aug‐cc‐pVDZ level have been carried out to study the geometry and electronic structures, stability, sensitivity and band gap of the possible isomers of aminonitropyrazole‐2‐oxides. Kamlet‐Jacob equations were used to determine the performance properties of model compounds. The performance properties of model compounds P5, P18, P20, P21, P22, and P23 are higher compared with 2,4,6,8,10,12‐hexanitro‐2,4,6,8,10,12‐hexaazaisowurtzitane (CL‐20) and octanitrocubane (ONC). The heat of explosion, density, detonation velocity and detonation pressure are related to the number and positions of NO₂ and NH₂ groups in pyrazole‐2‐oxide. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2012     

Crystal structure and photoluminescence correlations in white emitting nanocrystalline ZrO2:Eu3+ phosphor: Effect of doping and annealing

White emitting nanocrystalline ZrO₂:Eu³⁺ phosphors were synthesized by a simple precipitation route without using a capping agent. X-ray diffraction (XRD) study of ZrO₂ and ZrO₂:Eu³⁺samples revealed the presence of monoclinic and tetragonal phases. The monoclinic phase increases with increase in the annealing temperature while the tetragonal phase increases with increase in the concentration of Eu³⁺. This can be attributed to the presence of oxygen vacancy evolved when Zr⁴⁺ is replaced by Eu³⁺. Photoluminescence (PL) emission peaks of Eu³⁺ are observed at 591, 596, 606 and 613 nm on monitoring excitation wavelengths at 250, 286, 394 and 470 nm. The peaks at 591 and 606 nm were found to correlate with the tetragonal phase and those at 596 and 613 nm with the monoclinic phase. Intensities of these peaks are found to change as the crystal structure changes. The lifetime value corresponding to 591 nm peak increases with Eu³⁺ concentration at a particular heating temperature indicating increase of tetragonal phase with respect to monoclinic phase. The CIE co-ordinates of the doped samples were found to be close to that of white color (0.33, 0.33). The changes in the crystal structure of the doped samples due to doping and annealing did not affect the white color emission.     

Novel Oxidative Coupling of 2-Naphthols to 1,1'-Bi-2-naphthols Catalysed by Solid Lewis Acids Using Atmospheric Oxygen as Oxidant

l,l'-Bi-2-naphthol derivatives have wide applications as chiral inducing agents for asymmetric synthesis.¹ There are many good methods for resolution of racemic binaphthols to give enantiomeric binaphthols.² Therefore, it is essential to established simple, convenient, economically and environmental-friendly methods for preparation of racemic l,l'-binaphthol derivatives. A number of methods have been developed for the oxidative coupling of 2-naphthols usually by using Fe³⁺, Cu²⁺ or Mn³⁺ as oxidants. The reaction were carried out in organic solvent,^3a in solid state^3b and in aqueous Fe³⁺ solution.^3c However, all those cases by employing excess, usually 2 equivalents of oxidant. The excess Fe³⁺, Cu²⁺ and the resulted Fe²⁺, Cu⁺ and HCl were not acceptable from a view point of environmental protection. Recently, Sakamoto et at⁴ and Kantam et at⁵ independently reported two catalytic oxidative coupling procedure for preparation of l,l'-binaphthols using aerial oxygen as oxidant and Cu²⁺-exchanged montmorillonite as catalysts. However, both procedures were by using some toxic chlorobenzene as solvent and long reaction time (>2 h) and high temperature(>140℃) were needed. Consquently, there is still a great demand for catalytic oxidative coupling 2-naphthols to generate binaphthols under mild conditions, environmentally friendly procedure and rapid process. Herein we report novel oxidative coupling of to 1,1-bi-2-naphthols (2a, 2b) catalysed by a number of supported reagents using aerial oxygen as oxidant. The results are listed in Table 1.     

Reductive Cross-Coupling of a Vinyl Thianthrenium Salt and Secondary Alkyl Iodides

We report the first reductive vinylation of alkyl iodides. The reaction uses a vinyl thianthrenium salt, a palladium catalyst, and an alkyl zinc intermediate formed in situ to trap the L_nPd^II(vinyl) complex formed after oxidative addition before it undergoes undesired homocoupling to form butadiene.